New Jan Beta video, new Christmas setup recreation... Instant thumb up even before watching it! Now I am sitting at my desk with a cappuccino and enjoying this forty-six minutes of pure goodness! :D
Check your transistors using the diode setting on your meter, not just the resistance. The resistance may be fine but they may not be working as they are conducting in both directions. Also check your signals going between the 2 boards as you turn the colour adjustment pots. This will tell you which board is having issues and may help narrow down the problem. Good luck trying to get the old girl working again.
recommendation is to use a thinner wire at 15:13, if it's only a signal wire at 32:03 there are voltage levels on the diagram, might be worth checking those the bodge at 37:09 does not have to mean anything, it might be that the pot meter has been replaced with horizontal kind and then the middle leg has to be solderin in with a wire also i would check for wires broken inside, ie messure ohms on the wires. it sometimes happen that wires break without leaving signs on the outside
Yo listen up, here's the story About a little guy that lives in a blue world And all day and all night and everything he sees is just blue Like him, inside and outside Blue his house with a blue little window And a blue Corvette And everything is blue for him And himself and everybody around 'Cause he ain't got nobody to listen I'm blue da ba dee da ba daa Eiffel 65 - im blue.mp3
If you are using the C64 to test, I would set the background and border colors to something with red and green signals, then use your oscilloscope to follow the color signals from the input to the neck to see where they are cut out. POKE 53280,X for the border and POKE 53281,X for the background with X being the color value. X = 2 for red, X = 5 for green, and X = 6 for blue. Unfortunately the red and blue values are only half strength red and blue, and the green they use contains some blue as well. I didn't see in the video, but you should double check that the internal pots are set to a middle position to make sure they are at a reasonable level.
Yes, that makes sense. I think I'll rather use some RGB capable computer for serious testing though. Definitely going to revisit the repair when I have more time.
I have this monitor too, boxed. Was in my parents attic, untouched for 25 years. Was (and still is) working. Needed to replace the switch after about 10 cycles after bringing it down.
You mentioned a "high-pitched whine" coming from the monitor. We had a monitor like that as part of our Commodore setup (I assume C64, although it could have been used with our Amiga 500 also) at one point; we called it "The Screamer." We sold off The Screamer together with most of our Commodore hardware & software at a game convention auction in the mid-1990s. Actually, it didn't sell at the auction itself, but when we picked up our unsold items on the last day of the convention, one of the other sellers made us an offer to buy The Screamer directly from us -- which we were happy to do, as we had more than enough other stuff to bring home, between vacation purchases, our own luggage, and all of the things our 3 small children seemed to need, even for a short holiday.
Green is totally missing, so it could just be the output transistor for the Green drive has failed (TS712), and/ or the feed resistor to the Green gun has gone o/c (R723). It looks like from your measurements that supply choke (S723) is probably OK (double-check it, anyway). If that turns out to be the case, I would replace all three RGB drive transistors anyway, as they are all of the same type, and a relatively inexpensive part. Worst-case scenario: If your voltages are present and correct at each of the guns, and swapping the drives around doesn't yield any life out of the Green, then I'd suspect the CRT itself is faulty :/
Wow this does bring back memories ;). I had an a500 1988'ish, I had the A501 ( fast ram ) expansion kit too which was pretty nice ( a whole 1mb! ). From what I remember mine was one of the first with the v1.3 ACS Chipset/Kickrom. Looking forward to see how this progresses
My first amiga was a amiga500 as well, with the 0,5Mb memory expansion. Later i bought a harddrive expansion for it, with 2mb fastram buildt into it. But sold it all to afford my amiga 4000.
Excited to see another computer setup recreation series! I'm even lowkey inspired to hunt down the same model of Compaq Presario I had as a young lad in the late 90s 😁
I fix one of the 1084. There is a resistor that tend to break and disable flyback powerup. Resistor is R462. Also maybe flyback is fried or the HOT transistor is kput. Make sure you use the same package, I wrongly put one HOT with metal package and was short out with the aluminium. Use plastic package. Hope this tips works with you Jan.
I'm sure you'll get it fixed. Some good comments here as to where to continue. I have the Magnavox version of this monitor downstairs. It was on the curb here for trash pickup. I grabbed it, knowing they sell for well over $100 on ebay! Was quite dirty and with a good wipe down it looks great. The power button is also broken so I need to temporary fix it like yours. Need to test it.
Se if you can swap colors on the cable between main board and driverboard, to be sure where the error is. From school about 25 years ago (wery litle practice since) i remember that the voltages on the driverboard was high enough to trigger faults in transistors that could not be measured by transistor or diode tester. Solution was to see where the signal disappeared (by scope or by swaping known good color channel with the one with error) and just replace components where signal got distributed .
I was thinking something similar. I'm really chickening out on measuring the voltages while the thing is running though. Maybe I'll rather end up desoldering the transistors and checking them in a component tester.
I used to be scared on CRTs but that's gone. I do wear rubber gloves and rubber shoes while working on them, just for the case that, but simply stay away from the high voltage transformer and that cable. That is the only part that you really want to avoid getting shocks from. All the rest is below mains voltage, might be unpleasant, but won't kill you that quickly.
The sudden loss of power suggests to me the aging supply circuit is probably stressed. Try testing the voltage rails (especially logic voltages) for low resistance. While they are likely not shorted, they may be trying to push the supply too hard hence the sudden failure.
Hi Jan, I noticed that te adjustment pots on the neckboard are all very differently set and also some are near the extreme ends. I would suggest turning them all to the middle and work from there. Maybe they just turned down red and green off so to speak. Also measure the input stages of the rgb before they go to the neckboard while feeding fullscreen white picture and compare the values for the 3 components if all are similar than the inputs are ok, then check the inputs of the neckboard.... I had an 1048S once that had an faulty input stage in the composite in but rgb was still ok.
I measured the resistances of the pots but you may still be right. They might behave strange if voltage is applied. Definitely going to revisit the monitor when I have more time.
I own a Highscreen KP548, which is almost identical to the 1084 version you have there: Identical chassis, almost identical electronics board. The only difference is that is has no S-Video connectors, which makes it a bit less suitable for the Commodore 64. I plan to do some upgrades to this monitor and have already bought some parts. I want to install S-Video, upgrade the speakers to better ones, and replace the TDA4510 PAL decoder by a TDA4555 multi-standard decoder (the board is prepared for that). This should make it accept NTSC and SECAM signals too (but this depends on additional mods in order to be used, haven't studied this in detail yet). The only tip I have now is that I would scan the board with an oscilloscope at various places in the RGB part to the CRT, see where there is a signal and where there is none. However, when I will start my upgrades I will have to study the schematics in more detail and perhaps I'll have a few more tips then. By the way, the board in my monitor is suffering quite a bit from mechanical wear: You can bend it quite easy when it is mounted. Soldering joints have cracked or have even got loose from the PCB taking traces with them. I have done already multiple repairs on this and it is likely more will follow. Allthough I'm sure you have inspected the board closely, mechical damage is still something to look for on these monitors when there is a problem.
