Korg Poly800/EX800 Users

Hi Pete,

the problem is more likely NOT the actual clock circuit itself (found on the 
main board using half of IC36 and half of IC28 and sundry other discreet 
components). For details of that circuit see section "4" on the main circuit 
schematic in the files section.

More likely is that there is a problem with the speed slider pot itself or the 
the connector CN2.

The annoying part of this is that the service manual doesn't include an exact 
schematic diagram of the speed pot wired into the clock circuit.

So you will need to do some tracing yourself. But I would start by checking that 

the slider pot runs through a range of resistance first. You will need a 
multimeter for that. If you don't have a multimeter then you will need to find 
someone that does or else go buy one.

And then I would check to see that the three wires going from the main board to 
the display board via CN2 are not broken. Make sure all thee connections have 
continuity.

Mike