Thanks Mike for all your videos and help! I installed new mosfets and ran into a problem on AM with the Lincoln II plus and just a few minutes before finishing your vid I found a blown Tip36 lol!! I was lucky with the ferrite as all I had to do was tack it back in place. Thanks again!!
I guess im randomly asking but does any of you know a tool to log back into an instagram account? I was stupid forgot the login password. I love any help you can give me.
@Cade Thomas I really appreciate your reply. I got to the site thru google and I'm in the hacking process now. Looks like it's gonna take quite some time so I will get back to you later when my account password hopefully is recovered.
Mike is absolutely the best Tech ! Old school sense and more importantly knowledge, and he is genuinely a cool guy. My unending problem is how in the world does a person, potential customer contact him ??? any help here would be monumental !! Thanks !
Forget it. He quit responding entirely. I was a frequent customer and he repaired several radios for me. Then he quit responding and no one has been able to contact him.
Thanks Mike for addressing the Maxima mod. There is a certain TH-cam or self-proclaimed CB guru that preaches the radios gnocchi up without the max mod and I’ve always thought he was full of BS so I appreciate your addressing that with a commonsense approach.
On my Lincoln 2+ I moved my AM regulator to the back where the heat sink is. When it was on the side, it would get hot hast. I put a new Tip-36 on the back and it’s night and day difference. The regulator and the finals run nice and cool. That was about 2 years ago. No problem since.
Good crash course on radio electronics. I wish I had the attention span to learn electrical engineering. I would have a lot of old electronics that would be virtually immortal.
I had the same issue with a stryker 655 a guy brought in the shop and he actually admitted his antenna was bad. When it went took out the finals and tip36.
Had that experience. Basically, I've burned the output stage of an RF PA that I've made, due to a badly tuned antenna. Funnily, the PA is only capable of outputting 1W at best, and I was not expecting it to be damaged.
I have noticed several videos on blown finals. Many of the videos involve the President Lincoln II. I recently acquired a Lincoln II. Guess what? I blew the finals out. I've been into radio's for 20+ years and never ruined a radio. My swr was 1:4 and I have current chokes in line at the radio, shack entrance and at the antenna. My Lincoln had the 1310n transistors. I shipped it off and I was advised to go with better transistors.
I have always known about the SWR since I started using the radio, however I never knew exactly what finals were. I definitely learned something here. Thanks
I love your videos. I learn a lot about radio from watching your content, thank you. Question - if the finals get blown so frequently, and pass on current for more internal damage... shouldn’t they build in a fuse?
I did radio years ago.... Please note that you can tune your antenna on a specific channel. If you set it on channel 40, channel one will probably be higher. The best spectrum spread is to tune on channel 19 or 20. this is why truckers run channel 19.
what shit are you talking about ?? so why don't truckers run on 20 if that's your logic.. in fact if you take in to account the 'alpha channels truckers would use channel 22 or 23 as center of the CB spectrum 26.965 to 27.405 is channel 22.5 or 27.230Mhz. run on channel 19....ass..
Compare the lowest channel, 1, against the highest, either 23 or 40. Adjust the antenna(s) accordingly. Adjust dual antennas at the same time, not individually.
ALWAYS TUNE YOUR ANTENNA BEFORE PUTTING A RADIO IN SERVICE. Never trust the internal SWR circuitry. It lies, it lies and it lies. Use a good external SWR meter. One that has not been dropped and broken the solder connection inside of the box. 25 - $55.
Hi Mike, really enjoyed that video. I have the same radio and it's the first time I've seen what it looks like inside. Mine get's so hot where that regulator is, the case is almost too hot to touch if I run the rig above 5 watts - the finals heat sync never gets warm so I suppose that's a good thing? Is the heat normal for these radio's?
Mike, Good video...If the final has been replaced in a cobra 29 Ltd classic and still doesn't work, and let's say the regulator is also blown. What will the symptoms be for such a problem. Would the radio fail to key up ? By the way the driver has also been replaced along with the audio chip. Thanks, Billy
Good work ..👍thank you for the video .../// my mike is burn ..the cause false connection 🥺on my president jackson ..40 chanel...inf/sup etc but my square microphone don't answer ..i got to repair it...i slowly learn...
Why does everyone who know a little bit, like to dis a guy who makes a video for those that don’t know this? Be nice or be quiet and click on another video. Thank you for the video and the time you spent for some.
