AMI D40 not playing 21-40

My AMI D40 has stopped selecting records 21-40 recently. I don't here the familiar "click" when I pick one of those selections, but 1-20 still work fine. It could be related to one of the buttons (34), which occasionally would select on it's own. I've checked that one now, and the button itself isn't stuck, but perhaps something on the switch itself is stuck? Is there an easy way to get to those switches to take a closer look? I have an AMI B also, and that has easy access as you can just swing the selector "door" all the way down.
Scott

I do have the service manual, and it isn't obvious to me what components/circuits could be different for 1-20 vs 21-40.

Any thoughts on this issue? I can provide a copy of the schematic if it would help. I'm sure it is something simple, but I've not done a lot of troubleshooting with this jukebox, so I could be missing something simple.
Scott

Scott,
My simple mind says that there should be a jumper from switch 20 to switch 21--izzat shown on the schematic--izit there, in an un-broken form ? Or do they use a relay contact ( or different plug), for the first 20, and another one for the next 20 selections ? Ron Rich

Ron,
Thanks, I'll take a closer look at those areas when I get home this evening. I do know that there is a plug for each 5 sets of selections going to the mech (1-5, 6-10, etc.), so it would have made more sense if there were 5 selections not working.
Scott