Expert 120 Line input problem

[ogs]

I think (but am not sure) that the line in/phono card for the 120 was an extra which means it can be removed/re-inserted. Try to remove it, inspect the connector, then re-insert/mount it carefully again. If this doesn't remove the hum and none of your other troubleshooting helps I'm afraid there is an error in the card itself and it must be repaired or changed.