Zit Seng's Blog

A Singaporean's technology and lifestyle blog

How an IT Engineer Fixed His Home PC

200807203584The symptoms: No beep, no video. Sounds bad. What happened at the start was that the PC, which runs Linux full-time, had become unreachable over the network. There was nothing on the video, and keyboard/mouse provoked no response. The PC has not hung in a very long while, but perhaps it did for some strange reason this time. Nevermind, hit the reboot button. No beep, no video. Okay, power cycle. Still, no beep, no video.

A quick check on the web using my MacBook found that there were several possible things that could go wrong: faulty video card, motherboard components (such as RAM modules) having gotten loose, dead CPU, etc. I have two video cards. Actually, it is one video card, in addition to the built-in video card on the motherboard. First thing to try was to remove the video card and plugged my monitor into the onboard graphic card port. Still no go.

I had to go to work. So I abandoned the troubleshooting. It’s rather inconvenient, because I store all my emails in this Linux PC. All my email accounts were automatically consolidated, sorted, and filtered in this PC. All my emails were archived in there too. With the PC “down”, I would be going without access to my quadrillions of emails. I hadn’t expect the hard disk to be the problem (touch wood), so all my data would still be there, only just temporarily inaccessible.

After work and back home again, first order of business was to figure out the PC. Fortunately, things did not turn out that bad. I thought maybe I would need to change the motherboard or something. But I didn’t. It was really a combination of problems that turned out to be easy to fix.

Firstly, my monitor cable was loose. It was loose at the monitor end. I had not thought to check it in the morning.

After I got back my video display, it was much easier to see what was going on. My PC looked okay. I booted up Linux. Linux got stuck. It seemed like there was no network. I rebooted into single user mode to troubleshoot. Really, the network seemed to be dead. The network configuration was okay, the drivers loaded okay, no errors or anything logged by the system. But there was no network traffic, and nothing including my default gateway was reachable from the system. Linux could correctly detect loss and re-establishment of link state when I unplugged and plugged back in the network cable. Hmm, dead network cards usually should mean no link state too.

Okay, I went back to my MacBook and tried to access my wireless broadband router. I logged in to its web administration interface. Then I notice that it seemed to be the wrong wireless broadband router. I had logged in to my “old” wireless broadband router (yeah, over the years I ended up with more than one running at home). Okay, I checked my MacBook wireless connection, and realized it had associated to the wrong wireless network. I got my MacBook to associate to the correct wireless network. Hmm, I was prompted for a WPA password. It should not have done so. It is already saved. I re-enter it anyway, but I still couldn’t get in.

So, I suddenly realized: My wireless broadband router must have hung. I rebooted the router and sure enough, the network came back to normal. My MacBook could associate with the correct wireless network, and the network for my Linux PC came back okay.

What about the “no beep” problem? Well, now I’m not interested to troubleshoot it anymore. Most likely the speaker is spoilt.

So I was plagued with multiple problems simultaneously:

  1. The video cable came loose.
  2. The wireless broadband router hung.
  3. The speaker was spoilt.


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