S-Union240W Power Supply Unit Replacement for Dell OptiPlex 390 790 960 990 3010 9010 Small Form Factor System SFF H240AS-00 H240AS-01 H240ES-00 D240ES-00 AC240AS-00 AC240ES-00 L240AS-00 PH3C2

I received a Dell PC that wouldn't turn on at all, it was flashing the power light on the front. I replaced the power supply with this unit and it immediately worked just fine. The installation was pretty easy and it fit in place without issue. So far it works properly and I haven't noticed any issues.

It was a simple install using common sense that took less than 10 minutes start to finish. I turned the computer on and it worked. It has been working steadily for almost a week with no problems.

Certain models of Dell computers have gained a reputation for being built with less than quality power supplies which can fail without warning, leaving your business short a workstation. This replacement can save the day, and even someone with minimal experience inside a computer can swap it out for the faulty one in about an hour. If you have an experienced IT person available, it will not take long at all.Almost all of our Dell Optiplex 390 and 790 computers have had their power supplies fail now, so we keep one of these replacements on hand at all times so we don't have to go more than an hour without a machine. It's cheap insurance. We have not had a replacement fail yet- it's always the original we're taking out of a dead computer.How do we know when the power supply is the issue? First, it's one of our older Dells that isn't working, usually an Optiplex 390 or 790. Second, the computer was working fine yesterday, and today nothing happens when we push the power button. No fan, no lights, no beeps... just nothing, and all the cables are plugged in snugly and there's power to whatever surge strip or UPS it's plugged into. Sure, there are other things it might be, but so far a bad power supply has always been the culprit.I've replaced two of them myself. I have just enough experience inside computers to identify most of the parts, but I would not know where to put those parts in an empty case. It's really more my brother's area, and I try to have him do it when I can, but if a computer fails early in the day then I need to do it since he can't get to us until the evening.If you also don't have a lot of experience and yet somehow find yourself to be the best (or only) candidate for the job, here's what gets me through: (Credit goes to my brother, who's been doing this dusty, sneeze-inducing job since windows were still just for looking outside.)1. Unplug the cord from the back of the computer. Not only is this standard procedure when working inside a computer, but you have to anyway since the cord plugs into the power supply, and you'll be removing it. In fact, unplug everything and then bring the computer to a well-lit surface where you can work comfortably. Then ground yourself before touching anything inside the computer (touch the screw on a light switch, etc.) since a static shock can damage components.2. Grab your phone and take pictures of everything before you remove anything. Then you'll be sure you're putting everything back the way it was. This especially goes for any wires you unplug. Most only fit one way, but it still helps to know which way that is since they tend to fit snugly and it can be hard to tell if it's not lined up quite right or you have it completely backwards when you can't clearly see the receptacle due to the tight quarters inside some cases.3. Dells often don't require a lot of tools these days. There were three screws in the back of the power supply holding it to the case, but otherwise I looked for blue plastic pieces to remove, slide, push, or pull to get things out.4. Pull wire connectors straight out and push them straight in. Some are locked in with a clip. I used a long, skinny file to reach in and push these clips since my fingers wouldn't fit. A pair of small-nose pliers may help you get a firm grip on the plug. And of course never pull on the wires themselves.5. Work slowly and deliberately. If something seems stuck, try to figure out why rather than just pulling or pushing harder.6. If wires go under something, you'll probably need to move that something out of the way. You usually can't just slide the wires out, and it's even less likely that you can slide them back through. There's too much for them to catch on, and they may even be held in place with clips you can't see yet. I had to set the CD drive and the hard drive aside to get to one of the cables from the power supply. Both drives were held in place with blue plastic locking pieces, which I discovered after remembering tip #5.The nice thing is that the replacement power supply was a perfect match for the original. All the cables were the same length and the colors on the individual wires matched up. It makes it as easy as this job can possibly be, so hopefully you'll be back in business with a working computer in short order.

Worked good

Mi pc ya tiene tiempo con este producto lo volvería a comprarBuena calidad y muy potente

These Dells are tough and good. The use on the power source does take toll. Got the product next day and was up and running within minutes. Fresh screws and zip ties are included.

Good product

Works in Dell 970 without issues. Fraction of the cost of others.