Anyway, this post is about my first PC Repair in a while. I have done some troubleshooting and repairs in the past but by far, this was the worst case I ever. It all started as a request from my cousin to service their computer unit that stopped functioning.
When asked why it stopped functioning, they said it was struck by a power surge caused by lightning. Since then, I knew that major hardware changes will be present but I didn't thought it would be this major. What I did not expect was the time I needed to repair it. I thought it would only take about a day to change the motherboard, but it extended on to 5 days!
Computer Specifications before repairs:
ACER Aspire M5641 Desktop Computer
| CPU: | Intel Dual Core E5200 running at 2.50ghz |
|---|---|
| Motherboard: | NVIDIA GeForce 7100 |
| Memory(RAM) | 2 x 1gb ddr2 800mhz |
| Hard Disk Drive | 320gb Western Digital Caviar |
| Power Supply | 300watt single fan |
Day 1. Initial Diagnosis
After talking to my cousin about what happened about their computer, she mentioned that she had also consulted a computer technician before she asked me to see their computer. She mentioned that the technician diagnosed that the motherboard is nonfunctional and it needs replacement for Php4,500 (Philippine Pesos; about $100).
I also did my own diagnosis. There is not a single sign of activity or even a sign that power is being supplied to the motherboard so I concluded that the one at fault was the ATX power supply. I tried testing the ATX power supply by shorting-out pins 15 and 14. The PSU fan kicked on and thought I was wrong with my initial assessment.
So I told her that I would repair it with only Php2,200(about $50) - the cheapest motherboard I could find in the local market.
Day 2. Replacing the Motherboard
After buying a replacement motherboard, a G31t-M7 from ECS, I proceeded to replacing the old motherboard. Everything is going fine until I stumbled upon a tiny bit of a problem. The mounting of the CPU fan was glued tight on the old motherboard and I can't afford to buy a new fan just to have another mount.
It took me half a day to remove the mounting from the motherboard. From there, the CPU and CPU fan installation went smoothly. Finally, the installation is back to normal. I even mounted the new MoBo into the tower and everything is correctly connected.
Then, hooking the unit up to my old CRT, mouse and keyboard to test it out, I plugged it in and turned the power on. Then nothing. Nothing happened.
After a few minutes coping with the frustration, I reassessed the situation. I began pondering on the idea that the PSU is also damaged. I began unscrewing the PSU so I can start a more comprehensive test on it.
Day 2.b Testing out the PSU
Again, doing the same method, I shorted-out pins 14 and 15 (black and green, respectively). Sure enough, the PSU fan would kick on. Baffled, I sat in front of my good friend, Mr. Google for a minutes trying to ask him what could be wrong. No answers.
Without a proper tester for ATX power supplies, I am left there wondering until I stumbled upon a webpage that details how to test ATX PSUs with a multimeter. If you want to read it, you can find it here.
Basically, testing includes shorting-out the pins 14 and 15, then methodologically testing each pin for voltage output. Apparently, there is no voltage output by the PSU unless it is turned on.
Not surprisingly, the PSU failed the test at the 5Volts DC output. The 12v and 3.3v are working fine.
Now to buy a new power supply. Unfortunately, the stores are now closed (around past 6pm) so I have to wait until tomorrow to buy the new needed part.
Day 3. New ATX Power Supply
I went down the computer hardware store and brought a new ATX power supply just fit for the new motherboard. After installing the power supply in the case, I connected the cables just to find something wrong. The power supply they sold me have 3 cables for IDE Drives while only one cable for SATA, and the unit needs 2 cables, one for the HDD and one for the DVD.
I called upon the shop to ask for a replacement but surprisingly, they told me that all of their stocks have those kinds of cables. They even asked me to turn the unit in for them to service, (and for what, additional charges for me? No way!)
So I let my creativity run wild again. I uncrimped a SATA Cable from the fried PSU and exchanged it with the IDE Cable of the new PSU. Now everything is connected!
Testing it out, I again hooked it up to my old system and voila! I managed to get as far as the BIOS. I checked all the BIOS settings and what made me nervous was the fact that the HDD can't be detected! I was nervous because at first I thought it was my fault for simply changing the headers for the cable.
I took out my portable SATA HDD and plugged it in the same exact power and same exact SATA cable. It was properly detected. With a sigh of relief and frustration, I concluded that the HDD was also fried by the power surge.
Day 4. New HDD
Asking permission for additional costs from the owners, I bought another Php2,450(Approximately $45) worth of hard disk. After installing it in the system, it was detected and working fine.
After installing the OS, I even played around it for a while. Until I noticed something, the CPU fan isn't starting up. I tried interchanging the fan with my own CPU fan, and it worked fine. Now, I need to change the CPU Fan.
Day 5. New CPU Fan
Finally, after changing the fan and reinstalling the motherboard into the ATX casing, everything is working fine. :)
