[TechAssist] Re: RCA F35731MB CTC169JS6 - Shuts off when signalsource is connected.

LeRoy:
Pin 3 of the IC should be about .06V.  If it is high replace the emitter 
resistor for the Q4101 pn 200183 .18ohms 2w. and check SMD R4109 1K ohms 
and R4108 910 ohms.

Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, Fl.  32506-3310

Wayne@xxxxxxxxxxxxxxxxxxxxx
WWW.PensacolaTVRepair.Com

850-456-5995 voice
850-458-6369 fax


LeRoy Westlund wrote:
> Damon,
> The CRT is OK, cause I'm running it on a 27" test jig. I left the rest of
> the set in the home, where it was doing exactly the same thing.
> The resistors check OK off the emitter of Q4101.
> 
> You are right about "over currant" shut down being the problem, cause the
> voltage on the emitter of Q4101 is (.14) without a signal, and goes to
> ( .24 ) as soon as I connect the antenna on an active station. It should
> stay at (.14 ).
> Q2906 voltages are :
> E-No signal = 4.77 with signal = 4.33
> B-No signal = 4.71 with signal = 4.27
> C-No signal = .08  with signal = .18
> 
> 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
> 
> -----Original Message-----
> From: DAMON BRUNGER <damoneb@xxxxxxxxxxx>
> To: techassist@xxxxxxxxxxxxx <techassist@xxxxxxxxxxxxx>
> Date: Tuesday, May 31, 2005 7:25 AM
> Subject: [TechAssist] Re: RCA F35731MB CTC169JS6 - Shuts off when
> signalsource is connected.
> 
> 
> 
>><When it shuts off, I have to unplug the power for at least 5 minutes,
>>before
>>my standby voltages will return.>
>>
>>I have that happen when the SMPS goes into an overvoltage condition or
>>overcurrent condition....takes time for the SMPS Ic to reset.....when you
>>unplug the CRT it stops the overcurrent section from activating, and since
>>you can run the TV WITHOUT signal practically ALL Day....I think it
>>eliminates the overvoltage condition.....so you are getting overcurrent at
>>the SMPS, and since you have a GooD Picture...it can't be the CRT as far as
>>I know.
>>
>>You've been through this pretty thoroughly......just need to identify the
>>reason the PICTURE is causing your SMPS to activate overcurrent
>>circuitry.....how about those resistors on the SMPS output...the emitter to
>>ground resistors?
>>
>>I'm having problems believing the X-ray sense is at fault because it DOES
>>run all day, but it might be triggering....but I would expect you could
>>unplug it....wait 10 seconds....and it would start. Not 5 minutes.....that
> 
> 5
> 
>>minute wait just points to the SMPS overcurrent, plus the part about the
>>standby voltages not coming up. X-ray won't do that to the standby
>>obviously....
>>
>>Damon Brunger
>>Telrad Electronics
>>Fort Wayne IN
>>----- Original Message -----
>>From: "LeRoy Westlund" <llw@xxxxxxxxxx>
>>To: "TechAssist" <techassist@xxxxxxxxxxxxx>
>>Sent: Monday, May 30, 2005 7:40 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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