Ultimate Chorus

[Doc Stitches]

Fuse is good but nothing lights up or powers on. There is power to the switch.

I read the 12/27/2009 post and want to know where TB1 is located ? I do not see it.

I do see a TS1....is that what Jazz P Bass was referring too ?

Tracers for R175, R174, and C88, C89, and CR 68, and CR 69 all show signs of

excessive heat

Also the chorus depth pot knob is broken off and frozen so it won't turn.

Thanks
Doc

[nashvillebill]

Unplug connectors CP11, CP12, and CP13 from the circuit board. These connections come from the power transformer secondary. Now plug in the amp and turn on the switch. You should have AC coming from the transformer--measure the voltage from red to red wire (should be around 60 VAC), and then the voltage from each of the reds to the red/yellow wire (should be around 30 VAC).

If you do NOT have any AC here: measure CB6 to SB1 (the two black wires on the transformer). If you have 110V to the black wires, but no voltage on the red wires, the power transformer is shot.

If you do NOT have 110 volts going to the transformer, measure SA4 to SA1 (the switched side of the switch). No power between switch terminals 1 and 4, but power across terminals 2 and 5, the switch is bad. If 110 volts is between 1 and 4, then check that the jumper SA4 to TS1A is in place. Also check for the jumper between CP5 and TS1B. If these are in place, then measure TS1B to SB1. No power there means TS1 is open. (If all those check good, you must have voltage to the black wires, or else a jumper wire is broken internally)

If however you DO have voltage on the secondary of the power transformer (the two red wires and the red/yellow) then start looking for voltage after the rectifier diodes CR64 through 67.