Another classic for repair 

Diagnose:

not all voices are working and keyboard nok




lets open it








remove front pcb's




e
close inspection
what do i see




leaking elco's spotted
that's a recap









tact switches also need repair

and lots of cleaning





it exploded ....


2 voices cannot be tuned vco's are placed in oven to minimize drift by exterieur temp drift but it is an 470 ohm resistor gleud on top of vco now they have a tolerance of 1% so that is min 465 and max 475 ohm . when i check vco 2 and 4 one is 488 and the other 512 ohm so i decided to rerplace these .



gleud them with heat conducting silicones back on  vco 2033. 

and now i'm able to tune all 4 voices.


After this i build in midi tubutec modo poly interface and a line filter and new power cord





ok midi is working pitch had to be calibrated with external daw and pressing tubutec combo buttons.

Line filter added