Crate GX-40C schematic?

[jboots00]

Does anyone have a schematic? I have a very noisy one. Sounds like something is oscillating. I scoped the PS and I have several volts of ripple on both the - and + supplies and I don't know why. Isolated the preamp, changed filter caps, checked rectifiers, checked for intermittant cap shorts, bad resistors, cleaned and ohmed all jacks, switches, etc. Take the power IC's out and it stops. New power IC's and its back again. I'm at a loss without a schematic. Anyone run into this? Scratching my head and it hurts 'cause I'm thinning.

[pecorporation]

GX-40C Schematics.pdf

[Jazz P Bass]

Crate GX40C

It is possible to install only one output IC at a time?
Trying to narrow it down to one or the others circuit.

[bobsamps]

Here ya go.

Does anyone have a schematic? I have a very noisy one. Sounds like something is oscillating. I scoped the PS and I have several volts of ripple on both the - and + supplies and I don't know why. Isolated the preamp, changed filter caps, checked rectifiers, checked for intermittant cap shorts, bad resistors, cleaned and ohmed all jacks, switches, etc. Take the power IC's out and it stops. New power IC's and its back again. I'm at a loss without a schematic. Anyone run into this? Scratching my head and it hurts 'cause I'm thinning.

How's this? Ooop! Wrong model. Sounds like you got fixed!

[jboots00]

GX-40C+

Hey guys!
Thanks for your help and the schematics. Just for your info, I found two problems. D2 on the input measured fine on the diode tester, but turns out it was breaking down intermittantly and allowing the +10VDC to hit the input. Second problem was a faulty coupling capacitor (C35 or 36 if I remember) on the amp board. Just FYI in case you run into something similar. Thanks again!
JW

[mnow]

Hey Pecorporation, do you have the rest of the GX-40 schematic?
Lost signal between pre-amp and power-amp, thinking might be a DSP problem
But a roadmap would make it easier to trace.

Thanks

[pecorporation]

Sorry, I do not.
Have you tried plugging a guitar cable between the pre-amp out & power amp in to see if the signal comes back? The latching feature on power amp jack has been know to become open and fail to pass a signal.

[mnow]

GX-40C

Thanks precorporation.
Found some bad solder and a flaky insert jack.
Still don't know why Crate (aka Loud) doesn't have all of their schematics
available to their service centers.