Announcement

Collapse
No announcement yet.

Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

    Got this one for free because, well, it no worky.

    A little research and there are tons of complaints all over forums/the internet about premature failure of these switches. The observation everyone makes about these is "they run hot" and failure occurring as soon as 13 months, right out of warranty, of course.

    Upon removal of the cover I found a G0398-15011480A power supply that, when plugged in, was making a constant ticking noise. Multimeter confirmed the PSU was the issue. Output was cycling between 0 and about 20V. With output disconnected it sat around 20V.

    This thing is a huge pain to work on, but eventually I was able to remove the heatsink. Once I removed the heatsink, it was apparent the primary capacitor, a generic Chinese "STGCON" 450V/150uF, was bulged on top. other folks online had other components fail on theirs but the root cause may well have been the failure of this junk capacitor. It's a bummer because the rest of the caps on the PSU are Rubycon!

    I dissected an old PSU out of a hard drive RAID enclosure and scavenged a KXG 450V/100uF capacitor. I had to slightly rearrange another component to make the replacement cap lay down and between part of the original heatsink from this PSU and pieces of the heatsink from the other PSU I came up with a (temporary) solution that allowed me to a. make it work (solid 53.7V output) and b. put the cover back on the switch. Note that this is a very temporary solution and I don't recommend going this route lol.

    Before we continue, let's make it very clear that the failure of this power supply in the Ubiquiti switch is a design flaw due to inferior components and/or insufficient cooling. Adding a fan to this unit that runs 24/7 and cools the PSU would probably have made the low quality Capacitor last a lot longer, or they could have simply used a better primary capacitor.

    Other people online found that the Mean-Well ASP-150-48 power supply is a direct replacement with screw holes, connectors, etc. that line up perfectly and properly fit inside the case without any modification: https://www.amazon.com/PowerNex-ASP-.../dp/B01HTH8M1U

    And as per the reviews on that Amazon listing, multiple other people bought it to fix these switches. But, I'm not about to pay $100+ for a replacement power supply for a switch that's barely worth more than that. That said, if you need to fix one of these with a simple, plug-and-play solution in a business environment where a DIY solution is unacceptable or impractical, that's your solution.

    If you're like me and cheap AF, we're gonna do better. I found a "Cosel LEA50F-48-Y Power Supply, 48Vdc, 1.1A" on eBay for $12 ... That's on its way. Picture attached. Seems like the mounting holes and connectors are at least close to the original power supply. Another option would have been an external 48V DC power adapter but I didn't have any floating around and they were about $25 on eBay for decent looking ones. Worth noting that replacement power supply is only good for about 50W, however the max number of PoE devices this thing is gonna run is one, if any at all, so it's fine.

    Next thing up, a fan. I'm going to seek out either a small blower-style fan or one or more 30mm fans. As for how to run it, looks like a 48V DC to 12V DC converter is like $10 on eBay... or I could drill a hole in the casing and get a little barrel jack type of thing and use a separate 12V power adapter for the fan. But, obviously I'd prefer a free solution. Any ideas?

    Attachments:
    1. Original PSU as it came. As you can see, not only is the primary capacitor buried underneath a heatsink, but that heatsink is then covered in plastic, and there is no fan in this unit.
    2. Failed junk capacitor.
    3. Temporary repair of original PSU to confirm.
    4. Plastic shield from another junk PSU - safety first.
    5. Replacement PSU I will be using.
    Attached Files
    Last edited by shovenose; 08-11-2021, 01:34 PM.

    #2
    Re: Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

    reminds me of the watchguard firewall/routers, I forget if I put a picture of the ghetto mod I put in to get the PSU to work again as I don't have any spare 450V capacitors.

    The PSU failed even with cooling, then again, the fans tend to fail in the watchguard too, fans and 1U rackmounts are doomed to failure...

    Comment


      #3
      Re: Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

      Originally posted by eccerr0r View Post
      reminds me of the watchguard firewall/routers, I forget if I put a picture of the ghetto mod I put in to get the PSU to work again as I don't have any spare 450V capacitors.

      The PSU failed even with cooling, then again, the fans tend to fail in the watchguard too, fans and 1U rackmounts are doomed to failure...
      Meh, the auto parts store I work at finally retired their 10/100 netgear unmanaged switches. All of them w 40mm fans in them. 3/3 still worked fine after however many years. So it's possible to get a good little fan. It just seems most vendors want to go with fanless because it's silent. After all, once the 1-year warranty is over, who cares anyway, right?

      PS: Anyone that comes across this, I'm down to buy your broken us-8-150w/us-16-150w or other dead ubiquiti routers/switches if you don't want it anymore and don't want to fix it yourself.

      As soon as all the parts arrive I'm going to post exactly how to permanently fix your US-8-150W (and by that logic any other similar product) with 1. a good, cheap power supply 2. cooling fans in such a way it still looks stock from the outside... for like $30.
      Last edited by shovenose; 08-12-2021, 11:49 AM.

      Comment


        #4
        Re: Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

        Is this a 150W power supply? That Cosel is only 50W.

        Adding low-speed fans is still better than nothing, so being completely fanless is kind of silly.

        Comment


          #5
          Re: Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

          50W might work if PoE is not really being used perhaps, and dang, I'm still using a 10/100 switch...

          Well if most of the power is dissipated elsewhere and the PSU is efficient, then fanless is a possibility. Not so with the WG, it was feeding a i815, a few RTL8139's, and a Tualeron.

          Comment


            #6
            Re: Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

            Originally posted by lti View Post
            Is this a 150W power supply? That Cosel is only 50W.

            Adding low-speed fans is still better than nothing, so being completely fanless is kind of silly.
            Correct. However I will be using this for tops 2 unifi APs and they won't need much power.

            Comment


              #7
              Re: Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

              Just a question since you already identified the fault, why don't you just buy a properly fitting capacitor and call it a day?
              "The one who says it cannot be done should never interrupt the one who is doing it."

              Comment


                #8
                Re: Ubiquiti Unifi PoE Switch US-8-150W Power Supply Failure

                Originally posted by Per Hansson View Post
                Just a question since you already identified the fault, why don't you just buy a properly fitting capacitor and call it a day?
                Ah, yes, well the problem is the way this PSU is made it's a huge pain in the ass to put it back together properly.

                I have another dead switch coming and perhaps I will combine both PSUs into one that works using the original heatsink etc.

                I really need to get a new tip or new soldering iron but basically to get it apart I had to fish a screwdriver through the heatsink to hold the nuts that are on the other end of the screws that hold the components to the heatsink. Unless I desolder all of the components, reattach them to the heatsink, and then resolder everything, it's not going to go back together properly.

                I want to find a solution that's DIY friendly and doing that is definitely not.

                Comment

                Working...
                X