Tektronix A6902A Isolation Amplifier schematics

[xantia_99]

Hi

I just got a Tektronix A6902a isolation amplifier and need a service manual to adjust certain things.
I already got the A6902B version service manual howewer but that got another  PCB and components.
I wish to calibrate it. I have done that to 95 %.  It works great however the outlevels differ between the channels.

Hope anyone could help

Best Regards