[TechAssist] Re: RCA CTC169PF PTV with power supply problems
- From: "John @ Myers TV" <myerstv@xxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 27 Aug 2003 07:25:55 -0400
Thanks Bob,
I'll check those out. Yes, I did use the oem parts.
John Myers
Myers TV Service Co. Since 1984
Alliance, OH
Voice: 330-821-6545
myerstv@xxxxxxxx
http://members.ebay.com/aboutme/tvguy07/
http://members.ebay.com/aboutme/threads_r_us/
----- Original Message -----
From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: August 26, 2003 4:08 PM
Subject: [TechAssist] Re: RCA CTC169PF PTV with power supply problems
First let's correct that chassis number to be CTC169PF. Next thing is what
did you use to replace that regulator IC (RCA original or generic)? I have
seen quite a few previous posts from some of the five forums to which I
subscribe and have seen other techs going nuts only to find out that they
had used generic subs (some are okay and other are not) which were the root
cause of the existing problem. Having said that, here are a few more
components to check out:
C4145 (1000mfd/35v)
C4311 (4.7mfd/50v)
CR4101
CR4119
CR4122
R4110
Q4109
Q4111
Audio amp IC (should be U1900)
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@xxxxxxxxxxxxxxxx
geminitv@xxxxxxx
www.geminicomputertvsecurityalarms.com
----- Original Message -----
From: "John @ Myers TV" <myerstv@xxxxxxxx>
To: "Tech-assist" <techassist@xxxxxxxxxxxxx>
Sent: Tuesday, August 26, 2003 2:40 PM
Subject: [TechAssist] RCA CTC69PF PTV with power supply problems
> RCA Model # P52721LV , Chassis # CTC169PF
>
> Hi gang,
>
> This set originally started with a bad HV splitter. I replaced that to
find
> that the convergance was extremely distorted. I changed the small board on
> the splitter with no improvement. A few seconds later the set went dead.
> That's when I began to pull the lightbox, to take to the shop. At that
> point, we discovered that a mouse had taken up residence in the
convergance
> section.
>
> Now, it's a month later, and I'm still trying to repair the power suppply.
> The output voltages from the power supply in standby mode are low, &
> pulsing. The VCC to U4101 (regulator IC) is fluctuating between 8-10V.
> According to the RCA Training manual, this indicates possible overcurrent
> shutdown.
>
> The manual also indcates that if I monitor pin 8 of the chip, while
> grounding the VCC, I should see the voltage on pin 8 rise a bit from Zero.
> I'm not; it is staying at Zero.
>
> Here's what I've done:
>
> I've changed C4118, C4102, C4104, & C4108. I've changed U4101, and CR4118.
> I've also changed the filter cap on the reg B+ line (C4141).
>
> The last thing I did was to totally desolder the secondary of the
> transformer (T4102). I did this figuriong that would tell me if something
in
> the set was loading down the supply.
>
> The symptoms remain; It still appears to be in overcurrent shutdown. Oh
yes,
> I've tried running the regulator from an outboard DC Supply. it runs fine
in
> that mode, and I have good waveforms all the way to the base of the
chopper
> output.
>
> Sorry for the length of this post. I don't often get this frustrated by a
> 169.
>
> I'm open to suggestions.
>
>
> John Myers
> Myers TV Service Co. Since 1984
> Alliance, OH
> Voice: 330-821-6545
> myerstv@xxxxxxxx
> http://members.ebay.com/aboutme/tvguy07/
> http://members.ebay.com/aboutme/threads_r_us/
>
>
>
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