BIG DISCLAIMER: I have years of surface mount rework experience and the necessary tools. This is a job for a pro. So for any electronic techs out there with the skills, tools, correct solder, etc., hopefully this part number will be helpful. Otherwise, I'd suggest getting an RMA from Line 6 and paying them to do the job without causing damage. This post is just to help the techs have an alternate source for the LEDs. I'd hate for anyone to damage their Helix attempting to do this without experience, tools, and supplies, and any tech that has to try and fix it after someone damages the traces will probably curse you, your children, and generations to follow. Having said all that...
Mouser Electronics (mouser.com) has the footswitch LEDs. Mouser part number 710-15014M173100. Wurth (the manufacturer) P/N 150141M173100. Surface mount multi color LED. I bought 10 for $4.97 (May 2023).
