[TechAssist] Re: Panasonic Pincushion Problem
- From: "Jim Myers" <jr.myers@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 13 Sep 2001 10:53:09 -0500
Jeff, the B+ voltage for Q753 is developed in the damper diode and pc damper
diode circuit, D558, D559 and/or one or more of the caps, C567 and C568
should be replaced. Also the coil L751 could be bad.
I once had a RCA with this problem and same type of circuit and the pcc coil
had overheated to the point that the core had melted and was oozing out thru
the windings. Replacement of the coil, the two damper diodes and the
accociated caps fixed it.
Jim Myers
jr.myers@xxxxxxxxxxx
----- Original Message -----
From: "Shoreline Electronics" <jstielau@xxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, September 13, 2001 9:15 AM
Subject: [TechAssist] Panasonic Pincushion Problem
>
>
> Make : Panasonic
> Model : CT27S18S
> Sams:3418
> Problem : Hourglass/Pincushion distortion
>
> This one is a real head scratcher! Grab your Sams and follow along!
>
> All signals look good up to the base of Q753.
>
> The collector of Q753 is only 5VDC. Fusible resistor R768 (10 ohm/2watt)
is
> ice cold
>
> We've lifted/check all resistors on the PCC daughter board.
>
> I've pulled every cap & diode between L751 & H-yoke return side (pin4).
>
> Unless we have a diode breaking down under load...I don't see what I'm
> missing here!
>
> Anyone had odd problems like this one?
>
> Jeff Stielau
> Shoreline Electronics Repair
> 125 Beechtree Lane
> Westbrook,CT 06498
> 860-399-1861 Voice
> 860-664-3535 Fax
> jstielau@xxxxxxxx
>
>
>
> Help make your TechAssist online repair tips
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