[TechAssist] [Fwd: partial fix, update:Re: update Re: Gateway Vivitron 21 (fcc# BGBTHN9105K) smoked,dead,was off-H.freq intermittantly]
- From: Phil Bader <philbad@xxxxxxxxxx>
- To: "techassist@xxxxxxxxxxxxx" <techassist@xxxxxxxxxxxxx>
- Date: Sat, 10 Nov 2001 11:34:12 -0500
-------- Original Message --------
Subject: partial fix, update:Re: update Re: Gateway Vivitron 21 (fcc#
BGBTHN9105K) smoked,dead,was off-H.freq intermittantly
Date: Sat, 10 Nov 2001 09:15:32 -0500
From: Phil Bader <philbad@xxxxxxxxxx>
Organization: Jan Phyl TV Inc. Winter Haven, Fl. Estab. 1976
To: Phil Bader <philbad@xxxxxxxxxx>
References: <3BD6FC1E.34112ACF@xxxxxxxxxx>
<3BD86BC5.3A4623DA@xxxxxxxxxx>
Replaced shorted 11 volt zener D528, FET Q521 (2SJ307) and HOT Q506
(C5244A). Seemed OK on test generator. Today I entered menu,tried to
increase H. Width more. The OSD goes from 0-100 but no change.( a very
slight linearity change) Its a bit narrow by an inch or so both sides.
It's not the inch, it is the fact I cannot change the H. width,
indicating still a problem. No schemo...PLease help. TIA, Phil.
Phil Bader wrote:
>
> Here's what I have found: The short in the HOT collector line was due to
> a shorted zener diode D528 (A-11 on body)Unsolder zener,short gone. D528
> is in the source lead of shorted FET Q521 (J307). So, I know I have a
> shorted Q506 HOT (C5244A),shorted Zener D528,shorted FET Q506 (J307).
> Don't know what else.Don't find any other shorts. I need to find the
> value of the zener diode,and if the HOT C5244A has a suitable sub.I
> think B&D has it @ $20.00! I assume the FET is a 2SJ307. Thanks for any
> input.
>
> Phil Bader wrote:
> >
> > This was an intermittant problem for a long time. Would go off freq on
> > 800x600 ( probably all modes,but this was his "working" res.)sometimes
> > work all day.Customer said last night it smoked and went out totally. I
> > see no heated areas top or bottom,or source of smoke/burnt areas. I do
> > have a shorted HOT Q506. Unsoldering Q506 collector lead I still get a
> > short on the collector trace on board (HOT is also bad). I think I have
> > a shorted FET Q521 at the middle of board. A row of FET's near HOT are
> > all OK (Q517,518,519,520)No scan caps seem shorted. Lytics are not
> > bulged,tho I havn't ESR'd them yet (Many).This is a bear to get into. Is
> > there any info on these bad parts or the orig. instability that must
> > have lead to this? TIA, Phil
*****************************************
Help make your TechAssist online repair tips
database better! Submit your fixes here:
http://www.circuitwork.com/techassist/tip/#tips
*****************************************
To UNSUBSCRIBE write to:
techassist-request@xxxxxxxxxxxxx
with unsubscribe in the subject line.
Other related posts:
- » [TechAssist] [Fwd: partial fix, update:Re: update Re: Gateway Vivitron 21 (fcc# BGBTHN9105K) smoked,dead,was off-H.freq intermittantly]
