Marshall Schematic

[patlaw]

Is the bias supply still stock, ie standby mode deenergises HT AND bias?
Marshall had a decade long ‘lapse of reason’ in sending their 50 watters out like that.

It appears so. Since I don't have an accurate schematic, and since this is the first Marshall I've serviced, I assume it is stock. It does not appear to have been modified. The standby switch definitely removes the HT.

[Dave H]

Is the bias supply still stock, ie standby mode deenergises HT AND bias?
Marshall had a decade long ‘lapse of reason’ in sending their 50 watters out like that.

I had a 1986 wired like that. There was a huge current surge when switching from standby to play (as you'd expect) so I moved the bias supply input to the other side of the standby switch where it should be.

[drewl]

I think I did with my '73 50watter like in the 1st schem up top as I had it open recently to check something and bias comes up with the power switch.