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

[Rick <rick@xxxxxxxxxxxxxxxxxx>]

I'll post the 9- numbers in a couple hours (not near the TV at the moment).

I'm going to say "yes" to your question, however.  The left side has a 
signal board with all the inputs and a chip for the OSD
functions, the right side has the power supplies, etc.  I believe they 
are physically separate boards, although they're in a common plastic 
retainer so they look like one board at first.  Off to the right of that 
is the convergence amp board with the STKs and of course up front is the 
convergence adjustment board with all the POTs, mounted on a panel that 
doubles as an access door for the CRTs.

Thanks!

Star-Tech wrote:

>Hello Rick:
>
>               Not sure about this model but does this one
>have 2 boards on the bottom (sweep power on the
>right and signal board on the left) ?
>                                                         Greg Zumbro
>----- Original Message ----- 
>From: "Rick" <rick@xxxxxxxxxxxxxxxxxx>
>To: <TV@xxxxxxxxxxxxxxx>
>Sent: Monday, April 04, 2005 6:14 PM
>Subject: [TV] Zenith PVR5263RK - Need service manul and/or advice
>
>
>  
>
>>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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>  
>
>
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