[TechAssist] Re: RCA TV model F32632SB chas. CTC187CN3 HOT runs hot[UPDATE]
- From: "Webster TV" <webstertv@xxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 24 Dec 2003 10:55:37 -0600
Phil,
Thanks for the info on R4402, I've had several 187's that have had this
problem also, but have used in stock 22 ohm resistors to replace R4402. From
now on I'll make sure I replace it with RCA original.
Happy Holidays!
Dan Webster
Webster's TV
Shullsburg, Wi.
----- Original Message -----
From: "Philip Bader" <tjanphyl@xxxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, December 23, 2003 2:00 PM
Subject: [TechAssist] Re: RCA TV model F32632SB chas. CTC187CN3 HOT runs
hot[UPDATE]
> Read my own post/fix from past similar situation:
>
>
>
> Subject: RCA F31672ETyx1 (CTC187CL2) repl. fly,HOT,etc.HOT runs hot.
>
>
>
>
>
> This RCA F31672ETyx1 (CTC187CL2) 31" TV had no pix/no sound,dead,just a
> squeel if plugged in. At shop, found shorted HOT transistor Q4401
> (#223942,BUH-517) and a cracked flyback T401 (223952,2G25028-B1B). I
> replaced these, as part of my own "CTC187 kit" of common failure parts:
> One HOT Q4401(223942),C4402(206008),CR4402(242907),R4402(22 ohm# 175374
> ,base HOT),CR4403(243636),C4407(218492), U4401 (STK730-150).The TV comes
> on with a good picture.After about 5 minutes I noticed the HOT was VERY
> hot to touch. I went back and replaced the 22 ohm resistor R4402 with
> the OEM part( OEM# 175374),and now HOT runs normally warm. I orig. used
> a standard out-of -the-bin 22 ohm.It maybe had some inductance due to
> type of manufacturing (spiral resistive coating?).But this aparently
> effected the HOT's bias! All well now. Please note that the actual fix
> was probably the HOT/Flyback.I just add the others due to known high
> failure rates,and some that are stressed when an HOT or fly goes.- Phil
> Bader
> Philip Bader, Jan Phyl TV Inc.
> 3420 Recker Hwy,Winter Haven, Fl. 33880
> voice/fax: 863-299-8821
>
> Gary McCartney wrote:
> >
> > Thanks to all the replies about this CTC187CN3 running hot. I have tried
> > all the parts suggested (except the flyback) with little or no
> > improvement. Because I can't afford any more time, I left the new parts
> > in and installed an extra heatsink above the HOT. Now after 9 hours of
> > running the set, the temperature is now only 36 deg. C. which is 20 deg.
> > cooler than without it. I explained the situation to the customer so
> > they know that a fault could reoccur in the future. They use the set in
> > the bedroom, so maybe it doesn't run many hours anyways.
> >
> > Gary McCartney
> >
> > McCartney Electronics
> > Guelph Ontario Canada
> > Est. 1984
> > email: gary (at) number63.ca
> >
> > Webster TV wrote:
> > >
> > > Gary,
> > >
> > > You've replaced the parts that I usually have luck solving the
overheating
> > > problem with, but I did have two other parts written down that could
cause
> > > HOT overheating, so I'll give them to you also. C4303 and C4709.
> > >
> > > Dan Webster
> > > Webster's TV
> > > Shullsburg, Wi.
> > > ----- Original Message -----
> > > From: "Gary McCartney" <gary@xxxxxxxxxxx>
> > > To: <techassist@xxxxxxxxxxxxx>
> > > Sent: Tuesday, December 16, 2003 4:45 PM
> > > Subject: [TechAssist] RCA TV model F32632SB chas. CTC187CN3 HOT runs
hot
> > >
> > > > This 32" CTC187CN3 came in with HOT shorted. I replaced with OEM
BUH517
> > > > and noticed the HOT heatsink was running at 59 deg. C. (approx. 138
F),
> > > > measured directly on top of the transistor on the heatsink- which I
> > > > believe to be too hot. I remember having a couple of these sets that
> > > > were running cooler than that, maybe 45 deg. C.
> > > >
> > > > I tried another OEM BUH517 - no help
> > > >
> > > > Also replaced the following:
> > > >
> > > > -C4306 .047 250V
> > > > -hor. driver transformer -with new one
> > > > -R4402, 22 ohm
> > > > -R4305 4.7K 3W
> > > > -CR4402
> > > > -CR4403
> > > > -CR4106
> > > > -C4403 0.55uF
> > > > -C4707 .041 400V
> > > > -C4409, 47 uF 35V
> > > > -C4402 .0157 uF
> > > >
> > > > I measure 139.2 V dc on cathode of CR4106 (B+)
> > > > HOT collector waveform is 1100V p-p no distortion noticed
> > > > waveform at base of HOT is 15V p-p and looks ok (manual calls for
12V
> > > > p-p but my scope may be acting up a bit)
> > > >
> > > >
> > > > Thanks for any help.
> > > >
> > > > --
> > > >
> > > >
> > > >
> > > >
> > > > Gary McCartney
> > > >
> > > > McCartney Electronics
> > > > Guelph Ontario Canada
> > > > Est. 1984
> > > > email: gary (at) number63.ca
> > > >
> > > >
> > >
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> --
> 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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