6 ปีที่แล้ว +1
As it was suggested before my comment too, it's nice to connect the blue output to green then red pin of the tube, just to see, the tube is the problem. Also, I may would use a scope (preferably at least two channels) connecting the same point of the circuit at the "good" and one of the "bad" colour channels, starting from near the input circuity and following the schematics, going towards the tube itself. If the video signal is preferably white, it should have more or less same signal for R/G/B, so some can spot the first place where there is some major difference. But anyway, just an idea ...
They look roughly like what failed inverter caps look like so I think they might be a part of the HF switching for the guns. 32:25 seems to suggest they connect the mainboard transistors to ground and C619 is the Blue gun
Bummer. I'd have given up on such a project a year ago but now I think I can fix almost anything (except SMT stuff - so fiddly). I hope to see a video with it working someday.
Hello Jan, when i was a kid and my dad had a big CRT television that we rented, the guy who we used to rent it from used to re gun the tube and that fixed the problem of funny colours.
I think it is still more likely that it is the electronics than the tube. Tube damage you wouldn't expect so uniform over the screen. It could be the electron guns, but it is simply much more likely that it is a component on the board.
You see, what happens is that the capacitors are so dry that they can get shorted and that's why you lose the power (or some protection circuit may be getting triggered), to repair old CRT tv/monitors it's recommended to do a full recap, they will start failing one by one anyways and it can be dangerous if certain caps fail, like for example the bigger one that you find near the flyback, which can protect you against xray exposure. You may leave the bigger ones since it's harder for them to fail and get dry but you never know.
Hey Jan, as someone later born and who's only ever seen an Amiga in the wild once back when, I wonder where I should jump into the whole Amiga thing. I have zero nostalgia for anything, I'm just curious about it and want to experience it for myself first hand as I got a thing for old computers and game consoles. Which model would you recommend me? I've seen that some models go for quite a lot on eBay, as do some of the upgrade cards. Besides running games on it, I'd like to be able to expand the hardware later on (with cheaper modern upgrades like flash storage for a hard disk, a Gotek, and maybe CPU upgrade boards) but I don't want to spend a whole lot initially really. Or should I just get one of the low spec'ed Amigas first that maybe aren't all that upgradable? How fragile are the custom ICs in there? I guess getting a broken machine is a risky thing, is it? I'm able to diagnose and fix complex electronic issues myself, but if there is no hope because replacement ICs aren't available for any reasonable prices, there would be no point in getting a broken machine to save money. Cheers
The Amiga 500 should be a good choice. It is the model that sold most units, therefore it is not so rare, not so expensive and still has a huge software library. The A500 is from 1987, but chipset wise it is very close to the chipset of the original Amiga 1000 and thus also gives you a pretty good picture how revolutionary the Amiga was in 1984 by introducing a GUI, pre-emptive multi-tasking, blitters, and above all, the ability to display 4096 colours. People consider the best Amiga the Amiga 1200 and it has a much improved chipset over the Amiga 500. There certainly exists a software library that runs on the 1200 and not on the 500. On the other hand, the Amiga 1200 software library consists of many games that we also saw on MS-DOS PC's and therefore is much better known to many people than the Amiga 500 software library. Most important: The Amiga 1200 is much rarer and sells for rather high prices, making it less attractive as an entry into the Amiga world.
@@danielmantione The amiga 1200 is also more difficult to repair if something is broken, as it use a more modern type of motherboard. Also if some or any of the chips/ic's are broken, you will probably need to buy another amiga 1200 to use as spare parts. Thats was my problem with my amiga 4000, finding spare parts. Amiga 500 however, sold so well that its easy to get. Even so, it is quite pricey for being that old, but it is the cheapest and most available amiga you will find. Everything else is just much more expensive.
Thanks for your replies, guys. I'm used to pricey, I got two MSX machines. However, not Amiga level pricey. The A1200 currently sells for 300-400€ on eBay depending on extras. Even bare bones machines listed as not working go for 200€, which is fairly steep. The A500 can be had for 50-140€, so quite the difference. However, I worry that the same thing will happen that has happened to me before: that I get the entry level machine and later yearn for more: I got an MSX1 first, because I had gotten one handed down as a child and had nostalgia for it, but then later got an MSX2 additionally which is far more useful and rewarding. Virtually no good games run on the MSX1, they all require an MSX2 or better. So, it's not the same situation on the Amiga then, or is it? I guess I'll see if I can score a working A500 for around 50€, which is around the price point I don't really think about having wasted money on a machine I will later replace anyways. I of course already have a monitor for it. What about those desktop machines? I've read that some have extra blitter chips and what not, and there are of course the upgrade options with cards and CPUs for those. Would be neat, but unless I really wanted that video toaster thing I guess there is no real use for that, is there?
Yes, the Amiga1200 sometimes really sells for crazy prices. The A500/A1200 situation is certainly not comparable to the MSX1/MSX2. There is a 5 year difference between both machines: The A500 was the dominating 16-bit game platform world wide for a few years and "must support". When the A1200 came on the market, the world had changed. There was still a lot of commercial pressure to make software compatible with the large A500 installed base, but at the same time, the A1200 was facing strong competition with the PC. It never sold well in the US, and only got moderately popular in Europe. Still good enough to develop software for, but it never did dominate the game market like the A500 did. Facts remains that the A1200 is a much more powerful machine than the A500. I would ignore the desktops. They had the option of PC compatibility through installing a bridgeboard. We don't care about PC compatibility nowadays, I guess you have better ways to run old MS-DOS software. Further, indeed, you can install cards, but what cards would you want to install? Both the A500 and A1200 have an expansion port and there is quite a of hardware available for those, possibly even more than there were cards available for the A2000/A4000, so there is no need to worry that there is no way to expand an A500/1200. Also the form factor is a thing to me: The keyboard integrated case of the A500/1200 is a distinctive aspect of computer design back then. A desktop case speaks no design language to me, it is just a boring box of iron. When looking for Amiga deals on Ebay, be sure to look specifically on Ebay.uk. There was no country where the Amiga was more popular than in the UK. Deals do not always automatically show up on other Ebay sites. Because the supply is higher, prices are lower in the UK. You sometimes have to negotiate a bit about shipping, but is seldomly a problem.
If you can get one, you really need a CRT tester to check the cutoff threshold of each electron gun. They generally have a rejuvenator setting which can bring back guns that have deteriorated from use. That is a temporary fix. All the TV repair guys I know here in the states that did that work (there's not much call fr it nowadays) used the Sencore CR70; "The Beam Builder". You could probably do a full recap as well. In the end, I know you're trying to recreate the old setup, but I think it's best not bother with a CRT and get an adapter for a 4x3 beige flat panel display.
Internal adjustment "Sub Brightness" is set too high.. Find it and back it down a bit to get rid of the raster lines. Also check the main board as well. Bet there some cracked solder joints there too.
I've seen a video of a guy rejuvenating tubes for arcade machines with a special device. Actually there are a bunch of videos on this topic. What this did is actually test each gun and then fixing color problems by sending a higher voltage to the affected gun, retested, etc. The neck board was removed and the device is connected to the tube. It came with a bunch of adapters for different tube models. There was a manual for the device containing all the voltages for the different tubes. Quite complex process. It might be interesting if there is someone who does this in Germany.
Have a look at EEVblog #1020 - Is A $7 LCR / Component Tester Any Good? You probably won't get one from PRC in time for this project but good for transistor testing in future projects. I have one and it is useful. Usual caveats apply, it has its limitations, test out of circuit, use your own best judgement etc. But still worth having. Best of luck with this current project.
