Hi Peter. That was an amazing video. I have many years experience and I would not have gone as far as you did. Your videos and so informative that I have watched most all of them. you are one of the best I have ever learned from. I am retired now but i still dabble a little from now and then. thank you for your effort.
I see America isnt the only country with people who take the golden screwdriver to perfectly good radios... most techs wouldn't even touch a radio that was jacked up this way. Kudos do you Peter Peter you went well Way Beyond the Call of Duty on this one. We all can tell that you know how to accept a big challenge . The best tech on TH-cam in my book
I really appreciated and enjoyed this video. It brought back horror memories of my Kenwood TH-F6A that went into meltdown because the "ON/OFF" "switch" was not an actual switch but a "soft switch" which would not allow me to turn it off as it went into meltdown. The protective covers on the right side (mike, speaker, etc.) were missing and some jerk nearly hit me causing the contents of a coffee cup to be spilled into the rig via the jacks on the right side. The battery would not come off unless I removed the belt clip, and since I was driving down the interstate I had no screwdriver to do so. I do wish I could get it working again, but I fear that like the one you worked on in this video, it is simply not cost effective. There were a couple of times that I thought I saw a problem that you may have missed. One such item is at 38:24 in the video. In the upper right part of the screen is a bit of debris that it appears that you didn't see since it didn't show you removing it. There was also a bit of debris above the trace of the bottom left resistor between the trace and the ground plane. You may have taken care of both of those, but I didn't see it, so I couldn't know for sure. Keep up the excellent work!
I'm an electronics engineer, quite experienced with soldering (not that much of an expert in surface mount) and I got kinda nervous opening up my european IC-7000 (to open it up for the back then newly allowed 60m band) and took a lot of care and was relieved not to have fried anything.
I used to do electronics repairs some years ago in my spare time and I truly loved the process.... watching your videos brings back great memories and it also reminds me that there never really was enough money in component repair to earn a living wage because of the costs of time. I think it's impossible to "Make A Living" at it unless a person buys equipment that doesn't work, then repairs it and resells it on eBay/Online or to a Pawn shop. Take a car into the garage for repair and it's like $100 an hour plus parts for service work. Even working out of the home to repair electronic equipment, the repair costs would exceed the value of the equipment in just a few hours of repair work and most people wouldn't be willing to pay more to repair something than to purchase something new or buying even Used in Working Condition... I can see you have a lot of quality test equipment there and I know that it didn't come cheap so I can't imagine that you "Repair Electronic Equipment" for a living. This must be a hobby or a side job / second job for you. Keep making great videos, they are quite detailed and very informative and I appreciate watching them....although...a little lengthy...
I feel that you were very kind to the person who tried to "fix" the radio before--as if they were your in-laws. It's a self-esteem radio, to make you feel good about the quality of your work. The resistor was added for added inductance : )
I worked for years at a major electronics manufacturer. My first day on the job they made me take a class on proper soldering (and unsoldering) techniques. Even though I knew how to solder, I still learned a lot in that class! It's scary to see the mistakes that some people make: dirty tip on the soldering iron, wrong flux, not wetting the tip first, wrong tip shape for the task at hand, using an iron that is too hot, blowing on the liquid solder joint to "cool it down faster", not recognizing a cold solder joint (or not knowing how to prevent it), etc. etc. There's a lot of metallurgy and chemistry involved as well which can adversely affect the properties of the solder joint after it solidifies from the molten state. Just solder it correctly and let it cool at its own rate.
This video was quite useful to see how you try to repair such a mess. The work rebuilding the vias and traces was amazing. And I must be really interested, because I watched to the very end :)
I never seen do that before I have same radio since 2001 and still works to this day works great for me so far never have any problem with great video Peter !
I really enjoy the videos when you repair hack jobs and fried board traces. It really demonstrates your skill and gives me something to work towards in my own abilities. Thanks fir putting this together even though the repair wasn't successful.
I bought an FT-847 the first year they came out and I remember there was a recall for the power switch and I really didn't want to have to ship my 847 to Yaesu just to replace a silly power switch. My radio wasn't exhibiting any kind of problem but after talking with Yaesu they sent me the replacement switch, which I happily replaced on my own.
Excellent video, very informative. Just a suggestion, press the fast and lock buttons together at the same time and turn the radio on this will reset the micro, it’s just a suggestion but it might be that at boot up, some of the initialize code is corrupted, leading to an ‘unknown-status’. There is probably enough code available to ‘force-shutdown’ rather than enter a possible ‘burn-out’ status. One final suggestion, this is from my early PC service days, when a ‘486DX2-66’ was a fast processor. My original IBM PC has directional detection on the CPU Cooling-Fan, if the fan was seized, and not running, the system would lock-down rather than overheating, if the Fans on the FT-847 are not running, could that force the fault you are seeing? Great video again, Bye-4-Now - Neil G1OVH - UK-QTHR.
I have no knowledge of this radio. But is that an RS232 port on the back of the radio? Hook up a breakout box and see if the UART initializes (built into the processor?). If it does, is there anything on the TD or RD leads? I say this because as a programmer from this era it was very common to squirt out status messages during initialization of the system and to send error codes (in ASCII) if something goes wrong. Just a crazy random thought....
I know it's a 5 years old case, but anyway... I got similar fault in very fast, 2x9pin needle printer with huge power supply unit. The PS unit was switching off after about two seconds from Power On. All voltages were OK (I had to measure them with oscilloscope), no symptoms of shortage in the mainboard, motor drivers etc. The PS was receiving an "emergency power shutdown" signal from CPU. The problem was caused by one of the resistors in voltage divider measuring one of the PS output lines. It changed the value from 20k to 40k, so the measured voltage seen by CPU was 3V instead of 1.5V. So it looked like an overvoltage and CPU immediately halted the PSU. It took me 3 days to find this resistor as at first glance 3V looked quite a good value for a 5V Z80 based CPU, until I made proper calculation ;).
I just got mine back from a shop in Texas. I bought it used as a newly licenced ham from a reputable shop. There was a few months delay before I started using it on HF since I was only on UHF and didn't realize there was an issue. It had terrible receive quality on HF and I didn't realize the volume was very low. They did several mods including the power switch, found the short causing the issue and brought everything into compliance of spec. It works wonderfully now and its much louder..
Welcome to my world. The world of butchered and hacked up radios. I swear there are days I spend half the day just shaking my head in disbelief. The sad thing with this radio is before someone started butchering the radio it was probably a easy repair. People need to learn their limits. Good attempt on the repair.
TRX Bench FWIW, I feel it is perfectly fair to charge for time invested into a no-fix, but especially in the case of a butchered PCB where you are likely dealing with multiple atypical faults simultaneously as they can take enormous time to troubleshoot and repair.
Oh man.....1hr 20min video from Petr and at 6:00, we already see this is going to be another case of "The man with the Golden Screwdriver." This is going to be good, I already know it!
This was not a golden screwdriver, this was a golden sledgehammer. I have an FT-847 and it still works fine. It's a great radio and it saddens me to see one mangled like that. This is proof that some people shouldn't work on electronics.
@@paulmichaelson7203 You aren't kidding. I think there are some people who shouldn't even be allowed to own nice things, let alone electronics more complex than a hairdryer.
@@StreuB1 Yup, I bought my 847 new in 1997, I've put filters in it, done other mods like the MARS mod, never replaced the power switch and the rig still works like new. It is one of only a couple of rigs that will do cross band full duplex and makes SAT operation easy and fun. I love that little rig and I'll never sell it. It's a shame to see one go so needlessly. I bet 90+ percent of 847s are still operating. Nothing can live forever especially in the wrong hands. 73 de k8idx. 73 to you too Peter, I love your videos.
