[TechAssist] Re: RCA CTC169 35" Audio hum in standby, thumps@ turn on
- From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 28 Apr 2005 20:20:45 -0400
*Audio hum* when the set is turned off*
16.7VA source was present on U1901 pin 2, but was down to 14 volts.
Connecting a jumper between these two points eliminated the hum and also
increased the 16.7VA source to 17 volts. Because the location of R1902 was
near filter capacitor C1918, C1918 was not getting the voltage either.
Repaired the open trace to R1902 and C1918.
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager / Parts Manager
Gemini Computer, TV, & Security Alarms
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxx
----- Original Message -----
From: "Webster's TV" <webstertv@xxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, April 28, 2005 8:02 PM
Subject: [TechAssist] Re: RCA CTC169 35" Audio hum in standby, thumps@ turn
on
> Phil,
>
> What about C4108(47m-50v) in base circuit of Q4101(chopper output). Have
had
> this cap cause thumping or popping in speakers when the unit is off.
>
> Dan Webster
> Webster's TV
> Shullsburg, Wi.
> ----- Original Message -----
> From: "Phil Bader" <tjanphyl@xxxxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Thursday, April 28, 2005 8:55 AM
> Subject: [TechAssist] RCA CTC169 35" Audio hum in standby, thumps@ turn on
>
>
> > Sorry, no model. Assisting another shop. He says with this 35" RCA
> > CTC169 chassis, when he just plugs it in, he hears a low hum thru the
> > speakers. When he powers the set up, he hears a thump (or
> > thumps).Otherwise all works OK. I said to look on the upright audio
> > output board ( the one with the outputs and jacks) and locate the small
> > lytic caps near the front edge, next to the audio out IC's heat sink.
> > These caps sually leak. Usually are about 47mfd@16V. Am I overlooking
> > anything else,or any other fixes for this hum/thump symptom?
> > Thanks,
> > Phil
> >
> > --
> >
> > Philip Bader
> > Jan Phyl TV Inc. (estab. 1976)
> > 3420 Recker Hwy. Winter Haven, Fl. 33880
> > Fax (863) 299-8821
> > email: tjanphyl@xxxxxxxxxxxxxxx
> >
>
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