Did you try pulling the plugs on the audio board? also disconnect the convergence and see if it comes up. al marquardt ampm@xxxxxxx Al Marquardt Electronic Repair 206 W Main Girardville Pa. 17935 ----- 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/ > > > **************************************************************************** * > Classifieds! Buy or Sell! > http://sell.tech-assist.org > The Tech Address Book: > http://www.tech-assist.org/secure/tip/contact.htm > Add a Repair Tip Here, or Change/Remove your Email Address: > http://www.tech-assist.org/secure/tip/main.htm > Lost Password: > http://www.tech-assist.org and select "Lost your Login Info?". > Email Archives: > //www.freelists.org/archives/techassist/ > > ***************************************************************************** Classifieds! Buy or Sell! http://sell.tech-assist.org The Tech Address Book: http://www.tech-assist.org/secure/tip/contact.htm Add a Repair Tip Here, or Change/Remove your Email Address: http://www.tech-assist.org/secure/tip/main.htm Lost Password: http://www.tech-assist.org and select "Lost your Login Info?". Email Archives: //www.freelists.org/archives/techassist/