[TechAssist] Re: Sony KV27FS12, chassis BA5 - still too much width
- From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Mon, 23 May 2005 08:03:39 -0400
SYMPTOMS
Unit has what looks like severe pincushion problem with horizontal
compression on left
side of screen.
Pin amp adjustments have very little effect.
CAUSE
Unit has what looks like severe pincushion problem with horizontal
compression on left side of screen. Pin amp adjustments have very little
effect. e parabola signal normal at pin 2 of IC501 and varies in amplitude
with adjustment normally. R513 or R551 will overheat depending on position
of horizontal centering switches. Found both L503 and L504 shorted. part
number 140667711 for both. replacing these restored normal operation. found
several cases of this problem and it may well affect other BA-5 and
possibly BA-4 chassis with this circuitry.
RESOLUTION
Parabola signal normal at IC501/pin 2 and varies in amplitude with
adjustment normally.
R513 or R551 will overheat depending on position of horizontal centering
switches.
Found both L503 and L506 shorted. Replacing these restored normal
operation.
Found several cases of this problem and it may well affect other BA-5 and
possibly
BA-4 chassis with this circuitry.
The nominal resistance of the good 10 mh coil is about 15.3 ohms on the
Fluke 83.
The bad ones read between1.5 and 1.9 ohms with the Fluke 83 meter.
SYMPTOMS
D504 keeps shorting out.
RESOLUTION
Found the EW pulse from CN2006/pin 5 was not getting to the pin drive. This
pulse is supplied to Q501(base) Pin drive. If this pulse disappears D504 can
short out.
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager / Parts Manager
Gemini Computer, TV, & Security Alarms
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxx
----- Original Message -----
From: "KENNETH BARNES" <KENNYB928@xxxxxxx>
To: "techassist" <techassist@xxxxxxxxxxxxx>
Sent: Sunday, May 22, 2005 2:15 PM
Subject: [TechAssist] Re: Sony KV27FS12, chassis BA5 - still too much width
> Sony KV27FS12 chassis BA5 - problem: still too much width. Original
problem was: dead. Replaced flyback, HOT, IC301, IC502. All other
functions OK. Tried to adj H Size but get no response. Do not have a
diagram with wave forms or voltages to check. Checked out Q503, Q504, D506
and other components in pin circuit. All ok. L503 and L506 also ok. I
need to know voltages in pin circuit. Appreciate any help and/or
suggestions. TIA. Kenny
> Kenny Barnes TV
> 928 S. Marshall St.
> Boone IA 50036
> Ph 515 432 5250
> Email: KENNYB928@xxxxxxx
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