Yamaha G50-112II DC Board

[ohmboy]

I have a Yamaha G50-112II amp that wont deliver a signal to the speaker. After reading all available posts on this amp I am left wondering why the amp I have in repair doesn't resemble the circuitry shown for the same model. The serial # is 1494 and the DC board in question reads as LC85010. As far as I know this amp is an early 90's model, a+b channels, reverb and a parametric eq. Some of the traces are actually missing where the ICs go. It looks like someone pulled them off when trying to crudely remove the vr/ics. Ideally, I would like to replace the board entirely with another loaded one. Anybody know where to get this board ? I would like to find the exact schematic for it too. HELP

[captntasty]

I highly doubt you will be able to find a board for this one - you could contact Yamaha:

Amps & Effects



Don't remember where I got this but:

[J M Fahey]

*If* your board has to supply +/-15V from +/- around 20V raw supplies, you might replace that with a couple 7815/7915 regulators. They would need only a couple of external components and be able to be built on veroboard or even with no board at all, just "dead bug" style.

[Enzo]

Well that schematic looks to be the one.

[ohmboy]

Thanks everybody for helping me out. This forum is awsome ! I must have scrolled right past the parts side diagrams yesterday. Got it today and yes it's the right one. Link to Yamaha support is just what I needed. (Hard to find elsewhere) Now I'm well on my way to fixing the problem with this amp. I'm new here and have to say this is a great resource for techs in the trenches...THANKS again. I have a library of PDFs too and will help others if I can. Ohmboy