Page 1 of 2 12 LastLast
Results 1 to 10 of 20

Thread: Power Problems

  1. #1
    Newbie
    Join Date
    Nov 2007
    Posts
    3

    Power Problems

    Hi there as you'll see by the post count am a new guy to the scene here.

    So firstly my names Gary and I drive a MK6 fiesta. I am from Scotland I have been building a car pc for the last 5 months or so. Itís at the finishing stages of production and I am now into the tweeking stage.

    However and heres my problem that I hope someone will know the solution too or help me in the right direction. My pc randomly restarts on occassions. I cannot figure out why. From a cold boot the system will start up with no problems and run for a while. Without any warning it will just restart and after this go into an infinite loop of reaching the windows load screen and restarting.

    If I leave the system off for 10-15mins it will boot up fine again and run as normal before the random restart occurs at some point and the loop begins again.

    Also if I shut down the system with the power switch and try to boot the system straight after again, it won't and reaches the windows load screen before restarting and continuing in the loop as above.

    The system works fine in the house and no power issues have risen their head.

    The PC specs are as follows:

    mobo: AsRock K7S41GX miniATX
    CPU: AMD athlon 2100+
    Memory: 512Mb Geil DDR400 (limited to DDR333 as the mobo doesn't support 400)
    Hard Drive: Western Digital 80GB IDE 3.5inch 7200rpm
    Onboard graphics
    Display: Lilliput 7Ē touchscreen 629GL-70NP/C/T
    PSU: M2-ATX 160W 6-24V

    I have not tried running the pc in the house yet using the M2-ATX PSU powering it yet. I have just used a standard 500W one directly. I can only narrow the source of the problem down to perhaps the battery or possibly an issue with the M2-ATX.

    The pc is not ignition powered on. I have set up a power and reset switch with a couple of display LEDís as you would get on the front of any desk pc. The sound travels via the Headunits AUX in as I still wanted the use of this for short journeys when booting the pc up was too much of a hassle.

    Any help would be greatly appreciated as this problem has me stumped for now

    Here are some photos of my work.





    Thnx in advance Gary

  2. #2
    Neither darque nor pervert DarquePervert's Avatar
    Join Date
    Apr 2004
    Location
    Elsewhere
    Posts
    13,948
    Sounds like it's overheating, causing it to reboot.
    I'd check out some monitoring software like MBM5 to check the temp of your CPU. How are those fans configured? The ideal is to have one push and one pull air, creating airflow across the CPU whenever the PC is on.

    No guarantee its an overheating issue, though. It could be bad RAM or a flaky area on the HDD causing corrupt data or overload of the PSU.

    Sounds like you've investigated one or more of these possibilities to some degree.
    I think your next step would be powering the M2 inside to see if you have the same issues.
    Have you looked in the FAQ yet?
    How about the Wiki?



    Under normal circumstances, a signature would go here.

  3. #3
    Newbie
    Join Date
    Nov 2007
    Posts
    20
    Quote Originally Posted by DarquePervert View Post
    Sounds like it's overheating, causing it to reboot.
    I'd check out some monitoring software like MBM5 to check the temp of your CPU. How are those fans configured? The ideal is to have one push and one pull air, creating airflow across the CPU whenever the PC is on.
    Actually two fans is a poor idea in a box with only two holes. Even if one pulls air and one pushes air, you get an airflow problem where both those fans will be fighting one another.

    Put the fan above the CPU to pull in air (the air will be coldest at this point), and then it will exit the other hole. You can also add some homemade air plenums to direct the air where it needs to go most.
    Eastern Voltage Research Corp.
    http://www.easternvoltageresearch.com

  4. #4
    Neither darque nor pervert DarquePervert's Avatar
    Join Date
    Apr 2004
    Location
    Elsewhere
    Posts
    13,948
    Quote Originally Posted by eastvolt View Post
    Actually two fans is a poor idea in a box with only two holes. Even if one pulls air and one pushes air, you get an airflow problem where both those fans will be fighting one another.
    Please explain how two fans blowing in the same direction are "fighting one another".

    The logic of this configuration is one fan pulling ambient air into the case while the other fan (preferrably nearest the CPU) exhausts warmer air outside of the PC case. How on earth does that make the fans "fight"?

    Put the fan above the CPU to pull in air (the air will be coldest at this point), and then it will exit the other hole. You can also add some homemade air plenums to direct the air where it needs to go most.
    This is a matter of debate, actually.
    While your logic is sound, others (myself included) believe that the fan over the CPU should be exhausting the warm air (heated by the CPU) out of the case.

    Rather than relying on the suggestions of others, I suggest orienting the airflow of the fans and measuring temperatures in both configurations and go with whatever configuration produces the lowest CPU temps.
    Have you looked in the FAQ yet?
    How about the Wiki?



    Under normal circumstances, a signature would go here.

  5. #5
    Newbie
    Join Date
    Nov 2007
    Posts
    20
    Quote Originally Posted by DarquePervert View Post
    Please explain how two fans blowing in the same direction are "fighting one another".

