# Using a 3pdt switch to wire off board to a dpdt board



## Stelloh42 (Sep 19, 2020)

Hey all - I recently acquired a PCB for a reverb circuit that is meant to have a PC mounted DPDT footswitch. With no status LED. I was hoping to wire a 3PDT switch off-board and use the two outer columns of lugs for where the PC pins of a DPDT switch would normally go.

if I do this, could I then use the top lug of the vacant middle column for a status LED? And if so, should I then just leave the center and bottom lug empty? Or do I need to jumper them together?

the attached diagram is how I would be wiring the LED, assuming that the two outer columns could function as the necessary lugs for the DPDT switching.

thanks - I'm a little new to this and really appreciate the advice I've gotten here so far!

-Chris


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## Mcknib (Sep 20, 2020)

Yes that'll work a 3PDT is just 3 SPDTs side by side or 2 for a DPDT ground the middle lug LED cathode to top lug as shown

So you could wire it exactly like the DPDT and use the 3rd pole for the LED if you like

There's a wee explanation of how a 3PDT works here:






						Aion Gale No Bypass Signal
					

This is a replica of Schaffer-Vega Diversity System in a pedal from Aion Electronics.  There is no bypass signal. The LED doesn't light up when activated. When the pedal is activated signal passes through - I can verify this because turning the knobs change the sound (the volume make it louder...



					forum.pedalpcb.com


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## Stelloh42 (Sep 20, 2020)

Thanks McKnib - I got a little more info from someone who has built up this particular reverb board before, and the DPDT spot on the board is actually for a mode selector toggle. They also explained where the pads for wiring a 3PDT were - in seemingly random places around the perimeter of the PCB. But I appreciate the response, because, I'm the future I really would like to know that I've "got it" when it comes to, say, adding an LED and 3pdt to a vintage Rat (a cardinal sin from what I understand, hah)
Thanks again!

-Chris


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## Mcknib (Sep 20, 2020)

Use that method Chris it's the same as the ppcb method apart from your LED and CLR are on the main ppcb board

I hadn't read your question properly so just as well someone else told you (updated now) centre would be ground top LED cathode, no jumper

You'd only use the bottom one if you were using a common anode bi colour LED whereby you'd put your CLR  and power on the common anode LED centre pin and stick your 2 cathode pins one to top lug one to bottom with the middle ground lug connecting either cathode to ground and lighting each LED side / colour as you switch between them


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