Obviously someone has modified the circuit to hide a problem, that 0.81R resistor should not be there. Pin 50 of U13101, the Syscon micro should be high to bias the base of Q11900 to turn the transistor on and keep the collector low. Pin 50 should toggle with the mute switch. Defeating the mute circuit is also what causes it to have a loud pop when turned on or off. This should NOT be ignored unless the owner doesn't want to spend the money for a proper fix. The CTC197 schematic does not uses proper logic state labeling, it shows U13101 pin 50 having 4.9 volts and is labeled "speaker mute" with no bar while pin 5 of U11901 is labeled "mute" with no bar and shows 24.6 volts. If pin 50 is high then pin 5 should be low since Q11900 is an NPN inverter. ************************************************** Jim Myers Since 1972 Telrad Electronic Services Co. Fort Wayne, IN 46815 ************************************************* ----- Original Message ----- From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Wednesday, December 31, 2003 9:26 AM Subject: [TechAssist] Re: Question Thomson technical help. I have searched all my resources and can't find anything except for Q11900 itself but I see that has already been replaced. The only resistors I see off the collector of Q11900 are R11904 (1K that goes to pin 5 of the audio amp IC and R11926 (15K that goes to +31VS source in parallel with C11907 (1uf). What is the reference number of this .84 ohm resistor you mention because it doesn't make sense to have that value resistor off the collector of Q11900? 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: "Paul" <dntwntv@xxxxxxxxxxxxx> To: <techassist@xxxxxxxxxxxxx> Sent: Tuesday, December 30, 2003 9:12 PM Subject: [TechAssist] Re: Question Thomson technical help. > I have posted the problem and haven't come up with a fix. It is an RCA ctc197A. There are apparently variations in this circuit because the collector of the mute transistor Q11900 has a .84 ohm resistor to ground and 0 volts. If I lift that resistor I lose the sound. Other circuits show 31v on the collector. The problem is a delayed loud pop in the sound when plugged in and also when turned off. I have replaced the mute transistor and a couple of caps in the supply for the sound. Several have tried to help and I am not unappreciative, but maybe no one else has had this problem. Paul > "Phillip R. Hull" <phil245@xxxxxxxxxxxxx> wrote:You may be able to get more help here. Whats the problem?? > > Phillip R Hull STET > phil245@xxxxxxxxxxxxx > FAX 517--569-3075 > Professional Technicians only > ----- Original Message ----- > From: "Paul" > To: > Sent: Tuesday, December 30, 2003 4:57 PM > Subject: [TechAssist] Question Thomson technical help. > > > > Have any of you used Thomson technical assistance recently? If so how > would you rate it? Both AFS and non AFS. I have not called them in a number > of years,but the last time as I recall it was rather expensive and they > didn't help with my problem. Paul > > > > Paul ,B > Central TV&Video > Grover Beach Ca. > > > > > **************************************************************************** > * > > Lost Password: > > http://www.tech-assist.org and select "Login Problems?". > > Email Archives: > > //www.freelists.org/archives/techassist/ > > > > > > **************************************************************************** * > Lost Password: > http://www.tech-assist.org and select "Login Problems?". > Email Archives: > //www.freelists.org/archives/techassist/ > > > Paul ,B Central TV&Video Grover Beach Ca. > > **************************************************************************** * > Lost Password: > http://www.tech-assist.org and select "Login Problems?". > Email Archives: > //www.freelists.org/archives/techassist/ > **************************************************************************** * Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/ ***************************************************************************** Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/