Mini KoT no LED

[Jbanks]

I’ve finished the mini KoT and it sounds great but I can’t get the right LED to work. I’ve pulled it out of the enclosure and am testing just the board plugged in. Replaced the LED and no luck. The 4k7 LDR seems to look fine. Any thoughts on what gives?

Thanks in advance!
James

 

[pbrommer]

Honest question: did you try flipping the leads? I always seem to screw up the legs for the LEDs at least 1 out of every 3ish builds.

 

[Jbanks]

Yeah I flipped the new LED just to double check and no luck.

 

[PJS]

Check continuity on the switch. It doesn't really take all that much heat to damage a stomp switch

 

[Jbanks]

Ok. I’ll try replacing the 3pdt and daughter board.

 

[Erik S]

Check continuity

Ok. I’ll try replacing

Or maybe just check continuity like PJS suggested...

Jumping to replacement without verification of a failure is as likely to cause problems as solve them.

If you're not familiar with how to do that, this would be a good place to ask/ search for a post that explains the process.

 

[genXslacker]

It's usually best to diagnose the problem before trying to correct it.

Definitely check the continuity of the switch before you desolder anything else.

 

[Jbanks]

Very good point. Ok, how do I check continuity between the 3pdt and the LED? I’m assuming one point goes to the anode (+) side of the LED lug and one goes to a 3pdt lug? It looks like LUG 3 on a 3pdt is usually the LED signal? I’m using a PedalPCB daughter board too.

Thanks
James

Check continuity on the switch. It doesn't really take all that much heat to damage a stomp switch

 

[genXslacker]

Very good point. Ok, how do I check continuity between the 3pdt and the LED? I’m assuming one point goes to the anode (+) side of the LED lug and one goes to a 3pdt lug? It looks like LUG 3 on a 3pdt is usually the LED signal? I’m using a PedalPCB daughter board too.

Thanks
James

Check the switch first. Get your digital multimeter and put it in continuity mode. It usually has a little icon on it that indicates that it is going to make noise when it detects continuity.



In the on state:

There should be continuity between lugs 1 and 2, and they should not have continuity with lug 3.
There should be continuity between lugs 4 and 5, and they should not have continuity with lug 6.
There should be continuity between lugs 7 and 8, and they should not have continuity with lug 9.

In the bypass state:

There should be continuity between lugs 2 and 3, and they should not have continuity with lug 1.
There should be continuity between lugs 5 and 6, and they should not have continuity with lug 4.
There should be continuity between lugs 8 and 9, and they should not have continuity with lug 7.

 

[Jbanks]

I think my DMM is broke. I turned to what I’m pretty sure in the continuity tester. No beep when I touch tips together. No continuity on the switch that does work either so I think my DMM might be broke some how. Any thoughts?

Thanks
James

 

[Erik S]

I think my DMM is broke. I turned to what I’m pretty sure in the continuity tester. No beep when I touch tips together. No continuity on the switch that does work either so I think my DMM might be broke some how. Any thoughts?

Thanks
JamesView attachment 120140

Not all DMMs have a beep function, but that looks like it would be one to me.

Could you have a bad probe? Do other functions work?

In a pinch you could click over to the left and measure the resistance in ohms - no continuity expected on the switch = infinite ohms, continuity expected = some small number (similar to what you would measure touching the probes together.)

The beep function is very handy though.

 

[Jbanks]

Ok. I bought a new pair of wires and that helps. Now I get a beep on one of my DMM’s lol. Now after checking both the left 3pdt that works for the LED and the right side that the LED doesn’t work, both switches are showing continuity where they should and shouldn’t be.

The other bizarre thing I realized just now testing it again is that both sides control the other side in terms of pots. So when you turn on the left channel (top row of pots), the bottom pots for the other side also work!?! Something is amiss. Any ideas how to trouble shoot what is going on with the pots. And the bottom row also controls the top.

I tried to attach a video of it but it’s too large. But the bottom line is that either side controls the other side as well. And even in bypass, the gain, volume and tone pots work.

Thabjs
James