Sony TV KV32V36 powers off and back on

[John Smith]

Sony KV32V36 TV, it is a 32" model with top keypad. Turns itself off and
back on. When comes back on always to "Video1" input, which is default input
as I understand.

Problem is intermittent. May work fine for a few months, or start doing it
several times a day or even go crazy and switch it off and on few times at
once.

Was repaired 4 times by Sony without ever fixing the problem, TV is now
almost 6 years old and was doing it ever since I bought it.

No fault codes are stored in the processor, so out of 4 repairs Sony
replaced top keypad 3 times.

Repair tech. is saying that if it were a CRT or any other major component
problem processor would have stored the error codes.

Any ideas?



Thanks in advance.

 

[John Smith]

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[Jerry G.]

I have not worked on this model for a very long time. But, if you look
down the centre of the main board, I believe that there are a number of
voltage regulators in a row that are heatsinked to the top frame, using
a metal bar, or something like that. Re-solder all the pins on these.
Also resolder very well, the leads of the horiz line drive transformer,
that drives the HOT (horizontal output transistor). This is the small
transformer after the horiz line drive pre-amp stage that is before the
HOT.

Because you say that the set is going back to Input 1, this means that
something is doing a full reset. This means that the uPC is loosing its
supply, and thus re-setting. If this set is properly turned off and
back on again, it should come back to where it last was. In some models
of the Sony, there is a separate standby supply for the uPC. In your
model, I think that that the standby supply is part of the main power
supply. If this is so, this means that something is putting the complete
power supply in to protect, or it in itself is failing.

Also do an ESR test on all the electrolytic capacitors in the power
supply, the horizontal output stage, CRT board, and the vertical
deflection amp. I've seen problems with these in all of these areas,
especialy when these sets were getting old.

This is what I can remember that I used to do with these sets. If it
beyond this, then you will have a challenging job to find the fault. It
is able to be found, but you will need a lot of experience, and the
proper setup with the proper service information to find it.

--

Jerry G.
======

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