[TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off

  • From: "Jim Myers" <jr.myers@xxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Fri, 3 Jan 2003 12:06:19 -0500

A tip from Philips sez:
SET WILL NOT TURN OFF AND WILL NOT CHANGE CHANNELS.
REPLACE IC351 AND/OR Y320, L357 AND IC350
Looks like you've tried everything else.
************************************
Jim Myers
Since 1972
Telrad Electronic Services Co.
Fort Wayne, IN 46815
************************************
----- Original Message -----
From: "D Thunhurst" <dthunhurst@xxxxxxx>
To: "TechAssist" <TechAssist@xxxxxxxxxxxxx>
Sent: Thursday, January 02, 2003 4:59 PM
Subject: [TechAssist] Magnavox RK5554, 27P1 ch....can't turn off



Hi,
This Magnavox is eating my lunch.  The set comes on at plug in.  The relay
is used solely for degauss.  The on-off circuit is controlled by the micro
and is giving me "0" volts in the "on" position and ".6" volt at turn off.
I have replaced Q430, Q431, Q432, Q433, Z430, R437, C435, and C436.
The schematic shows that the base of Q432 is connected to the micro and I am
getting the biasing on that transistor (marked as on-off switch).
This set is very sensitive to temperature.  When components are heated, the
set can be turned off.
A simple solution you say??  I thought so too!!
Every component I stated I replaced was because when I would place the tip
of the soldering iron just close to each of the various components, the set
would function properly.  Freeze the parts and the set could not be turned
off.
I even mounted the parts in question on the bottom of the board as not to
heat or cool any other part and thought to have confirmed the culprit.
After replacing the part or parts in question using OEM parts,  the same
symptom occurred,  even with the new parts, absolutely no change.
I am now at a loss as I have replaced or subbed every part that was effected
by heating and cooling. Now I know how a new born calf looking at a gate
must feel.
Any ideas or advice would be appreciated.
Thanks
Daryl
Daryl's TV
3310 Dyer St.
El Paso, TX 79930
915-565-9184
915-564-1024 Fax
http://dynacomp.freeyellow.com

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