I own two FT-847's and to see this makes me very sad and a bit angry... I had a similar problem on one of mine but it was the power switch itself. If I held down the switch it stayed on. Eventually temporarily did the mod for the switch and then replaced it... Great video and keep up the work !
Excellent video too well done and very imformative, sad to see someone destroy a great radio. No sure why someone would do such a thing. Peter is really one of the best of the best lots of knowledge and patience and very kind and helpful.
I would try using an logic analyzer configured to trigger when the reset goes low. I would also set the LA so that there is a healthy pre-buffer before trigger, so you can connect many inputs of the LA to various test points on and around the processor, and then be able to go back and see what happened right before the processor reset. I would also make sure to monitor any interrupt type of pins in relation to the reset line. Could be an additional fault that is generating an interrupt signal that the firmware is decoding to be a power off condition. Last resort would be the "shotgun" approach and simply test all pins in relation to reset, again seeing if anything is happening right before the reset goes low. My last ditch effort would be to freeze the board real good and see if you have any caps or other components that have failed short. Ceramic caps of that era are known to fail short, so you might see that if any device instantly heats up. Should all that fail, I would suggest the owner buy a donor board like you suggested (that and revoke his soldering iron license till he takes a certified soldering class!). (edited to remove suggestion of tying the battery switch one way or the other, as i failed to notice your comment on the subject)
Good of you to show us even when it is not fixed. I would recommend focusing on the destroyed vias etc. in the mode area 1, 2, 3 and 4 at 7:41. Most of the time, it is the last thing that "changed" that is the culprit. The processor is booting up and even running long enough to switch modes and receive. So the processor is probably fine. It has to be some input to the processor, analog or digital input, if it is the processor shutting it down. I am sure you checked that any DC to DC power supplies are not causing the shutdown. Are there any protection circuits/blocks? Did they mess with the bias settings?
Thanks for that, nicely done. I have this radio so was even more interested than usual to see it repaired. Pitty about the outcome. I hope some sacrificial spares come available!
Now we know why you keep your hair so short Peter. It's so you don't grab handfuls of hair and pull it out when working behind people that make such a mess of the radios.
Those damaged pads next to xtal and the wrongly fitted 2k2 resistor are where the padding capacitor (along with another "select on test" SMD capacitor) is fitted which forms part of the main reference oscillator. What a mess! Big 👍👍 up to Peter for keeping his cool !!!!
Hi Peter. I had a similar problem with a stereo receiver. I would push the on/off button and the relay that provided power to the whole unit would vibrate. At first I thought the problem was the filter caps in the power supply but replacing them did not solve the problem Finally I started reading about how the reset of microprocessors worked and how the capacitors around the reset chip were a problem. I used the shotgun approach and replaced all of the capacitors around the reset chip and that fixed it. This seems to go along with Nikki Copper’s more rigorous analyses. Hope this helps. Also, thank you for the detail you presented about how processors control radio circuits. John C
Hi Peter at 7:37 it looks to me like there are two vias on the traces from the processor to solderbrigde 1 and 3. It doesn't look like these vias are conected to the traces anymore. And yes you are right, this mess is something anyone can do without special skills :-)
How can ANYBODY treat a radio that STILL sells for ~$1000 like that! It almost physically hurts me to see it! I know Peter loves a challenge, but surely this one was always well beyond the call of duty!
I am more amazed how people do something really bad, then try to undo and destroy more, and than just downplay their works. "I cannot understand why it doesn't work anymore" I hope you made him pay a pretty penny for this
Nice video Peter. I did have one of these rigs. It worked fine for a while and then did the exact same as this one. I think i saw i was loosing 5v signal down to 2.4 or something. After some troubleshooting just like you did, it lead me to a small smd regulator on the bottom side of the bord. It was near the relay area . I replace it and the rig would work real good for 19 out of 20 power ups. So once in a while it would not power up. I never did git it working any better than that. Hope this helps you or someone else.
Great video as always! Thumbs up! I had a peek at the schematics and had one far-fetched thought: What if the undefined state of the broken backup battey switch (S1001) confuses the CPU? Since that switch looked molten to death by a soldering iron and it is close to where the "mod" was done, I thought it might be a possibility even if it might not be a likely explanation. The backup battery switch leads straight to one pin on the CPU. In off state that pin is grounded via 10k and in on state it has 3V from the Lithium cell.
@@TRXLab The Backup Memory Switch is nothing to do with this problem the Radio will work without the Switch or indeed any Backup Battery, all that happens is it will not hold a y memories when powered off If you keep power connected then the Memories and the Radio will still work all ok...I have a Yaesu FT920 with very similar design with the Backup Switch and Battery...Best of Luck fixing it....Looks like a Butcher has tried to do Soldering with a large Hot Poker from the Coal Fire hi hi....Such a Shame.
I'm only at the point where you found the 2.2K resistor. I bought a broken radio for $300 that was dead. I troubleshot the radio only to find the 100ohm resistor was open. I thought that the resistor was too small and had too much current running through it and decided it needed to be larger. I replaced it with a 2.2K resistor and the radio came to life. I then happened to google the problem (after the I fixed it) and found this to be a common problem and Yaesu made an engineering change to replace the resistor with a 2.2K resistor :-) That may be why it was replaced...poorly so unfortunately.
Hello Peter,I can only tell you about an experience I had with a MEOS TV I have it did the same as your radio, I checked the capacitors, and the diodes in the power supply, all was well, board looked clean nothing showed up no smells, so I put freeze spray on section of the board at a time and switched on, eventually I went to one section powered on and immediately one component thawed out, it was one of those smd caps, so I got the part number off the schematic and I swapped it out, bingo the TV fired up, wife was happy I was relieved , so as the board your working on has been messed about with, could this method help you out. 73 Paul M0BSW
Great video!!! I have the same radio that I bought in 1999 for $1500, I've never used it, it's brand new, still packed in the box! Is there anything I should do with the new one that's been packed away for 20 years before I start it for the first time? Thank you in advance! Currently living in 🇬🇧 KE6MFK Merry Christmas 🎄
Ich würde als erstes nochmal den Ein/Aus-Schalter überprüfen ob der auch wirklich noch im gedrückten Zustand den Kontakt schließt und nicht nur während des drückens.. Wie du schon sagtest ist der bei dem Gerät anfällig, deswegen wurde die zweite Schalterhälfte ja schon mit Kabeln dazu geschaltet. Als zweites dann den defekten Backup Schalter neben dem Prozessor ersetzen, dadurch das der obere Teil fehlt wird ja jetzt gar kein Kontakt geschlossen, dadurch könnte der Prozessor vielleicht blockiert sein. Und natürlich die Batterie wieder anlöten nicht vergessen.
Me too I installed a TCXO on an FT847 while keeping the original assembly that I isolated by cutting a track and moving the 2k2 power resistor, as well as replacing a chemical condenser with a tantalum capacitor to be able to install the TCXO on feet welded to the board. On the rear face of the TCXO with English engraving I installed a power supply circuit with capacitor, regulator, choke, input and output to have a clean and stable power supply. I also installed a micro relay controlled by the ignition off / on switch to prevent the off / on switch from burning by overload. Very clean and invisible assembly for those who do not know the turntable.
