Circuit board found in 20+ year old Ibanez Tele

K

Kilroyonguitar

New member
Hello everyone. I'm restoring an old Ibanez Tele and found a circuit board hiding under the bridge pickup. I believe it's from an old MXR distortion pedal but I'm not sure. It seems that most the old MXR circuit boards had 5 wires and this one has 6. I would like to keep it in there but I need to figure out the wiring as it has issues that I can't figure out. Any help appreciated!

Regards

Kilroy

bottom of circuit board.jpgdiagram.jpgtop of circuit board.jpg
 
Re: Circuit board found in 20+ year old Ibanez Tele

LOL after researching for hours I thought I would post for help and then? I found a match. Looks like it's an early MXR M-133 Micro Amp.1982 MXR Micro Amp M-133.jpg
 
Re: Circuit board found in 20+ year old Ibanez Tele

Do you have to plug a battery into it to get it to work?
 
Re: Circuit board found in 20+ year old Ibanez Tele

I've figured out why it wasn't working now. One of the pickups ground was going into the MXR circuit board and wasn't grounded anywhere else and it had a 25K volume pot instead of 500K. I'll hopefully have some time tonight to sort that out. The boost is 26 dbl. so I think I need to figure out how to tame that a little as well.
 
Re: Circuit board found in 20+ year old Ibanez Tele

Wow, that is quite a project, that apparently didn't work. :) Good detective work, though! Are you going to try to wire it back in, or scrap it all?
 
Re: Circuit board found in 20+ year old Ibanez Tele

Capture.jpgThat's right. Guitar was noisy and terrible sounding which is why it's been in a closet for more than 20 years. I'm going to wire it up like the original installer was trying to do. I actually don't have that much to do to fix it. rewire the ground and put in a new SPDT 2 way switch and 500K pot. Should have it done tonight. I'll let you know if it works and how it sounds. I'm thinking a 26db boost is way too much so I'm going to research how to lower the maximum boost setting. It's been a very interesting project from trying to figure out what the heck the circuit board was from to learning a bit about making layout drawings and now to fix it.


Maybe someone with electronics experience can review and provide some feedback?
 
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Re: Circuit board found in 20+ year old Ibanez Tele

Keep in mind that if the volume control was after the amp. then 25k could be the proper value.
 
Re: Circuit board found in 20+ year old Ibanez Tele

I don't think it is. I'm not 100% sure this schematic is the same year but I don't think they would have varied much.

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Re: Circuit board found in 20+ year old Ibanez Tele

Cool schematic. I thought that maybe that pot came after the amp.
 
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