You could measure the resistance of the guns.. might show something. The bright lines on the screen are flyback lines, and that means the anode voltage is too high. Someone probably turned it up during diagnosis. The shutdown might have been X-ray protection circuitry kicking in due to that.
It didn't actually fully turn itself off. That was just video editing and me pulling the plug when the tube went blank to prevent further damage. The x-ray protection kicking in makes sense. I'll definitely revisit this repair and measure more thoroughly.
@@JanBeta It's definitely worth checking the power supply output voltages before doing anything else. Naturally, dont measure the anode voltage without the proper test probe!!
It was like that in the family for a long time. I got my father's old computers when he treated himself to the next generation. That's how I ended up with a glorious 68030 Amiga 2000, too. ;)
Yes, it is there from the factory. Check this page: gona.mactar.hu/Commodore/monitor/Commodore_monitors_by_model_number.html ... there are quite a few Commodore monitors with SCART.
@@danielmantione I'll be damned. I've never seen one here in Sweden, but they might exist I suppose. Thanks for the link btw! I have a dead 1084s-d1 that has been on the to do list for far to long.
I've got that model (1084) and it's missing the front panel, can't tell you just how aggravating that is from an ashetics point of view for me. It's NTSC of course so no scart. Bummer it's shutting down now. Looking forward to you sorting it out (if possible). Mine has an annoying hum that seems to mostly go away once the tube warms up (makes me nervous though).
Isn't there someone making 3D printed replacements? Obviously not a perfect solution but I think it's more pleasing than a "naked" control panel on the monitor. The hum might come from some bad capacitors, especially as it goes away when warmed up.
@@JanBeta Thanks for the tip on the 3D prints. The one I found was about $30.00, I'll keep looking :). The other thing about the hum I should've mentioned is that it's only after I turn on my C128 that I hear it.
yeah, you should just break out the oscilloscope, and measure the signal on the red and green trace route. and since some of this is close to high voltage, you might want to feed the signal directly as well to avoid turning the high voltage on. but also, your right about it haveing too many issues. so just scrapping it is an option as well. even if you get it working, it probably wouldnt live long before you have to fix it again. but then again, this is a classic monitor, the one that every amiga fan just loves.
I'm terrified measuring these things while they are powered on... I'm definitely going to revisit the repair and try my best but I might end up using it for parts (maybe fixing another 1084).
@@JanBeta Thats why im suggesting you use a signal generator, and feed low power signals in front of each component and measure it. You will have to move the point where you feed the signal from component to component since you use low voltage. If you have a signal generator that is. If not, it would be way to much work imo. Even with a signal generator it will take a while. Dont think anyone will be upset if you decide to use it for parts.
@iKarith Great advice and I'll do my best to take it on board when the day comes. Would love to get my hands on some thing like a SONY PVM in the future. I know there is also safety gloves you can get, have seen some TH-camrs use. Will be leaving it unplugged for some time with the power button on. I'll still be a little nervous :)
A couple of years ago, I was offered two 14inch PVMs from a local TV station FOR FREE and I declined the offer. I didn't have room at the time and wasn't really into retro computing yet. Still brings tears to my eyes thinking of that. :/
@@JanBeta Ive repaired alot of tv's. All crt. Seems nowdays no one cares about lcd repairs, they just buy new. I guess it's cause its cheap, or because theres always some new model thats better. But, at least i still have amplifiers i can repair and service. Got to admit im not getting rich doing electronic repairs, but i do like doing it.
Vielleicht hilft es ja, die Signale zumessen, die aus dem Mainboard an das Board an der Bildröhre gehen. Wenn es hier zu einem nachvollziehbaren Ergebnis kommt (mach mal das Bild weiß oder grau, dann sollten die Farben ähnlich verteilt sein), dann liegt der Fehler dahinter. Auf dem kleinen Board kann man vielleicht nur vorsichtig messen, weil dort die Spannungen so hoch sind. Man sollte sich vorher über die ungefähren Pegel im klaren sein. Vielleicht hilft auch ein sehr hochohmiger Spannungsteiler vor dem Tastkopf für das Scope. Tendentiell 10Mohm. Er muss ja nicht 500MHz Bandbreite haben. Und man kann ihn festlöten, damit der Tastkopf vom Scope einen festen Halt hat. Dann kann man auch mit der Hand von der Hochspannung wegbleiben. Ich habe keine Erfahrungen mit Farbfernsehern und den letzten S/W-Fernseher habe ich Mitte der 1980er aufgemacht. Ich kann also nur beim Raten helfen. Ich denke aber, dass man im Betrieb messen muss, um schneller an den Fehler zu kommen. Ein Trenntrafo am Netzanschluss des Oszi kann hilfreich sein, wenn der GND des Monitors nicht gegen PE referenziert ist. Also auch mal messen, bevor es am Tastkopf blitzt. Zur Vorsicht :-)
This will be an interesting and teaching series I guess. When I am dealing with high voltage circuits, I am a bit afraid (ok sooo afraid) and wearing a plastic glove :-) By that I feel much more comfortable. You could also try.
Oh, sure, if I don't find a use for the case you can have it. At the moment, I really want to have one of those monitors so I might end up buying one with broken flap and am going to need it myself then.
@@JanBeta Thanks, If you end up getting the newer shape 1084, i have an Almost pristine outer case for a 1084S-D stashed away in my garage, it's yours if you want it.
Eine weitere großartige Projektidee für dieses Jahr! Ich muss allerdings fragen, was hat jemand mit diesem Monitor getan, damit es jetzt so schlecht läuft?
Danke! Ich vermute der Monitor brach irgendwann zusammen und der Vorbesitzer hat einiges versucht, ihn zu reparieren. Das macht die Fehlersuche jetzt natürlich schwieriger, weil ich nicht weiß, was alles versucht wurde.
Zusammengebrochen? Der Gedanke macht mir Angst, dass er könnte. Es sieht zwar so aus, als ob ein gutes Stück gemacht wurde. Ich hoffe, du kannst es dann reparieren.
Does it do any good to discharge the CRT to a ground wire that isn't, in fact, grounded? I'm at the 11 minute mark and don't recall seeing or hearing about the monitor being connected to ground...
That’s absolutely fine, it behaves like a capacitor that is shorted to itself and discharges. No mains ground needed (the monitor isn’t mains earth referenced at all anyway).
Obviously fix the PSU first. Remember the first rule of troubleshooting: Thou shalt test voltages! Oscilloscope is the exact too for the colour problem diagnosis. Put a colour bars test signal in (or even just a grey scale) and trace each R/G/B signal from the decoder chip to the drivers. Be aware though, it may be a "live" chassis PSU, which makes an expensive bang and smell when you plug an oscilloscope ground on to it. The scope ground needs to be floating.
…if you manage to repair the rest, that is. The volume poti seems to be a stereo version, so you could isolate it on the board and run traces to the extra amplifier. Or maybe the built in amp IS stereo?
Danke! Ist zwar weitestgehend der gleiche Monitor, aber ich denke, ich komme mit den pdfs ganz gut klar. Im Lab ist nicht wirklich viel Platz zum große Schaltpläne ausbreiten leider. :)
Jan did you also check cbm8bit.com/8bit/commodore/server/bombjack.org/browse/commodore as they might have better documentation to solve your problem, like pretty detailed service manuals for various commodore equipment.