Hi! Nice video and explanations how different parts of the radio communicate to each other. And yes, this video should be a warning what can happen to all those who will take the old 100W big soldering iron that they used with great success in the 1960's. I have seen stuff like this. And if you still have the radio around, I would give you a hint to try. I have an FT-847 and I did a MARS mod to it, or tried to do. It was bought from German Ebay back around the 2010, so I think it came with your area software and settings. I followed the info on the internet and it didn't work, if I remember right I was on a same kind of situation where it just rebooted itself like that radio. I returned those "jumpers" to original and it worked again. I think there might be different versions of the processor or memory that will not work with MARS-modification settings or with info of the original settings you find from internet. But if you are really sure what pads were connected at factory this might be not the case. But still an easy one to try. By the way, excellent job with repairing those missing traces! I have a working FT-847 here so if you want some info to compare, you can message me.
A great video Peter, you showed remarkable patience. I put a suggestion about comparing the serial protocol between a working radio and the dead one. I2C or SPI would make that easier. I also wonder is there a message into the processor right before the shutdown? I wonder if that came from the front panel, or something else.
There is a shout down pin at the proicessor but the level is constant so the shut down circuit is not the problem. I put a fix external level to the pin just in case but it did not change the result.
@@TRXLab Hmmmm, so the processor is not being told to shut down, but the power to the rest of the radio is being turned off. So I'm wondering how power is being blocked from all the subsystems in the radio? What is the actual mechanism that causes power to be removed, and then what caused that mechanism to activate.
When power is switched off the voltage regulator for the processor is switched off that then activates the on/off circuit to shut the processor down. That all works....
it's not the processor. keep digging. (reheat the soldering of the processor, with hot air, without removing it from the board. The solder Yaesu used tended to crystallize and make intermittent or no contacts after 20 years of use.)
Thanks Pop that is a good hint. I know this issue when the solder melts it feels like chewing gum. I always test the IC pin by pin with a sharp hook and normally you will find a loose connection by this approach. In this case all the pins were in good condition.
Hey Peter... One of your longer videos but because of the content and the valid step by step analysis, the time flew watching this!! It is so unfortunate that FOR NOW, the radio must be put to one side. As you say, the radio seems to be operational, receiving, audio amp OK, mode switching, it just seems for some reason that the DC is not latching. I have no doubt that the owner is not fully forthcoming with the details attempted or the history of attempted repairs. Why would that through hole resistor be changed in the oscillator stage as well as damage to the long track beside it? I guess that there has been a million angry soldering irons attempting mods in that radio long before you were given it. If you cannot repair it, then not much hope of anyone else curing the issues. 73 as always Peter, Brian
Thanks Brian, yes that is what I really suspect we don't have the full truth..under that circumstances it is hard to work on a problem. For some reasons it looks like that some mods has been dismantled before I got the radio.. 73
Since even the panel lights shut off, I would assume that the power supply is receiving a disable command from somewhere. What supplies that command and can you monitor that control input to the power supply? Can you disconnect that line and maybe force the power supply to be enabled (or not disabled)? How about finding an FT-847 support group on Yahoo or Facebook where you can discuss this problem with hard-core enthusiasts? These groups often have community files with factory service manuals and a wealth of undocumented knowledge. The odds are high that you are not the first person to experience this auto shutdown condition.
Finding the source of the shutdown was my thought as well. It may just lead back to the processor, but there has to be some circuit triggered by the processor to cut off power. See if that circuit is rogue. Or being commanded. Also, if you can find a working radio, compare the startup serial protocol of the working radio to the dead one. If they are different, you might have another clue. All the better if you can get Yaesu to send you the protocol specs. I imagine the header includes a target device address. And the reply may have error codes that give a clue to the root cause. If the serial is I2C or SPI your scope may decode the hex values being sent.
@@TRXLab Yes, fine, but can you over-ride the shut-down system? Either disconnect it or strap it enabled, and see if the rest of the receiver might then work.
@@TRXLab So if you hard-strap the shut-down command signal to the power supply, the power supply still shuts down? That seems to tell us to look at why the PS is shutting down without a shut-down command. I have encountered military power supplies that go through some odd output excursions right after start-up, and internal watchdog circuits shut them down. Put an oscilloscope on the PS outputs and see how cleanly the power comes on. Also try running just the PS, with no connection to the radio. Does it still shut down? Lastly, look at the signal path from the shut-down input of the PS to the device in the PS that actually does the switching action. Perhaps we are in that strange land where the error protection circuit is causing the error.
I’m sure you covered these but the screw terminals even with power connected went dry joint and I had re-flow these. I had an issue where headphones were once plugged into CW socket in a clients radio and it went into TX as power on and over current. Obviously not what’s going on here but the surface mounts caps are normally 45c working from factory..... yes honestly they are as I worked on camcorders in the 1990s and must have changed 10,000 of the caps for 85c and 105c to give the camcorder a better future. Canon E90 especially. I had this problem on my C2 and trying really hard to remember how I fixed it. See my videos as my C2 is alive and working the birds. Let me check my notes but I’m sure I re-flowed something near the power section. 5 years ago or more....
These guys with the endless modifications to these radios, they can't seem to leave anything alone. It's amazing how much of this you see, and just say to yourself when one is in front of you, "hammy-bones strikes again."
Measure the base of Q1122. After hitting the power switch, Q1118 holds it low for a short amount of time, then it should get a hi signal from IC Q1106. Find out why that signal disappears. (and de-energizes relay RL1001) As you said, there are no PSU overloads, so I would even force that signal hi. (cut the trace before)
Perhaps the power supply is providing the correct voltage but it can't for some reason provide current and as the current tries to surge the processor shuts down? Or some other short pulling the power supply down?
I want to use SMD 0201 size, 0 ohm jumpers for the JP1 001 - JP1 006. I was wondering if this would be the correct size. BTW, I'll make sure I'm wearing a ESD Wrist Band. these jumpers are connected directly to the CPU. Very nice Videos...
Hi, it look's bad, I look at your video , where some broken traces from the CPU to solder settings , are there not somme missing vias for pullup at nr. 2 and 3 ?
Did you check the on/off switch as there was a mode out to put a relay in line so that the switch was only turning on a relay that supplied the power instead of going through the switch.
configuration selection jumper wires dectructed and u checked an told that they are true and left them but the vias on that lines simply should be connected to pull up resistors I think. The via on th "3" line is destructed too, so the line might be floating instead of being pulled up
what about the loose yellow wire ,near the lithium, that was the first thing i would fix , communication of the switches worked , because de dial changed the frequency during the first second,
Radio acts as though it's going through a POST routine, finding something missing and shutting down before more damage is done. If that is a multilayer PC board, perhaps one of the feed throughs was damaged in the original modification and not making contact in a middle layer.
Yeah that is really something which could be the case and the problem is that you don't know on witch portion of the radio the guy worked additional to what we have seen... That is the reason why I don't like to take radios in like this!
@TRX Bench: Did you doublecheck if the coding for the processor is really a valid combination? There's still one track ripped off the board that looked like it was bridged but the missing track makes it an open circuit? Maybe it is some combination of contacts that are not allowed? Since having exactly that TRX as well I might have a look at mine to see what that one would be "jumpered" to if it is not mentioned in service manual?
Hi Peter, When the radio shuts down, I hear a relay click, can you trace back from the relay to see what is shutting the relay down. Thanks for all the great videos.
Peter I know it's a long shot but have you tried the Processor reset procedure..I would also suspect the Guy with the Hot Poker has also fried some of the Capacitors, you only have to look at all the plastic that be has melted with his Iron to realise he hasn't got a clue how to do basic electronic soldering.
