Tweet
Lucky me!
Marshall AVT150 had both TDA7293's blown, the ac feed resistors to the +/- volt regulators were fried, OD channel IC8 was bad due to the problem the static mod fixes.
So after fixing everything the -15v supply was being shorted by something but only when either one of two cables to the front board that supply it's ground were connected.
I removed the -15v regulator and pumped in -15v to find the problem, probably a bad chip I figured....BUT NO.
D109 which is part of the FX loop was shorted, and even while pumping 6 amps into the -15v supply to find the bad component, it still did not get hot.
Luckily I HAD THE SCHEMATIC available to track down what on the -15v rail was loading it down.
Yes folks always consult your local schematics.
heh heh.
Marshall AVT150 had both TDA7293's blown, the ac feed resistors to the +/- volt regulators were fried, OD channel IC8 was bad due to the problem the static mod fixes.
So after fixing everything the -15v supply was being shorted by something but only when either one of two cables to the front board that supply it's ground were connected.
I removed the -15v regulator and pumped in -15v to find the problem, probably a bad chip I figured....BUT NO.
D109 which is part of the FX loop was shorted, and even while pumping 6 amps into the -15v supply to find the bad component, it still did not get hot.
Luckily I HAD THE SCHEMATIC available to track down what on the -15v rail was loading it down.
Yes folks always consult your local schematics.
heh heh.
Comment