I don't think you actually discharged anything. The chassis was not plugged into the wall or otherwise connected to ground. So when you connected the pin inside that round rubber thing to the chassis there was no path to flow towards ground.
CRTs hold voltage for several hours after they are powered off and unplugged. There really is no need to discharge them after several years of sitting idle with no access to mains voltage. That's why nothing happened, there was nothing to happen. [
I will. I think I just chickened out because I'm afraid to measure anything on CRTs while running. I'll definitely revisit this repair when I have more time though.
I have a broken power supply board of a monitor and I am too afraid to measure it with a scope because I think I don't have proper knowledge and an isolation transformer. So I decided to stay safe at the moment. But I measured a lot if things with multimeter and still could't find the problem.
@@JanBeta If your going to measure it live, you should be scared. That voltage is not to be fooled with. Also, might want to consider using high voltage protection gloves and shield. But i would recommend using a signal generator instead of measuring it live.
Moin,mein 1084 hat auch nach Jahren den Geist aufgegeben.. das Bild flackert..und nach 2 Minuten fällt das Bild komplett aus.. Power Lampe leuchtet noch,meine Vermutung..das vielleicht Kondensator hin ist..aber wie kann ich das Testen,hab nur nen stinknormales Messgerät zuhause..Hab schon im Internet gesucht..viele schreiben.. könnte auch am Zeilentrafo liegen..aber da will ich nicht ran..und Ersatzteil ist urschwer zu bekommen....muss ich mir echt jetzt nen neuen gebrauchten Monitor besorgen..bei eBay bezahlt man ja mittlerweile richtige Schweinepreise..vielleicht kannst du mir ja weiterhelfen,mfg Danny
Die Zeilentrafos sterben leider tatsächlich relativ häufig, aber wenn der Fehler erst nach einiger Zeit auftritt, sind lecke Kondensatoren auch eine mögliche Erklärung. Ich kann aus rechtlichen Gründen leider keine Reparaturen machen, gibt aber noch old-school Radio/TV-Reparaturläden, die alte CRTs reparieren und häufig gar nicht mal so teuer sind.
You can not repair any thing with the bloody covers on it. Before it died I was going to say measure the voltage on the cathodes with contrast and brightness set to min. Monitors are no worse to work on than high power audio amps. I have been working on CRT monitors since 1978 and still repair them to this day.
1084 monitors are expensive on ebay but can be found for nothing in local offers. If France it's not unusual to find some in working condition at 40€ but you have to pick it up. Here is a guy selling the entire configuration you are trying to set up for 90€ including the monitor. but you have do pay cash and pick it up. What about a little trip to France? www.leboncoin.fr/collection/1533023639.htm/ Tours is a very nice town by the way. I am pretty sure they do chrismas ferries and things.
procedure.. step 1 .. disconnect the tube base panel and check all tube base voltages.. they are on the schematic.... approx 90v on the cathodes.. and the first anode should be around 300v .. ?? the red screen with flyback lines at one point suggests there is something up there possibly also.. most likely the first anode feed resistor has gone high, and somebody has screwed around massively with the gun drive settings to try to cure that fault.. the most likely reason it's shutting down now is the first anode capacitor has gone more leaky.. it's probably the black electrolytic on the tube base board
@iKarith Its easy, just follow the signal route from the input to the output/crt cannon. However, its not safe to do this on high voltage. (when its on) You will need the schematics to see the trace route though.
Well, it's turning itself off which seems to suggest multiple issues. I would consider it a lost cause. To me CRTs are a black art, or a blue art in this case...
I probably wouldnt see it as a lost cause, but i would see the age and state that its in a problem. If he fix it, it will probably not live long, before he gets another issue again. Only question is how much time he is willing to put into it.
Don't mean to sound like a party pooper, perhaps spending too much time on the diagnostics may not be the smartest option. Being in the electronics repair business, it's often cheaper and less time consuming to simply cannibalize another main board from an identical broken unit and be done with it in half an hour. Just my 2cents. ;) And yes I know that it's getting harder to find these older 1084 monitor parts, but they are still out there, just gotta keep on looking.
"I don't know what I'm doing, don't take this as a tutorial".
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Since you know blue is working, couldn't you connect blue to the red and green on the tube to see if CRT is working for those colors?
How is the continuity between the transistors and the coil connector? Haven't noticed Jan checking that.
You could check the CRT by running the other guns with the blue driver This would tell if the CRT tube is OKay
I see I am 2nd on that
I love how happy you always are when stuff doesn't blow up. I'd be crapping myself.
New Jan Beta video, new Christmas setup recreation... Instant thumb up even before watching it! Now I am sitting at my desk with a cappuccino and enjoying this forty-six minutes of pure goodness! :D
I watched this over my morning cappuccino too :)
since it turned red when you adjusted some things, wouldn't that mean that the red gun also works?
Check your transistors using the diode setting on your meter, not just the resistance. The resistance may be fine but they may not be working as they are conducting in both directions. Also check your signals going between the 2 boards as you turn the colour adjustment pots. This will tell you which board is having issues and may help narrow down the problem. Good luck trying to get the old girl working again.
recommendation is to use a thinner wire at 15:13, if it's only a signal wire
at 32:03 there are voltage levels on the diagram, might be worth checking those
the bodge at 37:09 does not have to mean anything, it might be that the pot meter has been replaced with horizontal kind and then the middle leg has to be solderin in with a wire
also i would check for wires broken inside, ie messure ohms on the wires. it sometimes happen that wires break without leaving signs on the outside
Yo listen up, here's the story
About a little guy that lives in a blue world
And all day and all night and everything he sees is just blue
Like him, inside and outside
Blue his house with a blue little window
And a blue Corvette
And everything is blue for him
And himself and everybody around
'Cause he ain't got nobody to listen
I'm blue da ba dee da ba daa
Eiffel 65 - im blue.mp3
8 Bit Dreams nooooooooooooooooo
da ba dee da ba da
Eiffel-65 is quite appropriate for all this retro stuff, spot on that era. :)
If you are using the C64 to test, I would set the background and border colors to something with red and green signals, then use your oscilloscope to follow the color signals from the input to the neck to see where they are cut out. POKE 53280,X for the border and POKE 53281,X for the background with X being the color value. X = 2 for red, X = 5 for green, and X = 6 for blue. Unfortunately the red and blue values are only half strength red and blue, and the green they use contains some blue as well. I didn't see in the video, but you should double check that the internal pots are set to a middle position to make sure they are at a reasonable level.
Yes, that makes sense. I think I'll rather use some RGB capable computer for serious testing though. Definitely going to revisit the repair when I have more time.
I have this monitor too, boxed. Was in my parents attic, untouched for 25 years. Was (and still is) working. Needed to replace the switch after about 10 cycles after bringing it down.
You mentioned a "high-pitched whine" coming from the monitor. We had a monitor like that as part of our Commodore setup (I assume C64, although it could have been used with our Amiga 500 also) at one point; we called it "The Screamer." We sold off The Screamer together with most of our Commodore hardware & software at a game convention auction in the mid-1990s. Actually, it didn't sell at the auction itself, but when we picked up our unsold items on the last day of the convention, one of the other sellers made us an offer to buy The Screamer directly from us -- which we were happy to do, as we had more than enough other stuff to bring home, between vacation purchases, our own luggage, and all of the things our 3 small children seemed to need, even for a short holiday.
