Hardware

Fix disabled wireless in Ubuntu on Lenovo laptops

2014 edit: If you’re experiencing problems on Ubuntu 14.04 with wifi on your Lenovo laptop with a Centrino wifi chipset, try disabling wireless N.
See http://ubuntuforums.org/showthread.php?t=2208210&p=12943350#post12943350

—

Just updated my laptop to Natty Narwhal and I may write something about it in the future (spoiler: Unity sucks). Anyway this post is just about the solution I found for the broken wireless network manager applet in Ubuntu 10.10 and 11.04 in Lenovo B450 and probably most other Lenovo laptops.

Ever since I upgraded my laptop to Maverick Meerkat, my wireless isn’t automatically enabled on startup. It was no big deal back then since I could just simply tick the Enable Wireless in the network manager applet. But when I upgraded to Natty Narwhal, my wireless was permanently disabled.

After hours of trial and error, I found out the culprit. Running sudo rfkill list showed that I have an “acer-wireless” even though I wasn’t using an Acer machine:

bry@Abraxas:~$ sudo rfkill list
0: acer-wireless: Wireless LAN
        Soft blocked: yes
        Hard blocked: no
...

The solution to this was simple: disable it by adding blacklist acer-wmi at the end of /etc/modprobe.d/blacklist.conf.

Windows Memory Diagnostic

I wasn’t able to post a Thursday post because:

National Holiday (Eid ul-Fitr) meant that I had to be onsite on Thursday instead of Friday, and
when I turned on my rig that morning, it beeped continuously won’t go to POST once, but booted properly the next time I turned it on.

A quick Google search told me the computer problem was probably a memory error and so I set my PC to run Memtest86 on a loop before going to the office. When I came back, my RAM passed 13 tests with no errors.

And then when I restart the PC the continuous beeping returned. =/

With the memory out of the question, thus began my 3-hour trial and error session to isolate the problem. PSU problem? Nope, multimeter reads normal voltages for all lines. Overheating? Cleaned off the dust from the CPU and video card heatsinks to no avail. Extra devices screwing with the motherboard? Removed all but the HDD and video card but still the continuous beeping happens once every few reboots. Heck, I even tried replacing my HD4850 with my spare GTS8800 to remove the possibility of a busted video card.

Another run through similar problems via Google gave me an idea: what if Memtest86 was wrong and it really was the memory?

And so I tried the Windows Memory Diagnostic that came with Windows 7.

Windows Memory Dignostic

In less than a few minutes, I found out that my RAM really was busted.

Memtest86 was trumped by a Windows utility program. Weird.

PLDT DSL High Attenuation

Problem

After isolating the usual suspects (line problems, modem problems), my attenuation downstream for PLDT DSL is still 60+.

Cause

The polarity of my wall jack is wrong (I replaced it before because it got borked, my bad). Pin 2 should be positive.

Solution

Corrected the polarity of the wires. Now my attenuation downstream is 55: still low, but at least now my DL speed goes beyond 200KBps. May have to contact PLDT later.

Returning a Seagate Hard Drive for Replacement

This is a blog post from 2009. The information here is already out of date. Please contact your seller for updated details how to RMA a hard drive

Certified Repaird HDD

Problem

My 1TB Seagate hard disk drive died on me last July 21.

Cause

Hard drives randomly die for various reasons, from fired circuit boards to damaged magnetic platters. Anyone who has worked with computers should expect it to happen once in a while.

Solution

Thankfully, the RMA procedure for Seagate hard drives is well documented in a TipidPC post.

Continue reading “Returning a Seagate Hard Drive for Replacement”

Randomly Restarting PC

Problem

PC is randomly restarting once every day or two. I could replicate it easily by playing Call of Duty 4 for a couple of minutes.

Cause

I haven’t found the cause yet.

The most likely cause of the shutdowns would be overheating. I took a spare 120mm fan and put it inside the rig’s aluminum case.

Still shuts down when playing COD4.

Tried to double check the heating problem. I downloaded Orthos Stress Prime and Furmark to stress test the rig.

It doesn’t shut down even if the load is a lot higher than what COD4 does to the system.

Power supply problem? I highly doubt it because I’m using a Corsair HX 520 PSU. Just to make sure, I switched the rails used by the video card.

Still shuts down when playing COD4.

Maybe it’s the drivers. So I uninstalled the drivers then used DriverSweeper to scrub the drivers clean. Reinstalled the latest ++ATI Catalyst drivers.

Still shuts down.

Maybe it’s the video card itself. Besides, it is a factory overclocked video card. So I switched it with my old video card, an nVidia 8800GTS 320MB card. Of course, I re-scrubbed the drivers again.

Still shuts down.

Maybe it’s a memory problem. Ran memtest86+ using a Ubuntu installer cd I have lying around.

No memory errors.

—

At this point, the only possible cause for the shutdown I could think of right now is the motherboard itself. It is a quality motherboard, but even high-end devices can have defects later in their lifetime.

Before I could decide to replace the board, I have to try one last risky thing: flashing the mobo BIOS. Downloaded the latest version and flashed the BIOS with it.

Still shut down after 1.5 hours of COD4.

Looks like I’m going to have to buy a new one these next few weeks. Now the board itself is pretty stable and wouldn’t require replacement; I’m just worried that a random shutdown would affect the other hardware (e.g. the Seagate drive I had RMA’ed last week).

[August 14 Update:]

Solution

Bought a new motherboard to replace current one. This time, I was able to run through the first act of CoD4 without experiencing any crashes.