Thread: weird power problems

Originally Posted by trickyuno

M2ATX to power the following system
MB = FIC AZ11E
RAM = 1024mb pc133
GPU - GeForce MX4000 agp
Sound=Soundblaster Live 23bit
HD= 60gb notebook drive
USB Hub= Keyboard, gps, touchscreen

OK 12v constant connected to dash not directly to battery, switch connected to ignition, grounded to chassis. At first system booted fine, after shuting down and restarting only cpu fan and usb hub is powered. system does not boot. If I disconnect and reconnect the 12v+ while switch is on it will eventually boot, however as soon as I turn off the switch and try to reboot I only get the cpu fan and usb hub again.
Now here is the weird thing the m2 is apparently grounded somehow because if I disconnect the ground lead it will still power on the motherboard with no ground connected to the m2.
Computer is not in a case all components are mounted to plastic in rear deck not touching any metal.
Anybody got any ideas would be greatly appreciated. Also the few times I have got it to work I am getting a lot of engine noise even with system only powers on cpu fan and usb hub. Power, IGN and ground are all run on seperate side from audio, usb and vga cables.

Please Help

Thanks

Anybody have any suggestions at all on this.??

If the MB doesn't post, it may be a voltage issue. Try disconnecting peripherals one at a time to make sure that you are within the current limits of the power supply.

As for powering up with the ground lead disconnected, your power supply is finding a path to ground through one of the peripheral devices - most likely the LCD via the VGA cable.

Originally Posted by DarthTater

If the MB doesn't post, it may be a voltage issue. Try disconnecting peripherals one at a time to make sure that you are within the current limits of the power supply.

As for powering up with the ground lead disconnected, your power supply is finding a path to ground through one of the peripheral devices - most likely the LCD via the VGA cable.

Have removed everything except cpu, ram and graphics card still no consistent power, also next day after the original post I went outside and the battery was dead. M2ATX was set with no jumpers (dumb psu mode). I also find this that the usb hub and cpu fan will run when ign is off as if the M2 does not look for the ign signal only on the 12v constant line. Only way I have switching is if i connect the acc line to the 12v constant on the M2 then when switch is off M2 turns cpu off.

as for grounding through peripheral devices is this common, should this be happening or is this a sign of something wrong? I have found that you are correct here it will ground either with vga connected or sound card connected via headunits aux in.

Thanks for your input.

When in "dumb" mode the M2 will provide a constant 5V to the MB so that it can monitor the on/off switch - some MBs will also leave the USB ports on as well creating more drain on the battery. The M2 will NOT shut off due to low battery voltage in this mode. If you want to use the M2 as a switched device via the ACC line, you must set the jumpers for one of the power management schemes.

Also, if you are getting the +12V from the existing vehicle wiring, it may not support the current draw which could be causing your non-POST issue. Run a power line direct to the battery with a reasonable gauge of wire and it may solve your problems. Just don't forget to fuse the line within 12-18 inches of the battery or you risk a fire in the event of a short.

Yeah, the grounding thing is common. Hell, even your desktop PC shares the same ground plane across devices. If you pull the power cords on your PC and monitor leaving the VGA cable connected, you will find continuity between both devices through the ground prong on the plugs.

Hope this helped - good luck!

Originally Posted by DarthTater

When in "dumb" mode the M2 will provide a constant 5V to the MB so that it can monitor the on/off switch - some MBs will also leave the USB ports on as well creating more drain on the battery. The M2 will NOT shut off due to low battery voltage in this mode. If you want to use the M2 as a switched device via the ACC line, you must set the jumpers for one of the power management schemes.

Also, if you are getting the +12V from the existing vehicle wiring, it may not support the current draw which could be causing your non-POST issue. Run a power line direct to the battery with a reasonable gauge of wire and it may solve your problems. Just don't forget to fuse the line within 12-18 inches of the battery or you risk a fire in the event of a short.