My comment has more than likely already been covered, And this video is fairly old now, But all the time watching this i was thinking "I'm sure the backup battery has to be connected for it to power on" And when you first opened it there was a backup battery someone bodged in, but the backup switch was broken so the battery wasn't actually in circuit, Did you ever try a new battery and replace switch, Or solder the two tabs of the switch together so its on ?
hmm i only caught part of the video as it was 4am when i fell asleep watching it, now im more interested in the problems that was caused by the battery leak before, id even contemplate reworking the processor pads to clean them and freshen the solder.. however before i seen the bad battery replacement i was thinking bad cap or cracked resistor thats heating up.. what part of the system turns the power relay on/off? where does the signal come from? are you able to jump the relay to see if the signal to power the fet or transistor is stable?
@@TRXLab ok, hmm so what signal is being told to "shut down" and can it be "bypassed" i know its not factory setting but it'd get the old gal' up n running again even with another bodge lol, could it be a sense line from the rf circuit, i know some radios do shut down where others just reduce tx power... interesting issue, it really is
Hi I have a yaesu FT 847 with no audio on transmit on any band or any mode and also intermittent weak receive , if the PTT key is pushed sometimes the receive works again. Any help that you can offer would be greatly appreciated. Thanks in advance.
Hi there Peter. The thing that has now been bugging me is has you mentioned earlier. Anti-static protection. If who ever destroyed the PCB with a blunt red hot poker. Would he or it ! have had the brains to even think Anti-static strap before touching any part of the board.Once the damage is done, it's i repairable yea ? so how would you know if that is what may have been the case by whoever had their paws on the radio previously, ?. I was wishing that you would find what the fault was after so much time testing and fixing the damaged PCB. Well done for all the explaining of the tests and checks that you carried out. 73 de John - G0WXU.
Late saturday evening, without my tea...unususal...but i could not resist! Just hammering down some car jumper cables with a torch and huge amounts of lead isn´t fixing a problem..may we should produce an sell some stickers with that hint. I wonder, what triggers the unit to shout down, and what to do to bypass that behaviour. Ok, normally it should protect the unit to fail / burn/ lift off, but as you said, it works fine for 2 sec, no exessive current draw or things like that. So maybe it is possible to hard wire and do some rerouting to eleminate this shutting down? Problem is: How much time could you spend to this thing? There are many hours left to check every bus and voltage, every cap etc. Anyway: Fine job again so far, i like it very much. And be sure: You will get the Luis Rossman diploma for SMD and via-bridging repair! Thats for sure! 73 de Olaf
LOL yeah Olaf lets produce some stickers.....Ja das ist schon ein sehr interssanter Fehler nur die Zeit die es verschlingt die Zustände am Prozessor alle zu testen it einfach zu lange. Zusätzlich wissen wir leider nicht ob einfach irgendwo eine Durchführung zerstört wurde die wir zur Zeit nicht sehen. Bei all den komischen Vorschädigungen musst du mit Allem rechnen. Leider sind auch die Angaben in den Serviceunterlagen für solche Fehler mehr als mangelhaft und bei Yaesu hat niemand mehr Lust und Zeit sich mit einem Funkgerät zubeschäftigen das komplett aus dem Service raus ist. Auch bekomme ich die internen Fabrikunterlagen nicht. Die würden helfen das Problem weiter zu ergründen. Aber alles das wäre dann nur noch persönliches Interesse was ich aber gerne investieren würde, wenn ich mehr Informationen bekommen könnte. Du siehst solche Fälle ziehen einen Rattenschwanz hinter sich her...Aber wem sag ich das LOL.... Danke fpr Deinen Kommentar 73
What if he put the memory battery the wrong way round and it's that that is tripping the processor? If your sure it's the processor you could measure current down each of the pins to the processor although that wouldn't be very easy.
If the processor is damaged you might be able to freeze spray it to test it. It might stay on till it warms up. Perhaps Yaesu will be kind enough to get you one, they may have some at the back of a shelve somewhere?
As far as I'm concerned, the owner can do whatever he wants to his own radio. It's no skin off my nose if he bricks it. I am more distressed by people who decide it is helpful to heap criticism on top. That is contrary to the mission of amateur radio in that such criticism can discourage people from experimenting. It is amateur radio, not professional radio and I try to always be welcoming and encouraging to anyone who wants to participate. It is not a place to play "King of the Mountain".
Hi Peter. That was an amazing video. I have many years experience and I would not have gone as far as you did. Your videos and so informative that I have watched most all of them.
you are one of the best I have ever learned from. I am retired now but i still dabble a little from now and then. thank you for your effort.
Thank you!
I see America isnt the only country with people who take the golden screwdriver to perfectly good radios... most techs wouldn't even touch a radio that was jacked up this way.
Kudos do you Peter Peter you went well Way Beyond the Call of Duty on this one. We all can tell that you know how to accept a big challenge .
The best tech on TH-cam in my book
Thanks a million Peter for all your help and patience with the messed up radio. Great video with learning aspects
Great video. I learned some troubleshooting from you and I have been repairing for many years. You are one of the VERY best. Thank you
Thanks for your feed back, very much appreciated
I really appreciated and enjoyed this video. It brought back horror memories of my Kenwood TH-F6A that went into meltdown because the "ON/OFF" "switch" was not an actual switch but a "soft switch" which would not allow me to turn it off as it went into meltdown. The protective covers on the right side (mike, speaker, etc.) were missing and some jerk nearly hit me causing the contents of a coffee cup to be spilled into the rig via the jacks on the right side. The battery would not come off unless I removed the belt clip, and since I was driving down the interstate I had no screwdriver to do so. I do wish I could get it working again, but I fear that like the one you worked on in this video, it is simply not cost effective.
There were a couple of times that I thought I saw a problem that you may have missed. One such item is at 38:24 in the video. In the upper right part of the screen is a bit of debris that it appears that you didn't see since it didn't show you removing it. There was also a bit of debris above the trace of the bottom left resistor between the trace and the ground plane. You may have taken care of both of those, but I didn't see it, so I couldn't know for sure.
Keep up the excellent work!
Wow! That repair work on the vias was really amazing!
A man's got to know his limitations. The owner of this radio didn't know his.
you are 100% right
Got to have a good magnifier, good TEMP controlled soldering iron with right size tip as a minimum.
So many spoil good radios when can't do nothing enough good.
But here is always them who think can do everything.
I'm an electronics engineer, quite experienced with soldering (not that much of an expert in surface mount) and I got kinda nervous opening up my european IC-7000 (to open it up for the back then newly allowed 60m band) and took a lot of care and was relieved not to have fried anything.
I used to do electronics repairs some years ago in my spare time and I truly loved the process.... watching your videos brings back great memories and it also reminds me that there never really was enough money in component repair to earn a living wage because of the costs of time. I think it's impossible to "Make A Living" at it unless a person buys equipment that doesn't work, then repairs it and resells it on eBay/Online or to a Pawn shop.
Take a car into the garage for repair and it's like $100 an hour plus parts for service work. Even working out of the home to repair electronic equipment, the repair costs would exceed the value of the equipment in just a few hours of repair work and most people wouldn't be willing to pay more to repair something than to purchase something new or buying even Used in Working Condition...
I can see you have a lot of quality test equipment there and I know that it didn't come cheap so I can't imagine that you "Repair Electronic Equipment" for a living. This must be a hobby or a side job / second job for you.
Keep making great videos, they are quite detailed and very informative and I appreciate watching them....although...a little lengthy...
Peter, you don't give up easily! That radio was terribly abused. Thanks for the video!
