> For the complete documentation index, see [llms.txt](https://khalil-lab.gitbook.io/evolver/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://khalil-lab.gitbook.io/evolver/troubleshooting/vial-troubleshooting/replacing-photodiodes-and-leds.md).

# Replacing Photodiodes and LEDs

[Forum Guide](https://www.evolver.bio/t/replacing-photodiodes-led-on-smart-sleeve/155)

Additional tip: if you see strange raw OD values after swapping out LEDs or photodiodes, it's possible you have the positive and negative ends switched.