Fitting an M122 top case to an F122

[Green Maned Lion]

I have an F122 that works perfectly, however it has developed a new crack, and I had found that one of my M cases did, in fact, fit on it, so I went off in search of an M122 type I case, and I ultimately got my hands on one for a very reasonable price.

Except it didn't fit. Wait, what? But the other one fit! I compared the F-case to the M-case and could see places it doesn't fit and why, and concluded that modifying one to fit an F would not be impossible. But why did the M122 case fit the F122 in the first place?

Slight issue; I own six M122s, and while I knew that one of them couldn't be the one I used for the test fit, and I suspected I wouldn't have disassembled the two NOS ones I have, that left me with three possibles.

I figured it out. I bought a keyboard on ebay, second one I bought, for use in my van that was labeled a 1394125 from '87; the 4125 is an odd duck that uses the DIN180 connector. I had one, made only a few days different than what this purported to be. The price was right because the case had a few issues with it. But it wasn't a 4125; I don't know exactly what it is. I had sent it out to Brandon for a screwmod and we concluded that the key assembly and control card both hailed from 85, the bottom case was from a 4125, and who knows where the top case was from. I ultimately swapped a different case top onto the board, though, because with the stress it was undergoing in the van, I thought a non-cracked case would be better.

*That* is the case that fit. I studied it, and I realised that all of the modifications I had figured would need to be done by cutting or grinding were done to it. Logical deduction: somebody had, at some point is this things life, modified it to do just that! Obviously, whomever had owned it didn't mind mcguyvering things together. Whoever sold it to me, I feel quite certain, had no idea.

Anyway, its missing one of the stand offs on the top, and another of those stand offs is cracked, and in the application of being the top case on an F, it would only be using those three stand offs. I swapped the case I had bought for this purpose onto the board that was holding this case, and my new plan is to use this already modified case as the basis for the F.

My thought is that I am going to preserve the Fs case in its entirety in a box, and attach the new case using bolts and plastic washers (I'm open to persuasion about a different approach). I intend to cut off the cracked stand off, and replace both of these standoffs with metal stand offs screwed into whats left of the original stand offs, and krazyglued into place. But I have never done anything quite like this, so if somebody has advice for me, I'd love to hear it!

[Falkenroth]

I have no clue on this one. Never attempted doing this before. Good luck.

If you get it to work, document it and post it. Be interesting to see what had to be done to make it work.