PSU/mobo question

[jeffmoss26]

I got a new case a few weeks ago from a friend. It came with a RaidMax power supply. For some reason that PSU turned on right when it was plugged in to the wall, I tried it in a couple computers and the front panel switches would not turn the computer on or off. So I figured it was bad.
I bought a new PSU yesterday. Plugged it in and it did not come on automatically, which I thought was good. However, the switch in my new case would not turn it on or off. Got a new switch today, still nothing. Just to be sure I tried the new PSU and switch in another comp and they worked fine. So I'm leaning towards a motherboard problem. Hopefully someone can steer me in the right direction.
Thanks!
Jeff
(Feel free to move this to motherboards if need be)

 

[Ice Czar]

you decision to not employ the RAIDmax was a very good one

as far as the supply not starting
most supplies require a certain amount of load on them inorder to send the Power Good signal, the mobo maynot be providing a load that it can read, so add a few fans and HDDs and see if it will work

Power Good Signal
Power On Signal


and the obvious double checking that the mobo power on header is correctly attached to the switch

you can test the supply independently by again loading it with a few fans and drives then employing a paperclip or peice of wire at the main mobo connector shorting the green wire (Power On) to any of the black wires (Ground) , the voltage is +5V and less than 1A in other words not even enough for you to feel if your holding the paperclip, its perfectly safe and exactly what the mobo does

 

[jeffmoss26]

I tried that and the power supply is fine. So I guess it's a motherboard problem. Any suggestions?

 

[Ice Czar]

well that rules out the supply as a faulty unit
not quite the same as saying the mobo is the cause

which supply is it
and whats it trying to power?

 

[jeffmoss26]

It's a "White Box" 400 watt ATX power supply from Micro Center
I have a CD drive, floppy drive, 2 hard drives, and a case fan.

 

[Ice Czar]

without a mobo CPU and Vidcard I can see why your having trouble booting

the type of each would immensely help in determining your power consumption

 

[jeffmoss26]

I assumed you knew I had a CPU and mobo
CPU is P4 2.0
Mobo is MSI 845G max-L
onboard video (yeah, I know...)

 

[Ice Czar]

OK give me the amp figures on the sticker on the side of the PSU
for the +3,3V +5V and +12V rails

and if its listed the combined wattage for the +3,3V & +5V
and combined wattage of all three

 

[jeffmoss26]

Will have to get that info later as I am in school all day.
Thanks,
Jeff

 

[Ice Czar]

amp draw estimates for the +12V rail are as follows

P4 2.0Ghz 75.3W or 6.25A
mobo normally 0.5A but with an onboard VGA lets bump that to 2A might be more
Optical drive 2A
HDD 2A per or 4A
(drives would actually only need the full draw at spinup at which time you wouldnt be pegging the CPU, so lets say 1A and since the optical isnt spinning up normally discount it altogether)

even a properly functioning peice of junk old school ATX12V v1.2 or v1.3 PSU rated at some completely lalla land temperature like 21C and likely in that class rated 18A or so should be able to jump start the config

Im thinking short here
This is how I build a new config

dismount everything
start over
employ ESD precautions < very important

install CPU, heatsink\fan, speaker and (last) PSU > try for beeps
(no need to reinstall the CPU and if your confident the heatsink is properly mounted that either, verify that the heatsink fan is on the proper mobo header, sometimes a board wont start without a fan detected as a thermal cutout protection)
start the board by shorting the 2 pins on the mobo header with a screwdriver (refer to manual)
at which point if there are no beeps and fan activity turn off or unplug PSU and add a single HDD and try again
still no beeps skip to the last part below ####

if there are beeps

install memory, vidcard and monitor > try for a single beep and BIOS (make sure to check temperatures)
(unlikely but sometime a shorted component here, more likely just a dead component, but the board will generally beep like crazy)
make sure to unplug the PSU or turn it off with the switch on the back of the supply if it has one, ATX spec has power running to the mobo all the time (+5VSB) for wake on LAN, WAN and softpower on, refer to the ESD precautions link above

mount mobo into case and repeat to > BIOS (make sure to re-check temperatures)
(this is where it often falls apart there being a mobo tray stud in the wrong location, catches new builders all the time shorting to the back of the mobo)

Attach drives, fans > BIOS (again turn off or unplug PSU)
(if it suddenly stops working here you have a shorted component isolate which one it is)

Install OS & mobo drivers

install additional cards and drivers (again turn off or unplug PSU very important especially on the PCI bus which generally deals with wake on LAN and WAN when the NIC isnt onboard, even when it is the bus is partially powered)

secure computer then connect to internet
stress test components, especially test RAM (memtest86+)


#### I have next to no confidence in a MicroCenter 400W whitebox
and even if it does turn on with a minimal load I wouldnt completely rule it out as the source of the problem,
It could still easily be defective
Id suggest borrowing a high quality known good supply and trying that as well

at which point going through the above you have likely reduced the issue to the mobo

 

[jeffmoss26]

I will try this. This is not a complete rebuild, just transferring my system into a new case.
Thanks again for the tips.

 

[jeffmoss26]

well i tried what you said, to no avail. Not sure what's wrong. I think I'm gonna have to get a new mobo.
Thanks again,
Jeff