> Those wooden ends look great! ...

Agreed! It makes the Multitrak look a bit more like its sibling the
SixTrak.

>> I also have a Jupiter6 with 2 of the 6 voice noti sounding.
>> The boards and cables are in very good conditions,
>> I think the problem are the IC.
>> Anybody had the same problem?

There are a couple things which could be coming into play here. The Jupiter
6 can somewhat be thought of a 2+4 voice board, in that one of the voice
boards handles 2 of the voices, and another one handles the other 4. The
2/4 division also comes into play depending on panel mode (e.g., splits).

The first thing to try to rule in/rule out is whether perhaps the keyboard
is just in '4-voice' mode and/or if there's something wrong with the 2-voice
voice card (in general).

If not already installed, the Europa upgrade for the JP-6 is very
attractive:

www.synthcom.com/Europa

(If nothing else, the JP-6 mailing list noted on that page may be a very
good source of information/support to help diagnose the voice problem).

Good luck with the Polaris velocity issue.