Green is totally missing, so it could just be the output transistor for the Green drive has failed (TS712), and/ or the feed resistor to the Green gun has gone o/c (R723). It looks like from your measurements that supply choke (S723) is probably OK (double-check it, anyway).
If that turns out to be the case, I would replace all three RGB drive transistors anyway, as they are all of the same type, and a relatively inexpensive part.
Worst-case scenario: If your voltages are present and correct at each of the guns, and swapping the drives around doesn't yield any life out of the Green, then I'd suspect the CRT itself is faulty :/
Wow this does bring back memories ;). I had an a500 1988'ish, I had the A501 ( fast ram ) expansion kit too which was pretty nice ( a whole 1mb! ). From what I remember mine was one of the first with the v1.3 ACS Chipset/Kickrom.
Looking forward to see how this progresses
My first amiga was a amiga500 as well, with the 0,5Mb memory expansion. Later i bought a harddrive expansion for it, with 2mb fastram buildt into it. But sold it all to afford my amiga 4000.
I remember an arcade game I used to work on called Mad Dog McCree that used a laserdisc, an Amiga 500 and a genlock as it's main components.
I believe the Composite/RGB switch was for pairing with a Commodore 128.
Yes, I think this originally was meant to be used with the C128.
Excited to see another computer setup recreation series! I'm even lowkey inspired to hunt down the same model of Compaq Presario I had as a young lad in the late 90s 😁
"lowkey inspired" seems oddly fitting for that line of PCs ;)
@@silkwesir1444 lmao
Just started watching, but I love these kind of projects :)
I fix one of the 1084. There is a resistor that tend to break and disable flyback powerup. Resistor is R462. Also maybe flyback is fried or the HOT transistor is kput. Make sure you use the same package, I wrongly put one HOT with metal package and was short out with the aluminium. Use plastic package. Hope this tips works with you Jan.
I'm sure you'll get it fixed. Some good comments here as to where to continue. I have the Magnavox version of this monitor downstairs. It was on the curb here for trash pickup. I grabbed it, knowing they sell for well over $100 on ebay! Was quite dirty and with a good wipe down it looks great. The power button is also broken so I need to temporary fix it like yours. Need to test it.
Just keep the fire extinguisher close :)
Hi Jan, was there ever a part 2 for this? Did you manage to isolate the problem of the Blue Screen?
Se if you can swap colors on the cable between main board and driverboard, to be sure where the error is. From school about 25 years ago (wery litle practice since) i remember that the voltages on the driverboard was high enough to trigger faults in transistors that could not be measured by transistor or diode tester. Solution was to see where the signal disappeared (by scope or by swaping known good color channel with the one with error) and just replace components where signal got distributed .
I was thinking something similar. I'm really chickening out on measuring the voltages while the thing is running though. Maybe I'll rather end up desoldering the transistors and checking them in a component tester.
I used to be scared on CRTs but that's gone. I do wear rubber gloves and rubber shoes while working on them, just for the case that, but simply stay away from the high voltage transformer and that cable. That is the only part that you really want to avoid getting shocks from. All the rest is below mains voltage, might be unpleasant, but won't kill you that quickly.
Hi jan
Welcome back always good to see you
The sudden loss of power suggests to me the aging supply circuit is probably stressed. Try testing the voltage rails (especially logic voltages) for low resistance. While they are likely not shorted, they may be trying to push the supply too hard hence the sudden failure.
Hi Jan, I noticed that te adjustment pots on the neckboard are all very differently set and also some are near the extreme ends. I would suggest turning them all to the middle and work from there. Maybe they just turned down red and green off so to speak. Also measure the input stages of the rgb before they go to the neckboard while feeding fullscreen white picture and compare the values for the 3 components if all are similar than the inputs are ok, then check the inputs of the neckboard.... I had an 1048S once that had an faulty input stage in the composite in but rgb was still ok.
I measured the resistances of the pots but you may still be right. They might behave strange if voltage is applied. Definitely going to revisit the monitor when I have more time.
I own a Highscreen KP548, which is almost identical to the 1084 version you have there: Identical chassis, almost identical electronics board. The only difference is that is has no S-Video connectors, which makes it a bit less suitable for the Commodore 64. I plan to do some upgrades to this monitor and have already bought some parts. I want to install S-Video, upgrade the speakers to better ones, and replace the TDA4510 PAL decoder by a TDA4555 multi-standard decoder (the board is prepared for that). This should make it accept NTSC and SECAM signals too (but this depends on additional mods in order to be used, haven't studied this in detail yet).
The only tip I have now is that I would scan the board with an oscilloscope at various places in the RGB part to the CRT, see where there is a signal and where there is none. However, when I will start my upgrades I will have to study the schematics in more detail and perhaps I'll have a few more tips then.
By the way, the board in my monitor is suffering quite a bit from mechanical wear: You can bend it quite easy when it is mounted. Soldering joints have cracked or have even got loose from the PCB taking traces with them. I have done already multiple repairs on this and it is likely more will follow. Allthough I'm sure you have inspected the board closely, mechical damage is still something to look for on these monitors when there is a problem.
As it was suggested before my comment too, it's nice to connect the blue output to green then red pin of the tube, just to see, the tube is the problem. Also, I may would use a scope (preferably at least two channels) connecting the same point of the circuit at the "good" and one of the "bad" colour channels, starting from near the input circuity and following the schematics, going towards the tube itself. If the video signal is preferably white, it should have more or less same signal for R/G/B, so some can spot the first place where there is some major difference. But anyway, just an idea ...
Yeah, that definitely makes sense. I will revisit this repair as soon as I have more time.
37:08 C618 is toast, or very filthy. C617 and 619 look better, 617 might be toasted too considering the color variations between all 3
They look roughly like what failed inverter caps look like so I think they might be a part of the HF switching for the guns. 32:25 seems to suggest they connect the mainboard transistors to ground and C619 is the Blue gun
I took a picture of the schematic on Twitter and it's definitely green that's fully open circuit, red being high resistance it looks like.
I was looking at that cap too going "plz notice... plz notice..."
@@tbbw Considering how filthy that board is and how tiny those (tantalums?) are, i'm not surprised it blended right in
Definitely going to look into that. That would be an easy solution. :)
Bummer. I'd have given up on such a project a year ago but now I think I can fix almost anything (except SMT stuff - so fiddly). I hope to see a video with it working someday.
I hope to see it working again, too. Got some really good advice from people in the comments and via email so maybe I manage to fix it.
Great Video as always, Jan. Looking forward to the next part. :)
Hello Jan, when i was a kid and my dad had a big CRT television that we rented, the guy who we used to rent it from used to re gun the tube and that fixed the problem of funny colours.
Probably beyond my capabilities... CRTs still seem like black magic to me mostly, but I'm eager to learn. ;)
I think it is still more likely that it is the electronics than the tube. Tube damage you wouldn't expect so uniform over the screen. It could be the electron guns, but it is simply much more likely that it is a component on the board.
