[TechAssist] Re: Citizen 19" TV - JCTV1972SB - Dead After Lightning Storm

  • From: "majorthom@xxxxxxxxxxxxx" <majorthom@xxxxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Sun, 26 Jun 2005 14:11:21 -0700 (PDT)

Hi David,I looked & ng.I guess I'd either pulse the gate of switcher[never 
float it of course] or intermittently ground drain thru,say 100K resistor and 
follow the change thru SMPS.Good luck this fine Sunday-let me know
Pete
David Lessard <mr_fixit@xxxxxxxxxxxx> wrote:
G'Day Gentleman,

This TV is still quite new, October 2004 manufacturing date. Set came in
DOA after a lightning storm, found and replaced the following
shorted/leaky parts:

IC501 - Opto in SMPS - Internal LED shorted - Replaced with PC817 Opto
D517 - Zener - Marking B4.7 - Shorted - Replaced with 4.3V Zener
D515 - Small Glass Diode - Replaced with IN4148
Q507 - 2SC3198 - Leaky - Replaced with 2SC1815 (NTE85)
Q502 - 2SC3198 - B-E Shorted - Replaced with 2SC1815 (NTE85)

All these bad parts are in the SMPS/Opto circuitry. Still SMPS doesn't
fire-up at plug-in. I don't see any switching signal at gate of (main)
SMPS FET. +B is present (160VDC), HOT is not shorted, checked ALL diodes
and transistors in SMPS circuit. Not sure where else to start looking,
also not sure if zener marked B4.7 is a 4.7V zener, common sense tells
me it is though. Does anyone have this service manual? I really don't
want to buy a $40 manual for this $89 TV.

Thanks in advance,
God bless all of you!

David Lessard
Mr_fixit@xxxxxxxxxxxx
Alexandria, Ontario, Canada
K0C-1A0

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Peter Neal
Neal Electronics
1905 E. Wm.Cannon
Austin,TX  78756
 
 
 







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