board mounted pots on an etched pcb

[miter53]

I recently etched a 424 pcb with board mounted pots. By the time I finished monkeying around with it trying to get the pots soldered without shorts from pad to pad, I had lifted a couple of traces. I ran jumpers, which were working, until I boxed it that is. Now, not so much. Anyone have any tips or tricks for working with pin mount pots on single sided pcbs? I've re-etched the circuit and will try it again. I'm thinking of just trying to be super careful during the soldering operation, and then using some epoxy on the back side to stabilize the pins.

[Haberdasher]

it might not help you this time around, but one nice solution is to use solder lug pots with 3 very short wires instead of the pin type.  the pots still stay down under the pcb just the same and won't take up any more room, but they are flexible and thus more board friendly.  you still have to solder the wires to the copper side but it's a heck of a lot easier than starting over.

another trick (it only works on projects with symmetrical pot layouts) is to mount the pots to the enclosure upside down, like with the pins sticking out of the top of the enclosure, tightening the nuts on the inside.  careful, it's mirror image iirc and the pots have to go in reverse, like if the tone is on the left, you have to put it into the right handed hole.  drop the pcb onto all the pins so you know the pots are lined up perfectly and then turn the whole contraption upside down carefully.  try to solder just one pin on ea pot so they don't move.  you then undo all the pots from encl. and solder the rest.  mo matter what, you should probably also over-drill your pot holes by one size.

[miter53]

Good suggestions...Thanks!

[drolo]

If you still want to use a pot with PCB pins, you can also try to bend the pins against the PCB once inserted into the PCB holes and then solder. It will be sturdier but beware the day you have to replace a pot! ;-)

[davent]

I've used eyelets to create plated to create plated through holes for components so they could be changed from the topside of single sided diy pcbs. haven't tried it for pots but worked fine for other components. Mouser has a variety of sizes so shouldn't be hard to find an exact size for pot legs.

Wide roll eyelets. Drill a hole just big enough for the eyelet, insert crimp the edge over, solder to the trace and you now have a plated through hole.

http://ca.mouser.com/catalog/647/2164.pdf

These eyelets were quite large.



dave

[mmlee]

I'll probably never do it myself but that is a great idea davent, really great!

[davent]

Have some, i beleive, 534-23 eyelets and they look good for a pot, fit in a 1/16" hole and are long enough for a 1/16" thick pcb.

Flared over with the flaring tool and recently bought a chasing hammer at a jeweler supply house so can now flatten the backs to anal satisfaction, should make them easier to solder to the traces.





Backs of 1/8" eyelets flattened with chasing hammer, 1/8" board.

[miter53]

That is awesome...

[miter53]

Thanks, Dave...worked great!

[davent]

Man that looks super, very happy to know the idea's a keeper!
dave

[Matt]

If you still want to use a pot with PCB pins, you can also try to bend the pins against the PCB once inserted into the PCB holes and then solder. It will be sturdier but beware the day you have to replace a pot! ;-)

I use this for perfboard layouts when possible because I don't like floating pcbs. Works great!