Yamaha G50-112 Schematic Needed

[Metalmorphic]

Hi This is my first post. Can anybody tell me how to get to the pots on my Yahama G50 112 so I can clean them? There is a board (PA1 Board, from the schematics I've seen) covering where the pots would be. There are two small screws, but even after removing those, the board doesn't budge. I've never done this before, so any tips would be greatly appreciated.

[Enzo]

Can you post a photo?

ANy chance the board that is in the way is the one the pots are soldered to? In other words that board has to come out with the pots attached? In which case, pull all the knobs and all the nuts off the pot shafts and the whole thing comes out. Look like that might be the case?

[Metalmorphic]

Yes! That was it. I got everything out. Now, as I understand it, the little holes in the pots are where I spray my solvent (see attached picture). I've got something called "MG Chemicals Electrosolve Contact Cleaner". It says "zero residue" and I think I read that I'm not supposed to use that kind. Do you know anything about that? Thanks Enzo!

[rocknroller]

Yes! That was it. I got everything out. Now, as I understand it, the little holes in the pots are where I spray my solvent (see attached picture). I've got something called "MG Chemicals Electrosolve Contact Cleaner". It says "zero residue" and I think I read that I'm not supposed to use that kind. Do you know anything about that? Thanks Enzo!

[ATTACH=CONFIG]46947[/ATTACH]

You'll get much better cleaning and coverage if you can bend the tip of your cleaner and spray from the underside of the pot - where the 3 pins connect. Trying to get cleaner in that littel hole on top won't work well.

[Enzo]

Actually I use those little holes all the time. it is all open space inside.

But going in the main hole is always good.

If you can position the board for access great, otherwise...

My strategy for that instead of bending my tube, I use gravity. I hold the chassis up or the board up so I can get at it with the pots hanging down. Now I put the tip of my spray tube against the pot wafer and spray. The fluid goes in many directions, but mainly flows down into the pot.

SO like on a Marshall, I set one end of chassis on the bench, and lift the other over my head, so I am looking up into the chassis. Pots are legs up to the board, but hanging down at me. I go down the row.

[rocknroller]

Actually I use those little holes all the time. it is all open space inside.

But going in the main hole is always good.

If you can position the board for access great, otherwise...

My strategy for that instead of bending my tube, I use gravity. I hold the chassis up or the board up so I can get at it with the pots hanging down. Now I put the tip of my spray tube against the pot wafer and spray. The fluid goes in many directions, but mainly flows down into the pot.

SO like on a Marshall, I set one end of chassis on the bench, and lift the other over my head, so I am looking up into the chassis. Pots are legs up to the board, but hanging down at me. I go down the row.

For the brand cleaner I use (WD-40), I find the tubes too large for the little hole, thus most of the fluid just sprays out on the board instead of getting in the pot. Yes, you could hold up above your head use gravity to let flow down into the main hole, but as you said, it's goes in many directions. Why waste it? This stuff gets expensive. I just took a soldering iron and give a nice U curve bend to the tip of one nozzle and 100% shoots up into the pot, without holding boards over my head! Plus - it has the added benefit of flushing out as well, since the excess fluid will drip right out the main opening carrying any dust balls/debris with it. I keep a straight nozzle for other purposes obviously as well. But to each his own!

[Metalmorphic]

I just put the end of the spray tube against each hole and gave a little squirt, then turned the shafts a bunch and repeated the process a few times. Some of the spray dripped on the board but evaporated pretty quickly. I put everything back together and . . . no more crackling or cutouts! The Electrosolve worked like a charm! Thanks for the help everybody!

[MusicMangler]

Some help and a question:

First, most of the links in this ol' thread to the schematic are dead. (what brought me here in the first place). Some of the sites are still up but there's nothing behind them. However, I did manage to hunt down a working link after a lot of clicking an poking in Google images. So for now, you can find the elusive schematic specifically for the G50 Series III at this link. Free download once you sign up, yada, yada. Figured I'd share for the next guy:

https://manualmachine.com/yamaha/g50...559-schematic/

Second, a question:

Anyone have a copy of the service manual, or user manual for the G50 III? I have the G100 Service Manual, but I can't find the G50 Service Manual. I'd also like a user's manual. Yamaha Support had nothing. I've found a lot of old references but they are dead per above or point at the G100 Service Manual. I've yet to even see a user's manual for Series III.

[DrGonz78]

Back in my post from 2014, post #45, there is a direct link to the G20/G50 series III schematic. It is right on MEF so you don't have to sign up for that manualmachine site if you don't want to.

[MusicMangler]

Back in my post from 2014, post #45, there is a direct link to the G20/G50 series III schematic. It is right on MEF so you don't have to sign up for that manualmachine site if you don't want to.

Weird... when I tried that link last night I got a blank page. Thx.