[TenTec] Need help with corsair ii

[nf4r at comcast.net]

I am told that my corsair ll has low audio while on the air. Was using my 705 
mic.,have also tried my heil mics,with same reports. Both of these mics work 
fine on my paragon. Corsair was purchased from a friend that had not used it for 
3 or 4 years. sn. is 580 02129. I am no tech but have used schematics to 
troubleshoot and did some homebrewing. Problem is I only have a foggy idea of 
what I am doing. Traced mic input to audio processor board and found u2a,on pin 
3 has 3.7v instead of .9 and pin 5 of u2b also has 3.7v instead of .9 and pin 6 
has 4.1v instead of 1.0. On u1 pin 5 has 2v instead of 0. This is where I get 
lost and foggy. I have replaced the vfo with the n4yg board but can't see where 
it should cause my problem. I know the small electrolytic 
caps go bad but not how to check them. This my first post so am sure I 
did not give all information needed. 
Thanks for any help or insight. You can reply to nf4r at comcast.net 
de nf4r Dave