Discussion about the Korg PolySix synthesizer

i have another p6 that had battery leak problem. i've repaired bad traces and checked cpu, ic30 and 31 few times pin by pin and every connection seems to be ok. every function works, knobs work as they shouls, there are no problems with sound editing, saving etc. but still there are 2 things:

1. bank D and 4 are lit all time. bad connection around ic30 and 31? or what?

2. there is little vibratto on sound. it can be fixed when i set modwheel to 0 and level on panel to 0. but when i switch patch the vibratto appears :( i dont know what affects vco? i know that several ppl fixed it simply?

help