[TechAssist] [Fwd: fix !Re: Zenith SG5749BG (9-754 smps,9-959 main) dead,no +5V stby]
- From: Phil Bader <philbad@xxxxxxxxxx>
- To: "techassist@xxxxxxxxxxxxx" <techassist@xxxxxxxxxxxxx>
- Date: Mon, 14 Jan 2002 12:05:10 -0500
-------- Original Message --------
Subject: fix !Re: Zenith SG5749BG (9-754 smps,9-959 main) dead,no +5V
stby
Date: Mon, 14 Jan 2002 12:04:16 -0500
From: Phil Bader <philbad@xxxxxxxxxx>
Organization: Jan Phyl TV Inc. Winter Haven, Fl. Estab. 1976
To: Topics of interest to consumer electronics repair professionals
<CONSUMERELREPAIR-L@xxxxxxxxxxxxxxxxxxxx>
References: <3C3C7ABD.25AEFC96@xxxxxxxxxx>
I checked at the 5 volt stanby regulator on signal board IC6002 3 pin
reg (221-166) zero volts at input. Traced back to source at
power/deflection board 9-754 to a shorted power diode on a heat sink
near front: CR3411 (GI 037A, 103-360) TO220 case. Replaced with salvage
from another board.Also changed the associated electrolytic at it's
output, CX3440 (470 mfd@25V) it was leaking fluid.Unit working,has 5V
stby now. Zenith said change CR3407 and C3407 very common
failure.Did,tho both were OK and did not help.
Phil Bader wrote:
>
> last month I recapped both boards of the usual bad blue lytics.A dozen
> or so. Customer said came on with "power failure" warning, now
> dead.Cannot turn on. All fuses OK, has +105VDC at coll of HOT, at some
> points on chassis has+33VDC, +75VDC ,etc. Noticed has no +5VDC standby
> on any of the large chips like micro,the I/R reciever,etc,hence no start
> up. I assume the main SMPS is basically working. Where does the 5V
> standby originate? My first starting place...Thanks.
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- » [TechAssist] [Fwd: fix !Re: Zenith SG5749BG (9-754 smps,9-959 main) dead,no +5V stby]