Good evening from the south east coast of Pennsylvania...I found my first Marshall in the snow behind the music and arts store across the intersection from me...an ham-fistedly assembled MG series with reverb. I resoldered a bunch of stuff and it still sings! But I have a brother-in-law amp issue; his little 5501 bass amp needs volume and gain pots replaced for looseness and scratchiness and dead spots. I can't read the hand-written copied-off schematics I see online: what are the pot values? Backs of the pots reveal nothing; haven't got close to the circuit board yet to see if it's stamped there, as I'll have to desolder the speaker leads. Just wondering...Thanks!!!