Monthly Archives: October 2007

usb tv tuner problems (dvb-t) part 2: dangers of overclocking

Computer Aid Posted on by

So far, I have fixed up some antenna problems, but the dvb-t TV tuner (swann dvb-t SW112-DVB) still causes problems (the occasional PC lock-up… sometime more frequently than others)

On one PC I tested (P4 1.7 Ghz) the dvb-t worked without a hitch… a 10 hour overnight recording.

This PC has a PCI card to add an additional 4 USB ports, so I figure that my original PC might have had usb ports that were not able to sustain a high data rate.

So I plug in the PCI card into my sempron PC. XP installs the drivers for the card, but says there was some problem. Sure enough, the usb ports don’t recognise the TV tuner, and not even a usb drive.

After some head scratching, I eventually remember that a did some mild overclocking on this PC. I increased the memory clock from 200Mhz to 212Mhz. This also increased the CPU speed from 1600Mhz to 1696Mhz, and the PCI clock from 33Mhz to 35Mhz.

Obviously this must have been just enough to disrupt the timing / stability of the usb circuitry.

I went back to the default clock settings, and I now get crystal-clear digital TV reception, with no dropouts, using the built-in usb ports (and the PCI card also started working normally after that, but I remove it, as I figure I don’t need it.).

After a few days, I noticed that the built in USB port would still (occasionally) cause the PC to freeze.

OK, reinstall the PCI usb card, and that seemed to fix the issue… except… now the freezing seems even less frequent… but it still happens.

While watching TV, CPU usage is 20% – 25%, but if I watch a HD channel, then CPU usage goes to over 70%. (and the stuttering returns… unless I increase the priority of the totalmedia.exe process to “above normal” via process manager.

I don’t care much about HDTV, but I eventually ditch my sempron and ga-k8vm800m motherboard, and get a used intel d865glc mobo and 2.6 Ghz P4 with HT… and thats the start of another story…

usb tv tuner problems (dvb-t) part 1: you need a good antenna

Computer Aid Posted on by

After my VCR died a few months back, I decided to go “digital”, and I purchased a swann dvb-t (SW112-DVB) usb tuner for my main PC.

Once I plugged it in (and installed the totalmedia software), I noticed a few problems:

  • the picture/sound would sometimes stutter and jerk… sometimes it would pause for a second or two. It wasn’t too bad. I would often get a few minutes of continuous, uninterrupted TV
  • My PC would occasionally freeze, so that I would need to give it a hard-reset.

After a lot of research, I discovered a few things:

  1. If a digital tuner has poor antenna signal quality, then the image/sound don’t develop “snow” like the analogue equivalent. What happens instead, is you get the stuttering and jerking I mentioned above.
  2. If the PC isn’t powerful enough, then it could freeze while trying to handle the huge amount of data arriving via a usb port (or the picture could stutter and freeze).
  3. What you do on the PC (even just scrolling within a browser), can affect the TV.

Since the tuner was connected to my fastest PC (a sempron 2800+ with 1.5Gb of 400Mhz RAM), then it should work fine (assuming there is no AMD/mobo compatibility issue).

I also tried it on a 800Mhz PIII with a fast video card, but the PIII struggled to maintain 1 second of continuous TV.

I then tried a 1.5Ghz celeron M laptop. It did better than the PIII, but still struggled, with many stutters per minute.

I was thinking the DVB-T tuner might be faulty, but I wanted to eliminate the signal quality as a cause (since the normal TV was quite snowy).

While waiting for the antenna guy, I noticed that the DVB-T tuner got quite warm when it was operating. Could it be overheating? I took the cover off, and was contemplating a cooling fan for the warm chip.

I eventually got the someone from MrAntenna to take a look, and he fixed a few things (replaced an analogue splitter with a digital one (to me, both splitters looked identical), and put a better quality antenna cable to the PC.

After that, the stuttering stopped, but the PC lockups started happening every few minutes…

The antenna guy recommends sending the TV turner back under warranty.

I decide to try it on one more PC: I take my workshop test PC (P4 1.7Ghz), and carry it upstairs to the “office”. And it works flawlessly over a 10 hour TV recording.

to be continued…

defender error 0X80072EE2

Computer Aid Posted on by

I am finding so many bogus windows defender errors, most of which disappear once windows defender is restarted, or the PC is restarted. Most seem to happen only after the initial install of windows defender.

But this particular one (0x8007E22E) happened to a laptop that had been running windows defender for a few weeks… and the owner called me because windows defender wasn’t updating anymore.

The main problem was the the customer didn’t wait for windows defender to complete its updates. (Customer was on dialup internet, and defender gives virtually no feedback that it is currently updating itself (I found the only way to tell is to click on the arrow near the help circle, and if the “check for updates” menu option is greyed-out, then it is in the process of updating… very annoying).

Its odd, since windows defender will give visual feedback on some other PCs… its almost like there are a few “undocumented” versions of windows defender out there…

telstra bigpond adsl modem (2wire) restarts if username is wrong

Computer Aid Posted on by

A new customer was having difficulty getting a new broadband connection to work.

Most times, its just something trivial, but this one was unusual.

When I got there, I started the modem and PC, and they both started correctly.

Customer says she contacted Telstra, but they eventually said “there is something wrong with your LAN hardware”.

The modem (one of the new telstra-branded white modems, with the word “2wire” on the side), had the usual LEDs that can be either red or green.

As expected, I found most LEDs turned green, except the internet LED (which flashed red). OK, it looks like I just need to connect to the modem, and enter the correct username and password.

So I start IE, enter 10.0.0.138 into the address bar, and then nothing happens (I’m expecting the modem web screen). A glance at the modem shows most LEDs switched off (except for a flashing power led)… looks like the modem either lost power, or reset itself.

I check all the cables, and everything looks ok.

I go get a usb to ethernet adapter from the car (to eliminate a failed ethernet port), but it also gives the same error.

I also change ethernet cable, in case there is a faulty wire.

But the modem still resets most times it is accessed.

At this point, I’m ready to say “its a faulty modem” (or maybe an XP problem).

Before I do that, I decide to remove windows XP from the equation, and I boot my mepis live cd.

And would you believe I can access the modem without any problem?

I find the username / password page, and I notice the username is something like: a@pigpond.com@pigpond.com ie two @ and two domains.

I correct the username and check that I can access the internet (It works!).

I restart into XP (I get the feeling it won’t work… but I’m proved wrong) and it connects to the internet as if there was never any problem.

The antivirus starts updating, I check a few websites, I run an adsl speed check, play a quick game on teagames.com, and after 5 minutes, decide that the problem must have been the double @ in the username field.

I restart the PC, just to be sure, and then I’m back on the road again.

vista update code 8024402C and windows defender 0X8024402F

Computer Aid Posted on by

A customer had just purchased a brand new acer PC. They had just got it out of the box, but didn’t feel comfortable with the vista setup. And they also needed me to setup their new ADSL internet.

Everything goes smoothly, except when windows defender updates, it generated an error 0x8024402F.

I try windows update, and I get a very similar error: 8024402C

From experience, I know that a windows restart usually fixes defender errors, but not this time.

A quick search reveals that one option is that the internet connection is being blocked, usually by a firewall.

Well, the only firewall on the system is the vista firewall.

I disable the vista firewall, and then both updates work correctly.

After the updates, everything seems to fall into place, and vista is working normally again (even after the firewall is re-enabled).