In you professional opinion. I have an old Cobra 40 channel cb, LTD I think it was, that I used for 20 + years trucking. I spent over 35 years OTR & this was my 3rd radio. It has been boxed away for a dozen years or so. Are these worth going through, checking out & repairing if need be or is it better to buy something new. Just want to put it in my pickup just to have when I am on the road with my horses. Also I live on top of a mountain so I would like to see if it is like it was years ago where you hit the skip & could talk a long ways off. Just something to have some fun with. Also thought about hooking a linear to it. What's a good antenna these days? I always liked the K40's but didn't know if anything else is better. If I do what I am thinking of it will be mounted in a Dodge pickup. Thanks for your time.
I'm trying to set up a really old set , Midland . 50ohms impedence ? Hmm , I've heard that be fore . Impedence is resistance . But you still need a opposite polarity reflecter for antanna to work ( I think) . Just don't short it . Broken coax . Splices will cause problems too .
Great job as always Mike. Just curious if those finals were good what would the foward and reverse resistance be? Thank you for sharing your info on radio repair!
That's exactly what I was looking for in the comment section...what the reading would be had the finals not blown? Please let us know! Thanks again Mike for sharing your knowledge with us! Brian
Can the method you used to check the final be used on older radios? I've got a Robyn SB 520D with weak (if any) tx output. I didn't see any other damage. Would it be a good idea to replace the AM regulator also?
Hi mike, I set up a 148gtl and my swr on the radio is high!. I put a mjf antenna tuner between the radio and the antenna. The meter on the tuner is down to 1.1 but still high on the radio. Should I disregard the reading on the radio?. Thanks in advance, Ernie.
Mike, thank you for the videos, they're so helpful. Just curious, can you test the AM regulators and the drivers the same way you tested the finals? I'm trying to find out why a Cobra 25 LTD Classic won't transmit or receive. (I already checked the cb/pa switch and caps esr.) The sound chip makes noise when I put my finger on it. The signal meter isn't moving, but it's not "stuck", it moves freely - doesn't move when receiving signal is being broadcast. In the rear of the 25 there are two transistors. The one near L12 is the final, but what is the one in the very rear corner and what is the one by the volume/on/off switch? Thanks!!
When you say does not transmit, you mean you have a dead key but no audio ?? The audio chip on the side of the chassis might be your issue. The 29 and the 25 radios DO require those 2 thick rubber washers between the mount bracket and the case of the radio.... If their not in there then when you tighten the 2 knobs they pull the case away from the PCB slightly and the solder joints fail.... Example no receive in the speaker and no audio going out....I have seen that a few thousand times....
@@cajuncoinhunter Thank you for writing back. If you watch this video someone posted, this is exactly what happens with my Cobra 25 LTD...it's easier to watch his video than me trying to explain it, but everything that happens in his video is what happens with my 25 LTD...here's the link for you: th-cam.com/video/nzqjIKUKBsg/w-d-xo.html
Great explanatory video Mike. I'm wondering if you have an email I can write to you, for a possible peak, tune and alignment on my radio..? I'd appreciate it. I hope your New Years was a good one.
I have a galaxy 33hml and I checked from the ground on the transistor to the opposite side and had continuity between them on both and it didn’t matter which lead I used on the ground but there was no continuity from ground to the middle of the transistor. Does that sound burnt to you?
Just a reminder to those who make their own coax cables: Coax, (especially the foam core), can suck in water like a fish. It's amazing how much water can wick into your cable if it's not properly sealed. You can generally tell this is happening if your SWR is good on a dry day and they goes wonky after it rains. Then it dries out and your SWR is good again. Chances are you have water in the line or your antenna itself has some water intrusion somewhere. So make sure your antenna system is SEALED. The coax is overlooked and skimped on 99.9% of the time. Waterproof all connectors. You can use Mastic tape on connections you may want to remove later. Just make sure and SEAL it. Also routing your cable out of the direct weather is a good idea (under your house eave, car hoods, etc). Little exposure as possible. For underground runs, I put mine inside electrical-grade conduit for extra protection. A little extra work and expense, but It's cheap insurance. It also helps if you find yourself digging later around your coax. You'll hit the conduit first and not damage your coax. I also like to use heat shrink (the type with the glue inside) to seal where the coax enters the connector. I don't rely on the solder alone for sealing. Get GOOD GRADE heat shrink. Not that cheap Rat-Shack, Harbor Freight thin garbage. Get the 2 or 3:1 stuff with the heavy glue. This stuff will seal just about anything. Likewise it's tough to remove so be sure your solder and coax tests out OK before you install the shrink.
