Low Tide pedal works perfectly, except for the LED

[Laurenslamberts]

My Low Tide build works as expected, and sounds great.
The only issue is that the LED turns on for about half a second when the pedal is powered, and then fades out quickly. It won't turn back on for a while after.
The LED appears to emit a barely visible amount of light, which is also not being affected by the state of the footswitch.

I measured the VCC at the anode, checked the resistance of the resistors leading to ground and the capacitor. All seem fine.

I already tried replacing the LED, swapping anode/cathode of the LED and replacing the capacitor leading to ground.
The only difference I can find comparing to the build doc, is that my 25V 22uF capacitor is only 4mm wide instead of 5mm. But I don't think this should be an issue, right?

Any ideas are very welcome!

 

[music6000]

My Low Tide build works as expected, and sounds great.
The only issue is that the LED turns on for about half a second when the pedal is powered, and then fades out quickly. It won't turn back on for a while after.
The LED appears to emit a barely visible amount of light, which is also not being affected by the state of the footswitch.

I measured the VCC at the anode, checked the resistance of the resistors leading to ground and the capacitor. All seem fine.

I already tried replacing the LED, swapping anode/cathode of the LED and replacing the capacitor leading to ground.
The only difference I can find comparing to the build doc, is that my 25V 22uF capacitor is only 4mm wide instead of 5mm. But I don't think this should be an issue, right?

Any ideas are very welcome!

It sounds like the 4K7 LED Resistor might have a cold solder joint or SW Solder Pad on Footswitch or SW on PCB ????
Reflow with Solder at these points.
A Capacitor has nothing to do with Power to LED!

 

[benny_profane]

Short the SW pin (i.e., fourth from the left) to ground to rule out a switch issue. If the same behavior is exhibited, try removing the C21. It might be leaky and causing a short to ground. If that helps things, you can replace it with another or omit it if you’re not experiencing any switch pops or you don’t care for the LED fade out.

EDIT: After rereading the post, although there may be an issue with the cap—which could be causing the dim lighting at all times, this doesn’t address the fact that it doesn’t light fully when it should. Follow @music6000’s advice and verify that the switch is working properly.

 

[Laurenslamberts]

Many thanks for your ideas!

I tried reflowing all the points @music6000 mentioned, but unfortunately the issue still persists.
All the solder joints around the LED, it's resistors and the footswitch connections look fine to me.

When I take resistance measurements around the LED resistors, those look fine as well.
The combination of R54 and R55 gives me the expected 6.8k resistance (this is the reading. Should be 6.9k according to schematic, but I guess that's fine)

Any other ideas by chance?

 

[benny_profane]

it's resistors and the footswitch connections look fine to me.

Did you try shorting the SW pad to ground? You may have an issue with the switch itself. Are you using a breakout board or did you wire directly to the switch?

 

[Laurenslamberts]

When I short the SW pad (either on PCB or breakout board), the LED lights up.
This is the footswitch wiring i'm using;

 

[Fuzzonaut]

I think you might want to reflow those pads on the footswitch breakout bord again ...

 

[benny_profane]

I think you might want to reflow those pads on the footswitch breakout bord again ...

Yep. Your issues is with the switching. You could reflow the entire switch, but the top two pads of the middle column are what’s affecting the LED. While you’re at it, ensure that the pads for all of the off-board switch wiring look good.

 

[Laurenslamberts]

Good to have that isolated!

I just reflowed;

• all breakout board pads
• the pads at the other end of the tiny yellow cables
• the 3pdt lugs in the breakout board.

Same issue, unfortunately. The sound is there, the light is not.
FYI; The 3PDT switch is one from Alpha, and operates decently to switch the circuit in and out the signal chain.

 

[Robert]

Install a jumper wire across the two pads at the bottom of the breakout board.

That breakout board is designed to be used with an illuminated 3PDT (built in LED).

 

[benny_profane]

Install a jumper wire across the two pads at the bottom of the breakout board.

That breakout board is designed to be used with an illuminated 3PDT (built in LED).

Can you add a note to the product page for that board telling people they need to jump the onboard LED pads on the main pcb (if applicable) when using that board?

 

[Laurenslamberts]

Adding a jumper between those pads did it!
While ordering the breakout boards I misinterpreted the function of it.
Thought it was for a regular 3DPT, with possibility of adding a status LED.

Thanks you all for helping me with troubleshooting.
Now it's time to enjoy playing this pedal!

 

[Robert]

Can you add a note to the product page ...

That'd probably be a good idea, yep.

 

[music6000]

Read This for future troubleshooting :

Important: Supplying Pictures when an Issue arises with a PCB Build !!!

I have to raise this ongoing issue when Members ask for Help with an Issue with their Build. I keep repeating this saying '' Pictures are worth a Thousand Words'' !!! Please supply Pictures of PCB & ALL connections ( Footswitch, Input & Output Jacks, Power Jack ) to it along with a clear...

forum.pedalpcb.com

 

[Feral Feline]

@Laurenslamberts

Mark this one SOLVED!