I so much admire your skills and equipment to fix things. However, your willingness to share knowledge one step at a time overshadows it all. Thanks
Thanks for comment
I feel that you were very kind to the person who tried to "fix" the radio before--as if they were your in-laws.
It's a self-esteem radio, to make you feel good about the quality of your work.
The resistor was added for added inductance : )
I worked for years at a major electronics manufacturer. My first day on the job they made me take a class on proper soldering (and unsoldering) techniques. Even though I knew how to solder, I still learned a lot in that class! It's scary to see the mistakes that some people make: dirty tip on the soldering iron, wrong flux, not wetting the tip first, wrong tip shape for the task at hand, using an iron that is too hot, blowing on the liquid solder joint to "cool it down faster", not recognizing a cold solder joint (or not knowing how to prevent it), etc. etc. There's a lot of metallurgy and chemistry involved as well which can adversely affect the properties of the solder joint after it solidifies from the molten state. Just solder it correctly and let it cool at its own rate.
so true
I said that like number 67 was mine here in Brazil! Very good work and knowledge, congratulations TRX Bench.
Thanks Luiz!
This video was quite useful to see how you try to repair such a mess. The work rebuilding the vias and traces was amazing. And I must be really interested, because I watched to the very end :)
Okay thank you >> so that means my video was not to boring lol.
@@TRXLab No, not at all!
I never seen do that before I have same radio since 2001 and still works to this day works great for me so far never have any problem with great video Peter !
I really enjoy the videos when you repair hack jobs and fried board traces. It really demonstrates your skill and gives me something to work towards in my own abilities. Thanks fir putting this together even though the repair wasn't successful.
I bought an FT-847 the first year they came out and I remember there was a recall for the power switch and I really didn't want to have to ship my 847 to Yaesu just to replace a silly power switch. My radio wasn't exhibiting any kind of problem but after talking with Yaesu they sent me the replacement switch, which I happily replaced on my own.
Excellent video, very informative. Just a suggestion, press the fast and lock buttons together at the same time and turn the radio on this will reset the micro, it’s just a suggestion but it might be that at boot up, some of the initialize code is corrupted, leading to an ‘unknown-status’. There is probably enough code available to ‘force-shutdown’ rather than enter a possible ‘burn-out’ status.
One final suggestion, this is from my early PC service days, when a ‘486DX2-66’ was a fast processor. My original IBM PC has directional detection on the CPU Cooling-Fan, if the fan was seized, and not running, the system would lock-down rather than overheating, if the Fans on the FT-847 are not running, could that force the fault you are seeing?
Great video again, Bye-4-Now - Neil G1OVH - UK-QTHR.
Great video Peter, much patience and great skill. Thanks for sharing your videos. 73s Pasquale IW0HEX
Another FANTASTIC video!! Congratulations Peter from Brazil. 73 from PY5MM- Mauricio
I have no knowledge of this radio. But is that an RS232 port on the back of the radio? Hook up a breakout box and see if the UART initializes (built into the processor?). If it does, is there anything on the TD or RD leads? I say this because as a programmer from this era it was very common to squirt out status messages during initialization of the system and to send error codes (in ASCII) if something goes wrong. Just a crazy random thought....
Good point George...Thanks for comment
I know it's a 5 years old case, but anyway... I got similar fault in very fast, 2x9pin needle printer with huge power supply unit. The PS unit was switching off after about two seconds from Power On. All voltages were OK (I had to measure them with oscilloscope), no symptoms of shortage in the mainboard, motor drivers etc. The PS was receiving an "emergency power shutdown" signal from CPU. The problem was caused by one of the resistors in voltage divider measuring one of the PS output lines. It changed the value from 20k to 40k, so the measured voltage seen by CPU was 3V instead of 1.5V. So it looked like an overvoltage and CPU immediately halted the PSU. It took me 3 days to find this resistor as at first glance 3V looked quite a good value for a 5V Z80 based CPU, until I made proper calculation ;).
I just got mine back from a shop in Texas. I bought it used as a newly licenced ham from a reputable shop. There was a few months delay before I started using it on HF since I was only on UHF and didn't realize there was an issue. It had terrible receive quality on HF and I didn't realize the volume was very low. They did several mods including the power switch, found the short causing the issue and brought everything into compliance of spec. It works wonderfully now and its much louder..
Welcome to my world. The world of butchered and hacked up radios. I swear there are days I spend half the day just shaking my head in disbelief. The sad thing with this radio is before someone started butchering the radio it was probably a easy repair. People need to learn their limits. Good attempt on the repair.
Hi Mike I've seen your video's the patience of a saint, it's seems like let's kill a cb then send it to Mike
LOL yeah I know OUR world very well Mike and the issue is it take to much time for a no fix. I guess I have to update my no fix policy...
TRX Bench FWIW, I feel it is perfectly fair to charge for time invested into a no-fix, but especially in the case of a butchered PCB where you are likely dealing with multiple atypical faults simultaneously as they can take enormous time to troubleshoot and repair.
Oh man.....1hr 20min video from Petr and at 6:00, we already see this is going to be another case of "The man with the Golden Screwdriver."
This is going to be good, I already know it!
This was not a golden screwdriver, this was a golden sledgehammer. I have an FT-847 and it still works fine. It's a great radio and it saddens me to see one mangled like that. This is proof that some people shouldn't work on electronics.
@@paulmichaelson7203 You aren't kidding. I think there are some people who shouldn't even be allowed to own nice things, let alone electronics more complex than a hairdryer.
@@StreuB1 Yup, I bought my 847 new in 1997, I've put filters in it, done other mods like the MARS mod, never replaced the power switch and the rig still works like new. It is one of only a couple of rigs that will do cross band full duplex and makes SAT operation easy and fun. I love that little rig and I'll never sell it. It's a shame to see one go so needlessly. I bet 90+ percent of 847s are still operating. Nothing can live forever especially in the wrong hands. 73 de k8idx. 73 to you too Peter, I love your videos.
I own two FT-847's and to see this makes me very sad and a bit angry... I had a similar problem on one of mine but it was the power switch itself. If I held down the switch it stayed on. Eventually temporarily did the mod for the switch and then replaced it... Great video and keep up the work !
Yeah the power switch is a known issue on this radio...
Excellent video too well done and very imformative, sad to see someone destroy a great radio. No sure why someone would do such a thing. Peter is really one of the best of the best
lots of knowledge and patience and very kind and helpful.
Thank you Mike
The conclusion is send your radio to a professional to make the modification. Great video Peter thanks for posting
you are right.Thanks for watching 73
I would try using an logic analyzer configured to trigger when the reset goes low. I would also set the LA so that there is a healthy pre-buffer before trigger, so you can connect many inputs of the LA to various test points on and around the processor, and then be able to go back and see what happened right before the processor reset. I would also make sure to monitor any interrupt type of pins in relation to the reset line. Could be an additional fault that is generating an interrupt signal that the firmware is decoding to be a power off condition. Last resort would be the "shotgun" approach and simply test all pins in relation to reset, again seeing if anything is happening right before the reset goes low. My last ditch effort would be to freeze the board real good and see if you have any caps or other components that have failed short. Ceramic caps of that era are known to fail short, so you might see that if any device instantly heats up. Should all that fail, I would suggest the owner buy a donor board like you suggested (that and revoke his soldering iron license till he takes a certified soldering class!).
(edited to remove suggestion of tying the battery switch one way or the other, as i failed to notice your comment on the subject)
Thanks for comment
I assume he doesn’t do this work for free! At some point it just doesn’t make sense for him to keep billing hours!
