Discussion about the Korg PolySix synthesizer

Hi guys, I am a new one here... was just wondering if anyone could advise me how to check if I definitely have a RAM memory chip gone (or going) on my Poly6..?

It has had a new battery installed a while ago by a professional tech, and that battery still reads good. Is there any way of confirming that the SRAM chip if faulty?

It remembers random sounds but each patch seems to have a full-on modulation come in after holding a key down a while. Also, some patches infinitely sustain etc. I can re-programme and re-save a patch - which will then hold until the unit is turned off. When powered back on it is the same story.

Many thanks for any help you can give me.
Cheers,
TOM