POE Failure on WS-26-400-AC
Posted: Wed Nov 12, 2025 2:04 pm
ve a WS-26-400AC that had it's power supply die. As a test I pulled a brand new WS-26-400-AC out of the box and put the power supply from it into the dead switch. The switch will power on but it will not deliver POE on any port. Everything behaves like it is working but the radios will not turn on. Switch is on 1.5.26 and I have tried a factory reset. Is this a candidate for out of warranty repair?
Note on the screenshots below. Port 14 shows a 1.3w power draw. That's with a Mikrotik Cube plugged in but it does not power up. If I unplug it, the port shows a 0w reading.
If I disable POE on port 2 and run cable Diagnostics to my Laptop it passes.
Jan 1 00:00:56 UI[1415]: PORT 2 PoE: Off => 48VH
Jan 1 00:00:57 switch[1459]: PoE enabled on port 2, PoE Smart is starting cable check
Jan 1 00:01:02 switch[1459]: Port 2 cable check results: Open, Open, Open, Open
Jan 1 00:01:02 switch[1459]: Port 2 passed PoE Smart cable check, turning on power
Jan 1 00:01:07 UI[1415]: PORT 14 PoE: Off => 24V
Jan 1 00:01:09 switch[1459]: PoE enabled on port 14, PoE Smart is starting cable check
Jan 1 00:01:14 switch[1459]: Port 14 cable check results: Open, Open, Open, Open
Jan 1 00:01:14 switch[1459]: Port 14 passed PoE Smart cable check, turning on power
Note on the screenshots below. Port 14 shows a 1.3w power draw. That's with a Mikrotik Cube plugged in but it does not power up. If I unplug it, the port shows a 0w reading.
If I disable POE on port 2 and run cable Diagnostics to my Laptop it passes.
Jan 1 00:00:56 UI[1415]: PORT 2 PoE: Off => 48VH
Jan 1 00:00:57 switch[1459]: PoE enabled on port 2, PoE Smart is starting cable check
Jan 1 00:01:02 switch[1459]: Port 2 cable check results: Open, Open, Open, Open
Jan 1 00:01:02 switch[1459]: Port 2 passed PoE Smart cable check, turning on power
Jan 1 00:01:07 UI[1415]: PORT 14 PoE: Off => 24V
Jan 1 00:01:09 switch[1459]: PoE enabled on port 14, PoE Smart is starting cable check
Jan 1 00:01:14 switch[1459]: Port 14 cable check results: Open, Open, Open, Open
Jan 1 00:01:14 switch[1459]: Port 14 passed PoE Smart cable check, turning on power