Fender Stage 112SE BIAS setting

[Feufeu]

Hello at all.

I repair a Fender stage 112SE . The output transistors have blow.
I replaced them , (amp run on limter lampe for the moment).

when amp run with no load output signal is correct , but when i connect my 8R load ( no speaker, 8R300W resistor)
with our oscillo plug on the load, i have crossover distortion.

Amp run on automatic BIAS. no trimmer potentiometer for adjust...

How to ajust BIAS in this amp type ?

i joint the schematic

tanks in advance for your help, and sorry for my bad English i'm French .