I have been replacing output ICs for many years and have never believed this to be true. There are cases where it makes sense to change both. If I can identify the bad one and there is no other reason to change the second, I don't unless the client chooses to do so. In the Sony sets, some can be impractical to troubleshoot to a single chip. Others, like the ones with the two 4278s on the same heat sink, require both because removing one without removing the other is not possible and damage to the pins inside the chip is likely when getting them off of the heat sink. I have never found the second chip to fail anytime soon after replacing the first in the sets where we replace only the defective. Leonard Caillouet Service Manager Electronics World Gainesville, FL ----- Original Message ----- From: "Kevin's TV Repair" <kevintv@xxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Tuesday, July 26, 2005 4:01 PM Subject: [TechAssist] Re: STK 392-110 testing I believe that if one STK fails that the other one is not far behind. Another shop told me that Sony always says to replace both. Their experience (years ago when the STK's were $90 each) of replacing just one to save money ended up having the second STK fail after just a few months. My question is, what percentage of the time have you replaced the STK's and found it was something else causing the convergence problems? Thanks. Kevin Wilks Kevin's TV Repair Penticton BC Canada kevintv@xxxxxxx -----Original Message----- From: techassist-bounce@xxxxxxxxxxxxx [mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of Larry Sent: Tuesday, July 26, 2005 9:39 AM To: techassist@xxxxxxxxxxxxx Subject: [TechAssist] STK 392-110 testing over a few months i have replaced many stk392-110 sin pares, but probably only one was bad. also replaced and found it was no help to the convergence problems. i am sure 75% of these are good. is there any way to check them. the ones i know are bad i have scrapped, but now i have a box of used and probably good ones also. i have tried resistance readings compared to a new one and they are identical. but i dont trust them, even though some new ones seem to last shorter than the old ones. It bothers me to just always replace the stks every time i have convergence problems and then end up finding something else later. How can they be tested??? Larry -- Schneider TV & Electronic Inc. 5415 N. Wooster ave. Dover, Ohio 44622 www.geocities.com/schntv2000/ 330-343-0768 FCC. first class & Extra class K8WLY ------------------------------------------------------------------------ ----- This Email List is Public. Remove: http://www.tech-assist.org/remove.htm Set Vacation mailto:ecartis@xxxxxxxxxxxxx?subject=set%20techassist%20vacation Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/ ----------------------------------------------------------------------------- This Email List is Public. Remove: http://www.tech-assist.org/remove.htm Set Vacation mailto:ecartis@xxxxxxxxxxxxx?subject=set%20techassist%20vacation Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/ ----------------------------------------------------------------------------- This Email List is Public. Remove: http://www.tech-assist.org/remove.htm Set Vacation mailto:ecartis@xxxxxxxxxxxxx?subject=set%20techassist%20vacation Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/