This one is not normal.
The patient here is a Dell OptiPlex GX280 (tower). It has been diagnosed with power supply failure, and requires a power supply transplant. First, lets take a look at the patient:
As you can see, this is an older Dell. It's still utilizing ATX form-factor, instead of BTX. This one has a P4 3.2 GHz processor and 2 GB of DDR2-667 memory.
This Dell came with a 250W ATX power supply, model number PS-5251-2D52, made by Lite-On Electronics, Inc. After several checks with a multimeter and pin-out charts, I am glad to find that this power supply uses standard pin-out. The board takes the standard 24-pin ATX power connector, and the 4-pin 12V power adapter.
The power supply has a special casing which contains two rectangular holes that mate with metal clips on the Dell chassis. Here is the clip in question:
The green handle is attached to a metal tongue which locks the power supply in place.
These "features" will prevent a normal ATX power supply to fit, so I tried to find a direct replacement. A trusted source told me that, even if I could find one, it is not going to be cheap.
This is where the hacking and modding starts...
The replacement power supply is a Cooler Master eXtreme Power Plus 460W ATX power supply, model number RS-460-PMSR-A3. According to this review, it is a nice affordable unit but with an exaggerated output rating. Since the Dell will never consume power close to the conservative (430W) rating, this power supply is absolutely fine for this operation.
Lets put the two power supplies together:
The physical dimensions are the same. Looks like a quick and easy project, right? Wrong! The problem lies in the (lack of) on/off switch on the power supply. The following picture will show what exactly is the problem:
The chassis has no opening for the switch on the replacement power supply. With the switch protruding at the back, the power supply will simply not fit. Hence, it must be removed. To remove it, the power supply must be cracked open, like so:
The wiring is a bit messy, but who cares. Now lets focus on the switch:
The blue and brown (the standard color for neutral and live respectively) wires go from the IEC socket to the on/off switch, then to the power supply circuit board. The modification involves (1) cutting the wires off the switch, (2) removing the switch, (3) connecting blue wires together and brown wires together without mixing them up, (4) soldering and insulating the connections, and (5) covering the hole for the switch with electrical tape. Here is what the outcome looks like:
With a slight bend on that protruding metal clip on the chassis, this replacement power supply fits perfectly. After screwing the power supply in place, it is just a matter of plugging all the stuff back.
With the new power supply, this Dell is back to life and ready to work:
