JoshAZ
New member
I have been working on my dad's qr 949. The first problem was the relay not engaging. I first swapped out 2sa726 with matched ksa992s, 2sc869 was changed out with ksc2383yta, and 2sc1451 with ksc3503.
After that I reinstalled the amp and adjusted the bais and offset voltage. I found that one channel the offset was at 1.5 volt and would not adjust lower them 1.4v. I then measured the resistance of c6 .47uf 35v tantalum capacitors one showed a resistance of 9.3k ohms and the other 3 the resistance was around 270k. The capacitor measured .34uf. So once I changed out that bad cap I finally got the offset down to 0v...
Now the only parts I need is a scope motor and a mpx transformer Atm-011-0 and it will be about ready for my dad to use again. That's unless he wants me to recap it and it will a few more weeks of fun!
After that I reinstalled the amp and adjusted the bais and offset voltage. I found that one channel the offset was at 1.5 volt and would not adjust lower them 1.4v. I then measured the resistance of c6 .47uf 35v tantalum capacitors one showed a resistance of 9.3k ohms and the other 3 the resistance was around 270k. The capacitor measured .34uf. So once I changed out that bad cap I finally got the offset down to 0v...
Now the only parts I need is a scope motor and a mpx transformer Atm-011-0 and it will be about ready for my dad to use again. That's unless he wants me to recap it and it will a few more weeks of fun!
