Thanks for the tips Leonard, I also match up the transistor by the date code and have went as far as measuring the EB junction on the diode check to match as closely as possible. I will check the duty cycle next chance I get to insure 50 %. I get one of these supplies every now and then ( usually on the 35" TV) that no matter what I change it still will over heat the regs and self destruct within an hour. you mentioned the transformer in the pws reading bad, what problem did it cause ( overheating or instant destruction). Tony Saracco TCS ELECTRONICS Elgin , IL 60120 847-695-1928 tcselectronics@xxxxxxxxxxxxxxxx ----- Original Message ----- From: "Leonard G. Caillouet" <lcaillo@xxxxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Monday, September 22, 2003 12:25 PM Subject: [TechAssist] Re: KV35S36 regs in thermal runaway > Tony, > > Check the duty cycle, it should be pretty close to 50%. IF it is not, look > to one of the components in the primary or try matching your transistors. I > buy them in batches and they seem to match up pretty well but mixing batches > can get you in trouble, even with Sony replacements. Generics are fine if > they are the Shindingen parts and not some copy. I fix dozens of these > power supplies (using Tritronics generics made by Shindengen just like the > Sony pars) and never have a recall due to bad transistors. Check all of the > caps and diodes out of circuit. Check or replace VDR601, especially if R622 > is open. I believe that one is a 430v rating. > > Look to the secondary, like a problem in the 9v regulator. I just had one > kill Q601,2 that had a shorted SI3090C (IC641). > > I also had one once with a bad T603. It rang good on all windings but I got > lucky and had one to compare it to that was reading differently. That was a > lightning damaged set and the only convertor that I have seen bad in a Sony > PS. > > Does it fail if you run the PS unloaded out of the set? > > Leonard G. Caillouet > Electronics World > Gainesville, FL > 352-332-5608 > 352-332-5668 (fax) > > > > > > ----- Original Message ----- > From: "tony saracco" <tcselectronics@xxxxxxxxxxxxxxxx> > To: <techassist@xxxxxxxxxxxxx> > Sent: Monday, September 22, 2003 12:11 PM > Subject: [TechAssist] KV35S36 regs in thermal runaway > > > I have changed the .47uf bird tird caps, .22uf blue caps, 2 - .001uf blue > caps ( basically all caps in primary side of reg circuit) statically check > all other reg components but Q 601 an 602 still over heat and die after 45 > min. I even tried making heat sinks with no luck there. YES i am using > generic C4834's but can get away with it most of the time without thermal > probs. Have tried both P's and M versions. > any advise or maybe a pws part # if it is still available, Not listed on > tritronix model part list. > > could use the SM if someone wants to Email it to me. > > thanks much > > Tony Saracco > TCS ELECTRONICS > Elgin , IL 60120 > 847-695-1928 > tcselectronics@xxxxxxxxxxxxxxxx > **************************************************************************** > * > 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/ > > ***************************************************************************** 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/