Sorry I was thinking of those IBM relays.

Do you have an S and/or a F relay? Are they in?

I believe 2LR pulls in from a hall call. Since you disconnected 2SU & 2SD we know it's not a hall call button stuck. If you go from SC(-) to 2LR(+) what do you read on DC volts? 2LR is on the intermediate board...

Make good choices,

JKH