Yeah, the grounding thing is common. Hell, even your desktop PC shares the same ground plane across devices. If you pull the power cords on your PC and monitor leaving the VGA cable connected, you will find continuity between both devices through the ground prong on the plugs.

Hope this helped - good luck!

Ran +12v direct to battery but still no post, mb is good works on bench with desktop psu. Cant be insufficent 12 rail on M2 reduced to cpu, 512mb ram, graphics card and hard drive but still no post. Any ideas?

Okay, so here's another test, try starting the MB manually (direct switch to the MB, not the M2) well after the M2 has been powered up. It's possible that the MB is checkiing the power on the rails before the PSU has had a chance to get the voltage up - that would prevent the PC from booting. If it doesn't work on the first try, hold whatever MB on/off switch you connect closed for 10 seconds and try again (but don't shut off the power supply).

Looking at your MB specs, you are right, the powersupply should handle the current okay. I am using the M2 with an MSI 6340, Duron 1100, 3.5" 7200rpm HD, G200 AGP video card, sound card, and wi-fi card with no problems whatsoever. I have set the MB bios to allow a +/- 1.5% tolerance in the bus speed - so that may be another thing to try. My MB had similar symptoms until I did that.

I know it's frustrating, but hang in there and you'll figure it out!

Originally Posted by DarthTater

Okay, so here's another test, try starting the MB manually (direct switch to the MB, not the M2) well after the M2 has been powered up. It's possible that the MB is checkiing the power on the rails before the PSU has had a chance to get the voltage up - that would prevent the PC from booting. If it doesn't work on the first try, hold whatever MB on/off switch you connect closed for 10 seconds and try again (but don't shut off the power supply).

Looking at your MB specs, you are right, the powersupply should handle the current okay. I am using the M2 with an MSI 6340, Duron 1100, 3.5" 7200rpm HD, G200 AGP video card, sound card, and wi-fi card with no problems whatsoever. I have set the MB bios to allow a +/- 1.5% tolerance in the bus speed - so that may be another thing to try. My MB had similar symptoms until I did that.

I know it's frustrating, but hang in there and you'll figure it out!

will try connecting power button and advise if this works, you lost me on the bios settings for allowing tolerance in bus speed, currently my bus speed is set to auto detect. How are you allowing for tolerance?

I definetely wont give up nor be defeated.

Originally Posted by DarthTater

Okay, so here's another test, try starting the MB manually (direct switch to the MB, not the M2) well after the M2 has been powered up. It's possible that the MB is checkiing the power on the rails before the PSU has had a chance to get the voltage up - that would prevent the PC from booting. If it doesn't work on the first try, hold whatever MB on/off switch you connect closed for 10 seconds and try again (but don't shut off the power supply).

Looking at your MB specs, you are right, the powersupply should handle the current okay. I am using the M2 with an MSI 6340, Duron 1100, 3.5" 7200rpm HD, G200 AGP video card, sound card, and wi-fi card with no problems whatsoever. I have set the MB bios to allow a +/- 1.5% tolerance in the bus speed - so that may be another thing to try. My MB had similar symptoms until I did that.

I know it's frustrating, but hang in there and you'll figure it out!

Ok, I tried using a manual power button and I dont think the results are good.
Here is what happened, cpu fan ran as usual but no post. moved manual power button to reset pin and held button for manual reset. This booted system 1 out of every 5 tries, however all of a sudden I lost the 5v rail from the power supply and now the system does nothing. Tested m2 with voltmeter and only getting voltage on 12v rail 5v rail post no reading or reading of .02v. Did I kill the m2?

Wow, sorry to hear that. I suppose it's possible that the M2 is smoked - maybe you had a bad board from the get go. I haven't had one lick of trouble with mine. I don't really have any great advice to offer at this point, maybe someone else will jump in; but if it were me, I would disconnect everything, double check the wiring, reconnect making sure everything is seated properly and try again. Have you tried emailing the manufacturer for support?