I remember years ago, operators stating that their match would improve in the rain. I never tried to disprove or prove that because I never gave it much thought. Recently I have learned the importance of sealing the coax and the connection that faces the weather on a daily and nightly basis.
Self amalgamating tape is is good also, especially if you live in a area with destructive birds that like chewing on coax ends. Though usually they are that particular, gotta chew it all in some parts of the world.
Mike can you tell me can you tell me if the a.m. regulator would have anything to do with me mod fading out on the FM frequency after about 20 seconds it goes right back signal stays good but the mods fades out on the FM band I am in the UK and the radio is a Stryker sr955.thinks
Question about the finals, I know that the 2sc1969's would need to be a matched pair, but do mosfets for example, irf520's need to be a matched pair? I'm still learning all this stuff, thanks.
hi, i have an ic-735 that was my grandfather's. I've been playing around with it for a while now and I've been having high SWR issues. I'm slightly worried that it blew up at some point before I got it, or maybe i destroyed it without knowing. Is there any definitive way to tell that I screwed it? I just recently got my license and set up an 80-meter dipole and I've been having issues getting contacts.
I had some serious damage done to my Anytone 5555N it have 3x 13n10 but the board looks the same as yours, the TIP36S was burning hot even when not transmitting, it just happend a morning i turned on the radio while i key the mike the display got dim and the radio basicly turned of untill you released the button. It even melted the fuseholder. I saw some one talk about those 13n10 are bad, and recommend to replace them with IRF520's - anything else to replace?
Mike, I have a dual band amateur radio I picked up second hand from another ham who said the UHF side of the radio no longer worked due to a shorted N to SO239 adapter. The radio still works fine on VHF and receives UHF fine. With an analog watt meter into a dummy load, I can see the needle just barely lift off 0 while in low power UHF, but if I key the radio on high power it blows the 15 amp inline fuse before I can see anything happen. Do you think replacing the Mitsubishi ra60h3847m1 PA module would potentially fix this radio or has more damage been done that I cannot properly diagnose or detect? I am having a hard time finding any information about testing PA modules and was hoping to find a way to test with a multi meter like you show in the video. RF in, Gate voltage and Drain voltage all short to ground with high resistance while RF out does not short at all and the meter reads OL. Is that a sign that the finals have fail and are no longer letting RF through the PA module? Any help or comments would be greatly appreciated.
There is a project but to see the signal strength that the radio is receiving, for example, a weak but audible international station lights up 2 LEDs and one is coming in strong as if it were local, lights up 5 LEDs for a radio receiver. Do you know or have a project like this?
I have a Cobra 29 soundtracker in my truck and I recently put speakers headlamps in my truck and now my RF reflection is really high how do I get it back down
I’m having problems with my SWR high it goes to three no matter which way I put it on channel 1- through 40 still stays the same three I can’t get it down I checked the coax coax is fine the ground it’s fine but how can you tell if the antenna I have a trucker 2000 I’m thinking he’s got some kind of a gram problems on the van I have it on the van back of the van
The MFJ Antenna Analyzer (259 or 269) is the best money that a new Ham can spend, IMO. Say what you will about MFJ, but this piece of gear is worth it's weight doing antenna work.
Now, if I could make heads or tails of my switching power supply layout vs. schematics to fix it. It blew out the mosfets... strange because it is supposed to have overheat, over current, over voltage protection, but when doing testing using it, it overheated and did puff the magic dragon on me. I have replaced those, but the supply is stuck in protection mode, and I'm at an impasse. Alinco DM330MVT
Mike, are there different SWR meters for different bands, or are they all the same? I have one that I used for my CB, will that work with my Marine VHF?
No, they are not the same. You would need to look at the specification sheet for the meter you have but most meters used on the amateur radio HF bands and on CB only cover up to 30MHz and maybe a little higher.
I had a lighting strike one of the antennas that I had up. I had my ham radio unhooked. but I had a free play radio and a am drake which both got hit by the lighting. magic smoke came out of the drake. still got it around here some where. after it killed those two radios. it by passed the big screen i had bought was fine but it went on past and fried the misses computer. go figure.
Any repair tips for fixing a STANDARD ECLIPSE GX1245S VHF Marine radio? Current draw is 600 mAmp. Display is blank but the illumination light is lit. Haven't been able to locate a schematic. Service manual is MMGX1240S (covers GX1240/1245 models ). Thank you for any info you may provide.
Unknown, that's not enough information. The SWR curve usually looks like a spread out U or high SWR on either side of the resonant point. Measure the SWR on channel 1, 20 and 40 and take readings. Remember that as you go up in channels you are going up in frequency. Higher frequency means shorter wavelength and thereby a shorter antenna. Lower in frequency means longer wavelength and thereby a longer antenna. So if you have a lower SWR on channel 1 than on 40 shortening the antenna would shift the resonant point to the higher channel / frequency. If you have a lower SWR on channel 40 than on 1 lengthening the antenna would shift the resonant point to the lower channel / frequency.
I don't have a schematic for it, own one and have never worked on one but if the final is bad that's probably all it needs. I would probably probe around with a oscilloscope first to verify it's the problem and if it is take some voltage measurements. Basic troubleshooting.
After just watching a video claiming this can't happen it was refreshing to come back to reality. Great explanation.
I love your videos and greatful you take the time to explain what you do and why you do it. Cheers, 73's!
Thanks Mike for all your videos and help! I installed new mosfets and ran into a problem on AM with the Lincoln II plus and just a few minutes before finishing your vid I found a blown Tip36 lol!! I was lucky with the ferrite as all I had to do was tack it back in place.
Thanks again!!
I guess im randomly asking but does any of you know a tool to log back into an instagram account?
I was stupid forgot the login password. I love any help you can give me.
@Spencer Alfredo Instablaster :)
@Cade Thomas I really appreciate your reply. I got to the site thru google and I'm in the hacking process now.
Looks like it's gonna take quite some time so I will get back to you later when my account password hopefully is recovered.
@Spencer Alfredo You are welcome :D
High swr on Lincolns or any radio with high watts Could be with cheap finals, 💥!! You are a good radio guy!!
Love your humour Mike.
I drew inspiration from your method for how I publish my How-to- Fix videos.
Thanks for these videos Mike, i have learned a lot. Going through them again, i think i missed a couple of them.
Your video's are excellent and very informative.
Alan in the UK
Sure miss you real banter and no BS chat Mike, hope you are well and enjoying life.
Care sent.
Hey there. This may be a shot in the dark but, can you tell me the proper avenue to contact Mike??
No one , and I mean no one knows.😢 thanks. Mark.
Thanks Max Mike! You at least tried to teach some of us to work on our stuff! 😃
Thinks Mike for the great information. That first part was nuts ! No max mod for me. Thanks!
Mike is absolutely the best Tech ! Old school sense and more importantly knowledge,
and he is genuinely a cool guy.
My unending problem is how in the world does a person, potential customer contact him ??? any help here would be monumental !! Thanks !
Forget it. He quit responding entirely. I was a frequent customer and he repaired several radios for me. Then he quit responding and no one has been able to contact him.
Great TIPs Mike. No pun intended.
Thanks for the video Mike great info.
Thanks Mike for addressing the Maxima mod. There is a certain TH-cam or self-proclaimed CB guru that preaches the radios gnocchi up without the max mod and I’ve always thought he was full of BS so I appreciate your addressing that with a commonsense approach.
Very informative video, Thank you!
I'll trust MikesRadioRepair he's pretty good this guy is expert on radios just don't rush him.
Wise words as usual Mike!
On my Lincoln 2+ I moved my AM regulator to the back where the heat sink is. When it was on the side, it would get hot hast. I put a new Tip-36 on the back and it’s night and day difference. The regulator and the finals run nice and cool. That was about 2 years ago. No problem since.
Very useful Tips.
I wish you lived in the Uk, I have a High Gain 5 I really need tuned and setup.
It works, and had the channel Mods done on it.
Hi poss may be able to help with sorting your Hygain 5 radio
Can e mail me on mrianjones@live.co.uk
Very nice shared ideas that helps...!