    The logic of this configuration is one fan pulling ambient air into the case while the other fan (preferrably nearest the CPU) exhausts warmer air outside of the PC case. How on earth does that make the fans "fight"?
    It is simple fluid dynamics and basic 101 for any mechanical engineer who is designing and building cabinets. Firstly, you can only exit as much air as you are forcing into a closed box. Input airflow = Output airflow. The problems arise in the fact that even identical fans will have different airflow characteristics depending on the particular motor and rotor design. This is bad in this configuration as all kinds of weird pressure gradients and vortices are created due to the mismatching and airflow is compromised. One fan in this configuration ALWAYS works better than two because of this.


    Rather than relying on the suggestions of others, I suggest orienting the airflow of the fans and measuring temperatures in both configurations and go with whatever configuration produces the lowest CPU temps.
    I'll agree with that.
    Eastern Voltage Research Corp.
    http://www.easternvoltageresearch.com

  6. #6
    FLAC
    Join Date
    Oct 2006
    Location
    Las Vegas
    Posts
    1,286
    Quote Originally Posted by microATX Thermal Design Suggestions
    Version 1.0 page 18
    Employing multiple (identical) fans in a system does provide some marginal increase in
    airflow. The exact amount of margin depends on many factors, including fan speed and
    configuration, as well as chassis airflow impedance. If the fans are not identical, then the
    figures will change slightly, but the trends will be similar. The general rule is: if the chassis
    has high impedance, place the fans in series; if the chassis has low impedance, place the
    fans in parallel.
    Link

  7. #7
    Low Bitrate
    Join Date
    Dec 2006
    Posts
    75
    athlon CPU's would be probably the worst configuration in a car PC enviroment. They are inefficient and run at high temperatures even at idle. i suggest changing to another cpu one that is low wattage maybe a sempron

  8. #8
    Newbie
    Join Date
    Nov 2007
    Posts
    20
    Quote Originally Posted by h3rk View Post
    Actually, this has to do with computer cases which are by no means closed systems. They have vents etc... all over the place where can can enter and exit as necessary.

    With a high impedance system, you would use fans in series as this would give the air more pressure to push through tight spaces, large finned heatsinks etc...
    With a low impedance system, (lots of open space), then pushing in parallel (higher velocity airflow) would benefit.
    Eastern Voltage Research Corp.
    http://www.easternvoltageresearch.com

  9. #9
    Newbie
    Join Date
    Nov 2007
    Posts
    3
    Seems as if I unearthed a heated discussion on air flow there, no pun intended

    I have only one fan installed at the rear of the box rite next to the cpu acting as an exhaust. The other hole on the lid was positioned above the hard drive as I know they can become rather hot and expel most of the wasted heat in a computer system when enclosed in a small space.

    I have noticed that when the lid is open the cpu fan spins slower than when closed. But I narrowed that down to the fact that heat from the heatsink is traveling upwards once blown by the fan and hitting the lid which then pushes it back down onto the fan, so its spinning faster to disperse the extra air. I am gonna cut an extra hole positioned above the cpu's fan and this should solve that problem.

    I ran the computer with the lid closed in the house for an hour or so with the standard 500W PSU, then went into the bios to check temp lvls, and the cpu never went above 40C. Leveling out around 35C in most cases. I know these temps can be crude but they give off a rough estimate.

    I will also note that my althlon 2100+ is actually underclocked to a 1500+ because the motherboard doesn't seem to stay stable when changing the motherboards FSB jumper to 133Mhz to produce the 1733mhz that the 2100 should process at. So therefor is at 100Mhz FSB with multiplier of 13 as standard. The Athlon I found gives out a peak 72W. This is of course before its underclocked so its possibly producing less. I know the 12V rail on the M2 gives out 96W. Is this possible cutting it a bit fine?

  10. #10
    Neither darque nor pervert DarquePervert's Avatar
    Join Date
    Apr 2004
    Location
    Elsewhere
    Posts
    13,948
    Quote Originally Posted by Alfredbra View Post
    athlon CPU's would be probably the worst configuration in a car PC enviroment. They are inefficient and run at high temperatures even at idle. i suggest changing to another cpu one that is low wattage maybe a sempron
    That's a blanket statement that isn't correct in all circumstances.
    Your suggestion to use a Sempron CPU doesn't remedy the matter much, since there are some Sempron CPUs that suck down as much (or more) power as their Athlon64 big brothers.

    Rather than try to say "this CPU is bad and this one is good", it's a much better methodology to check the power draw of compatible CPUs to determine what works best for you and your installation.

    Both Intel and AMD make some power hungry CPUs. They also both make some very efficient CPUs. Neither brand is better or worse for power draw ON THE WHOLE.
    Have you looked in the FAQ yet?
    How about the Wiki?



    Under normal circumstances, a signature would go here.

Page 1 of 2 12 LastLast

Similar Threads

  1. Power problems with m2atx.Please help.
    By sanjaym in forum Power Supplies
    Replies: 2
    Last Post: 09-13-2007, 07:14 PM
  2. Power Problems
    By FeynmanSum in forum Power Supplies
    Replies: 2
    Last Post: 08-18-2007, 05:22 PM
  3. DC-DC Car Power for Mac Mini
    By MikeH in forum MacCar
    Replies: 53
    Last Post: 02-19-2005, 12:13 PM
  4. Power Problems Please Look
    By kmfdmk in forum General Hardware Discussion
    Replies: 15
    Last Post: 02-15-2004, 08:39 PM
  5. HELP!!! Need advice - power problems...
    By mwinkler in forum General Hardware Discussion
    Replies: 9
    Last Post: 02-23-2001, 06:54 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •