Vintage Synth Explorer Forums

Anyone here who owns or services Micromoogs know what would cause the pitch ribbon to not work? I have hinted at this in other posts before; my ribbon hasn't worked since I bought my Micro 3 years ago. I remember asking this back then to someone (forgot who) and he said to replace the band-aid-like tape that covers the ribbon itself. He sent me the tape, figuring mine was all worn out, but that didn't fix it. I had disassembled the entire pitch ribbon, even testing it without the tape to see if it even responded and it never did. Would this more likely be something in the main board circuitry than in the actual ribbon assembly itself? Just given what the assembly consists of I would think all it had to do to work was be conductive to heat sensing aka finger push...

PS - I am reading the service manual... I wonder how hard it would be to find a ribbon assembly somewhere online.

Not to easy to find, but not impossible.

As far as the ribbon goes, its a strip of 5k resistor with a contact wire. (Going from memory).
With the micro off, put a multi-meter on it, press at the top of the ribbon, what does it read? Press at the bottom. No reading means (most-likely) the contact wire is broken.

With the micro on, is there +15 on the top and -15 on the bottom of the element?

And kindly remember, I'm only looking a schematic. That doesn't mean I know what I'm talking about.

Ok, I'll definitely try that. Thanks for the info.

I guess what you're saying is there's really no way for the strip of resistor material to break itself, right? I do remember there was some rubber casing around it or under it, but I doubt it affected the ribbon. Also it does not look like it ever sustained any kind of damage, other than the tape covering being slightly worn...

So, I took apart my Micro and attempted to fix the ribbon.

Here's what happened: I got the assembly out and I played around with the metal strip, and by jostling it around a bit it may have made better contact with the traces underneath, and it started working. So, great, I'm thinking... I figure lets clean the traces (contacts) with a pencil eraser and lets start putting it back together slowly and continually test it. So far so good. I got it back together completely, and it still worked!

I walked away from it for about a half hour, and then it malfunctioned again. This time, a different error. Now it's reacting to touch (where it hadn't before) but it's just jumping to a set pitch now no matter where you push... Wtf?

Just to close up this topic, I wanted to report back and say the ribbon is working fine now... just powered off and let sit for a while, powered on and it was working, and has been fine now the entire weekend. I guess if it goes funky it's just a temperamental flaw from a 31-year old synth.

Was the metal broken or bent?