[TechAssist] Re: Sony KV32XBR96S (repeated audio amp IC failure)
- From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 22 Jul 2004 11:56:48 -0400
Thanks. I wouldn't wish this one on any of you. You are all aware that I am
at least vaguely familiar with Sony power supplies. See this response from
another forum but I don't think he is talking about the same power supply as
there are no mylar caps or fuse resistor in this one:
Always replace Q601,602, both VDRs, all the diodes 4 in some, 8 in others,
and the two mylar caps in series with the transformer primary, and the fuse
resistor. Disconnect the HOT , and plug the set into a variac set to 30 v
AC. With a scope, verify a 50 khz sine wave at the transformer primary. With
a DC meter, measure the B+ at the fuse resistor. DC at Q602 (E or C memory
fails) should be EXACTLY 1/2 the B+ Dc voltage. If it is not, other parts in
the Q601,602 circuit, especially the transformer are bad. If it is exact,
reconnect the HOT and try the set with series lamp. No shortcuts!
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager / Parts Manager
Gemini Computer, TV, & Security Alarms
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxx
geminitv@xxxxxxx
www.geminicomputertvsecurityalarms.com
----- Original Message -----
From: "Jim Myers" <jr.myers@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, July 22, 2004 11:38 AM
Subject: [TechAssist] Re: Sony KV32XBR96S (repeated audio amp IC failure)
> A couple of tips mention Q605 on the G board, you probably should look
> at that if you haven't already. Good luck on this one, sounds like a job
> none of us would want to be stuck with.
>
****************************************************************************
***************************************
> Since 1972
> Jim Myers
> Telrad Electronics
> Fort Wayne, Indiana
>
>
> Gemini Computer & TV wrote:
> > Update! Besides the audio amp IC (IC1401) being blown again and
replacing it
> > along with D1409, D1410, D1411, and C1407, I have found the following
> > defective components in the power supply and replaced them:
> >
> > Q603
> > Q604
> > VDR602
> > R623
> >
> > After replacing these and every electrolytic on the "G" (power supply)
> > board, when plugging in the set the relay starts to chatter repeatedly
and
> > Q603 and Q604 get very hot immediately and shortly thereafter short
again
> > (even with connector G5 disconneted for audio amp B+). this time
however,
> > R623 remains normal. I can't seem to locate why and I am spending far
too
> > much time on this set and the customer is very anxious to get it back. I
had
> > previously replaced C662 and C668 but as I indicated, all electrolytics
have
> > been replaced (again for some of them). Anyone have some sugestions?
> >
> > Bob Waterman, CET® #RI-28
> > Master Technician License #9109
> > Service Manager / Parts Manager
> > Gemini Computer, TV, & Security Alarms
> > (508)695-7302
> > (508)695-7769 FAX
> > geminitv@xxxxxxxxxxx
> > geminitv@xxxxxxx
> > www.geminicomputertvsecurityalarms.com
> >
> >
> > ----- Original Message -----
> > From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxx>
> > To: "Techassist" <techassist@xxxxxxxxxxxxx>
> > Sent: Monday, June 28, 2004 8:24 AM
> > Subject: [TechAssist] Sony KV32XBR96S (repeated audio amp IC failure)
> >
> >
> >
> >>I have a customer (who is an electronics engineer) with a Sony
KV32XBR96S
> >>who brought in his set (as he lives outside my in-home service area)
back
> >
> > in
> >
> >>January for a dead set condition. I had found the front audio amp IC
> >>(IC1401) blown with a hole in it. There were also other damaged
components
> >>as well that were replaced with Sony originals. Here is a list of those
> >>parts:
> >>IC1401
> >>IC1501
> >>D1409
> >>D1410
> >>D1411
> >>C661
> >>C662
> >>C668
> >>VDR602
> >>R623
> >>
> >>Everything was fine until the beginning of June when the customer once
> >
> > again
> >
> >>brought it in for a dead set condition again. This time I found and
> >
> > replaced
> >
> >>the following components with Sony originals:
> >>IC1401
> >>D1409
> >>D1410
> >>D1411
> >>
> >>I completed the repair on Friday, 06/18/2004 and let the set run
> >
> > continously
> >
> >>around the clock until he picked it up on Thursday, 06/24/2004. I had
> >>informed the customer that IC1401 once again had a hole blown in it and
> >
> > had
> >
> >>him check the external speaker wire connections to make sure that none
had
> >>excessive length of exposed bare copper at either end when he returned
> >
> > home.
> >
> >>The set ran great Thursday, Friday, and part of Saturday but then the
> >>customer states he lost audio for about 15 minutes, then lost the
picture,
> >>smelled burning, and the set returned to it's same old dead set
condition.
> >
> > I
> >
> >>just got off the phone with him and explained that it sounds like that
> >>IC1401 may have blown again but I am at a loss to explain the reason for
a
> >>repeated failure and that I would pose this question to my fellow
> >>technicians on the various email forums to which I am a member. So now
let
> >>me request your collective ideas!
> >>
> >>Bob Waterman, CET® #RI-28
> >>Master Technician License #9109
> >>Service Manager / Parts Manager
> >>Gemini Computer, TV, & Security Alarms
> >>(508)695-7302
> >>(508)695-7769 FAX
> >>geminitv@xxxxxxxxxxx
> >>geminitv@xxxxxxx
> >>www.geminicomputertvsecurityalarms.com
> >>
> >>
> >>
>
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> >
> >
> >
>
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