MIDIBox SID Project Blog

A COMMODORE 64 BASED MUSIC SYNTHESIZER

Mistake-O-Rama

Well today was a mistake-o-rama. Nothing major, just annoying for my own lack of attention. My Arrow order came, so I sat down thinking I had all the new parts only to realize that I ordered a polarized 330nF (0.33uF) cap for C2 in which it appears a non-polarized is required because C2 doesn’t indicate a positive pad. I’ve reached out to the forums and they said that I can use it still as long as I get it in the right direction (which would be the lower hole is positive). I have to place an order anyway for more parts though because I seem to have lost some new caps so I might as well get a non-polar cap for C2 as well since its just a few dimes.

I’m now returning to the control surface. My original plan of having the keys press down and push tactile switches has hit a flaw in that the base of the switch is a little too tall and so when plunger has the rubber bit in the end it causes the switch to be already activated. If you remove the rubber bits the interior of the plunger is wide enough to fit the whole switch so what I need to find is something that I can stick up inside the plunger that will push on the switch.

After searching through my office looking for possibilities I found that the holders I purchased for the small 3mm LEDs fit pretty well and was the right height when I tested it with some old tactile switches I had left over from the Korg keyboard I fixed. I did some testing and then removed the key and realized that instead of staying stuck up inside the plunger the LED holder actually stuck itself onto the switch activator. Kind of a hack job, but it works and, well, much of this project is a hack job. Unfortunately the switches I already purchased are too short and too fat, so I’ll have to order more of the Alps SKHHANA010 that I purchased to repair the Korg.

I'll be using a Dremel for the rest, but this was my test drilling using a hand drill. One hole (the lower left) is a little off its mark.
Despite the arrant hole, the switch fits great. Unfortunately, these switches are too short and will be replaced.
Keyboard plungers. These are what make contact with the keyboard PCB. One of the doesn't have the rubber pad in it.
A left over switch from my Korg repair. It has part of a 3mm LED holder stuck on the top.

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