Gary; Check that trim pot for bad solder connection. I see various Magnasonics in my database that point to this trim pot as bad solder connection on board. For intermittant shut down. VR451. -Ed- Ed Gaidies Tel-Tek Electronics Ontario-Canada teltek3@xxxxxxxxxxxx ----- Original Message ----- From: "Gary McCartney" <gary@xxxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Thursday, August 07, 2003 6:12 PM Subject: [TechAssist] Magnasonic TV model GCT5532 B+ not regulating > I have a Magnasonic TV model GCT5532 (unknown chassis no.) which I > replaced the HOT, shorted darlington B+ regulator transistor Q601 > (2SD1197), and an open 3.9 ohm 5W resistor also in power supply. The B+ > to the HOT will climb to 140V or more if I increase the variac AC input > up toward 120 VAC. The set works otherwise. I don't know exactly what > the normal operational B+ level is supposed to run at and I don't notice > any labels on the board specifying so either. > > I have checked all the resistors and caps in the regulator circuit plus > the 5.5V regulator IC651 (has 5.5V output). The 220 Ohm 20W bypass > resistor is ok. The B+ adjust trim pot tests ok and varying it doesn't > make any difference in the B+ output. > > THanks for any help. > -- > > > > > Gary McCartney > > McCartney Electronics > 7134 Fife Rd, RR 7 > Guelph Ontario Canada N1H 6J4 > Fax: (519)821-1530 > email: gary (at) number63.ca > > **************************************************************************** * > 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/