Good of you to show us even when it is not fixed. I would recommend focusing on the destroyed vias etc. in the mode area 1, 2, 3 and 4 at 7:41. Most of the time, it is the last thing that "changed" that is the culprit. The processor is booting up and even running long enough to switch modes and receive. So the processor is probably fine. It has to be some input to the processor, analog or digital input, if it is the processor shutting it down. I am sure you checked that any DC to DC power supplies are not causing the shutdown. Are there any protection circuits/blocks? Did they mess with the bias settings?
Thanks James, yeah destroyed vias are a problem but can't find any additionally..DC/DC has been checked out and are found good...
Thanks for that, nicely done. I have this radio so was even more interested than usual to see it repaired. Pitty about the outcome. I hope some sacrificial spares come available!
Thanks for watching
Now we know why you keep your hair so short Peter. It's so you don't grab handfuls of hair and pull it out when working behind people that make such a mess of the radios.
I've been looking for any FT 847 boards...but 800 to 1200 USD for a 20+ year old radio...got to love the US ham market . :)
Those damaged pads next to xtal and the wrongly fitted 2k2 resistor are where the padding capacitor (along with another "select on test" SMD capacitor) is fitted which forms part of the main reference oscillator. What a mess! Big 👍👍 up to Peter for keeping his cool !!!!
Hi Peter. I had a similar problem with a stereo receiver. I would push the on/off button and the relay that provided power to the whole unit would vibrate. At first I thought the problem was the filter caps in the power supply but replacing them did not solve the problem Finally I started reading about how the reset of microprocessors worked and how the capacitors around the reset chip were a problem. I used the shotgun approach and replaced all of the capacitors around the reset chip and that fixed it. This seems to go along with Nikki Copper’s more rigorous analyses.
Hope this helps.
Also, thank you for the detail you presented about how processors control radio circuits.
John C
Thanks for feed back John
That was a great effort! Thanks for sharing it with us. Greetings from Arizona. Mike K8MB.
Hi Peter at 7:37 it looks to me like there are two vias on the traces from the processor to solderbrigde 1 and 3. It doesn't look like these vias are conected to the traces anymore. And yes you are right, this mess is something anyone can do without special skills :-)
If you have access to an infra red camera you may be able to see the offending component at power on.
Jeff.
How can ANYBODY treat a radio that STILL sells for ~$1000 like that! It almost physically hurts me to see it! I know Peter loves a challenge, but surely this one was always well beyond the call of duty!
I am more amazed how people do something really bad, then try to undo and destroy more, and than just downplay their works. "I cannot understand why it doesn't work anymore"
I hope you made him pay a pretty penny for this
Nice video Peter. I did have one of these rigs. It worked fine for a while and then did the exact same as this one.
I think i saw i was loosing 5v signal down to 2.4 or something. After some troubleshooting just like you did, it lead me to a small smd regulator on the bottom side of the bord. It was near the relay area
. I replace it and the rig would work real good for 19 out of 20 power ups.
So once in a while it would not power up. I never did git it working any better than that. Hope this helps you or someone else.
Thanks Grant, I believe you mean Q1134 witch is the voltage regulator for the processor....The Q1134 is working fine. Thanks for support! 73
Great video as always! Thumbs up!
I had a peek at the schematics and had one far-fetched thought: What if the undefined state of the broken backup battey switch (S1001) confuses the CPU? Since that switch looked molten to death by a soldering iron and it is close to where the "mod" was done, I thought it might be a possibility even if it might not be a likely explanation. The backup battery switch leads straight to one pin on the CPU. In off state that pin is grounded via 10k and in on state it has 3V from the Lithium cell.
Yes you are right. For testing I had the switch hard wired for exactly this purposes. Good thought thanks....
@@TRXLab The Backup Memory Switch is nothing to do with this problem the Radio will work without the Switch or indeed any Backup Battery, all that happens is it will not hold a y memories when powered off If you keep power connected then the Memories and the Radio will still work all ok...I have a Yaesu FT920 with very similar design with the Backup Switch and Battery...Best of Luck fixing it....Looks like a Butcher has tried to do Soldering with a large Hot Poker from the Coal Fire hi hi....Such a Shame.
You have so much patience. Great video. Show the owner a red card in the future! 73’s Lynton
Thanks Lynton 73
I'm only at the point where you found the 2.2K resistor. I bought a broken radio for $300 that was dead. I troubleshot the radio only to find the 100ohm resistor was open. I thought that the resistor was too small and had too much current running through it and decided it needed to be larger. I replaced it with a 2.2K resistor and the radio came to life. I then happened to google the problem (after the I fixed it) and found this to be a common problem and Yaesu made an engineering change to replace the resistor with a 2.2K resistor :-) That may be why it was replaced...poorly so unfortunately.
Hello Peter,I can only tell you about an experience I had with a MEOS TV I have it did the same as your radio, I checked the capacitors, and the diodes in the power supply, all was well, board looked clean nothing showed up no smells, so I put freeze spray on section of the board at a time and switched on, eventually I went to one section powered on and immediately one component thawed out, it was one of those smd caps, so I got the part number off the schematic and I swapped it out, bingo the TV fired up, wife was happy I was relieved , so as the board your working on has been messed about with, could this method help you out.
73 Paul M0BSW
Thanks Paul very good approach and a valuable step forward! 73
i just wrote this in a reply to an earlier comment, glad you came up with this one.
Great video!!! I have the same radio that I bought in 1999 for $1500, I've never used it, it's brand new, still packed in the box! Is there anything I should do with the new one that's been packed away for 20 years before I start it for the first time? Thank you in advance! Currently living in 🇬🇧 KE6MFK Merry Christmas 🎄
hf transceiver repair is a lot fun, you must have a ball doing it.
Ich würde als erstes nochmal den Ein/Aus-Schalter überprüfen ob der auch wirklich noch im gedrückten Zustand den Kontakt schließt und nicht nur während des drückens.. Wie du schon sagtest ist der bei dem Gerät anfällig, deswegen wurde die zweite Schalterhälfte ja schon mit Kabeln dazu geschaltet. Als zweites dann den defekten Backup Schalter neben dem Prozessor ersetzen, dadurch das der obere Teil fehlt wird ja jetzt gar kein Kontakt geschlossen, dadurch könnte der Prozessor vielleicht blockiert sein. Und natürlich die Batterie wieder anlöten nicht vergessen.
Der Ein Aus Schalter ist nicht das Problem da ich den auf dem CNTL Board gebrückt habe...Der Back Up Schalter ist mit einem Kabel verlötet..
I have been using this radio for a very long time. for comfortable work on the VHF bands, I installed TCXO
Me too I installed a TCXO on an FT847 while keeping the original assembly that I isolated by cutting a track and moving the 2k2 power resistor, as well as replacing a chemical condenser with a tantalum capacitor to be able to install the TCXO on feet welded to the board. On the rear face of the TCXO with English engraving I installed a power supply circuit with capacitor, regulator, choke, input and output to have a clean and stable power supply. I also installed a micro relay controlled by the ignition off / on switch to prevent the off / on switch from burning by overload. Very clean and invisible assembly for those who do not know the turntable.
Have you tried doing a factory reset on the radio? when I have done this kind of mod on other types of radio sometimes the CPU gets confused.
