Mesa/Boogie MARK 1 owner manual Tube Task Chart, Mark, View from above - looking down on chassis

MARK I		TUBE TASK CHART	NOTE: Before changing tubes, flip the POWER SWITCH to the off position or to STANDBY.
			CAUTION: Tubes are HOT when they have been in use.
	Partial View Of Chassis
			12AT7	12AX7	12AX7	12AX7

B

GRAY

REVERB

WHITEV

A	B A	B A	B A
4	V 3	V 2	V 1

B A

(Each 12AX7 contains two separate Triodes)

V 5

12AX7

6L6 6L6 6L6 6L6

PAGE 8

( View from above - looking down on chassis )	REAR OF CHASSIS
Description of Tube Functions
V1 A = Input 1 - Stage 1	V4 A =	Reverb Drive
V1 B = Input 2 - Stage 1	V4 B =
V2 A = FX Return Stage	V5 A =	Phase Inverter
V2 B = Final Pre-Amp Stage	V5 B =

V3 A = Tone Control Recovery Amp

V3 B = Reverb Return Stage