Thank you for your sage advice
I love it good
Keep uploading videos like this
Good crash course on radio electronics. I wish I had the attention span to learn electrical engineering. I would have a lot of old electronics that would be virtually immortal.
Thanks for showing!
I had the same issue with a stryker 655 a guy brought in the shop and he actually admitted his antenna was bad. When it went took out the finals and tip36.
What are the best antennas for this type radio?
@@justbeforethereturnofchris2393 CB antenna!
@@PeterDad60 .....yea I found one that works with this CB radio...
Had that experience. Basically, I've burned the output stage of an RF PA that I've made, due to a badly tuned antenna. Funnily, the PA is only capable of outputting 1W at best, and I was not expecting it to be damaged.
I love your ability to teach me radio repair you explain it I understand it ! ps Im an auto obd tech my nails look worse than yours!
I have noticed several videos on blown finals. Many of the videos involve the President Lincoln II. I recently acquired a Lincoln II. Guess what? I blew the finals out. I've been into radio's for 20+ years and never ruined a radio. My swr was 1:4 and I have current chokes in line at the radio, shack entrance and at the antenna. My Lincoln had the 1310n transistors. I shipped it off and I was advised to go with better transistors.
i remember getting "suspect " output transistors that had the numbers either blacked out with a felt pen, or sanded off! lots of magic smoke!
Thank you sir 👍
Were is mike ???, he is needed !!!!!
Excellent video! I have about four old radios laying around I think this will fix! Thank you so much, and I just subscribed.
My grandfather liked black walnuts. He used his workshop vice to open them.😅
Good Advice.......Customer wanted "Fars" but only got "Swrs" !!! ......Whoever messes with Coax or Antenna better check Reflected Power.....
Good video ☺️
I have always known about the SWR since I started using the radio, however I never knew exactly what finals were. I definitely learned something here. Thanks
Thank you.
I love your videos. I learn a lot about radio from watching your content, thank you. Question - if the finals get blown so frequently, and pass on current for more internal damage... shouldn’t they build in a fuse?
Read the support boards for the ubitx theres a nice protection mod using a P-FET like the IRF9540 as finals draw power from the 12volt input
I did radio years ago.... Please note that you can tune your antenna on a specific channel. If you set it on channel 40, channel one will probably be higher. The best spectrum spread is to tune on channel 19 or 20. this is why truckers run channel 19.
what shit are you talking about ??
so why don't truckers run on 20 if that's your logic..
in fact if you take in to account the 'alpha channels truckers would use channel 22 or 23 as center of the CB spectrum 26.965 to 27.405 is channel 22.5 or 27.230Mhz.
run on channel 19....ass..
They ran 19 back when it was only 23 channels. 11 was a calling frequency, and of course, 9 was for emergencies.
That's probably why 9 was for emergencies because it was a mid spectrum channel when they were 23 channel
Compare the lowest channel, 1, against the highest, either 23 or 40. Adjust the antenna(s) accordingly. Adjust dual antennas at the same time, not individually.
ALWAYS TUNE YOUR ANTENNA BEFORE PUTTING A RADIO IN SERVICE. Never trust the internal SWR circuitry. It lies, it lies and it lies. Use a good external SWR meter. One that has not been dropped and broken the solder connection inside of the box. 25 - $55.
Hi Mike, really enjoyed that video. I have the same radio and it's the first time I've seen what it looks like inside. Mine get's so hot where that regulator is, the case is almost too hot to touch if I run the rig above 5 watts - the finals heat sync never gets warm so I suppose that's a good thing? Is the heat normal for these radio's?
Mike, Good video...If the final has been replaced in a cobra 29 Ltd classic and still doesn't work, and let's say the regulator is also blown. What will the symptoms be for such a problem. Would the radio fail to key up ? By the way the driver has also been replaced along with the audio chip. Thanks, Billy
Come back to you tube,Mike . I need some radio work done…
Good work ..👍thank you for the video .../// my mike is burn ..the cause false connection 🥺on my president jackson ..40 chanel...inf/sup etc but my square microphone don't answer ..i got to repair it...i slowly learn...
Why does everyone who know a little bit, like to dis a guy who makes a video for those that don’t know this?
Be nice or be quiet and click on another video.
Thank you for the video and the time you spent for some.
Maybe they think the info is incorrect
Thanks for letting people know about the Max Mod ripoff! I've been trying to tell people for years about that scam. Well done!
