[tvservice] Re: New Post--Fuse keeps blowing; Dead TV
- From: "graytv" <graytv@xxxxxxx>
- To: <tvservice@xxxxxxxxxxxxx>
- Date: Mon, 26 Apr 2004 10:06:25 -0400
Hi Russ
First thing I would do is disable the B+ to the flyback and sacrifice
another fuse.
If it doesn't blow then check the horizontal output transistor for a short.
If it's ok then you might have a bac flyback.
If the fuse still blows, then check the secondaries for shorts.
BTW, a good check to see if the primary side is ok, after disconnecting the
B+, is to check pin 1 of U4101 for -40v to hot ground. If that is good then
the regulator circuit is almost certainly (never say never), working
properly.
hth, Russ Gray, A+, Pres.
Gray's Electronics Inc.
201-C Commonwealth Blvd.
Port Orange FL USA 32127
386-322-0904 voice
386-322-3809 fax
graytv@xxxxxxx email
----- Original Message -----
From: "Mike Selnick" <selnick@xxxxxxxxxxx>
To: <tvservice@xxxxxxxxxxxxx>
Sent: Saturday, April 24, 2004 5:25 PM
Subject: [tvservice] Re: New Post--Fuse keeps blowing; Dead TV
> Thanks, Russ. Hello List members. My first time aboard. It's been
decades
> since I did TV repair work.
>
> I'm working on a 31-inch RCA GE 31GT659, Code 45104, Chassis CTC 186/7
> bought from Sears in Feb. 1996. Set is completely dead. Fuse f4001 is
> open.
>
> I replaced the 5A. fuse and 2.3-ohm 15-watt power resister r4001 and
plugged
> the power cord into 120VAC power. *Even before* I had a chance to turn
the
> set ON, the Fuse immediately opened and f4001 resister was very hot to the
> touch. A good on-line troubleshooter recommended (for similar model RCA
GE
> set) that ic U4101 (STK730-010) is probably shorted and should be
replaced.
> I tried that and burned up another fuse. I did quick ohmmeter checks of
all
> the diodes and resistors in the power supply and they look ok.
>
> Question: What jumps out as the most likely faulty component to replace
and
> how would you test it beforehand? ( B+ filter? Degauss relay k4201 or
> thermistor rt4201, Switch Mode xformer T4101, Hybrid Switch Mode Reg U4101
> ic, Closed caption filterQ3302?)
>
>
> ----Original Message Follows----
> From: "Hoyt's TV" <hoytstv@xxxxxxxxxxx>
> Reply-To: tvservice@xxxxxxxxxxxxx
> To: <tvservice@xxxxxxxxxxxxx>
> Subject: [tvservice] Re: New Post
> Date: Sat, 24 Apr 2004 09:36:29 -0400
>
> I think you have the honor of making the first post, Mike.
> I signed up for the list on March 21st and yours is the first I've seen
from
> it.
>
> Russ Hoyt
> Hoyt's TV
> Exeter, NH
>
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