Hi! Nice video and explanations how different parts of the radio communicate to each other. And yes, this video should be a warning what can happen to all those who will take the old 100W big soldering iron that they used with great success in the 1960's. I have seen stuff like this. And if you still have the radio around, I would give you a hint to try. I have an FT-847 and I did a MARS mod to it, or tried to do. It was bought from German Ebay back around the 2010, so I think it came with your area software and settings. I followed the info on the internet and it didn't work, if I remember right I was on a same kind of situation where it just rebooted itself like that radio. I returned those "jumpers" to original and it worked again. I think there might be different versions of the processor or memory that will not work with MARS-modification settings or with info of the original settings you find from internet. But if you are really sure what pads were connected at factory this might be not the case. But still an easy one to try. By the way, excellent job with repairing those missing traces! I have a working FT-847 here so if you want some info to compare, you can message me.
A great video Peter, you showed remarkable patience. I put a suggestion about comparing the serial protocol between a working radio and the dead one. I2C or SPI would make that easier. I also wonder is there a message into the processor right before the shutdown? I wonder if that came from the front panel, or something else.
There is a shout down pin at the proicessor but the level is constant so the shut down circuit is not the problem. I put a fix external level to the pin just in case but it did not change the result.
@@TRXLab Hmmmm, so the processor is not being told to shut down, but the power to the rest of the radio is being turned off. So I'm wondering how power is being blocked from all the subsystems in the radio? What is the actual mechanism that causes power to be removed, and then what caused that mechanism to activate.
@@TRXLab Great work repairing those mangled and destroyed traces. That's something I need to practice more.
When power is switched off the voltage regulator for the processor is switched off that then activates the on/off circuit to shut the processor down. That all works....
O like número 67 foi meu aqui no Brasil !Muito bom o trabalho e conhecimento,parabéns TRX Bench .
do not understand what you mean..
it's not the processor. keep digging. (reheat the soldering of the processor, with hot air, without removing it from the board. The solder Yaesu used tended to crystallize and make intermittent or no contacts after 20 years of use.)
Thanks Pop that is a good hint. I know this issue when the solder melts it feels like chewing gum. I always test the IC pin by pin with a sharp hook and normally you will find a loose connection by this approach. In this case all the pins were in good condition.
This is a painful video to watch on so many levels. No other comment necessary.
yeah you are right
Wohl mit dem Brotmesser auf der Herdplatte gelötet, so ein Murkser. Gut dass du die Sauerei wieder hinbekommen hast.
HaHa ja so sieht es aus...
Hey Peter... One of your longer videos but because of the content and the valid step by step analysis, the time flew watching this!! It is so unfortunate that FOR NOW, the radio must be put to one side. As you say, the radio seems to be operational, receiving, audio amp OK, mode switching, it just seems for some reason that the DC is not latching. I have no doubt that the owner is not fully forthcoming with the details attempted or the history of attempted repairs. Why would that through hole resistor be changed in the oscillator stage as well as damage to the long track beside it? I guess that there has been a million angry soldering irons attempting mods in that radio long before you were given it. If you cannot repair it, then not much hope of anyone else curing the issues. 73 as always Peter, Brian
Thanks Brian, yes that is what I really suspect we don't have the full truth..under that circumstances it is hard to work on a problem. For some reasons it looks like that some mods has been dismantled before I got the radio.. 73
very informative, well done
Since even the panel lights shut off, I would assume that the power supply is receiving a disable command from somewhere. What supplies that command and can you monitor that control input to the power supply? Can you disconnect that line and maybe force the power supply to be enabled (or not disabled)?
How about finding an FT-847 support group on Yahoo or Facebook where you can discuss this problem with hard-core enthusiasts? These groups often have community files with factory service manuals and a wealth of undocumented knowledge. The odds are high that you are not the first person to experience this auto shutdown condition.
Finding the source of the shutdown was my thought as well. It may just lead back to the processor, but there has to be some circuit triggered by the processor to cut off power. See if that circuit is rogue. Or being commanded. Also, if you can find a working radio, compare the startup serial protocol of the working radio to the dead one. If they are different, you might have another clue. All the better if you can get Yaesu to send you the protocol specs. I imagine the header includes a target device address. And the reply may have error codes that give a clue to the root cause. If the serial is I2C or SPI your scope may decode the hex values being sent.
I have tested the shout down circuit and it is working just as it should. Anyway good thought thanks
@@TRXLab Yes, fine, but can you over-ride the shut-down system? Either disconnect it or strap it enabled, and see if the rest of the receiver might then work.
yes I have hard wired from an external voltage supply to overrule the circuit but no change...
@@TRXLab So if you hard-strap the shut-down command signal to the power supply, the power supply still shuts down? That seems to tell us to look at why the PS is shutting down without a shut-down command. I have encountered military power supplies that go through some odd output excursions right after start-up, and internal watchdog circuits shut them down. Put an oscilloscope on the PS outputs and see how cleanly the power comes on. Also try running just the PS, with no connection to the radio. Does it still shut down? Lastly, look at the signal path from the shut-down input of the PS to the device in the PS that actually does the switching action.
Perhaps we are in that strange land where the error protection circuit is causing the error.
Check the POR of the cpu. The power rails. The cpu can be found and be replaced ( in the worst case ) if the program memory is outside of it.
I’m sure you covered these but the screw terminals even with power connected went dry joint and I had re-flow these. I had an issue where headphones were once plugged into CW socket in a clients radio and it went into TX as power on and over current. Obviously not what’s going on here but the surface mounts caps are normally 45c working from factory..... yes honestly they are as I worked on camcorders in the 1990s and must have changed 10,000 of the caps for 85c and 105c to give the camcorder a better future. Canon E90 especially. I had this problem on my C2 and trying really hard to remember how I fixed it. See my videos as my C2 is alive and working the birds. Let me check my notes but I’m sure I re-flowed something near the power section. 5 years ago or more....
These guys with the endless modifications to these radios, they can't seem to leave anything alone. It's amazing how much of this you see, and just say to yourself when one is in front of you, "hammy-bones strikes again."
Measure the base of Q1122.
After hitting the power switch, Q1118 holds it low for a short amount of time, then it should get a hi signal from IC Q1106. Find out why that signal disappears. (and de-energizes relay RL1001)
As you said, there are no PSU overloads, so I would even force that signal hi. (cut the trace before)
For testing the Q1118 was out. The 1118 is the over voltage protection which pulls the Q1122 to ground in order not to kill the radio..
Acid core solder and a 500 watt iron works every time!
very good video from Gary in the UK.
Perhaps the power supply is providing the correct voltage but it can't for some reason provide current and as the current tries to surge the processor shuts down?
Or some other short pulling the power supply down?
I want to use SMD 0201 size, 0 ohm jumpers for the JP1 001 - JP1 006. I was wondering if this would be the correct size. BTW, I'll make sure I'm wearing a ESD Wrist Band. these jumpers are connected directly to the CPU. Very nice Videos...
The golden screw driver strikes again soldering with a hot nail
I think you meant against ... TEF
What about that solder blob at 29:05?
Great job, that radio was a mess.
Hi, it look's bad, I look at your video , where some broken traces from the CPU to solder settings , are there not somme missing vias for pullup at nr. 2 and 3 ?
Thanks Peter! I would try reflowing the processor and other IC's. You may have mentioned that you did and I just missed it.
Thanks Robert. No I have not reflowed it but tested the IC pin by pin with a sharp hook. Normally you would find any lose pin with this approach...
