US-48-500W power supply repair

Julien ARNAUD

One of our US-48-500W died at work. Since Ubiquiti has bumped the price and shifted the range quite a lot, I decided to repair it to keep it as a spare. 

I first confirmed that the PSU was the culprit by powering the switch with my lab PSU.

Using a meanwell PSU (RD-125-2448) providing both 24V and 48V rails ,we don't reach the original 500W of PoE power, but that's still enough for our needs (some phones, cameras, and access points).

As per the datasheet, you are getting up to 48W on the 24V rail, and up to 96W on the 48V rail.
The 96W are all available for PoE devices.
On the other hand, the 48W are shared between the switch itself, and any "passive PoE" devices that might require 24V. Typically other ubiquiti devices such as access points.

 

I didn't put much efforts into PSU placement in the rack.

If you are in the same situation, you can quite easily find which rails/cable are 24V and which are 48V (all yellow or all red), replace the PSU with an off-the-self one. All that's left is to wire stuff neatly and safely.