Archive of the former Yahoo!Groups mailing list: Vintage Simmons Drums (UK) Users Group

Did you ever manage to fix this ?

You can check the 311, D-A converter and the VIA by altering the tempo pots and seeing if the readout changes.

Sounds like there might be a problem somewhere between the sync select switch on the expansion board and where that tells the CPU you want to use the internal clock - have a look at IC6 and see if that's doing what it should...