Hi, new guy here. I have an Ensoniq SQ2 and the power supply is making a buzzing noise that does not change volume with the master volume. My guess is bad filter caps, as I disconnected the power supply from the keyboard, plugged it in and turned it on and the buzzing was still there .The info printed on the caps (2 small & 2 large ceramic?) is not very helpful for capacitance rating only voltage, 250v and I cannot find a schematic. Would anyone here know the rating and type of caps these are. Thank you for any help.
Another possibility for buzzing is loose laminations in a transformer, if there is one.
Hi and thank you for the info, had not thought of that. I will keep that in mind.
Hi Mal, I think your right, bad transformer. I followed the wires from the power supply board to another board ( which I should have done in the first place, live and learn ) and they went right to a row of diodes and electrolytic caps. I found 1 bad solder joint on the power supply board and repaired it but no change. I also disconnected the power supply board from the keyboard, plugged it in and turned it on with no connections to anything and the buzzing was still there. I am on the waiting list here for a power supply. Again, thanks for the help.
Update to my power supply problem. Looks like it is the transformer. You suggested that laminates may be loose and vibrating so I did an experiment. I took an all plastic clamp, placed it on the laminates and the buzzing is almost gone. I just need to figure out a permanent solution. Thank you for the help.
Update to transformer issue. After some research on the web & youtube it was suggested to paint clear lacquer on the laminates letting it soak in and squeeze them together and let dry and harden. I did that and used 2 thick zip ties to squeeze them together. After a few days I reinstalled the board and put rubber bushings between the board and the aluminum body of the synth to isolate it. The buzzing is all but gone. I have been using it for a couple of weeks now and it is still dead quiet and no funny smells coming from the transformer so nothing seems to be melting. Thanks to everyone for all the help. A happy Ensoniq player.