2 keys are chipped along the front edge on the underside. See photos for a good idea of the overall condition. The headphone output jack is working fine and the keyboard sounds great. Here is the info I found online. I repaired my SY22 that had the same problem.
The transistor that pulls in the low side of the output isolation relay RL1 was bad. I think it was Q103 and I used a 2N3904 to fix it. There is also a Tech Update that replaces the 100 ohm resistor with a jumper.
This is only on the very earliest SY22's. You can use this by using the stereo headphone 1/4 output jack or see about the repair stated above.All other functions and keys working fine. Comes with aftermarket power supply that works perfectly. Listing is for (1) Yamaha SY22 Synth with AC power supply only, as pictured. GRAB IT WHILE IT LASTS!
Please do not open any cases or claims without contacting us first. We will be able to resolve any problems directly and make sure that any issues are taken care of immediately. Our near perfect feedback speaks for itself. THANK YOU FOR YOUR BUSINESS. The item "Yamaha SY-22 Music Synthesizer Keyboard Headphone Out Works, No Sound from L/R" is in sale since Friday, August 28, 2020.This item is in the category "Musical Instruments & Gear\Pro Audio Equipment\Synthesizers". The seller is "newyorkmusicmall" and is located in Brooklyn, New York. This item can be shipped to United States.