::: Crumar Bit 99 : Part One :::

What an odd beast. I remember seeing one back in the 90's at a local music store. Remember those!? Although the price was right I didn't buy that one because it had lost it's memory and was full of nonsense patches. This type of problem makes many of these old instruments seem catastrophically scrambled. But upon inspection the scramble has a surmountable solution. You can replace the battery and either sysex dump or tape dump the patches back in and often you are good to go.

The real issue with the more rare instruments like this one is availability of service info. For instance it's easy to find ( almost ) any Roland service manual to trouble shoot a synth but Crumar and many rarer instruments can be mysterious about their ailments.

What are the power supply voltages supposed to be?

What was the final OS version?

How do i calibrate the voices so that they match and perform properly?

These are the mysteries that lie beneath the hood of this Crumar Bit 99. It's built like a tank. The metal chassis is rugged and fully hinged like old Roland synths. The voices are all firing ( nonsense at the moment ) and the display is working. There are some messed up keys that i am still sorting out. Some were broken but i used epoxy and toothpick pieces to reattach the hooks and re enforce them. The other key problems have to do with triggering properly and triggering with velocity. That's right! this synth has VELOCITY on the keybed.

That my friends is why this is an awesome instrument.

It's much like the old Ensoniq Mirage keybeds which i have fixed many times in the past. There's a spring that is stretched through a window at each key. The spring moves from one contact to the contact on the other side when a key is pressed. The CPU determines what the velocity of the key press was from the way the spring travels across the divide. Pretty raw and clunky but it does work as long as the contacts are clean and the springs are not mangled. Several of the springs are really mangled and barely working on this keybed so i am going to go scavenge an old parts Mirage keybed for springs.

But i have been unable to get the tape dump to take. It fails half way through. There are error codes that come up but without the service manual i don't know what they are! The manual doesn't list any user issues or troubleshooting info. It's otherwise a fairly well laid out user manual though! I do have a sysex dump of the patch info and i will probably resort to that. I read somewhere on the net that people have issues with the tape inputs on these so maybe this one suffers from that too. I imagine it's lumpy power or old capacitor related interference.

There will be updates!

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