Citation TwentyFive

[The Judge]

Hi! I have a Citation 25 preamp and i have a somewhat weak output on Left out. I have replaced C501 and C509 because i had -0.43 volts at the - leg and 0 at the + leg.
On Right channel C510 there is 0 volts at both legs.
What may cause the voltage on C509 - leg?

 

[huggygood]

The 25 is known to have a number of problems with switches, maybe start there.