Hello all --

I have a Sony KV-32XBR48 that was manufactured in October, 1997. The
problem is that the picture blinks on and off at about a one second rate.
The audio is constant, and the problem happens whether the video source is
from the tuner or a video input. One other symptom is that it seems to me
that the time for the picture to come on the first time is much longer than
it used to be, and when the picture first comes on, it only stays on for a
brief time, and stays off for quite a while. As the set warms up, it gets
to about one second on, and one second off.

I have spent a fair amount of time looking at the set, and what I see is
that the video signal looks good going into IC351 which is a Sony CXA2025 Y
chroma/jungle IC. The RGB video drive signals out of this chip change
directly as the picture blinks on and off. One other thing is that pin 26
of this same chip changes with the picture blinking on and off. This seems
to make sense since it appears to be essentially a flyback transformer
current sense. Both the picture on and picture off voltages at pin 26 are
much higher than the schematic from SAMS indicates it should be. The only
way I see for the voltage to get lower is to draw more current through the
flyback. The voltage I see is about 9 volts when the picture is off, and
about 8 volts when the picture is on. (I can get more precise readings if
that is helpful.) The SAMS predicted voltage at that point is 1.6 volts.

I have checked power supply voltages, and they seem reasonable. None of
them fluctuates with the picture on/off. I have resoldered the joints at
the flyback transformer, but no others.

Any tips at this point would be greatly appreciated.

Thanks in advance

Dave Miller
Tucson, AZ