Nice !!.......thank’s for posting !Everything is original even the power tubes (Mullards) and preamp tubes (Brimar)
The main disconnect has been replaced and the standby switch, other than that it was all original when I got it.
Because it's going to be a "player" for me I did a full cap job (F/T)
Mains - 100uF+100uF
Screens - 32uF+32uF
PI - 32uF+32uF
Preamp - 32uF+32uF
Bias caps - 16uF
I also lightly modded it but kept all the original parts to put it back to stock if need be down the road.
1971 one great year for Marshall, always loved the sound of these amps with the laydown PT's.