I have a wireless bridge that is USB powered in a remote location. I have a standard 802.3af PoE injector on one side of an ethernet run, and PoE splitter on the other side of the run. The POE splitter then provides USB power for the bridge. This has worked fine for ~3 years. Exact parts: injector, splitter.
This has stopped working, and I do not know how to diagnose if it's the splitter or injector that has failed.
I've used a USB meter to try to diagnose the problem and this is what I've found.
- The bridge works fine when powered by a standard USB power bank. It draws 0.14A @ 5V.
- When nothing is plugged into the splitter, it reads 5.05V 0A, which is within tolerance.
- However when I plug the bridge into the splitter, the voltage sags immedietly going as low as 4.20V, and it shows 0A being drawn.
What are the next steps to diagnose this, or can you already tell which device is at fault?