Sony KV-20XBR Question

Hi Don I was just going to suggest that. Sony's had A LOT of cold solder problems. Is it vibration sensitive? Are you certain that it's that old? If it is the chassis I'm thinking of look at the three pin regulators especially. The first thing I would do is pull the chassis and resolder anything that looks suspicious. If the AVboard plugs in fromthe back and swivels down to remove check the connections on both boards, especially the mother board. Resoldering fixed a lot of them. Then try it again. You might get lucky. Let me know. Lenny.

I don't know what is wrong/right/different about my eyesight but I would consider it torture being placed in front of a pixelated screen rather than CRT for more than a couple of minutes. Every modern screen I've looked at (briefly) - anything moving across the image , judders across , in an intensely annoying manner . So I will will stay with CRT TV for as long as possible.

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There could be a number of causes of the problems mentioned. Lets start with the "simple" potential fixes:

1) Check the driver transistors on the board that resides on the neck of the CRT. Check for poor solder connections first. Check the transistors with a checker for shorts as well. These should be marked as R, G, B. 2) Check the solder connections at the flyback transformer. These often crystalize. 3) There should be 2 controls on the flyback transformer itself. One marked screen and one focus. Try working the screen one back and forth a bit. I have seen poor contacts inside these cause a dimming of the picture as well.

Perform the above and report back with the results. I will lok up the service manual for this model and post any additional common failures later today.

Dan

I'm betting on the CRT. This happened to my KV-1920.]

If it's a cold solder joint, a few minutes' work should fix it. If it's a bad drive circuit (not likely), a 'scope will show whether the signals are present.

One other point...

I believe a Trinitron has a single cathode. It's possible the cathode's emission has fallen to the point where you can't get a picture.

No - separate cathodes. I'm not sure, but I think the "one gun" description covers it's single focus element. It's possible that he has a red cathode failure. If the OP has access to a CRT tester, Trinitrons are checked in the same manner as any color CRT.

OP should reflow the CRT board and flyback, and check solder on all the TO-220 regulators he can find. After that, it's tracing with a scope.

Do you have an oscilloscope??

Do you have an oscilloscope??

and an isolation transformer for it of course

Yes, I have a scope, and isolation transformer. I do not have a CRT tester, but I've collected a fair amount of test equipment over the years. I will attack this problem soon. Thanks.

s

Yes, it's that old! I purchased it new in April 1986 - hard to believe it's been that long!

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Thanks to everyone for all of the responses. I appreciate it, and this will help me begin the process. I know what you mean regardless viewing TV on a CRT vs. a LCD. I agree. That being said, my daughter recently purchased a Panasonic 32" LED-LCD with a IPS Alpha panel. It's pretty impressive, and I can actually watch it without getting eyestrain!

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Thanks to everyone for all of the responses. I appreciate it, and this will help me begin the process. I know what you mean regarding viewing TV on a CRT vs. a LCD. I agree. That being said, my daughter recently purchased a Panasonic 32" LED-LCD with a IPS Alpha panel. It's pretty impressive, and I can actually watch it without getting eyestrain!