I was testing out one of the scopes we have here and while at it I’d figure I’d take a look at some waveforms from the MC-202. It’s nothing too serious but it’s interesting to see the raw waveforms along with the mixed ones
It’s been a busy week so unfortunately there has been a distinct lack of posts on the blog. I’ll try not to let that happen too often, but sometimes it’s unavoidable. The memorymoog has been placed to the side while we contemplate the next steps. On the workbench at the moment is an ARP Odyssey III. This is the late revision Odyssey that has the PPC controller as standard (it was an upgrade option on the earlier versions). The problems with this unit were the CV input not functioning, the keyboard bushings were worn out and the sample and hold circuit not acting as it should. After some troubleshooting I managed to repair the CV input. I was using the MC-202 to test the CV input, however this MC-202 doesn’t send a strong enough gate signal to open the Odysseys gate so I had to hook up a 9 volt battery to trigger it (or just hold a key instead). I’m not sure if it’s a problem with this MC-202 or if it’s just an incompatibility between manufacturers, I’ll check that out at some point. After fixing the CV in I proceeded to replace the bushings for the keyboard. The Odyssey key mechanism is quite an odd set-up, it uses so-called “whiskers” that when a key is pressed make contact with a couple of metal bars and discharge a capacitor. It’s quite a piece of work really, it sort of reminds me of those wacky contraptions you often see in museums. Needless to say it’s over complicated and there’s much that can go wrong with them easily but hey it’s from the 70’s so what can we expect really. My next task is to tackle the sample and hold section.