Marshall DSL 20CR

[Hump]

Gentlemen,
I have another uncooperative Marshall on the bench,and without a schematic I am lost.
There is no output on any channel or power setting,and no pop thru the speaker when checking B+ at tube pins. There is B+ which rises a bit when switching from low to high power,other than that I don't know where to go next. Does anyone remember when amps were easy to work on?

[Hump]

On follow up there seems to be no filament voltage on the PI tube,all others seem appropriate.