Did you check the on/off switch as there was a mode out to put a relay in line so that the switch was only turning on a relay that supplied the power instead of going through the switch.
configuration selection jumper wires dectructed and u checked an told that they are true and left them but the vias on that lines simply should be connected to pull up resistors I think. The via on th "3" line is destructed too, so the line might be floating instead of being pulled up
what about the loose yellow wire ,near the lithium, that was the first thing i would fix , communication of the switches worked , because de dial changed the frequency during the first second,
Radio acts as though it's going through a POST routine, finding something missing and shutting down before more damage is done. If that is a multilayer PC board, perhaps one of the feed throughs was damaged in the original modification and not making contact in a middle layer.
Yeah that is really something which could be the case and the problem is that you don't know on witch portion of the radio the guy worked additional to what we have seen... That is the reason why I don't like to take radios in like this!
@@TRXLab
Yep. Hope you win the battle.
maybe the battery backup switch either needs to be in the on or off position?
@TRX Bench: Did you doublecheck if the coding for the processor is really a valid combination? There's still one track ripped off the board that looked like it was bridged but the missing track makes it an open circuit? Maybe it is some combination of contacts that are not allowed? Since having exactly that TRX as well I might have a look at mine to see what that one would be "jumpered" to if it is not mentioned in service manual?
Thanks for comment
Hi Peter, When the radio shuts down, I hear a relay click, can you trace back from the relay to see what is shutting the relay down.
Thanks for all the great videos.
Thanks Rich, I have by passed the relay to see if everything works stable...
@@TRXLab - And, Peter, by- passing the relay, whats happen then?
@@MrPerrey Please watch the video. 1:07:31
@@stargazer7644 - Now I saw it. Peter did o many things - I'm convinced that's the uC, sadly...
excellent video with you hints tips thank you
Thanks for watching Mark
Peter I know it's a long shot but have you tried the Processor reset procedure..I would also suspect the Guy with the Hot Poker has also fried some of the Capacitors, you only have to look at all the plastic that be has melted with his Iron to realise he hasn't got a clue how to do basic electronic soldering.
24:43 Sad... What a stupid way to ruin a beauty high-class radio !..
Seriously, I can't believe it..
Somehow disappointing that there was no rescue. But I learned a lot what can be done and a lot more what you should never do.
My comment has more than likely already been covered, And this video is fairly old now, But all the time watching this i was thinking "I'm sure the backup battery has to be connected for it to power on" And when you first opened it there was a backup battery someone bodged in, but the backup switch was broken so the battery wasn't actually in circuit, Did you ever try a new battery and replace switch, Or solder the two tabs of the switch together so its on ?
hmm i only caught part of the video as it was 4am when i fell asleep watching it, now im more interested in the problems that was caused by the battery leak before, id even contemplate reworking the processor pads to clean them and freshen the solder.. however before i seen the bad battery replacement i was thinking bad cap or cracked resistor thats heating up..
what part of the system turns the power relay on/off? where does the signal come from? are you able to jump the relay to see if the signal to power the fet or transistor is stable?
Yes I have bridged the relay for testing, all regulators stable. On/Off circuit processor works perfect...
@@TRXLab ok, hmm so what signal is being told to "shut down" and can it be "bypassed" i know its not factory setting but it'd get the old gal' up n running again even with another bodge lol, could it be a sense line from the rf circuit, i know some radios do shut down where others just reduce tx power...
interesting issue, it really is
Hi I have a yaesu FT 847 with no audio on transmit on any band or any mode and also intermittent weak receive , if the PTT key is pushed sometimes the receive works again. Any help that you can offer would be greatly appreciated. Thanks in advance.
I'm sorry to many root causes possible that I can't say on remote.
Hi there Peter. The thing that has now been bugging me is has you mentioned earlier. Anti-static protection. If who ever destroyed the PCB with a blunt red hot poker. Would he or it ! have had the brains to even think Anti-static strap before touching any part of the board.Once the damage is done, it's i repairable yea ? so how would you know if that is what may have been the case by whoever had their paws on the radio previously, ?. I was wishing that you would find what the fault was after so much time testing and fixing the damaged PCB. Well done for all the explaining of the tests and checks that you carried out. 73 de John - G0WXU.
Yeah you are right John it is always a pain....Thanks for feed back 73
Yaesu Christ, it's a wonder the person who did the messy damages, found the right screwdriver to open the case.
lol yeah hard to believe..
I have one of these rigs and have done a few mods but used a soldering iron not a poker! 73's One rig QRX
i am watching this at 2am as i cant sleep but i am hooked on your video now i am wide awake totaly enjoy you video de gm0ioa
glad that you liked it. Thanks for feed back
Moral of the story. Do not open the case if you don't know what you are doing. A good tech is worth the price.
Was this mod done with a blowtorch? Another great vid, 73 de Malc 2E0EZP.
Yes most likely a Plumber by Trade (No disrespect to Plumbers) or a Red Hot Poker.
Late saturday evening, without my tea...unususal...but i could not resist! Just hammering down some car jumper cables with a torch and huge amounts of lead isn´t fixing a problem..may we should produce an sell some stickers with that hint. I wonder, what triggers the unit to shout down, and what to do to bypass that behaviour. Ok, normally it should protect the unit to fail / burn/ lift off, but as you said, it works fine for 2 sec, no exessive current draw or things like that. So maybe it is possible to hard wire and do some rerouting to eleminate this shutting down? Problem is: How much time could you spend to this thing? There are many hours left to check every bus and voltage, every cap etc. Anyway: Fine job again so far, i like it very much. And be sure: You will get the Luis Rossman diploma for SMD and via-bridging repair! Thats for sure! 73 de Olaf
LOL yeah Olaf lets produce some stickers.....Ja das ist schon ein sehr interssanter Fehler nur die Zeit die es verschlingt die Zustände am Prozessor alle zu testen it einfach zu lange. Zusätzlich wissen wir leider nicht ob einfach irgendwo eine Durchführung zerstört wurde die wir zur Zeit nicht sehen. Bei all den komischen Vorschädigungen musst du mit Allem rechnen. Leider sind auch die Angaben in den Serviceunterlagen für solche Fehler mehr als mangelhaft und bei Yaesu hat niemand mehr Lust und Zeit sich mit einem Funkgerät zubeschäftigen das komplett aus dem Service raus ist. Auch bekomme ich die internen Fabrikunterlagen nicht. Die würden helfen das Problem weiter zu ergründen. Aber alles das wäre dann nur noch persönliches Interesse was ich aber gerne investieren würde, wenn ich mehr Informationen bekommen könnte. Du siehst solche Fälle ziehen einen Rattenschwanz hinter sich her...Aber wem sag ich das LOL.... Danke fpr Deinen Kommentar 73
The radio is on for a few time. Solution: replace the on switch with a 555 timers ;-)
Hahaha!
All I can say is BRAVO.
What if he put the memory battery the wrong way round and it's that that is tripping the processor? If your sure it's the processor you could measure current down each of the pins to the processor although that wouldn't be very easy.
If the processor is damaged you might be able to freeze spray it to test it. It might stay on till it warms up.
Perhaps Yaesu will be kind enough to get you one, they may have some at the back of a shelve somewhere?
As far as I'm concerned, the owner can do whatever he wants to his own radio. It's no skin off my nose if he bricks it. I am more distressed by people who decide it is helpful to heap criticism on top. That is contrary to the mission of amateur radio in that such criticism can discourage people from experimenting. It is amateur radio, not professional radio and I try to always be welcoming and encouraging to anyone who wants to participate. It is not a place to play "King of the Mountain".
Great video as always!
Call or email Yaesu UK - they may be able to provide that chip for you. They helped me find an obsolete part for another rig.
might have been worthwhile to re-flash the firmware to see if that cleared the problem