Hi Jaro,

If my theory has any merit it is more than likely that the problem is in the Bank No. as you say all channels are set to silent. The KN7000 Reference Guide (Blue Book) that came with your keyboard has a complete listing of Patch/Bank No's. used in the KN7000. GM Basic and GM2 both use MSB 121. GM basic uses only LSB 0 whereas GM2 accesses the alternative sounds through LSB 1, 2 etc.
If you do not have the Reference Guide I have the KN7000 Patch/Bank No. listing in an Excal file and can email it to you.

Cheers
Len C.