Langevin 252a Slider Contacts
« on: March 14, 2021, 04:02:42 PM »
I recently picked up this Langevin 252a with some broken/ugly contacts. Does anybody have experience repairing these? As it stands it seems like these contacts may work, but I don't want to risk damaging the circuit board traces...

I'm also in the process of drawing up a schematic, I hope to post that soon.


Re: Langevin 252a Slider Contacts
« Reply #1 on: March 14, 2021, 04:03:20 PM »
Some (I think?) normal working contacts for comparison

Re: Langevin 252a Slider Contacts
« Reply #2 on: March 14, 2021, 04:03:53 PM »
Board that the contacts slide on

Re: Langevin 252a Slider Contacts
« Reply #3 on: March 14, 2021, 04:04:44 PM »
The rest of this band (800Hz)

abbey road d enfer

Re: Langevin 252a Slider Contacts
« Reply #4 on: March 27, 2021, 09:15:37 AM »
I recently picked up this Langevin 252a with some broken/ugly contacts. Does anybody have experience repairing these? As it stands it seems like these contacts may work, but I don't want to risk damaging the circuit board traces...

I'm also in the process of drawing up a schematic, I hope to post that soon.
I can see that some have already been "repaired" with solder...
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

abbey road d enfer

Re: Langevin 252a Slider Contacts
« Reply #5 on: March 27, 2021, 09:16:26 AM »
Some (I think?) normal working contacts for comparison
These are a different version, flatter contact area, different material.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Re: Langevin 252a Slider Contacts
« Reply #6 on: March 29, 2021, 03:03:49 PM »
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.


 

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