Sony KV-32V25 intermittant shutdown after flyback replacemen

[Mark Dahl]

I'm working on a Sony KV-32V25 TV which intermittently shuts down the HV
after the set has been on 2+ hours. Cycling the power immediately makes
things right until it decides to shut down again, tens of minutes later.
Note that I had a very difficult time adjusting the flyback screen pot
for a point between where the horz retrace was not visible and where the
HV would not shut down. I think it's just barely working thus the
intermittent action when it gets warmed up.

I'm wondering if I used the right flyback? The part I installed is a
1-453-207-11 (number taken from the SamPhotofact parts list) and it's
apparently a generic replacement, no obvious mfg id on it. The part I
took out I now see is Sony 8-598-969-00. I gather from some web
searching that these parts are equivalent but are they? Should I order
a 8-598-969-00 part and have another go at it or do any of you have any
sage advice for me?

Background:
This set just died one afternoon. Thanks to help gleaned from postings
in this group I found it suffered the classic Sony AA-2
chassis power supply death. I replaced the usual parts in the supply
(Q601, Q602, VDR601, R507) and the shorted HOT, checked for bad solder
joints in the horiz circuit, etc. but still had no HV. Played with it
long enough to blow up the sully again. Replaced all the previous parts
again along with the flyback and oh joy, now had a picture.

Thanks in advance,
Mark

 

[Jerry G.]

Look for high ESR caps in the power supply, protection circuit area, in the
scan gen area, and horiz output stage. Check the high voltage at the anode
cap (proper probe required) to see if there is excessive high voltage, or it
is on the edge.

It is very important that the original Sony parts are used especially for
the semiconductors. It is also better to use the original flyback as well.
Unfortunately it may no longer be available. You would have to check with
the Sony parts department. The Sony parts are select on test for proper
match. Generic replacement parts tend to fail in these sets.

After you are very sure that there are no high ESR caps in these areas, go
through the hold down procedure and the high voltage tests, as per the
service manual for your set. This is in the service set-up procedure. When
changing a flyback and you know for sure that there are no other defective
parts, it is important to check the hold down specifications, and that the
high voltage output is correct. If these parameters are out a little, the
set may do exactly what you are describing. The window of operation is very
narrow. This is mainly to protect against X-Ray emissions radiated from the
CRT due to excessive high voltage.

If the CRT is a bit weak, and is pulling a bit too much current, it will
also cause shutdown. This can be compensated a bit by offsetting for this
in the hold down adjustment. But, there is a possible safety factor for the
X-Ray emissions when doing this.

If the set-ups comply, then you may have a cold solder connection, or
something else. It is very common to have some problems or cold solders to
the leads of the horiz drive transformer in many of these models. It is
rare, but sometimes the horiz driver transformer can be intermittent
internally.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Mark Dahl" <markd@teleport.com> wrote in message
news:40160820.129A42E6@teleport.com...
I'm working on a Sony KV-32V25 TV which intermittently shuts down the HV
after the set has been on 2+ hours. Cycling the power immediately makes
things right until it decides to shut down again, tens of minutes later.
Note that I had a very difficult time adjusting the flyback screen pot
for a point between where the horz retrace was not visible and where the
HV would not shut down. I think it's just barely working thus the
intermittent action when it gets warmed up.

I'm wondering if I used the right flyback? The part I installed is a
1-453-207-11 (number taken from the SamPhotofact parts list) and it's
apparently a generic replacement, no obvious mfg id on it. The part I
took out I now see is Sony 8-598-969-00. I gather from some web
searching that these parts are equivalent but are they? Should I order
a 8-598-969-00 part and have another go at it or do any of you have any
sage advice for me?

Background:
This set just died one afternoon. Thanks to help gleaned from postings
in this group I found it suffered the classic Sony AA-2
chassis power supply death. I replaced the usual parts in the supply
(Q601, Q602, VDR601, R507) and the shorted HOT, checked for bad solder
joints in the horiz circuit, etc. but still had no HV. Played with it
long enough to blow up the sully again. Replaced all the previous parts
again along with the flyback and oh joy, now had a picture.

Thanks in advance,
Mark

 

[john]

Watch the resistor off the Black VDR
also look for bad joints at the Horiz Osc Transistor
and surrounding areas.
As a last resort get that Generic IHVT out of there
and replace with a Sony orig.
--
kip



"Watch the return E-Mail addy its false"
"Mark Dahl" <markd@teleport.com> wrote in message
news:40160820.129A42E6@teleport.com...

I'm working on a Sony KV-32V25 TV which intermittently shuts down the HV
after the set has been on 2+ hours. Cycling the power immediately makes
things right until it decides to shut down again, tens of minutes later.
Note that I had a very difficult time adjusting the flyback screen pot
for a point between where the horz retrace was not visible and where the
HV would not shut down. I think it's just barely working thus the
intermittent action when it gets warmed up.

I'm wondering if I used the right flyback? The part I installed is a
1-453-207-11 (number taken from the SamPhotofact parts list) and it's
apparently a generic replacement, no obvious mfg id on it. The part I
took out I now see is Sony 8-598-969-00. I gather from some web
searching that these parts are equivalent but are they? Should I order
a 8-598-969-00 part and have another go at it or do any of you have any
sage advice for me?

Background:
This set just died one afternoon. Thanks to help gleaned from postings
in this group I found it suffered the classic Sony AA-2
chassis power supply death. I replaced the usual parts in the supply
(Q601, Q602, VDR601, R507) and the shorted HOT, checked for bad solder
joints in the horiz circuit, etc. but still had no HV. Played with it
long enough to blow up the sully again. Replaced all the previous parts
again along with the flyback and oh joy, now had a picture.

Thanks in advance,
Mark

 

[David]

Very high probability that the crt is the problem. Very common on
that vintage 32" sony tube. Given the fact that you had a difficult
time getting correct AKB feedback when adjusting the G2 voltage and
the history of intermittent cathode shorts in that set, good chance
the crt is toast.

David

Mark Dahl <markd@teleport.com> wrote in message news:<40160820.129A42E6@teleport.com>...

I'm working on a Sony KV-32V25 TV which intermittently shuts down the HV
after the set has been on 2+ hours. Cycling the power immediately makes
things right until it decides to shut down again, tens of minutes later.
Note that I had a very difficult time adjusting the flyback screen pot
for a point between where the horz retrace was not visible and where the
HV would not shut down. I think it's just barely working thus the
intermittent action when it gets warmed up.

I'm wondering if I used the right flyback? The part I installed is a
1-453-207-11 (number taken from the SamPhotofact parts list) and it's
apparently a generic replacement, no obvious mfg id on it. The part I
took out I now see is Sony 8-598-969-00. I gather from some web
searching that these parts are equivalent but are they? Should I order
a 8-598-969-00 part and have another go at it or do any of you have any
sage advice for me?

Background:
This set just died one afternoon. Thanks to help gleaned from postings
in this group I found it suffered the classic Sony AA-2
chassis power supply death. I replaced the usual parts in the supply
(Q601, Q602, VDR601, R507) and the shorted HOT, checked for bad solder
joints in the horiz circuit, etc. but still had no HV. Played with it
long enough to blow up the sully again. Replaced all the previous parts
again along with the flyback and oh joy, now had a picture.

Thanks in advance,
Mark