QX8000A Hiss in right rear channel

[jd3rdcoast]

i have repaired this unit for a friend which had multiple burnt components on both amp boards front sides. Replaced most of the transistors on both amp boards front sides, new output caps and rebuilt the tone board. Getting a hiss out of the left rear channel.

I was wondering if could be an original driver transistor going bad or not liking paired with newer on with higher gain then originals. Also still have original Output transistors in Rear.

I’ll need him to bring it back to me to trace signals through the board. Any other suggestions to help speed up isolating the cause?

 

[john stumpf]

i dont know exactly what is SPECIFICALLY wrong,but i do know the thing probably needs a recap in total and has a lot of crummy (noisy) transistors through out. it doesnt answer your actual question but i'm willing to bet its got a lot to do with it. that said,even if you narrow down the specific culprit(s) today, whats to say that another part doesnt fail next week? if you pull the pre out jumper for the effected channel does it go away?