[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

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
> 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
> the power cord into 120VAC power.  *Even before* I had a chance to turn
> 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
> set) that ic U4101 (STK730-010) is probably shorted and should be
> I tried that and burned up another fuse.  I did quick ohmmeter checks of
> the diodes and resistors in the power supply and they look ok.
> Question: What jumps out as the most likely faulty component to replace
> 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
> it.
> Russ Hoyt
> Hoyt's TV
> Exeter, NH
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