Yamaha G50-112 Schematic Needed

[micachee]

yamaha G50-112-3 schematic

thank you again now i can get this amp done and out

[gozilla]

Yamaha Amp Schematics

There's lots of Yamaha amplifier schematics at http://www.schematics.ca There is a Yamaha G50-122 schematic diagram and a Yamaha G50-112 service manual as well.

[lesoufs]

Hello everybody I am planing to recap my G50 112
my question is can I use
NEW Rubycon VXP 80v 1000uf cap in place of the 75V 1000uf
or does someone has link to 75V 1000uf cap with good audio grade.

thanks again this place is a gold mine

[Jazz P Bass]

The 80 volt caps will be fine.
I don't believe that they make 75 volters anymore

[lowell]

Maybe I missed this in the thread but the bias figures ARE in the service manual. Took me a while to find em. They're on pg. 3. NOT on the actual schematic page. CN101 should have 5mv across pins 1/2. Give or take 2mv. Got one in here that's blowing fuses but not immediately. Customer picked it up and they blew again. The 4AT dual high v supply fuses. I'm trying slo-blo this time and adjusting the bias as it is reading 10mv.

[rickEb]

Here's a shot in the dark! Inow own two of the Yamaha g50 112 ii amps and like most have said in the forum, they're great little amps with good sound for 50 watts. I received my second one this week and was trying to work out some amp switching with panning effects andf stereo. The problem I am having is that with the limited amount of info available about the amp itself, there is absolutely no information available about theoriginal footswitch that came with the amp. Doew anyonr happen to have one? Can someone possibly provide a picture of both exterior and close-up of the interior? is the switch simply wired or is there a pcb? Any info would be greatly appreciated! Also, does anyone happen to know of an aftermarket or other amp footswitvh that works with this amp? The switch Doctor has one that I requested, but, it utilizes a battery for the LED activation. Thanks.

Regards,

Rick

[Jazz P Bass]

The footswitch is a simple maintained on/off switch that is used on the Dist Ch & the Rvb.

When On, the circuit is connected to ground using a 1/4" plug.

The factory switch did not have LED indicators.

I think the factory switch ran a separate cable for each function with a 1/4" plug on each end.

If you decide to make one, you can use one 3 conductor cable & split the two 1/4" plugs at the amp. (less wire)

[rocknroller]

Yamaha GS III amp dead - HELP!

I have a G50-112 III that works, up to the "headphone out" and "pre-amp out". Nothing from the output stage is working, (speakers and "direct out")

I have everything BUT the schematic for the G50-112 III. I have a 15 pg "service manual" consisting entirely of exploded diagrams, parts listings and pictoral of circuit board parts lay-out, but I am missing the actual schematic. The schematics for series I and II are different than the III series.

I have a working G100 III head, and G100 III schematic. Putting aside the differences in preamp circuitry, the G50-112 III output stage looks like "half" a G100 output stage, in basic design. I have been trying to "extrapolate" from my G100 schematic, and voltages taken from the working G100 head, what is wrong with the G50...to no avail.

Since I do not understand the theory behind the circuit, I have been replacing parts from the output xstrs, forward, still without success. Having the actual G50-112 III schematic would be better than trying to guess from what i have.

I know this is a very old thread, but I have the exact same issue with my amp. Bought it at an auction. Plugged it in at home and worked perfect. Moved it to another room and it sat (listed on craiglist waiting for the right buyer to come along. A few bites but offering too low for it ) Happened to plug it in the other day and found it was dead - exactly as above everything up to the speaker and direct outs were fine, but nothing after. Now I'm wishing I had sold it! Did a quick fuse check, all seemed fine on external and internal fuses. No obvious circuit board damage, loose connectors etc. At a total loss as to what might have failed between then and now. Has anyone solved this specific problem and know what part(s) have failed and need to be replaced? Particularly interested in Wizrd's solution since it is exactly the same problem as mine and sound like he tried a bunch of stuff prior to finding schematics (which I can't locate and the pdf's here and link to schematic.ca no longer seem to have them).

[DrGonz78]

I am not sure which amp you have G100 iii G50 iii...? The schematics are all readily available on a google search and if you let us know exactly which amp(model) then we can attach it. I would start a new thread so the crew here can help you out better. Read the sticky about the dreaded switching jack>>>
http://music-electronics-forum.com/t28549/

Schematics
http://www.owner-manuals.com/-manual...a_filter_id=71

[DrGonz78]

Read this foremost:
http://music-electronics-forum.com/a...ck-problem.pdf

Follow those steps on the pdf and also make sure the speaker is good too.

Edit: Fixed the link on this post too...

[rocknroller]

I am not sure which amp you have G100 iii G50 iii...? The schematics are all readily available on a google search and if you let us know exactly which amp(model) then we can attach it. I would start a new thread so the crew here can help you out better. Read the sticky about the dreaded switching jack>>>
http://music-electronics-forum.com/t28549/

Schematics
List of YAMAHA User and Service Manuals starting with G - Page 1

Sorry - It is the GS50-112 model Series III (Which IO don't see posted in that link, though there are other GS50 models there)

Funny you mention the sticky jack. I literally just finished watching a YouTube video about that on a crate amp effects loop. Definitely something I will look at tomorrow!

[rocknroller]

Read this foremost:
http://music-electronics-forum.com/a...ck-problem.pdf

Follow those steps on the pdf and also make sure the speaker is good too.

This PDF doesn't load? Tried both firefox and IE.

[DrGonz78]

Sorry about that one. The link is also in the thread but some of the links are dead...

Try this one...
http://music-electronics-forum.com/a...ck-problem.pdf

[DrGonz78]

Yeah finding that schematic might be hard to do... So try referring to the G100 iii as it might help a bit for now. It's on the link below>>>
http://music-electronics-forum.com/t32980/

Main thing to try would be injecting signal into the power amp in jack to see if you get any sound through the output. A simple mp3 player or what not will do, just don't turn it up full blast. If you hadn't tried already plug a guitar cable from the pre-out to power amp-in. Lots of times an amp will sit and the jacks get all dirty and it cut the signal out hence "Dreaded switching jack."

[DrGonz78]

Here is a partial of the G50 III from another thread. It looks very similar to the G100 so that is good. Would probably be a good idea to clean the send/return jacks etc etc...


Edit: Ahhhh!! I found it! It is under as G-20 III / G50 III. So as Enzo always says the schematic might be shared by two different amps. Well here it is...