Sunday, 31 January 2016

Fixing a worn out power supply in a computer

A bit of a nerdy one today.

I have recently gotten an older PC that I will be using as a Home Theatre PC (HTPC) Unfortunately it has been having issues with instability and would shut down randomly and then when shut down properly it would not boot back up again. Sometimes it would not even reach POST (Power On Self Test), others there would be an issue with the POST. Once I even had it say there was a problem with the BIOS flash memory itself.

The original Stats. It's had a RAM upgrade and a new graphics card.
As you can see, not the most exciting computer. But it has a discrete graphics card which immediately blows anything else I have here out of the water for a HTPC. The computer I had been using did work, however there was often a lot of stutter during playback and complete CPU usage. This machine does not have that issue.

Here we see the new power supply next to the case. Originally it had a 300W supply. I have upgraded it to a 550W as the newer graphics card recommended somewhat more than the orginal 300W. I think this may have been one of the contributing factors that lead to the original supply failing. Often a supply will handle being overloaded. But it will cause it to fail much much sooner.

It's a pretty tight fit in this case. The only way for me to un plug the motherboard power cable was to first remove the hard drive and personal media drive bay. I was lucky that it came apart fairly easily and soon I had the motherboard un plugged.

With the motherboard and drives all un plugged; all that needs doing to remove the old PSU is taking out the 4 screws on the back. These all came out easly like they should. If this had been in a factory or somewhere where it's likely to corrode a bit it would've been a different story.

Here we have a side by side comparison to check that the old (left) and new (right) are actually the same size. They were. Time to reverse everything and put it all together.

If I was willing to spend the money on this computer I could've gotten a modular power supply. With a modular PSU you can remove some of the cables so you don't get a mess like the one above. As it was I was lucky enough to have to find a way to get this spaghetti monster into the case without jamming in a fan.

Before putting too much effort in I like to check that I have fixed the problem. This is what you see here. I plugged in only enough for the motherboard to boot off the BIOS chip and run it's POST. With that done I can finish buttoning up the system and getting the loungeroom back to a reasonable state.

With a little coaxing it all went back together reasonably well.

Success. Now I just need to set up Mythtv on here. If anyone is interested in seeing a writeup on how to configure a Mythtv Frontend, Master Backend and Slave Backends please let me know. I am not particularly happy with the current arrangement and if it would be of interest to someone then I would be happy to document the process.

Replacing a power supply is something that is not too difficult once you know what plugs go where and you are willing to take your time to work out what each part does the first time around. Also like this computer that was likely to be tossed, it is a relatively easy test that you can do that can extend the life of your computer.

Any questions, or thoughts please leave them below in the comments.

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