Oki ML590 Serial Interface Board Issue

Hi

Had an old ML590 with RS232 serial card that stopped working (spindle that advance ribbon broke) so I purchased a working used on ebay.

Printer powers up and seems fine. Put serial board from old printer in working ebay unit but no printing happens.

Does anyone know if there are any jumpers or switches needing attention in printer that never had this board in it before?

We're running SCO Unix with Real World accounting. I know there are port setups in Unix but I was thinking that this new printer should just work with board slipped in.

Any knowledge out there?

Thanks