Sony ,How to test a VDR

[Charlie East]

Working on a Sony kv32s20, Had the clasic symptom , Q601, 602, H-out
shorted, R607 open. replaced parts and blew them again., Resolder H drive
trans and the transformer. Replaced parts with a kit Which included the
VDR.601.Check all the secondary output from T605, no Shorts, Check H-out, no
shorts.ESR caps ok.None of the regulators show a short. So I plug in at
70VAC while monitoring B-+ to H-out. B+ was at about 70 VDC., As I was about
to check the other voltages , R622(10 ohm fusable in series with VDR601)
smoked. Unplug quick, but not quick enough.This time only Q601 shorted,R607
did not open and the h-out is good
I checked the VDR and it reads 28 ohms, Compared to the old one I had
removed which read open, The # on the new one wasV10241U, the # on the old
one is 10431U,
So now I am wondering if the kit had the wrong part, Any way to test these
things?

Charlie
ceast@bellsouth.net

 

[Mark D. Zacharias]

We've seen lots of substandard semiconductors, including those "Sony" kits.
(I'm not the TV guy in my shop)

Others with more experience on these might disagree, but I think running at
70 volts might have been a problem. I think I remember hearing that you need
to get these up over 90 volts pretty quickly.

Mark Z.



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"Charlie East" <ceast@bellsouth.net> wrote in message
news:9GUwb.2453$17.161@bignews6.bellsouth.net...

Working on a Sony kv32s20, Had the clasic symptom , Q601, 602, H-out
shorted, R607 open. replaced parts and blew them again., Resolder H drive
trans and the transformer. Replaced parts with a kit Which included the
VDR.601.Check all the secondary output from T605, no Shorts, Check H-out,
no
shorts.ESR caps ok.None of the regulators show a short. So I plug in at
70VAC while monitoring B-+ to H-out. B+ was at about 70 VDC., As I was
about
to check the other voltages , R622(10 ohm fusable in series with VDR601)
smoked. Unplug quick, but not quick enough.This time only Q601
shorted,R607
did not open and the h-out is good
I checked the VDR and it reads 28 ohms, Compared to the old one I had
removed which read open, The # on the new one wasV10241U, the # on the old
one is 10431U,
So now I am wondering if the kit had the wrong part, Any way to test these
things?

Charlie
ceast@bellsouth.net