Question about Aion Eclipse

[Ariosto]

I recently mounted all the components in the PCB (with the +/-15V mod) according to the specs. surprisingly I become a very strange kind of sine wave -like a cheap synth- in intervals (used two differents 9v PS), even with the input cable disconnected. Of course I can add pictures later if soemone is around and curious. Had anyone experienced such anomaly? Thanks in advance!
Ariosto

[gordo]

Post some pictures of the top and bottom of the board.  That'll give us a place to start.  I'll check mine, I think I built the 15v version and no issues.