Rockola wallbox 507

Hi
Got a few of these a couple of months age, have two working but the other one won't work. I can't get it to select it seems if the selection assembly is dead.The select light will come one when it is credited, but the bulb for the first digit or other digts will not come on and solenoid will not energise. Have given the switches a good cleaning and have swapped over another keyboard with no successs, has anuone any ideas
regards
seancalla