My Ensoniq sq1+ has issues

Synth Repair
1

Hi. I have this Ensoniq sq1+ (non 32 voice) keyboard. I’m the original owner. Lately, it’s developed a slight hum, and I think it’s in the main board. The sound seems to be coming from under the display, if that tells anyone where it might be.
I don’t use the internal sounds any more, but just use the keyboard for midi and it worked quite well…until this hum started. The keyboard still works, but after a while, it does strange things. If you’re familiar with the keyboard, sometimes it plays keys at max volume, similar to if the little wire that senses the velocity of a key is dirty. This isn’t the case here, because it’s not always the same key. and sometimes it doesn’t happen at all.
I’ve noticed sounds that require what I’d assume to be a lot of RAM (such as grand piano sounds or multiple sounds at the same time) cause this to happen more often. And other than this hum and the occasional max velocity of some keys, the keyboard still seems to function fine. Of course, since I don’t use the internal sounds, they might not work. I don’t know. If necessary, I could find this out.

What I need to know is, if anybody knows what board could be doing this. Is it the main board that’s humming and is that all I’d need to replace? And another thing. All I’ve found is a board for the 32 voice model. Since this isn’t the 32 voice model, would that board work as a replacement? And if not, if I can’t find the correct board for my older model, would it be possible to somehow fool the keyboard with a 32 voice switch over of some sort?

I just want the thing to work again. It’s a great keyboard, I love the metal case and I’ve got all sorts of midi settings that I’d hate to have to configure again on another keyboard. Just call me an old stuck in the mud keyboard player, I guess.

If anybody has any smarts on this, I’d appreciate some insight. And if you need more information, don’t hesitate to ask. Thanks, so much.

2

I think this is an issue with the key scan circuitry (or software), not with the keybed. The contact spring for each note makes contact in the up position and then in the down position, and the note velocity is determined from the time difference between the two.

The first thing to try would be to reinitialize the keyboard (which will restore it to the factory settings, so make sure everything is saved first). That will clear up any software glitches. If the problem persists after that, my guess is that it is a main board issue.

You can swap a 32-voice board into yours without any modification, and it will upgrade it to the extra voices.

3

Thanks for the reply. This gave me a lot of information. I tried reinitializing the keyboard but that didn’t help. But, when I moved the keyboard a bit, I noticed the midi cables were causing a loud hum, similar to a ground hum. I don’t know if this has advanced from a smaller issue and that it might be related to this issue I have. I’m going to open up the keyboard to see if the midi connections need to be resoldered to the board. Then I’ll see if my problem has been corrected. If not, it would seem I’d need a new main board, but I wonder if any will be available to purchase. This could eventually be a lost cause.