Desktop Repair – Faulty fan

I’d like to think most of the times I get things right and can spot a problem straight away. However on this particular repair I was wrong every step of the way, which may seem a strange thing to admit on a blog advertising my services.

I received an email asking about a desktop computer which was reporting an error on boot-up saying that the CPU fan wasn’t working. In addition to this when playing games the owner could only get 15 minutes out of the game before it crashed. That to me seemed pretty cut and dry, a failed CPU fan was causing the processor to overheat when put under strain (which games usually do more than generalwindows usage). My original plan was to go round, open up the case, see what type of fan I needed, order it and then fit it when it arrived. Simple.

I was wrong.

I arrived, opened it up and saw the fan happily spinning and keeping the CPU cool. The reason for the error was that it had been plugged in to the power socket for the “case fan”, the motherboard therefore didn’t think the CPU had a fan attached, nothing serious. So why was the game crashing? Upon booting the game it showed some pretty severe graphical corruption on the loading screen. Bright rainbow colours and flickering lines were present. Aha! It’s the graphics card, I’ll swap to onboard graphics to test and I bet they’ll work.

I was wrong.

I took out the graphics card and booted up the computer using the onboard graphics. The problems were still present and the game still crashed after a small amount of time. So what was left?

Fortunately the customer had a spare desktop pc hiding away, a computer that had become virus-ridden and was therefore banished to the cupboard, broken. This desktop machine was of a very similar specification (almost identical) to the troublesome computer. I reasoned if it wasn’t the graphics card then perhaps it was the Power Supply failing. Again, games draw more power than bog standard windows usage so it’s possible the power supply just couldn’t provide the juice.

I was wrong.

Power supplies were swapped around and I booted everything back up. The problems were STILL there. For good measure I swapped the memory around, that wasn’t the problem either.

So it came down to the motherboard and CPU, it’s rare that they would expire like this, normally they just outright fail. Still, I had the spare parts so there was no harm in trying. The customer admitted they were rather fond of their old computer, so rather than remove the motherboard and CPU and put it in to the case, I moved the contents of the newer desktop in to the old case. That included the hard-drives, memory (well, I mixed and matched, boosting their memory by 256mb in the process), graphics card, etc.

I booted up the ‘new’ computer and Windows informed me it wasn’t ‘activated’. That’s not unusual, as a security measure XP usually needs activating after a big hardware change, and you don’t get much bigger than swapping motherboard and CPU. I ignored the activation for the time being, more concerned with the performance of the PC.

I put in the game, crossed my fingers (because if this didn’t work I was pretty much out of ideas) and it worked, at last. Final diagnosis, it was the motherboard and/or the CPU. I took the pc home that evening so I could tidy everything up inside the case, activate windows and make sure all the drivers were installed and then returned it back to the owner.

My Fee: £25
Parts: £0 (fortunately managed to swap and change between the two broken computers and come out with one working one!)

Total: £25

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