Awesome video ! What do you mean "if we enjoyed it".. of course we enjoyed it ☺️
The raster lines mean that the tube or flyback voltage is too high, lower the "brightness" or "screen" pot in the back of the monitor.
For the color, did you try to set the neck color pots?
For the shutdowns, change the capacitors in the primary power section maybe? I'm not an expert.
You see, what happens is that the capacitors are so dry that they can get shorted and that's why you lose the power (or some protection circuit may be getting triggered), to repair old CRT tv/monitors it's recommended to do a full recap, they will start failing one by one anyways and it can be dangerous if certain caps fail, like for example the bigger one that you find near the flyback, which can protect you against xray exposure. You may leave the bigger ones since it's harder for them to fail and get dry but you never know.
Hey Jan,
as someone later born and who's only ever seen an Amiga in the wild once back when, I wonder where I should jump into the whole Amiga thing. I have zero nostalgia for anything, I'm just curious about it and want to experience it for myself first hand as I got a thing for old computers and game consoles. Which model would you recommend me? I've seen that some models go for quite a lot on eBay, as do some of the upgrade cards. Besides running games on it, I'd like to be able to expand the hardware later on (with cheaper modern upgrades like flash storage for a hard disk, a Gotek, and maybe CPU upgrade boards) but I don't want to spend a whole lot initially really. Or should I just get one of the low spec'ed Amigas first that maybe aren't all that upgradable? How fragile are the custom ICs in there? I guess getting a broken machine is a risky thing, is it? I'm able to diagnose and fix complex electronic issues myself, but if there is no hope because replacement ICs aren't available for any reasonable prices, there would be no point in getting a broken machine to save money.
Cheers
The Amiga 500 should be a good choice. It is the model that sold most units, therefore it is not so rare, not so expensive and still has a huge software library. The A500 is from 1987, but chipset wise it is very close to the chipset of the original Amiga 1000 and thus also gives you a pretty good picture how revolutionary the Amiga was in 1984 by introducing a GUI, pre-emptive multi-tasking, blitters, and above all, the ability to display 4096 colours.
People consider the best Amiga the Amiga 1200 and it has a much improved chipset over the Amiga 500. There certainly exists a software library that runs on the 1200 and not on the 500. On the other hand, the Amiga 1200 software library consists of many games that we also saw on MS-DOS PC's and therefore is much better known to many people than the Amiga 500 software library. Most important: The Amiga 1200 is much rarer and sells for rather high prices, making it less attractive as an entry into the Amiga world.
@@danielmantione The amiga 1200 is also more difficult to repair if something is broken, as it use a more modern type of motherboard. Also if some or any of the chips/ic's are broken, you will probably need to buy another amiga 1200 to use as spare parts. Thats was my problem with my amiga 4000, finding spare parts. Amiga 500 however, sold so well that its easy to get. Even so, it is quite pricey for being that old, but it is the cheapest and most available amiga you will find. Everything else is just much more expensive.
Thanks for your replies, guys.
I'm used to pricey, I got two MSX machines. However, not Amiga level pricey. The A1200 currently sells for 300-400€ on eBay depending on extras. Even bare bones machines listed as not working go for 200€, which is fairly steep. The A500 can be had for 50-140€, so quite the difference. However, I worry that the same thing will happen that has happened to me before: that I get the entry level machine and later yearn for more: I got an MSX1 first, because I had gotten one handed down as a child and had nostalgia for it, but then later got an MSX2 additionally which is far more useful and rewarding. Virtually no good games run on the MSX1, they all require an MSX2 or better. So, it's not the same situation on the Amiga then, or is it?
I guess I'll see if I can score a working A500 for around 50€, which is around the price point I don't really think about having wasted money on a machine I will later replace anyways. I of course already have a monitor for it.
What about those desktop machines? I've read that some have extra blitter chips and what not, and there are of course the upgrade options with cards and CPUs for those. Would be neat, but unless I really wanted that video toaster thing I guess there is no real use for that, is there?
Yes, the Amiga1200 sometimes really sells for crazy prices.
The A500/A1200 situation is certainly not comparable to the MSX1/MSX2. There is a 5 year difference between both machines: The A500 was the dominating 16-bit game platform world wide for a few years and "must support". When the A1200 came on the market, the world had changed. There was still a lot of commercial pressure to make software compatible with the large A500 installed base, but at the same time, the A1200 was facing strong competition with the PC. It never sold well in the US, and only got moderately popular in Europe. Still good enough to develop software for, but it never did dominate the game market like the A500 did. Facts remains that the A1200 is a much more powerful machine than the A500.
I would ignore the desktops. They had the option of PC compatibility through installing a bridgeboard. We don't care about PC compatibility nowadays, I guess you have better ways to run old MS-DOS software. Further, indeed, you can install cards, but what cards would you want to install? Both the A500 and A1200 have an expansion port and there is quite a of hardware available for those, possibly even more than there were cards available for the A2000/A4000, so there is no need to worry that there is no way to expand an A500/1200. Also the form factor is a thing to me: The keyboard integrated case of the A500/1200 is a distinctive aspect of computer design back then. A desktop case speaks no design language to me, it is just a boring box of iron.
When looking for Amiga deals on Ebay, be sure to look specifically on Ebay.uk. There was no country where the Amiga was more popular than in the UK. Deals do not always automatically show up on other Ebay sites. Because the supply is higher, prices are lower in the UK. You sometimes have to negotiate a bit about shipping, but is seldomly a problem.
If you can get one, you really need a CRT tester to check the cutoff threshold of each electron gun. They generally have a rejuvenator setting which can bring back guns that have deteriorated from use. That is a temporary fix. All the TV repair guys I know here in the states that did that work (there's not much call fr it nowadays) used the Sencore CR70; "The Beam Builder". You could probably do a full recap as well. In the end, I know you're trying to recreate the old setup, but I think it's best not bother with a CRT and get an adapter for a 4x3 beige flat panel display.
Internal adjustment "Sub Brightness" is set too high.. Find it and back it down a bit to get rid of the raster lines. Also check the main board as well. Bet there some cracked solder joints there too.
I've seen a video of a guy rejuvenating tubes for arcade machines with a special device. Actually there are a bunch of videos on this topic. What this did is actually test each gun and then fixing color problems by sending a higher voltage to the affected gun, retested, etc. The neck board was removed and the device is connected to the tube. It came with a bunch of adapters for different tube models. There was a manual for the device containing all the voltages for the different tubes. Quite complex process. It might be interesting if there is someone who does this in Germany.
i think you have to measure the output of color decoding ic of the 3 colors with a scope.
Have a look at EEVblog #1020 - Is A $7 LCR / Component Tester Any Good? You probably won't get one from PRC in time for this project but good for transistor testing in future projects. I have one and it is useful. Usual caveats apply, it has its limitations, test out of circuit, use your own best judgement etc. But still worth having. Best of luck with this current project.
I actually have one of those cheapo testers. I'm definitely going to revisit the repair and try my luck with that when I have more time.
You could measure the resistance of the guns.. might show something.
The bright lines on the screen are flyback lines, and that means the anode voltage is too high. Someone probably turned it up during diagnosis. The shutdown might have been X-ray protection circuitry kicking in due to that.
Ah, no.. i see it's now off.. so i guess the primary fuse blew :(
It didn't actually fully turn itself off. That was just video editing and me pulling the plug when the tube went blank to prevent further damage. The x-ray protection kicking in makes sense. I'll definitely revisit this repair and measure more thoroughly.
