[TechAssist] Re: RCA PTK169PGB mod#P52731WK
- From: "Damon" <DAMON101@xxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 15 May 2002 08:24:28 -0500
No Color , check CR4118 for less than 12 Volts.
80% vert deflection on a previously repaired Vert circuit could be CR4713
and CR4702 off pin 5 of IHVT (neg side of 26v supply), pin 8 is 26v to vert
op amp, it has l4702 and r4701 in parallel (10 ohm). Pin 7 of IHVT produces
a 90v h-pulse and connects to r4542 (5100 ohm) to cr4501 to pin 2 of
u4501....check cr4512 6.2v zener in parallel with this signal line (pulse
limiter/clipper).
Same 90v pulse goes to vert height pot r4522 to smd 4514 (51 k ohm) to
cr4502 to smd rt4501 (thermistor) to smd r4507 (910 kohm) to base of
darlinton q4506 which is the vert ramp limiter. The emitter then goes to smd
r4509 to pin 3 of vert op amp u4501.
Most likely failure is the vert supply diodes, also check cr4701 and c4703
on that same line as it supplies 200 v to the crt and may be loading down
the vert supply.
hth
Damon Brunger
damon101@xxxxxxxxxxxxxx
Telrad Electronic Services
Ft Wayne, IN 46815
----- Original Message -----
From: "Doug Keller" <dek@xxxxxxxxxx>
To: "TechAssist" <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, May 14, 2002 11:23 AM
Subject: [TechAssist] RCA PTK169PGB mod#P52731WK
>
> This thing has turned into a nightmare. To begin with, 9 months ago it
> was dead. Took care of that. Then intermittent vertical deflection. Then
> the black stretch adapter board had some bad solder joints. Now, it has
> only about 80% vertical deflection and no color. Does anyone have any
> idea as to what this may be now?
> Doug
>
> --
> Doug Keller "Don't be afraid to go after what you
> Wis-Kel Electronics want to do and what you want to be, but
> 101 Freeland Ave. don't be afraid to be willing to pay
> Terra Alta, WV the price"
> USA 26764
> 1-304-789-3165
> dek@xxxxxxxxxx
>
>
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