The diagram, shown in post 23, has some mistakes.
I checked part PB-300, single channel output boards.
- The connection from R324 and C303 to the drain
of Q307 is wrong, these are on the collector.
- "R311" appears two times, on Q310 drain read R307.
There may be more errors that I did not see.
Please note that the bord layout for Q304 and Q305 is for
a japanese bipolar transistor, but they installed the JFet
devices shown on the diagram which have a different pinout.
The circuitry of this output amp has no stable operation and
I will probably comment on it later.
The host for the diagram picture is not always available. I
can not upload it here again, because the file size is twice
of that allowed. Available from me on request.