@@JanBeta It's definitely worth checking the power supply output voltages before doing anything else. Naturally, dont measure the anode voltage without the proper test probe!!
“I got a Commodore 64 and he bought himself an Amiga 500”
That’s hilarious 🤣
It was like that in the family for a long time. I got my father's old computers when he treated himself to the next generation. That's how I ended up with a glorious 68030 Amiga 2000, too. ;)
The Scart port, is it there from factory? I've only seen these monitors with a 9-pin dsub for RGB.
Yes, it is there from the factory. Check this page:
gona.mactar.hu/Commodore/monitor/Commodore_monitors_by_model_number.html
... there are quite a few Commodore monitors with SCART.
@@danielmantione I'll be damned. I've never seen one here in Sweden, but they might exist I suppose.
Thanks for the link btw! I have a dead 1084s-d1 that has been on the to do list for far to long.
Hello. Mayby you have flap for this monitor for sale?
I've got that model (1084) and it's missing the front panel, can't tell you just how aggravating that is from an ashetics point of view for me. It's NTSC of course so no scart. Bummer it's shutting down now. Looking forward to you sorting it out (if possible). Mine has an annoying hum that seems to mostly go away once the tube warms up (makes me nervous though).
Isn't there someone making 3D printed replacements? Obviously not a perfect solution but I think it's more pleasing than a "naked" control panel on the monitor. The hum might come from some bad capacitors, especially as it goes away when warmed up.
@@JanBeta Thanks for the tip on the 3D prints. The one I found was about $30.00, I'll keep looking :). The other thing about the hum I should've mentioned is that it's only after I turn on my C128 that I hear it.
man. i'm trying to do the same. i have a 500, a590, but i need an 8833 'lips' monitor which seem to be unobtanium and a supra turbo 28mhz accelerator
What a pain in the ass Jan it may be the tube but I lack the knowledge to inform you further. Great Vlog as always 😁😁😁 Kim 😁😁😁 Merry Christmas🎅🎅🎅
yeah, you should just break out the oscilloscope, and measure the signal on the red and green trace route. and since some of this is close to high voltage, you might want to feed the signal directly as well to avoid turning the high voltage on. but also, your right about it haveing too many issues. so just scrapping it is an option as well. even if you get it working, it probably wouldnt live long before you have to fix it again. but then again, this is a classic monitor, the one that every amiga fan just loves.
I'm terrified measuring these things while they are powered on... I'm definitely going to revisit the repair and try my best but I might end up using it for parts (maybe fixing another 1084).
@@JanBeta Thats why im suggesting you use a signal generator, and feed low power signals in front of each component and measure it. You will have to move the point where you feed the signal from component to component since you use low voltage. If you have a signal generator that is. If not, it would be way to much work imo. Even with a signal generator it will take a while. Dont think anyone will be upset if you decide to use it for parts.
An Atari on a Commodore monitor? What's next? Cats and dogs living in harmony? lol
lol
The 1084 is not an ugly monitor, though she is a bit generic-looking. I wish more monitors were as gorgeous as the Commodore 1702
you probably need to turn the blue gun down seems set to high need an old tv pattern generator to readjust the raster.
CRT's scare the hell out of me. It's a shame, I have one or two and they work fine now but I know in the future I may need to work on them.
@iKarith Great advice and I'll do my best to take it on board when the day comes. Would love to get my hands on some thing like a SONY PVM in the future. I know there is also safety gloves you can get, have seen some TH-camrs use. Will be leaving it unplugged for some time with the power button on. I'll still be a little nervous :)
A couple of years ago, I was offered two 14inch PVMs from a local TV station FOR FREE and I declined the offer. I didn't have room at the time and wasn't really into retro computing yet. Still brings tears to my eyes thinking of that. :/
@@JanBeta Ive repaired alot of tv's. All crt. Seems nowdays no one cares about lcd repairs, they just buy new. I guess it's cause its cheap, or because theres always some new model thats better. But, at least i still have amplifiers i can repair and service. Got to admit im not getting rich doing electronic repairs, but i do like doing it.
Vielleicht hilft es ja, die Signale zumessen, die aus dem Mainboard an das Board an der Bildröhre gehen. Wenn es hier zu einem nachvollziehbaren Ergebnis kommt (mach mal das Bild weiß oder grau, dann sollten die Farben ähnlich verteilt sein), dann liegt der Fehler dahinter. Auf dem kleinen Board kann man vielleicht nur vorsichtig messen, weil dort die Spannungen so hoch sind. Man sollte sich vorher über die ungefähren Pegel im klaren sein. Vielleicht hilft auch ein sehr hochohmiger Spannungsteiler vor dem Tastkopf für das Scope. Tendentiell 10Mohm. Er muss ja nicht 500MHz Bandbreite haben. Und man kann ihn festlöten, damit der Tastkopf vom Scope einen festen Halt hat. Dann kann man auch mit der Hand von der Hochspannung wegbleiben. Ich habe keine Erfahrungen mit Farbfernsehern und den letzten S/W-Fernseher habe ich Mitte der 1980er aufgemacht. Ich kann also nur beim Raten helfen. Ich denke aber, dass man im Betrieb messen muss, um schneller an den Fehler zu kommen. Ein Trenntrafo am Netzanschluss des Oszi kann hilfreich sein, wenn der GND des Monitors nicht gegen PE referenziert ist. Also auch mal messen, bevor es am Tastkopf blitzt. Zur Vorsicht :-)
Another fascinating video 👍
This will be an interesting and teaching series I guess. When I am dealing with high voltage circuits, I am a bit afraid (ok sooo afraid) and wearing a plastic glove :-) By that I feel much more comfortable. You could also try.
Does that PlayStation have a Wu Tang sticker on it? Dang, would've never guessed.
If you cant get it to work, can i have the front flap? Mine works fine but the flap broke off. When I say "have" a mean Buy from you.
Oh, sure, if I don't find a use for the case you can have it. At the moment, I really want to have one of those monitors so I might end up buying one with broken flap and am going to need it myself then.
@@JanBeta Thanks, If you end up getting the newer shape 1084, i have an Almost pristine outer case for a 1084S-D stashed away in my garage, it's yours if you want it.
Although crt's are not my thing, as always, educational and your motivation is great
Eine weitere großartige Projektidee für dieses Jahr! Ich muss allerdings fragen, was hat jemand mit diesem Monitor getan, damit es jetzt so schlecht läuft?
Danke! Ich vermute der Monitor brach irgendwann zusammen und der Vorbesitzer hat einiges versucht, ihn zu reparieren. Das macht die Fehlersuche jetzt natürlich schwieriger, weil ich nicht weiß, was alles versucht wurde.
Zusammengebrochen? Der Gedanke macht mir Angst, dass er könnte. Es sieht zwar so aus, als ob ein gutes Stück gemacht wurde. Ich hoffe, du kannst es dann reparieren.
Does it do any good to discharge the CRT to a ground wire that isn't, in fact, grounded? I'm at the 11 minute mark and don't recall seeing or hearing about the monitor being connected to ground...
That’s absolutely fine, it behaves like a capacitor that is shorted to itself and discharges. No mains ground needed (the monitor isn’t mains earth referenced at all anyway).
