Dim LED

[DeadAirMD]

So I built the Aion DZ4 preamp (love it) a while back, and have been having a ton of LED issues. The LED is insanely dim, I can barely tell when the pedal is engaged or not.

I've changed the CLR all over the board, removed the connection from the LED pads on the PCB to all over the board, changed LED colors multiple times........I'm at a total loss.

Any suggestions on what to do?

 

[chris.knudson]

Any chance your LED has its own CLR built in? Have you tried jumpering the CLR?

 

[DeadAirMD]

Started with the LED soldered to the LED pads, beyond dim, likely barely lit. Changed LED, still didn't work, changed LED color, no luck. Jumped the LED with/without clr from the 9v Jack, same result. Never had this happen before, beyond stumped.

 

[xefned]

Have you tried dropping the CLR value to something low, like under 1k?

 

[DeadAirMD]

I'm gonna give that a try when I get to my shop today. Not sure if the DC-DC converter is causing this issue or not. The docs call for the usual 4.7k, but you have to cup your hand over the light to make sure it's even on.

 

[KR Sound]

Are your LEDs good to begin with?

 

[DeadAirMD]

Yeah for sure, this is the only pedal they don't light up on. I have some from SDP, Amazon, GPCB, Amp Parts, Antique Elec, so it's definitely not the LEDs.

 

[DeadAirMD]

Is there another place on the actual PCB I can jump the LED to from the 9v DC jack to try that also? I used the breakout board for the foot switch as well, the LED struggles big time on its led pads.

I remember seeing in a post here a diagram for jumping an led from the DC connection to another place on the board, but can't seem to find that.

 

[KR Sound]

Let’s see a pic of your build. This breakout board has more going on that his typical ones. I don’t even see it in his schematics.

 

[DeadAirMD]

Absolutely, I'll be to my shop in an hour. I also built the PPCB version (Valhalla), so if all else fails, I'll fall back on that. Just like the signal I'm getting from Aion a bit more for my rig.

 

[DeadAirMD]

Sooo, the LED is blinding when I connect it from the DC jack to ground. So looks like the LED pads on the foot switch PCB are kaput.

Where else can I connect the cathode of the LED on the switch or main PCB so it turns on/off with bypass?

 

[benny_profane]

Sooo, the LED is blinding when I connect it from the DC jack to ground. So looks like the LED pads on the foot switch PCB are kaput.

That tells me your LED already has a CLR in it. An LED without a CLR would fail almost instantly when connected to +9V.

Again, please provide pictures.

 

[DeadAirMD]

The yellow wire is going to the CLR/anode LED under the PCB, white unsoldered wire is cathode. CLR on anode is 2k2. Only works when I touch cathode to ground of 9v jack of course. LED pads on PCB do not work. Heat shrink on led under PCB. Effect works perfect minus no led.

If the LED pads don't work, what else can I attached the LED cathode to?

 

[Nic]

Could you clean this ?

 

[benny_profane]

I think the CLR/LED pads may be fine once the daughterboard I/O and switch pads are cleaned up. You can also verify continuity with a DMM to confirm that they are not connected properly.

 

[chris.knudson]

Check the voltage on the anode side of the LEDR pad on the daughterboard. You should be seeing close to 9V. If you don't get something close, check the voltage where +v connects to the daughterboard, if those voltages don't match, the problem may be in the footwsitch. If they do match, and they are less than 9v, then you have an issue with the power supply getting to the daughterboard. .

EDIT: Of course you need the pedal engaged to see voltage on the LEDR pad in case that wasn't obvious.