[TV] Re: Zenith PVR5263RK - Need service manul and/or advice
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[TV] Re: Zenith PVR5263RK - Need service manul and/or advice
Rick. on the 5% resistors, you cant go wrong. Thats usually whats in there.
john
>From: Rick <rick@xxxxxxxxxxxxxxxxxx>
>Reply-To: tv@xxxxxxxxxxxxxxx
>To: tv@xxxxxxxxxxxxxxx
>Subject: [TV] Re: Zenith PVR5263RK - Need service manul and/or advice
>Date: Wed, 06 Apr 2005 17:25:27 -0700
>
>Thank you everybody who suggested this. I pulled the 120k resistor on
>the blue crt board and it was indeed up around half a meg.
>The other two were OK but since I took them out to check I just put new
>ones in.
>
>It looks like the original resistors were high tolerance. I only had
>1/2W 5% carbons on hand so those are what I used as replacements.
>Is the tolerance critical on these parts or am I OK?
>
>Next I think I am ready to attempt to converge the CRTs. Any tips on
>this process would be welcome. This is the first PTV I've
>repaired so this will also be my first time trying to converge. I have
>test patterns on the Video Essentials DVD including:
>Dots (both dense and not so dense), overscan, Snell & Wilcox, pluge,
>color bars, and a few others. I don't think I have not yet found
>a plain-jane crosshatch pattern but I have found a few lined patterns
>that look like they will do.
>
>Thanks,
>Rick
>
>John Conti wrote:
>
> >Rick, On the something wrong with the blue. look on the blue crt board
>and
> >check or replace r5102
> >(120k 1/2w) its either getting high in res. or getting ready to open. you
> >might also replace the ones on the red and green crt boards or they'll
>come
> >back to haunt you later.
> >John
> >
> >
> >
> >>From: Rick <rick@xxxxxxxxxxxxxxxxxx>
> >>Reply-To: tv@xxxxxxxxxxxxxxx
> >>To: tv@xxxxxxxxxxxxxxx
> >>Subject: [TV] Re: Zenith PVR5263RK - Need service manul and/or advice
> >>Date: Wed, 06 Apr 2005 03:01:49 -0700
> >>
> >>OK everyone, here is an update: Some things fixed, some things possibly
> >>not right...
> >>
> >>I took John's advice (below) and checked the voltage at the diodes. The
> >>mess was still there
> >>on the -26v diode so I replaced the diode and filter cap. The set was
> >>stable for a long time. I thought
> >>the problem was solved but eventually the "bounce" came back.
> >>
> >>I decided to check the +26v side and noticed that the convergence board
> >>was not getting +26v, but it was
> >>there at the diode. Blown fuse on the +26v supply. I hadn't noticed it
> >>before because the glass window was
> >>covered with a blob of adhesive. I determined that dead side of the fuse
> >>wasn't grounded out and jumped it with
> >>a fused ammeter to see what would happen. Current through the meter was
> >>not high so I jumped the blown fuse with
> >>a wire. Of course now the convergence POTs have significant affect on
> >>the TV compared with before. Also,
> >>the odd pulsating has not returned on the -26v supply. I let the TV warm
> >>up for quite some time and all seems well.
> >>There does seem to be some noise on the +26v supply, however, so I will
> >>replace it's filter cap.
> >>
> >>There's something up with BLUE, maybe someone has seen this before.
> >>When I pull up a PIP box or the menu, blue is missing from the vertical
> >>lines of any borders/boxes.
> >>If I go to the convergence adjustment setting in the menu, the two
> >>vertical lines are not white because there is very
> >>little blue in them. If I then turn off the red and green CRTs the
> >>vertical lines for blue are tiny slivers compared to the
> >>thick lines of R and G. Also on this menu all the text at the top
> >>("Press FREEZE to select the color...") is in blue only and
> >>is virtually unreadable because of the lack of vertical blue lines.
> >>
> >>Thanks everyone, I'll keep you posted...
> >>
> >>-Rick
> >>
> >>rick@xxxxxxxxxxxxxxxxxx wrote:
> >>
> >>
> >>
> >>>Thanks John,
> >>>
> >>>-26v is the line that pulsates. I looked at it on the scope last night
> >>>and it looks like it drops to ground potential for a split second, then
> >>>quickly rises back up and repeats.
> >>>
> >>>I will check the diode and perhaps filter cap esr and post results.
> >>>
> >>>Thanks,
> >>>Rick
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>>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
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> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
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> >>>>>>
> >>>>>>
> >>>>>>
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> >>
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> >
> >
>
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