I can see that some have already been "repaired" with solder...
Yes, those “repairs” were done by a previous owner...
These are a different version, flatter contact area, different material.
I got a 251a from Igor recently, opened that up and the contacts look quite different, like you say. I read in a Langevin catalog that these use “bifurcated” spring contacts, and I wrongly assumed that the “bifurcation” was the connection between the two contacts. On the 251a each contact pad is two-pronged.
I’ve looked through a lot of new PCB spring contacts but haven’t found any that seem like viable candidates. Looking like I’d need to rebuild this with switches... I have a bunch of Grayhill rotary encoders, and was thinking it may be more cost effective to use those (and an Arduino) to control sets of relays on each band. Otherwise I think I’m looking at like $1500 in switches.
July 20, 2004, 09:22:32 PM