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

["John Conti" <contitv@xxxxxxxxxxx>]

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
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