[TechAssist] Re: RCA F35731MB CTC169JS6 - Shuts off when signal source is connected.
- From: "DAMON BRUNGER" <damoneb@xxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Mon, 30 May 2005 21:00:27 -0500
CR4118 Voltage is too low in RUN mode.....should be about 14V with a fresh
new one.
That may be affecting the operation of the Horiz FREQ, and I suspect the
lack of sync allowing it to run all day ,then crap out with a synced picture
indicates a possible HV increase when
synchronized.
Start with Cr4118 1st, that supplies 9V to video jungle which is associated
with H Sync.
Of course you did that already......so maybe the voltages on the SMPS supply
is off a little, which leads me to wonder if the 143V cap on the secondary
may be dried out....normally when they go bad, the voltage ACTS like it
floats....my digital voltmeter will read 139 then 147, then 157, then 139
then.......and it could cause shutdown I suppose.
And it could cause the Cr4118 voltage to float between 12 - 14 V also.....
I know the cap I'm talking about is 180uf/200WV or 200uf/180WV. It's located
right next to the Horiz heat sink close to the SMPS, real big tall cap. I
had to use a scope to see the bad waveform on that, and it caused my DC
digital voltmeter readings to constantly vary.
Damon Brunger
Telrad Electronics
Fort Wayne IN
----- Original Message -----
From: "al m" <ampm@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, May 30, 2005 7:56 PM
Subject: [TechAssist] Re: RCA F35731MB CTC169JS6 - Shuts off when signal
source is connected.
> What does the waveform look like on the HOT collector?
> Al Marquardt
> ampm@xxxxxxx
> Al Marquardt Electronic Repair
> 206 W Main
> Girardville Pa. 17935
> ----- Original Message -----
> From: "LeRoy Westlund" <llw@xxxxxxxxxx>
> To: "TechAssist" <techassist@xxxxxxxxxxxxx>
> Sent: Monday, May 30, 2005 8:40 PM
> Subject: [TechAssist] RCA F35731MB CTC169JS6 - Shuts off when signal
source
> is connected.
>
>
> > Hi members,
> > This set will run all day with raster only. As soon as I hook up a
signal
> > source (Antenna, or external input), it will shut off after about 10
> > seconds. Picture is beautiful, and all voltages from the power supply
read
> > normal, for that length of time.
> > When it shuts off, I have to unplug the power for at least 5 minutes,
> > before
> > my standby voltages will return.
> >
> > Parts replaced so far, with OEM part numbers :
> > Regulater chopper output. (200165)
> > Regulator IC (200419)
> > Regulator caps. (2.2 @ 100 195691),(15 @ 63 214756),(470 @ 35
190496),(39
> > @
> > 100)
> > Horz cap (.48 @ 250 197518), CR4118 (164589), C4703 (47 @ 250).
> > B+ cap (470 @ 180 200147).
> > Tested luminance buffer Q2906= OK.
> >
> > Voltage readings:
> > B+ = standby = 143.2 (Run = 138.2)(adjusted B+ standby for 140, no
help).
> > CR4118 = standby = 13.4 ( Run = 12.1)
> > Voltage Q4101-Base = standby = -.19 ( Run = -1.4)
> >
> > If I pull the CRT socket, set will run OK, and not shut-off.
> > Works the same on my 27" test jig in the shop, as it does hooked up in
the
> > home, to the original Yoke / CRT load combination.
> >
> > Would it be wise to replace the IFT at this stage of the game ? Customer
> > does not want to spend more then $200 for this repair. I may need to
> > refund
> > about $100-165, that I already collected. It worked for about 1/2 hour
> > when
> > I first took it back, but, it went out again after customer already paid
> > me.
> >
> > Anymore help on this would be appreciated.
> > LLW
> >
> > LeRoy Westlund
> > Westlund TV & Electronics
> > 97 North Main " I forgot,..to remember,..
> > Centerfield, UT 84622-0087 to forget "
> > Ph./Fax 435-528-3822
> > mailto:LLW@xxxxxxxxxx
> >
> >
>
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