"Shoreline Electronics" wrote in message
. com...
Do you have a voltmeter? Measure the collector B+ on the Horizontal
Output.
Careful! 130VDC and 1100V AC on there!
I have an HP 971A DMM that is rated to 1000V Ac and DC. Are you saying that
the collector of the HOT is at 1100V AC or 130V DC (or 1100V AC riding on
130V DC bias?).
I also have poor man's scope - a Tektronics 2510 multichannel waveform
analyzer - basically a very primitive multichannel data logger. It is
limited to +-100V AC and the sample rate is very low (maybe 50ksps).
I've also got a copy of the Sony training manual for the AA-2/BA-3 chassis.
Sadly my EE degree is 25 years older than the TV in question, so it may not
help much.
Mike
--
==========================
Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)
========================
"J. Michael Milner" wrote in message
...
"b" wrote in message
oups.com...
J. Michael Milner wrote:
My 1997 vintage KV32S22 died completely during the final moments of
the
AFC
playoff game last month. After reading this group and a bunch of
googles, I
decided to give repair a chance. A few minutes with a meter showed
the
common failure mode of a shorted HOT (Q502) that killed the PS
choppers
(Q601 &Q602) and the fusible resistor (R607). I replaced the failed
transistors with quality OEMs and R607 with a Sony OEM. I removed,
cleaned,
and resoldered the HDT. The set now powers up, responds to the
remote
(on/off, channel up/down, volume, mute, etc.), and provides sound but
no
picture. The standby blinks at a constant rate which I understand
means
a
bus problem or IK issue. Since the remote functions, I'm assuming
the
issue
is IK.
I don't have an Oscope but I'd like to continue down a repair path.
If
the
IK issue is due to a bad tube (common on the 32" sets like mine) I
guess
it
means a new TV. Any easy way to test this? If not, what do I check
next?
Any "most likely" part replacement for this condition?
Mike
if the picture was ok before the set died, then why do you think the
tube is suddenly to blame? I dont think that is likely. This could be
a missing voltage ( open resistor?) somewhere in or near the power
supply. did you move the crt neckboard? are all cables in the right
position after reassembly?
-B..
I didn't see the picture tube as the set died (turned away during a
commercial or time-out) but the picture was OK up to then. The tube
being
the initial source of the failure is just a guess based on what I've
summarized from google searches - 32" tubes seem to be a weak link for
this
vintage of Sony TVs. Since the tube isn't a quick or cheap fix, I'd
like
to
rule it in or out before investing more in the repair process.
I did remove the crt neckboard as well as the anode cap to free the A
board
from the chassis so I could get it to my workbench to do the parts
replacement. I've double-checked all the wire harness connections but
I'll
triple-check again.
I see where the G board can be tested in isolation on this model so I'll
first check all the resistors and then see what the voltages are (one
hand
in pocket).
Any other suggestions?
Mike