Zenith SR3587DT Sound OK, No Picture????
you may be right about not exciting the driver.
Here is what I have come up with.
There is 1.8VDC comming into the board through the cable comming from the
scan gen IC, and there is only .1VDC at the driver. and 41vdc at the
collector.
any ideas?
and there should be 5V p-p comming from the IC, but it might go through
resistors, dropping it down.
"Bill Jr" wrote in message
...
IS the frequency of that square wave accurate?
IS the amplitude sufficient to turn on the horiz driver transistor?
Bill Jr
"Mike" wrote in message
...
P.S., the heatsink on the QX3201 stays cool.
the other 3 in the chopper circuit get regularly warm, thats the only
one
that stays cold.
could that be something? it junction tests good.
"Mike" wrote in message
...
ok, I finally got to it.
All volteges are presant and none of the fuses are blown.
now, there was a pin problem.
Now, I set my scope up, and did some more testing on the tv,
the scan gen IS working. there is a square wave pulse on the pin 8.
there
is
a square wave pulse on the base of the horizontal driver transistor.
BUT,
there is NO DRIVE PULSE on the collector of the driver transistor. so,
i
guess its a bad transistor. I did some voltege measurements, and there
is
about 41VDC on the collector.
There is 158VDC B+ on the HOT.
I did a BtoC, and BtoE check in circuit on the transistor, and it
checks
OK,
but i never pulled it out of circuit.
Any Ideas?
"Q.E.D." wrote in message
...
Looking for input into whether this June 1996 build TV is worth
having
repaired.
TV has worked great since purchase in 1996. Never got a great deal
of
use...maybe 10 hours a week on weekends to watch mainly movies on
DVD
or HBO. I figure less than 4000 hours total use. Set had been on
for
about 4 hours one day and the picture just went blank...like someone
turned it off. No warning of trouble before that...no picture fade
or
blooming, it just went dark. Sound still works OK.
The TV is long out of warranty but due to it's light use I was
thinking it might be worth repairing. Can anyone give me an idea
how
much would be a fair rate for a repairman to come out and diagnose
(I
live in Philadelphia, PA)? What's an average repair cost on a 35"
set? I realize the repair costs would be on top of the initial
estimate depending on what is wrong. On that note, are my TV's
symptoms indicative of a common problem? Based on my novice
research
I think it could be a high voltage problem.
The neighborhood repair guy went out of business about three years
ago. Choosing a repair service, I'm finding, is almost impossible
to
decide on blindly.
Any advice would be appreciated.
Thanks
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