[TV] Re: Zenith PVR5263RK - Need service manul and/or advice

["John Conti" <contitv@xxxxxxxxxxx>]

Rick, I'm sending this message again because I don't think it went through. 
But all I have left on this one is to check cr3419 and cr3420 and make sure 
you have a clean waveform. This is you + & -
26volts for convergence. somtimes these diodes break down under a load or 
the filters get dry and do not filter right and there is ripple.
good luck on this one
john

>From: Rick <rick@xxxxxxxxxxxxxxxxxx>
>Reply-To: tv@xxxxxxxxxxxxxxx
>To: tv@xxxxxxxxxxxxxxx
>Subject: [TV] Re: Zenith PVR5263RK - Need service manul and/or advice
>Date: Mon, 04 Apr 2005 19:07:32 -0700
>
>No dice...
>I pulled the two resistors and checked them out-of-circuit. They were
>within tolernce and physically look as good as new.
>Just to be sure, I measured resistance while accosting them with a heat
>gun (not a hair dryer, but a real heat gun).
>They both held up remarkably well.
>
>Thanks for the suggestion!
>
>John Conti wrote:
>
> >Rick, on the 9-1302 check two resistors, they are r3243 (110k 1/2 watt 
>and
> >r3244 (82k 1/2 watt)
> >they either change values or open up. They are located next to the 
>upright
> >board that stands vertical. I think your having the same problem that I 
>had
> >a few months ago and if so, drove me crazy before I located the problem. 
>Let
> >me know how you came out on this, for if thats the problem it will sure 
>save
> >others a lot of time.
> >
> >good luck
> >john
> >
> >
> >
> >>From: Rick <rick@xxxxxxxxxxxxxxxxxx>
> >>Reply-To: tv@xxxxxxxxxxxxxxx
> >>To: TV@xxxxxxxxxxxxxxx
> >>Subject: [TV] Zenith PVR5263RK - Need service manul and/or advice
> >>Date: Mon, 04 Apr 2005 15:14:05 -0700
> >>
> >>Hello, I have a Zenith 52" rear projection TV.
> >>Would somebody please help me obtain a service manual or schematics for
> >>this TV?
> >>I have tried from a couple of places but met dead ends.
> >>
> >>The problem I am having is hard to explain but I will do my best.
> >>
> >>What follows is a long account of everything I have observed and tried
> >>so far.
> >>
> >>First the convergence is way out of whack and although I get slight
> >>movement
> >>when adjusting the POTs on the convergence board, it's nowhere near
> >>enough to
> >>bring it back into whack =)
> >>
> >>Second, after the TV warms up, the voltage supplied to the convergence
> >>board and convergence amplifier
> >>(same circuit) becomes "unstable."  On a scope the line representing
> >>this DC voltage will begin to bounce slowly
> >>at first, then more rapidly (up to 2 or 3 times per second) and the
> >>amplitude of this oscillation increases.
> >>
> >>Since this distortion is in the convergence circuit, it manifests as
> >>picture movement on the screen and affects all three
> >>CRTs.  As the TV warms up and the voltage begins to drift, the top of
> >>the screen will bow down then bounce in time
> >>with the fluctuating voltage.
> >>
> >>I visually inspected all components, especially resistors, and did not
> >>find any obviously burned or otherwise expired components.
> >>Next I took a can of air used it to cool parts in suspect places.  I
> >>found a couple transistors and a resistor, all near each other, that
> >>when cooled slowed or even stopped the strange voltage fluctuation.
> >>Next I replaced the parts thinking they may have tired out, but the
> >>problem persists.  Now I suspect too much current is going through that
> >>section of the circuit for whatever reason and blowing air over the PCB
> >>only cures the symptom, not the underlaying problem.
> >>
> >>The front convergence board with the POTs has a Disable jumper to
> >>disable the convergence correction.  Setting this jumper will
> >>immediately stop the voltage oscillation.  Upon re-enabling the jumper,
> >>the voltage will be stable for a few seconds and then ramp back up to
> >>full oscillation.
> >>
> >>Disconnecting just the BLUE input to the convergence amplifier will stop
> >>the bouncing and then the red and green convergence adjustments have
> >>much more effect on the picture than with the blue input connected.
> >>
> >>Disconnecting the output coils of any of the RGB amplifiers stops the
> >>bouncing but probably only because of reduced current draw through the
> >>whole system.
> >>
> >>I replaced the STKs which solved nothing, but neither did it break
> >>anything.
> >>
> >>At this point I feel like I'm just shooting in the dark (and especially
> >>without a schematic).
> >>Somebody please help!
> >>
> >>-Rick
> >>-------------------------------------------------------------------------------
> >>To remove yourself DO NOT Email TV@xxxxxxxxxxxxxxx you MUST email
> >>TV-REQUEST@xxxxxxxxxxxxxxx with REMOVE as the subject.
> >>Sent VIA Tech Assist's email server- tv@xxxxxxxxxxxxxxx
> >>TV email Archives at: http://www.circuitwork.com/archive/TV/
> >>-------------------------------------------------------------------------------
> >>
> >>
> >>
> >
> >_________________________________________________________________
> >Don?t just search. Find. Check out the new MSN Search!
> >http://search.msn.click-url.com/go/onm00200636ave/direct/01/
> >
> >-------------------------------------------------------------------------------
> >To remove yourself DO NOT Email TV@xxxxxxxxxxxxxxx you MUST email
> >TV-REQUEST@xxxxxxxxxxxxxxx with REMOVE as the subject.
> >Sent VIA Tech Assist's email server- tv@xxxxxxxxxxxxxxx
> >TV email Archives at: http://www.circuitwork.com/archive/TV/
> >-------------------------------------------------------------------------------
> >
> >
> >
>
>-------------------------------------------------------------------------------
>To remove yourself DO NOT Email TV@xxxxxxxxxxxxxxx you MUST email
>TV-REQUEST@xxxxxxxxxxxxxxx with REMOVE as the subject.
>Sent VIA Tech Assist's email server- tv@xxxxxxxxxxxxxxx
>TV email Archives at: http://www.circuitwork.com/archive/TV/
>-------------------------------------------------------------------------------
>

_________________________________________________________________
Express yourself instantly with MSN Messenger! Download today - it's FREE! 
http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/

-------------------------------------------------------------------------------
To remove yourself DO NOT Email TV@xxxxxxxxxxxxxxx you MUST email
TV-REQUEST@xxxxxxxxxxxxxxx with REMOVE as the subject.
Sent VIA Tech Assist's email server- tv@xxxxxxxxxxxxxxx
TV email Archives at: http://www.circuitwork.com/archive/TV/
-------------------------------------------------------------------------------