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Sony KV27V36 picture problem

awehmann

Jun 28, 2012
2
Joined
Jun 28, 2012
Messages
2
Our Sony KV27V36 (purchased 11/1/97) has developed a problem with its picture. On 6/28/12 the vertical size of the picture shrunk to the top part of the screen, became somewhat fuzzy and then disappeared. I removed the back and tried poking things with a plastic rod. The picture temporarily returned when I poked the flyback transformer, but I now don't regard that as conclusive. I disassembled things to the point where I could examine the circuit boards and look for anything suggestive of a bad solder joint. I didn't find anything, so I put things back together, powered up and the picture was good for ~20 minutes, but then went bad once again. Having no 120 volts AC connected to the PS board for quite a while (days) may be of significance, in having the picture be good for that length of time.

I've since tried leaving the 120 volts AC unconnected overnight. When the set is turned on the picture is good for a minute or so and then shrinks vertically and eventually goes blank.

If I had full confidence that this is due a bad capacitor I might convince myself to invest ~$200 in an ESR meter that tests the capacitors in place--but I don't have such confidence. Reading online postings that appear to describe similar problems hasn't given me the confidence that I understand what is causing the problem.

I'm considering going back to poking at components with the back off once again, since that is a zero cost effort.

If the number of blinks of the red light on the front is significant, I counted 10 before the picture showed up (temporarily).

I'm close to deciding to replace this television--if I don't have the problem narrowed down any better than currently. Taking it to a repair shop for service isn't a serious consideration (the TV set is too heavy for one person to handle, it may be near "end of life", and the cost is likely to not be money well spent).
 

CocaCola

Apr 7, 2012
3,635
Joined
Apr 7, 2012
Messages
3,635
Ten blinks - Check Q8014 and Q8013 for shorts, leakage, or bad solder connections on the " D" board. If the transistors are bad, check R8051 and IC8005, also on the "D" board.

IMO I wouldn't waste much time, instead I would let it rest and move on... It's old tech and the picture quality is far inferior to even a cheap TV now...

If you are even considering spending $200 for a tool to help diagnose a problem, just spend the $200 and get a new TV, of comparable size... Same with even a consideration to take it to a repair shop, it's simply not cost effective any longer...
 
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