Looks like I got the right plans, for some "pc506..." board.
Now it's about + 0.7 V DC out, for the speaker out port.
He says that value is ok, But it varies, and he can't figure out why.
When he cools the two "Differential steps", (called Q1 and Q2: "2122" or 4249?) one gets to plus + 2-3V, the other to minus - 2-3V.
It's some kind of balancing coupling.
The repairman cant figure out if it should be a difference on the two steps like that.
, if he should keep looking for a fault or stop there, since what should happen in the amp, with it's values etc, is not clear.
If someone knew?
He gets a 25V + DC at times
It's a -71-78 make amplifier module