Thanks Jan. As a lowly programmer, I still find electricity mysterious and magical, and temperamental as the gods of old.
model looks alot like a Tulip 14" Vga that came with my first 386 16Mhz PC.
I love the recreate theme.
Obviously fix the PSU first. Remember the first rule of troubleshooting: Thou shalt test voltages!
Oscilloscope is the exact too for the colour problem diagnosis. Put a colour bars test signal in (or even just a grey scale) and trace each R/G/B signal from the decoder chip to the drivers. Be aware though, it may be a "live" chassis PSU, which makes an expensive bang and smell when you plug an oscilloscope ground on to it. The scope ground needs to be floating.
Put a small amp into it, add another input and a matching speaker and turn it into a 1084s!
…if you manage to repair the rest, that is. The volume poti seems to be a stereo version, so you could isolate it on the board and run traces to the extra amplifier. Or maybe the built in amp IS stereo?
Keep up the good work!
Do you have RGB test pattern device?
No, unfortunately not. I think I am just going to use some test pattern software on an Amiga or something like that.
Nice job,jan!
Ttl rgb is for 80 colomn c128(cga)
Herrlich!💪 Darf ich mal fragen was du so beruflich gelernt hast vor yt?:D
Den Schaltplan eines 1081 hätte ich noch als beidseitiges A3 hier. Wenn es hilft.
Danke! Ist zwar weitestgehend der gleiche Monitor, aber ich denke, ich komme mit den pdfs ganz gut klar. Im Lab ist nicht wirklich viel Platz zum große Schaltpläne ausbreiten leider. :)
Jan did you also check cbm8bit.com/8bit/commodore/server/bombjack.org/browse/commodore as they might have better documentation to solve your problem, like pretty detailed service manuals for various commodore equipment.
Yes, checked that but it has the same version of the service manual I found. Still a great site! :)
I don't think you actually discharged anything. The chassis was not plugged into the wall or otherwise connected to ground. So when you connected the pin inside that round rubber thing to the chassis there was no path to flow towards ground.
CRTs hold voltage for several hours after they are powered off and unplugged. There really is no need to discharge them after several years of sitting idle with no access to mains voltage. That's why nothing happened, there was nothing to happen. [
I have a amiga in box. With monitor and tons of floppies. For sale
Great video. Thanks.
I don't think that the shock from an unplugged CRT can actually kill you.
@@hdfgjldfkgjdfklgd A capacitor is not a battery.
You can look at www.eevblog.com/forum/vintage-computing/commodore-1084s-p1-crt-repair/
the proof that you can hear pictures is the PS1 boot logo.
Break out a O'scope, lots easier to troubleshoot.
I will. I think I just chickened out because I'm afraid to measure anything on CRTs while running. I'll definitely revisit this repair when I have more time though.
I have a broken power supply board of a monitor and I am too afraid to measure it with a scope because I think I don't have proper knowledge and an isolation transformer. So I decided to stay safe at the moment. But I measured a lot if things with multimeter and still could't find the problem.
@@JanBeta Just stay away from the Flyback circuits and using a scope is easy.
@@JanBeta If your going to measure it live, you should be scared. That voltage is not to be fooled with. Also, might want to consider using high voltage protection gloves and shield. But i would recommend using a signal generator instead of measuring it live.
You have to use your scope. I think it's the backboard.
Moin,mein 1084 hat auch nach Jahren den Geist aufgegeben.. das Bild flackert..und nach 2 Minuten fällt das Bild komplett aus.. Power Lampe leuchtet noch,meine Vermutung..das vielleicht Kondensator hin ist..aber wie kann ich das Testen,hab nur nen stinknormales Messgerät zuhause..Hab schon im Internet gesucht..viele schreiben.. könnte auch am Zeilentrafo liegen..aber da will ich nicht ran..und Ersatzteil ist urschwer zu bekommen....muss ich mir echt jetzt nen neuen gebrauchten Monitor besorgen..bei eBay bezahlt man ja mittlerweile richtige Schweinepreise..vielleicht kannst du mir ja weiterhelfen,mfg Danny
Die Zeilentrafos sterben leider tatsächlich relativ häufig, aber wenn der Fehler erst nach einiger Zeit auftritt, sind lecke Kondensatoren auch eine mögliche Erklärung.
Ich kann aus rechtlichen Gründen leider keine Reparaturen machen, gibt aber noch old-school Radio/TV-Reparaturläden, die alte CRTs reparieren und häufig gar nicht mal so teuer sind.
You can not repair any thing with the bloody covers on it. Before it died I was going to say measure the voltage on the cathodes with contrast and brightness set to min.
Monitors are no worse to work on than high power audio amps.
I have been working on CRT monitors since 1978 and still repair them to this day.
Manchmal enthalten die alten Röhrenmonitore Asbest.
Is it just me, or does that original soldering look ham-fisted? Looks to me like they used way too much solder overall.
1084 monitors are expensive on ebay but can be found for nothing in local offers. If France it's not unusual to find some in working condition at 40€ but you have to pick it up. Here is a guy selling the entire configuration you are trying to set up for 90€ including the monitor. but you have do pay cash and pick it up. What about a little trip to France?
www.leboncoin.fr/collection/1533023639.htm/
Tours is a very nice town by the way. I am pretty sure they do chrismas ferries and things.
So these old monitors had sound? (Sorry I always only had a TV to use). That's better than pretty much ALL PC monitors.....ever.
procedure.. step 1 .. disconnect the tube base panel and check all tube base voltages.. they are on the schematic.... approx 90v on the cathodes.. and the first anode should be around 300v .. ?? the red screen with flyback lines at one point suggests there is something up there possibly also.. most likely the first anode feed resistor has gone high, and somebody has screwed around massively with the gun drive settings to try to cure that fault.. the most likely reason it's shutting down now is the first anode capacitor has gone more leaky.. it's probably the black electrolytic on the tube base board
Man you really need an oscilloscope
So why not use it?
@iKarith Its easy, just follow the signal route from the input to the output/crt cannon. However, its not safe to do this on high voltage. (when its on) You will need the schematics to see the trace route though.
Some clearer schematics for you:
www.devili.iki.fi/Computers/Commodore/C1084S/schematics/
Hat Disney schon Stress gemacht?
Das Dings ist putt, gib's mir :3
christmas bummer, a coal in your stocking
Well, it's turning itself off which seems to suggest multiple issues. I would consider it a lost cause. To me CRTs are a black art, or a blue art in this case...
I probably wouldnt see it as a lost cause, but i would see the age and state that its in a problem. If he fix it, it will probably not live long, before he gets another issue again. Only question is how much time he is willing to put into it.
Don't mean to sound like a party pooper, perhaps spending too much time on the diagnostics may not be the smartest option. Being in the electronics repair business, it's often cheaper and less time consuming to simply cannibalize another main board from an identical broken unit and be done with it in half an hour. Just my 2cents. ;)
And yes I know that it's getting harder to find these older 1084 monitor parts, but they are still out there, just gotta keep on looking.
At some point though, cannibalizing broken stuff is just thinning the pool of existing vintage hardware even further!
I think you have exaggerated a bit in discharging the screen, it is dangerous to try to remove the connector with the screwdriver.
weak crt...