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-   -   How to save a 1974 Trinitron (http://www.videokarma.org/showthread.php?t=270044)

Sealtest 01-24-2018 08:18 PM

How to save a 1974 Trinitron
 
Hello all, I have been messing with a trinitron that really needs to live. This unit is pretty rough and has a cataracted screen, but the cataract is minor and doesn't bother me at all. The main issue right now is that the screen does not fill up all the way. On the top and sides there are very large gaps of black. Does anyone know what is going on? It may also be me, but it seems that the flyback or something around it sounds strained. Also the speaker static is pretty weak.

Robert Grant 01-24-2018 08:47 PM

Sounds like it could be anywhere in the deflection, or (more likely), the power supply circuits.

Prime suspects are any of the electrolytic capacitors.

Popester 01-24-2018 08:59 PM

Let's see a picture. I've never seen a Sony CRT that had a cataract.

Sealtest 01-24-2018 09:28 PM

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What section of this unit do you think the bad caps are most likely to be? Since the flyback sounds a bit strained I’m guessing the power supply section. If the issue is deflection what do I do? Tv repair is a new hobby to me, but I repair anything no without a screen.

Hopefully my pictures attatched. I’m replying via mobile so it may have issues. I will have to pull my shoplight over to really show details, but the yellow sections are the cataract, ans there are hazy sections in addition to small circles of oxidation. I’ve seen more cataracted Sony trinitrons than anything else oddly enough, so hopefully my 1980 kv-1913 keeps on going strong.

Popester 01-24-2018 09:40 PM

Jug on this looks a little weak. This set will have filaments to CRT always energized. These sets were know for bad solder connections due to all the interconnect connectors. Can you get an image from an RF modulator on it? This was a fairly complicated set. I never got to work on colored Sonys when I was employed. Got stuck servicing all the B/W stuff and their Betamax products. Good luck. It's a really nice set when working.

Popester 01-24-2018 09:45 PM

Do you have any tv test equipment? It would be nice to see what a crosshatch pattern looks like. Count on replacing electrolytic so at the age of this baby. If jug has a decent grey scale it would make a great tv.

Sealtest 01-24-2018 10:40 PM

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I was able to sorta get a picture from it but the picture is quite awful. A picture should be attached to show what all is going on. I agree with this being a nice set. This thing may be horrifically beat and abused, and it’s sat in a mostly abandoned repair shop since 1998, but it really has a good feel to it. It has a more quality feel than any other tv sitting around here. Though the picture is skewed the color is very nice on it. If it’ll live it’ll have a permanent home here and will certainly get used every day. Fingers crossed


Unfortunately I don’t have any TV test equipment. I’m really new to this so I just have the equipment for working on vintage hifi equipment.

mbates14 01-25-2018 08:21 PM

Well if it was sitting in a repair shop previously, it likely came in with that problem. Could be capacitors, could be alot of things.

Electronic M 01-25-2018 09:04 PM

If the 'cataract' is only visible with the set on then it is NOT a cataract.

MadMan 01-25-2018 09:13 PM

To get a test pattern, I use a laptop displaying a fullscreen image of a test pattern -> VGA to composite converter ($20 on ebay) -> old VCR with composite input -> RF/Coax output.

But duck hunt works too. :P

Popester 01-25-2018 10:11 PM

Sealtest, I have the exact same set lol with a Sony KV-4000 sitting on top of it. Also a Betamax SL2000 and a TT2000 on it. Currently has Verticle deflection shrinkage and needs some recapping. It is the next project in line after getting my Sony 5-303W finished. When I worked at the shop this set had a bad CRT and the customer didn't want to fix it so the shop inherited it and I said I would buy it. Back then you could buy new replacement CRT's. I think they were new because they had a plant in San Diego way back then. Buy yourself a schematic from Howard SAMs. They offer downloads or paper versions. Start recapping vert and Horiz sections and power supply area. Your jug doesn't look that bad. These were fairly reliable when they worked. SG613 components could be a bear when they shorted out. So from what I see you already have a raster and tuner and video circuitry working so that's half the battle. Just keep going. Keep the forum updated as you have question and enjoy the project. Good to you. It's always great seeing old vintage stuff working.

Popester 01-25-2018 10:26 PM

Seal test, having a closer look at the picture it looks like you have the label econoquick on it. Econoquick meant that when you turned it off it was completely off. I must have a slightly older model as my CRT heater filaments always have power to them. That is why I just leave it unplugged. Do you get any smear of the video when you raise the brightness or picture controls? If you do, that usually meant the CRT was weak. Sony tubes aren't recommended for rejuvenation as they wouldn't hold up. Hope this all helps.

Sealtest 01-27-2018 05:15 PM

I seem to be getting behind on replying to these things. Some of us don't know how to limit themselves to one project at a time, so I have 2 benches full.

About this unit being in a repair shop, it may have certainly had an issue when it was there, but the owner of the shop had this set up as his personal tv up on a 5ft tall filing cabinet. It was positioned so it could be watched from where he always sat. It may have just had an issue he decided to live with.


In regards to the cataract, it is a cataract. With the screen off you can see the yellow in between the layers and small cracking spots here and there.


I have a sl2000 betamax as well, and it would be great with this TV once both are fixed. My tv is a 1974, what is yours?

When adjusting controls the smear doesnt seem to change at all, but I will mess with it soon.

I ordered some caps for the powersupply just to see how it all goes, but overall this TV has gotten better in some aspects. When it was powered up in the shop the black line was still at the top of the screen, but the tv would not pick up any input. After a Deoxit bath it started getting a picture, but you all saw the picture it gave.


If this thing needs a new tube it'll have to sit. Finding TV parts in rural Tennessee is impossible.

Popester 01-30-2018 09:40 PM

Sealtest, I'm not sure what year mine is, but it doesn't have econoquick like yours. It's still probably a 1974, but maybe earlier. I don't think this was a model in 1973 so I'm not exactly sure.

Sealtest 02-05-2018 09:46 PM

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Hello everyone, just an update on this tv. I rebuilt the multi-cap and replaced some power supply caps with no improvement. Despite that I happened to notice a bad looking resistor on the board to the right of the supply. Only issue now is finding out what the resistance is which is unlikely.


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