bias adjustment on a mackie 808s

[avsrjax]

Hi, folks. I just got an 808s backup and running. it was pretty burnt up. Does any one know what the bias should be set at? Channel 1 is running way two hot and channel 2 crackles at volumes past 12 o'clock. Thanks

[Jazz P Bass]

Here is the Service manual.

The problem on Ch 2 does not sound like a bias issue.

PPMsm.zip

[The Dude]

Agree with Jazz. The Ch 2 problem is not likely to be solved with a bias adjustment. You will probably find that out when you attempt to bias the channel. My bet is that it won't bias correctly.

[Jazz P Bass]

I have found out that the limiter ic (ssm2164) goes bad if, during a blowout, you lose one of the opamp supplies.
At high volume levels the failed ic can do all sorts of stuff to the output.
It usually is apparent more so with a load than without one.