DIY PCB help with names

[Toastman]

Hello everyone, I recently acquired a bunch of diy PCBs, I don't have schematics for them. Everything makes sense, expect I can't figure out what could JI, JO, PI, PO mean?
I initially thought it could mean Jack, power input/output, but I am not so sure

The IN and Out + ground is on the top.

EQD black ash for reference...

Thanks in advance

 

[Aleph Null]

JI = Jack in
PI = Pedal in
JO = Jack out
PO = pedal out
SW= LED switch

 

[Toastman]

It seems to be connected to the middle lug of the volume knob.
I will measure it all

 

[Robert]

My guess is that those are JACK IN, JACK OUT, PCB IN, and PCB OUT (or Pedal as Aleph suggested).

PI and PO being the actual circuit input and output, and JI and JO being convenience pads (connected directly to the IN/OUT pads at the top) for wiring up the 3PDT footswitch.

SW would be the low side of the LED, pulled to GND by the footswitch to light the LED.

 

[Toastman]

Oooh, that makes sense.
It's an older photo, I had already populated it.
I'll try wiring it this way, I hope it works...

Thanks very much.

 

[Toastman]

Hello, little update.
Finished it and it was the way you said, works great, but it's a little bit too muddy for my ears, even with the tone at full.

Anyone know what I could do to increase the treble/high frequencies? Any mods changing values? I tried changing the input and output cap from 4,7uF to 2,2uf, but it didn't really do that much

Thanks

 

[Cybercow]

Hello, little update.
Finished it and it was the way you said, works great, but it's a little bit too muddy for my ears, even with the tone at full.

Anyone know what I could do to increase the treble/high frequencies? Any mods changing values? I tried changing the input and output cap from 4,7uF to 2,2uf, but it didn't really do that much

Thanks

The last cap in the circuit (between the Top and Volume pots) is a 2n2. I suggest increasing that value to taste, starting with a 4n7 to bleed more bottom end to ground.