Hackaday · Creativity & design

Ubiquiti Switch PoE++ Repair

A Ubiquiti 24-port switch with 2.5 Gbit RJ-45 and 10 Gbit SFP+ ports had its PoE++ feature fail. The switch otherwise functioned normally, but all ports reported a bad PwrGood status, and logs showed PoE power status request errors.

Diagnosis confirmed the PoE functionality was dead. After disassembly, a short and hot spot on the PCB connecting to the PoE power board was found. The short persisted even after removing the board.

While a TVS diode checked out fine, two protective thyristor surge protection devices (Trisil), functioning as crowbar devices, were found to be shorted. These devices had likely sacrificed themselves during an electrical event.

Replacing one of these Trisil devices restored the switch's PoE status, allowing it to power a DC fan via a PoE splitter. The repair highlighted the importance of understanding protective circuit functionality for efficient fault diagnosis.

AI-samenvatting op basis van de bron.