Power Amp calibration (Morris MBA-85EF)

[saint gillis]

Dear all, I'm repairing this old big combo amplifier called Morris MBA-85EF.

I have retro engineered the PA section, as I'm not a power amp specialist, I'm asking the forum for some help and good advice.
How would you trim VR3 and VR4 ? And what's the purpose of L1 ?

 

[saint gillis]

https://groupdiy.com/threads/morris.86951/ (for anyone who owns of them)

 

[saint gillis]

Q6 was burnt, I've put another one, there's still something putting too much current across it..
Any thought ?

 

[saint gillis]

Schematic updated, I corrected few mistakes
I think I'm going to adapt a Fender solid state Deluxe on this, this circuit looks weird