SQ-80 locks up after random times

I thought I had an overheating issue but this seems different.
I just bought the SQ-80 in good faith and was told that after hours it locks up.

However, for me I can go sometimes 20 seconds after a normal bootup or sometimes 20 minutes or even an hour before the display, keys, and buttons do not respond and a reboot is needed.

Any ideas on what this could be?


I’ve never owned an SQ-80, but I do own an Ensoniq Mirage and would experience the same sort of symptoms on it and it was caused by socketed chips coming unseated. Back in the 80s and early 90s when I used to gig with my Mirage I took the screws off of the flip top and made velcro latches that would hold the top down so that I could quickly open the Mirage up and push down on all the socketed chips when I got to a gig. It just became part of the routine of gigging with the Mirage. I still have my Mirage but it doesn’t travel but it will still do that from time to time even sitting still in my studio.

Try opening your SQ-80 up and gently pushing down on each socketed chip to reseat them in the socket. Hopefully that will fix your problem.

Thanks for this suggestion.

I had random lockups on my ESQ-1 similar to your SQ-80. Pushing down on the main board around the processor socket would restore it for a while but it would always fail again. I got fed up and pulled the main board and checked the solder joints under the processor. Many solder joints did not look too good.
I ended up installing a new socket. Now the keyboard starts up first time and dosen’t lock up anymore.
Have you also checked the power supply capacitors and tested all voltages?

I am going to borrow a scope from work and check this as well!


Reminds me of the Atari Twist we used to have to do with the first generation of Atari ST computers from time to time to reseat the CPU.

Oh and check the bottom of the keyboard too to see if it’s missing any screws. The keybed on a lot of older synths was often used to give the case extra rigidity and sometimes just a couple of missing screws holding the keybed down would give the keyboard case enough flexibility to unseat a chip or two.

All great suggestions!

On one of my cable ties of the SQ-80 there is a tag that says REV E.
Does anyone know anything about what the REV E was in regards to the SQ-80?

REV E probably means “REVISION E”. Synths (like any electronic stuff) have some modifications and improvements over time, called Revisions.

I was asking if anyone knows what was done in Revision E,
as in the words “Rev E in regards to the SQ-80”.