reposting

Gobzo wrote:
Leonard:

Here are all the symptoms of the problem:
- The unit may start normal and work for days or may not start at all.
- Once on it may go off any time.
- While off the TV supplies power to the U3101 and buttons/IR sensor PCB.

I will try my best to describe what I diagnosed, but without schematics
my description will not be worth much, anyway this is what I did before
reading the FAQ:

- Traced the power button connection to the pin 5 of the U3101 and
checked that the signal reaches there.
- Checked all pins of that chip and figured that pin 6 and some others
will have two states consistent with pressing of the power button. I
came to a conclusion that the microcontroller was Okay.
- Checked that secondary AC on the power source transformer is rectified
and filtered to +147V at C107

Now I am at the point where I have no idea where the DC power goes, what
stabilizes it and what actually turns the power on and off. If I new
what pin of the microcontroller is used for switching the power, I would
be able to find what happens when the TV refuses to turn on.

I read the FAQ and found that I my problem is only briefly mentioned.
This unit had no tuner problems whatsoever: the picture is crisp and
geometry is good on all channels, sound quality is also fine. After
inspecting the soldering I could not find any problems at all. It looks
like the soldering problem has been fixed, can you confirm? The
manufacture date is 1997, which seems to be more recent than all horror
stories in the FAQ.

The idea of total resoldering does not sound like a good solution from
my point of view. This unit apparently has a problem with power and just
blindly soldering every joint may not do any good.

So does anyone here have schematics for this model that they could
share? I am pretty sure I only need the power source portion of it.

Any ideas and help appreciated.

Gobzo

Leonard Caillouet wrote:

"Gobzo" wrote in message news:3fa85db9_4@aeinews....

Post as much detail as you can about the diagnostics you perform and the
problem and you might get some help.