[Ham-Computers] RE: Computer shutting itself down

[Hsu, Aaron (NBC Universal)]

Dave,

You've received a bunch of good suggestions and your problem truly does point to an under-powered power supply.  Please allow me to offer a couple more suggestions...

By default, if Windows halts with a STOP eror (aka a Blue Screen of Death or BSOD), it's default out-of-the-box action is to create a small memory dump (minidump) file and then reboot.  If this happens, after the reboot, you'll find a .DMP file in the C:\WINDOWS\MINIDUMP folder - there may be several if your system as BSOD'd more than once.  Each file is named with the date of the dump plus a sequential number.  For example, the 2nd dump on April 30, 2007 would be named "mini043027-02".  The dump file is unintelligible by most people, but if you have Microsoft's Debugger tool, you can get more info on what might have caused the BSOD.  In your case, check to see if you have any .DMP files.  If so, there might be something else other than the power supply causing the problem (as Windows doesn't have time to create the dump file if the power is cut).  If you have any DMP files, e-mail me and I can take a quick look at them.

Good detective work on your system cooling!  Your system isn't all that bad.  The biggest heat generator is probably the 3.4GHz P4 CPU which has a TDP of 90 watts.  The GF4200Ti can also consume a bit of power (and generate heat), but it's a 5-year old design and doesn't compare thermally with more recent video cards.  Hard drives can also dissipate quite a bit of heat, but newer drives are relatively cool.  Rather than buying a fan at Rat Shack, goto http://www.newegg.com and buy a "decent" fan (aka, anything not from Rat Shack).  The most common sizes for case fans are 80mm, 90mm, and 120mm.  You don't need anything really fancy (such as blue/red/green/white/purple/etc LED's).  Link Depot fans are cheap and will work fine.  If you want to spend the extra $$$, then there are many options available - the choice is yours.  For reference, a Link Depot fan costs under $3.  More expensive case fans are about $15.  If you're interested in keeping your system "quiet", then get a thermally (or manually) controlled fan or look for one with a lower dB rating (usually lower RPM's).  Once you're on NewEgg's site, click on "Cooling Fans", then "Case Fans".

Another option is to take an 4x6 index card (or other card stock), cut it to size to cover the vent holes, then tape in place.  The case I use has mounting locations for five 120mm fans, but only comes with three fans (2 optional).  This left two large areas of ventilation that didn't contribute to good airflow.  I covered the rear fan vent with an index card and that helped with proper airflow.  With three fans creating "negative" pressure, the front opening didn't need a fan - plenty of "incomming" airflow created by the other fans.

One last thing relating to fans...make sure you get the airflow correct!  If you have both front and rear fans, make sure the rear are "exhaust" fans and the front are "intake" fans.  If you make them all "exhaust", then where is the are comming in from?  Also, if your rear fan is near the CPU fan, then  suggest it be an exhaust fan...don't need to "distribute" hot air from the CPU to the rest of the computer!

Case cooling is an art.  It use to be a "geek" thing, but now everyone's into "modding" their system.  I tend to use the KISS principle - just enough to keep things cool.


73,

  - Aaron Hsu, NN6O (ex-KD6DAE)
    {nn6o}@arrl.net
    {aaron.hsu}@nbcuni.com
    No-QRO Int'l #1,000,006
    . -..- - .-. .-   ".... . .- ...- -.--"
 



-----Original Message-----
Sent: Saturday, April 28, 2007 2:51 PM
Subject: [Ham-Computers] Computer shutting itself down


    Amazing number of replies to this issue! Many thanks to all. Here's 
the latest on it.

    Just ordered a 500-watt power supply for it. Sure can't hurt, and in 
all likelihood will cure the problem.

    However - Someone suggested I map out the airflow in the case. While 
I didn't attach little strips of tape as suggested, I do see a serious 
design flaw in this case! This is a tower unit, and the power supply is 
mounted in the upper rear of the case. There is an opening at the bottom 
front, supposedly for air inlet. When a placed a piece of light tissue 
by this front opening there was no indication of airflow at all. Opening 
the case showed the vent clear of obstacles or dust. When I looked at 
the rear of the case, the problem was obvious.

    The fan mounted on the CPU is blowing the heat from the CPU directly 
into the power supply. But worse than that is a vent in the rear of the 
case, about the size of a small box-fan, _directly under the power 
supply_! Outside air has no chance to get to the CPU, as it is drawn in 
through that rear opening and  sucked into the power supply and 
exhausted out by that outflow fan!

    My first thought is to pick up a small box-fan from Radio Shack and 
mount it on that rear opening blowing in. That would put 
room-temperature air almost directly onto the CPU, then to be blown into 
the power supply and out through that. If I then tape closed the front 
vent opening, it would insure good air circulation.

    Thoughts on this?

Thanks again for all the help! It's greatly appreciated!
73
Dave
KB3MOW