It has one serious problem. The two gate outputs are outside of spec. The manual says they are 10V, but after testing mine and confirming with another SQ-1 owner, they run hot, at close to 14V, which is outside of the Eurorack safe range.
I'm going to patch mine using a couple of zener diodes and resistors to fix this, and I'll post the results here when I do.
2023-03-06 Update:
I determined that there is enough resistance already to solve the problem by just adding the diodes. I recommend this mod to everyone to bring the Korg SQ-1 into a Eurorack-safe voltage range. Just solder two 8.2V Zener diodes from the top to the bottom contact of the jack, with the stripe facing towards the center of the circuit board.