The price of repairing both radios was still less than half of what a new radio would cost.
Good to see you are still around on the platform, Mike.
In you professional opinion. I have an old Cobra 40 channel cb, LTD I think it was, that I used for 20 + years trucking. I spent over 35 years OTR & this was my 3rd radio. It has been boxed away for a dozen years or so. Are these worth going through, checking out & repairing if need be or is it better to buy something new. Just want to put it in my pickup just to have when I am on the road with my horses. Also I live on top of a mountain so I would like to see if it is like it was years ago where you hit the skip & could talk a long ways off. Just something to have some fun with. Also thought about hooking a linear to it. What's a good antenna these days? I always liked the K40's but didn't know if anything else is better. If I do what I am thinking of it will be mounted in a Dodge pickup.
Thanks for your time.
I'm trying to set up a really old set , Midland . 50ohms impedence ? Hmm , I've heard that be fore . Impedence is resistance . But you still need a opposite polarity reflecter for antanna to work ( I think) . Just don't short it . Broken coax . Splices will cause problems too .
Great job as always Mike. Just curious if those finals were good what would the foward and reverse resistance be?
Thank you for sharing your info on radio repair!
That's exactly what I was looking for in the comment section...what the reading would be had the finals not blown? Please let us know! Thanks again Mike for sharing your knowledge with us! Brian
From as radio guy, just remember a SWR meter "measures" swr, it doesn't fix it. it's not a tuner (they sell tuner's separately)
Can the method you used to check the final be used on older radios? I've got a Robyn SB 520D with weak (if any) tx output. I didn't see any other damage. Would it be a good idea to replace the AM regulator also?
Hey Mike Bruce from Columbus can you get or is there available a frequency display for a ranger RCI 2960 FJP one leg is starting to flicker???
Which mosfets do you like to use for replacements? I see some TIP36C from galco but looking for the FQP13N10 mosfets and there are so many options.
Mike, I think I have the High Gain 5 Schematic, that I need to find and send you a copy of.
Amazing information. My question is how much did the repair for those radios cost? Would such a repair be close to the price a new radio? Thank you.
Hi mike,
I set up a 148gtl and my swr on the radio is high!. I put a mjf antenna tuner between the radio and the antenna. The meter on the tuner is down to 1.1 but still high on the radio. Should I disregard the reading on the radio?.
Thanks in advance,
Ernie.
Mike, thank you for the videos, they're so helpful. Just curious, can you test the AM regulators and the drivers the same way you tested the finals? I'm trying to find out why a Cobra 25 LTD Classic won't transmit or receive. (I already checked the cb/pa switch and caps esr.) The sound chip makes noise when I put my finger on it. The signal meter isn't moving, but it's not "stuck", it moves freely - doesn't move when receiving signal is being broadcast. In the rear of the 25 there are two transistors. The one near L12 is the final, but what is the one in the very rear corner and what is the one by the volume/on/off switch? Thanks!!
When you say does not transmit, you mean you have a dead key but no audio ?? The audio chip on the side of the chassis might be your issue. The 29 and the 25 radios DO require those 2 thick rubber washers between the mount bracket and the case of the radio.... If their not in there then when you tighten the 2 knobs they pull the case away from the PCB slightly and the solder joints fail.... Example no receive in the speaker and no audio going out....I have seen that a few thousand times....
@@cajuncoinhunter Thank you for writing back. If you watch this video someone posted, this is exactly what happens with my Cobra 25 LTD...it's easier to watch his video than me trying to explain it, but everything that happens in his video is what happens with my 25 LTD...here's the link for you: th-cam.com/video/nzqjIKUKBsg/w-d-xo.html
Thanks for confirming the Max Mod scam.
This is exactly what happened to my new Lincoln II+
Great explanatory video Mike. I'm wondering if you have an email I can write to you, for a possible peak, tune and alignment on my radio..? I'd appreciate it. I hope your New Years was a good one.
I have a galaxy 33hml and I checked from the ground on the transistor to the opposite side and had continuity between them on both and it didn’t matter which lead I used on the ground but there was no continuity from ground to the middle of the transistor. Does that sound burnt to you?
Do you figure it is exceeding the max voltage or the max current or both that blows those finals when SWR / RL is bad?
any thing over three . start checking the antenna or coax.. one point five you can live with one to one is best.
