N00b Question: using a backwards 3PDT daughterboard

J

jcpst

Well-known member
I’m out of footswitches for a few days while I wait for a delivery.

So I dug in my box of fuckups and pulled out this dude:

image.jpg

From one of my first builds. Whoops 🤦‍♂️😁.

Can I still use this by just flipping which in/out jacks my wires go to?
 
jcpst said:
I’m out of footswitches for a few days while I wait for a delivery.

So I dug in my box of fuckups and pulled out this dude:

View attachment 73986

From one of my first builds. Whoops 🤦‍♂️😁.

Can I still use this by just flipping which in/out jacks my wires go to?
Click to expand...
No, I had this same question at one point too. The ground and onboard/offboard wires aren't routed symmetrically so they don't work correctly when the board backwards. There's a reason why it says that side down.
 
Hmm I actually think it might work if you went
Switch-board
Input-output
Board in-board out
Ground-ground
Switch-switch
Board out-board in
Out-in
I think the circuit output would be grounded on bypass instead of input. Also the wires will be a criss crossed mess.
 
Yep, I figure if there’s a way it might be a mess, but I’d rather have a mess than burning up that LMS soft-click trying to remove the board.
 
I've removed backwards boards before. It's not that hard so long as the pins are quite a bit smaller than the pads, which in is likely the case, given how much clearance there is with most 3PDT. Just hit a few at a time if you're worried about the heat. And use good wick.
 
IIRC, what the 3PDT-daughterboard is doing is this:

3PDT WIRING WITH GROUNDED PCB INPUT.jpeg

Note how lug 1 is jumpered to lug 6, this grounds the effect's input during bypass, lowering noise/chance of bleed-through.


Here it is flipped:

3PDT WIRING WITH GROUNDED PCB INPUT flipped.jpeg

Ignoring the backwards PCB, if the PCB were right-way round, and you wire the boards up as though the daughterboard were a mere mirror image, the output from the board (Lug-7) is now sending the signal to ground in bypass.


Rather than desoldering/cutting/junking anything...

Potentially it could still work, but the wires from the PCB to the 3PDT-daughterboard will NOT be in the correct order, and much DMM-sleuthing will be required to figure out which wire goes where and massive increases in chances that it will require trouble-shooting...



Here's what I propose you try:

3PDT-DAUGHTERBOARD WIRING DIAGRAM PedalPCB FLIPPED.png
 
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I was in a very similar position and wound up desoldering it - whadda pain! It did work, but mostly due to the awesome solder sucker - the Engineer is excellent and made it FAR less maddening than it could have been.
 
I'd switch the wires around. If you do desolder it, the likelihood of the switch failing in the future will increase. I had foot switches fail on me in the early days because I would overheat them.
 
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