Peavey Butcher won't come off standby

[methodofcontrol]

i have a peavey butcher that won't come off standby. the switch itself checks out for continuity, so i'm assuming the problem lies on the board. R49 looks suspect to me, it's got some discoloration like it overheated and i can't get a reading on it. it's supposed to be 400 ohms, but if it went open or just drifted way up does that make sense that it would affect the amp's ability to come off standby?
thanks!

[Enzo]

Well of course. That 400 ohm 10w resistor is between plate and screen nodes on the B+. If it is open, no B+ to the screens or any of the small tubes.

And look below that resistor a little ways on the drawing. You have a powr LED that lights up whenever there is low voltage supply. But the status light is another LED driven by transistor Q1, which lo and behold is controlled by the presence of B+ at its base comiong down from that screen node which is no longer getting power because of the open resistor.

Replacwe the 400 ohm 10w, and be prepared to replace the power tubes. That resistor is stressed when tubes fail, just like any screeen resistor. When it burns out, it is a sign the power tubes may have croaked.

400 ohms is an odd value. If you don;t find it on the shelf, use a 390, which IS a standard value. Even PV sometimes installs 390 ohms when production quantities of 400 o hms are not available.