Just a reminder to those who make their own coax cables:
Coax, (especially the foam core), can suck in water like a fish. It's amazing how much water can wick into your cable if it's not properly sealed. You can generally tell this is happening if your SWR is good on a dry day and they goes wonky after it rains. Then it dries out and your SWR is good again. Chances are you have water in the line or your antenna itself has some water intrusion somewhere.
So make sure your antenna system is SEALED. The coax is overlooked and skimped on 99.9% of the time. Waterproof all connectors. You can use Mastic tape on connections you may want to remove later. Just make sure and SEAL it. Also routing your cable out of the direct weather is a good idea (under your house eave, car hoods, etc). Little exposure as possible.
For underground runs, I put mine inside electrical-grade conduit for extra protection. A little extra work and expense, but It's cheap insurance. It also helps if you find yourself digging later around your coax. You'll hit the conduit first and not damage your coax.
I also like to use heat shrink (the type with the glue inside) to seal where the coax enters the connector. I don't rely on the solder alone for sealing. Get GOOD GRADE heat shrink. Not that cheap Rat-Shack, Harbor Freight thin garbage. Get the 2 or 3:1 stuff with the heavy glue. This stuff will seal just about anything. Likewise it's tough to remove so be sure your solder and coax tests out OK before you install the shrink.
I remember years ago, operators stating that their match would improve in the rain. I never tried to disprove or prove that because I never gave it much thought. Recently I have learned the importance of sealing the coax and the connection that faces the weather on a daily and nightly basis.
Very good post... Very well said. Listen to this guy; he knows his stuff...
Self amalgamating tape is is good also, especially if you live in a area with destructive birds that like chewing on coax ends. Though usually they are that particular, gotta chew it all in some parts of the world.
Mike can you tell me can you tell me if the a.m. regulator would have anything to do with me mod fading out on the FM frequency after about 20 seconds it goes right back signal stays good but the mods fades out on the FM band I am in the UK and the radio is a Stryker sr955.thinks
I hope Horatio is okay!
Question about the finals, I know that the 2sc1969's would need to be a matched pair, but do mosfets for example, irf520's need to be a matched pair? I'm still learning all this stuff, thanks.
Yes they do.
hi, i have an ic-735 that was my grandfather's. I've been playing around with it for a while now and I've been having high SWR issues. I'm slightly worried that it blew up at some point before I got it, or maybe i destroyed it without knowing. Is there any definitive way to tell that I screwed it? I just recently got my license and set up an 80-meter dipole and I've been having issues getting contacts.
I had some serious damage done to my Anytone 5555N it have 3x 13n10 but the board looks the same as yours, the TIP36S was burning hot even when not transmitting, it just happend a morning i turned on the radio while i key the mike the display got dim and the radio basicly turned of untill you released the button. It even melted the fuseholder. I saw some one talk about those 13n10 are bad, and recommend to replace them with IRF520's - anything else to replace?
Hello Mike do you know of any cb/Ham radio repair courses?
Mike, I have a dual band amateur radio I picked up second hand from another ham who said the UHF side of the radio no longer worked due to a shorted N to SO239 adapter. The radio still works fine on VHF and receives UHF fine. With an analog watt meter into a dummy load, I can see the needle just barely lift off 0 while in low power UHF, but if I key the radio on high power it blows the 15 amp inline fuse before I can see anything happen. Do you think replacing the Mitsubishi ra60h3847m1 PA module would potentially fix this radio or has more damage been done that I cannot properly diagnose or detect? I am having a hard time finding any information about testing PA modules and was hoping to find a way to test with a multi meter like you show in the video.
RF in, Gate voltage and Drain voltage all short to ground with high resistance while RF out does not short at all and the meter reads OL. Is that a sign that the finals have fail and are no longer letting RF through the PA module?
Any help or comments would be greatly appreciated.
The radio is a Connect Systems CS800D and my testing had been done on analog FM
Hi I need to know if you repair mark 3 browning
Higher swr causes the finals to heat up more they go into thermal overload.
If I want to send my cb in for repair where would I send it to for you to work on it?
There is a project but to see the signal strength that the radio is receiving, for example, a weak but audible international station lights up 2 LEDs and one is coming in strong as if it were local, lights up 5 LEDs for a radio receiver. Do you know or have a project like this?
