I have a problem with my JX-3P. When I use SOURCE MIX knob in PG-200 during mixing DCO’s levels (between DCO1 and DCO2) every few keys/notes are sounding quieter than the rest and after some time other set of keys/notes are quieter. I made a service diagnostic test and all six voices are fleshing one by one but in random order seems to be ok. I also found that some of the lowest keys sounds not in full like with disappearing second oscillator.
Is it damaged IR3109 VCF chip (it also controls the SOURCE MIX under VCF) or something else?
I have possibility to buy IR3109, but first need to be sure those symptoms are from this chip or something else (small caps in mainboard? I don’t think so).
Will be gratefull for any help, maybe someone had similar problem.