BYOC KoT issue... Only one side working

[zelcanada]

Hi everyone,
I recently built a KoT clone from BYOC, but there are some strange things happening:

- I have no guitar signal on bypass.
- The"left" side (right side of the PCB in the photo) works fine.
- The "right" side, when engaged also had no signal, although the led goes on.
- interestingly, if I have the left side on, then the right side works when engaged. All the knobs and switches do what they are supposed to do.


(I know I still have to cut the leads off of my LEDs)

I have checked continuity on the foot switches (and their wires) and they all seem good.

Obviously input, output, and power are all fine because the pedal works on the yellow side!


The "yellow" part of the schematic is the one that's working fine. It's the "green" one (and both bypassed) that doesn't work.

I've tried to figure out the switching on the schematic to pinpoint the problem, but I'm too new to this to really grasp it.

This is such a weird specific issue, I'm hoping that someone with a better understanding of circuits will be able to identify the problem right away! Why would both sides work when both are engaged, but not one side when engaged alone?

Thanks!

 

[Nic]

Edited since BrainDrain opened my mind :
My guess, check the left side bypass.

May be a problem of bad switch. Check continuity between pins 8 and 9 and jumper from 4 to 9. 2-3-5-6 when in bypass... they should all have continuity. Find if the problem is the 3-6 jumper or bad internal connexion between 2-3 or 5-6

 

[zelcanada]

My guess, check the left side bypass.

May be a problem of bad switch. Check continuity between pins 2-3-5-6 when in bypass... they should all have continuity. Find if the problem is the 3-6 jumper or bad internal connexion between 2-3 or 5-6

Thanks Nic. I checked continuity on those pins and they are all good. Jumper is fine too

 

[Tommygun011198]

so if both circuits are off is there no signal? if theres no signal when both circuits are bypassed it would suggest that there is a break in the connections between the jacks and the footswitch, or that the signal path is being sent to ground somewhere. i think check your solder joints between the jacks and the board and the foot switches and the board. check continuity of the true bypass signal path, i.e. input jack to footswitch 1, footswitch 1 to footswitch 2, and then footswitch 2 to output jack all while bypassed. then check the input jack to the output jack continuity.

i would then check for signal path to ground. its quite easy to accidentally bridge your signal path to ground which will cut the sound entirely. if the input jack and output jack have continuity when bypassed then your guitar signal should go through just fine.

i know its annoying to hear as its usually most peoples suggestion without looking, clean up loose component leads and solder joints, itll make trouble shooting a lot easier!

if you find continuity between your guitar signal and ground, and the jacks and footswitches look fine, youll need to trouble shoot the board. if everything is cleaned up what i sometimes do is hold a light behind the PCB and check it from both sides. if the PCB is a simple green soldermask you can normally see the traces, ground planes, solder joints etc. when held up to a light. by doing this it makes it easier to see where any accidental short circuits might be

good luck! its a great circuit, i recently built one too and it sounds incredible, hope you can get it working!

 

[BrainDrain]

Turn both switches off. Looking at it from the gut shot check for continuity between lugs 8 and 9 of the “right” foot switch (the one below the 5mm clipping LEDs) Double check all the jumpers on both foot switches and check those for continuity too. My guess is the footswitch on the right side isn’t working as it should. If it’s the wiring it probably wouldn’t work when they’re both switched on and the fact that one side only works when the other is switched on is telling me it’s a switch issue. Try putting a jumper between lugs 8 & 9 of the right footswitch when it’s in bypass.

 

[BrainDrain]

My guess, check the left side bypass.

May be a problem of bad switch. Check continuity between pins 2-3-5-6 when in bypass... they should all have continuity. Find if the problem is the 3-6 jumper or bad internal connexion between 2-3 or 5-6

Think you’re right about the bad switch. I might be looking at this wrong but Isn’t the 3-6 jumper for ground connection? Lug 1 looks like the LED, Lug 2 ground, and lug 5 looks like the circuit input. If any of those weren’t making connection inside the switch during bypass the circuit input wouldn’t be grounded but the pedal should still bypass the signal. I’m thinking lugs 8 & 9 might be the issue when in bypass.

This is what I see when looking at the switches:

1. LED
2. Ground
3. Jumper to 6
4. Input
5. Circuit input
6. Jumper to 3
7. Circuit output
8. Output
9. Jumper to 4

 

[Nic]

@BrainDrain

Edited : You are right !

2 and 5 are for the signal to come in and out (of the switch).
3-6 jumper is where the signal is routed when bypassed.
1-4 are the signal going to and back from the circuit.

SO, from the IN pad, the signal will go straight to pin 2 of the right side (left switch in your picture as we are looking at the guts.)
PIN 5 from right side should run straight to PIN 2 on the left side (right switch when looking at circuit.) PIN 5 will go to the OUT pad.

jumper from 4 to 9 grounds the board signal when in bypass (and the led)

SO (somebody correct me if I'm wrong here)
1. To circuit input
2. Input
3. Jumper to 6
4. From circuit output
5. Output
6. Jumper to 3
7. To Led
8. Ground
9. Grounds Led and circuit output in bypass

 

[BrainDrain]

@BrainDrain
2 and 5 are for the signal to come in and out (of the switch).
3-6 jumper is where the signal is routed when bypassed.
1-4 are the signal going to and back from the circuit.

SO, from the IN pad, the signal will go straight to pin 2 of the right side (left switch in your picture as we are looking at the guts.)
PIN 5 from right side should run straight to PIN 2 on the left side (right switch when looking at circuit.) PIN 5 will go to the OUT pad.

jumper from 4 to 9 grounds the board signal when in bypass (and the led)

SO (somebody correct me if I'm wrong here)
1. To circuit input
2. Input
3. Jumper to 6
4. From circuit output
5. Output
6. Jumper to 3
7. To Led
8. Ground
9. Grounds Led and circuit output in bypass

View attachment 95731

Idk, looking at the schematic I think what I listed is correct. There’s a few ways to wire a 3PDT but I’d trust the schematic over anything else. This way of wiring it is pretty much the same way Devi Ever did it. The gut shot is from a “Rocket” owned by another forum member. Looking at the left foot switch (input jack side) it’s pretty much the same except the input and output lugs (4 & 8) are swapped.

 

[Nic]

Idk, looking at the schematic I think what I listed is correct. There’s a few ways to wire a 3PDT but I’d trust the schematic over anything else. This way of wiring it is pretty much the same way Devi Ever did it. The gut shot is from a “Rocket” owned by another forum member. Looking at the left side it’s pretty much the same except the input and output lugs (4 & 8) are swapped.

Well, now that I see it that way, I might have been totally wrong !

So yeah that invalidates a lot of what I said ... and that switch might really be bad.

 

[Nic]

Turn both switches off. Looking at it from the gut shot check for continuity between lugs 8 and 9 of the “right” foot switch (the one below the 5mm clipping LEDs) Double check all the jumpers on both foot switches and check those for continuity too. My guess is the footswitch on the right side isn’t working as it should. If it’s the wiring it probably wouldn’t work when they’re both switched on and the fact that one side only works when the other is switched on is telling me it’s a switch issue. Try putting a jumper between lugs 8 & 9 of the right footswitch when it’s in bypass.

So yes, by the schematic the internal connection between pins 8-9 could be bad (if the jumper between 4 and 9 is good)