Vintage Synth Repair

Hi everybody,
my minimoog #3271 with R.A.Moog boards strikes. In this afternoon it worked very well, but 
now, four hours later I switched it on and can not hear oscillator 1 and the other both oscs 
have a very bad scaling - they are completely out of tune. What can this be? The Synth was 
stored away for a lot of years, i woke it up last week, cleaned all switchs + key-contacts and 
after that it worked  PERFECTLY! 
Now I swapped the Oscillator board with a newer one (also an older version with seven pots) 
- that works. But I love the R.A.Moog board and will repair it. Does anybody know, which 
caps should be changed after this long time? 
Thanks for your answers
+best regards from 
a very unhappy Martin