Acoustic G60T Combo - No channel switching

[chrisofoz]

Hi Guys,

I was discussing this before christmas with 52 Bill, about my channel switching issues.
I checked the voltage on the footswitch and i have nothing. Good news is though the transformer is putting off the appropriate having voltage of near 65 volts in to that part of the circuit, its just not getting to the vactrols which control the channel switching on this amp.

So i have determined i have voltage before D1...looking at the pcb...and attempting to trace this design(what a doozie) i have tried all the diodes, and im getting 50v after D2 but nothing before D1.
cheers

chris

[chrisofoz]

just another quick note im getting nothing appearing on the 20 volt line that heads to the daughterboard with all the control knobs on it.

cheers,
chris

[Jazz P Bass]

In the future please identify which circuit you are describing.
The statement that you made above is confusing.
"So i have determined i have voltage before D1...looking at the pcb...and attempting to trace this design(what a doozie) i have tried all the diodes, and im getting 50v after D2 but nothing before D1"
Do you have voltage after D1 or not.

[Jazz P Bass]

Acoustic G60T Power Supply & Preamp Schematics

For the 20 volt supply to work D1 & Q1 must function.
Q1 is a 2N6474 NPN used as a pass voltage regulator.
The zener diodes (D3 & D4) set the base voltage.
C8 is a filter.
A fault in this circuit could be a random failure or it was caused by something wrong in the switching circuit.
(located on the preamp schematic)
The transistor of that circuit is the came. 2N6474.