I have a Cobra 29 soundtracker in my truck and I recently put speakers headlamps in my truck and now my RF reflection is really high how do I get it back down
I’m having problems with my SWR high it goes to three no matter which way I put it on channel 1- through 40 still stays the same three I can’t get it down I checked the coax coax is fine the ground it’s fine but how can you tell if the antenna I have a trucker 2000 I’m thinking he’s got some kind of a gram problems on the van I have it on the van back of the van
Would extremely high swr cause the modulation to go bad?
I wish you'd come back
Would this cause it to melt? Not sure mine melted it was just an old Motorola cb burnt my hand too
SWR stands for Standing Wave Ratio...how do you get SWR's? People do the same thing with RPM...pet peeve of mine I guess...
bit like when people say 73's...
Because he's a CBer.
Christ almighty...
All about the reflection
@James Marquis Don't try pushing your bullshit on me.
My antenna must have gone south and when I keyed up my Telsat 140 I lost receive and transmit. What should I look for ? Finals blown??
The MFJ Antenna Analyzer (259 or 269) is the best money that a new Ham can spend, IMO. Say what you will about MFJ, but this piece of gear is worth it's weight doing antenna work.
You can wash your hands with raw lemon juice…then your good 👍
Mike, are you still doing cb repairs? Can I send mine in for service?
Matt
I run a Francis 5.5ft whip on my truck and the SWR is 1.0 on my Lincoln II+
Now, if I could make heads or tails of my switching power supply layout vs. schematics to fix it. It blew out the mosfets... strange because it is supposed to have overheat, over current, over voltage protection, but when doing testing using it, it overheated and did puff the magic dragon on me.
I have replaced those, but the supply is stuck in protection mode, and I'm at an impasse.
Alinco DM330MVT
I've got a cobra lt 29 and I have one switch is bad how hard is it to change or fix
Mike, are there different SWR meters for different bands, or are they all the same? I have one that I used for my CB, will that work with my Marine VHF?
No, they are not the same. You would need to look at the specification sheet for the meter you have but most meters used on the amateur radio HF bands and on CB only cover up to 30MHz and maybe a little higher.
@@mikesradiorepair Thank you!
will this work on a uniden 510xl and the 520 xl
How do I get in touch with you, to conduct business or at least ask questions
I had a lighting strike one of the antennas that I had up. I had my ham radio unhooked. but I had a free play radio and a am drake which both got hit by the lighting. magic smoke came out of the drake. still got it around here some where. after it killed those two radios. it by passed the big screen i had bought was fine but it went on past and fried the misses computer. go figure.
Any repair tips for fixing a STANDARD ECLIPSE GX1245S VHF Marine radio? Current draw is 600 mAmp. Display is blank but the illumination light is lit. Haven't been able to locate a schematic. Service manual is MMGX1240S (covers GX1240/1245 models ). Thank you for any info you may provide.
Sorry I do not have any service information on any marine or aircraft radios. You need a GROL license to service them which I do not have.
Mike questio for you. Does is stand true for any antenna whether vertical, random wire, etc. If Swr is 2.5 and you want 1.25 you shorten length?
Unknown, that's not enough information. The SWR curve usually looks like a spread out U or high SWR on either side of the resonant point. Measure the SWR on channel 1, 20 and 40 and take readings. Remember that as you go up in channels you are going up in frequency. Higher frequency means shorter wavelength and thereby a shorter antenna. Lower in frequency means longer wavelength and thereby a longer antenna. So if you have a lower SWR on channel 1 than on 40 shortening the antenna would shift the resonant point to the higher channel / frequency. If you have a lower SWR on channel 40 than on 1 lengthening the antenna would shift the resonant point to the lower channel / frequency.
On an FM only radio Btech GMRS-50X1 if the final is burned out, is there any other component that should be premptively replaced?
I don't have a schematic for it, own one and have never worked on one but if the final is bad that's probably all it needs. I would probably probe around with a oscilloscope first to verify it's the problem and if it is take some voltage measurements. Basic troubleshooting.
I have one those workman swr meter and antenna matcher it easy way shortcut tune swr.
Wonder if he connected them to a marine VHF antenna?
Anyone know what Moffett finals and am regulator part numbers would be for a Connex 3300hp?
Yup, I know exactly what you mean about Walnut shells.
What's it mean when I key my mic the needle doesn't move?