Discussion about the Korg PolySix synthesizer

Hallo to all p6 lovers!
I' m Pietro from Italy and I have a question for you ..
After ten years of good playing my p6 start to don't save the sound anymore....I mean that the old sound were still there but nothing on new one saved so I thought ...bad battery....no.
So I decide to do the adjustement procedure explained in the service
manual...the voltages were ok but when I disconnected the 56k resistor the normal (program a1) does not comed back (trying to switch from test to normal too).(It is possible I shorted the 2p connector accidentaly)
Panic 
switch off and on again but nothing.
all the light are on always.

so I check the board (klm367) with the tester and seems ok ...no acid leaking around.

Maybe the uP is dead ! but I don't know how to test it.

I need HELP. 

thanks to you all.
Pietro