Ensoniq TS-10 in reboot loop

Hi folks,

I picked up an Ensoniq TS-10. Everything worked fine on the seller’s end but upon arrival, when powering up, only the “Seq/Songs” button would light, and pressing the bank select buttons would just queue up digits on the display. Skipping the long story of working with the seller as to possibly putting in a claim with the shipper and considering it an unfortunate loss, I decided to try to fix it.

I took it apart completely, down to removing the keyboard assembly. I actually had to put it back together twice due to incorrectly installing the keyboard assembly the first time. I was thrilled when it booted up!

I played with it for a couple of hours and was going through the tutorial on the sequencer. At one point the unit spontaneously rebooted. I wondered about it but kept going. Soon it did it again. This got to happening repeatedly with increasing frequency until it was basically in a reboot loop, and I just had to shut it off.

Since that incident I have not had time to get back to it, but it seems like some kind of power problem, as if it is getting switched off and back on somehow. While I was using it during those two hours or so, I wasn’t moving it much.

I’m wondering if anyone has had a similar experience and might have an idea as to what the problem is.

It is a great unit and I am pretty determined to get it in good running shape, so I’m all ears as to what I might try.


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One possibility is that your KEYBED module is not starting up in time. There is a small capacitor on the keybed board that ENABLES the keybed CPU to run a second or two after powering up which gives the main board cpu time to startup and run. If the time is too short or too long, the main board will think the keybed is not there and will halt on starting the keyboard.

The capacitor is part of the 555 timing circuit. I dont recall exactly which one but if you pull 555 timer circuit schematics and compare them to the circuit on the keybed, you should be anle to figure it out.

I hope this will help

Usually good to check out the power supply first and make sure everything is good there. Check out pages 7 and 8 of the TS-10 service manual (available via Google) for details on how to do that.

Thanks for the tips, folks. I’ll check these out. I’ve noticed that the problem of rebooting kicks in after a while; the first time, I was probably using the TS-10 for about two hours. It sat for a week or so because I was busy with other things. Yesterday I had a second long session with it in which it took a similar amount of time (probably a bit longer, between two and three hours). Today I started it up and ran a timer and it started doing it around 1:15h.

I’ll chase up these tips, but I wonder if something is warming up with time or whatever to some point at which something fails.

Also, during my long session yesterday, I’d made a couple of sequences. These survived the initial reboot fits yesterday (I briefly turned it off for a bit), but today the memory was wiped. The unit doesn’t complain about low battery problems, so I am guessing that the rebooting issue is somehow wiping the memory.

Best regards,