Vintage Synth Repair

Recently I tried to switch on my two CS40m synths which I have used  
for the last time about 7 years ago. Main fuse on both machines was  
blown after one second.

So I have recapped both PSU, and tried to switch on again. On one  
machine big two resistors connected in series to output rails +15 and  
-15 V became so hot that  their textile envelope (yes, they were  
covered by some textile pipe) started to smoke. (On the other machine  
not so bad, but again main fuse and another one in the secondary  
circuit was blown.) I have immediately switch off, put both PSU out of  
the instrument, switched on without a load, and both PSU are OK,  
everything works. So I could set all four voltages to their spec  
levels (+15, -15, +5, -10).

Am I right to suppose there's a short circuit on some board? I wonder  
how it could happen when the instrument was not at all used for years.  
In one instrument there was small leakage of RAM battery (as they use  
standard 2 AA size batteries in battery compartment, no damage was  
caused by this). Otherwise everything looks well.

Has somebody any advice how I should continue and where to find the  
source of this problem? Could it be some shorted tantalum capacitor? I  
can't use PSU and switch on the instrument. I plan to recap, clean and  
check all boards, clean connectors... usual stuff. Then try again to  
switch on... If it will work without blowing the fuses or burning  
components, then I can check voltages and signals. I have Service  
manual.

Thanks in advance for any hint.

Daniel Forro