Power supply won't fire up with 'on hand' motherboard

[Shoogle]

Originally I had this good system with a VIA Gigapro motherboard. I
replaced it with another inorder to plug in a All-In-Wonder video card
which requires a VGI (?) slot.
Well, I thought I would get another case with p/s and build up another
system with parts I have. The new power supply is good (tested by the
shop) BUT the thing won't power up when plugged into the VIA board! I
Know, it 'probably' is the mother board but how could it die just moving
out of the case and having it stored carefully away in the anti-static
bag. I have checked and checked the jumpers, the mounting, even the CMOS
battery-- I can't think of anything else to do. I don't want it to be the
motherboard, please, please <g>.

 

[JAD]

no CPU cooler connected?

 

[spodosaurus]

Originally I had this good system with a VIA Gigapro motherboard. I
replaced it with another inorder to plug in a All-In-Wonder video card
which requires a VGI (?) slot.
Well, I thought I would get another case with p/s and build up another
system with parts I have. The new power supply is good (tested by the
shop) BUT the thing won't power up when plugged into the VIA board! I
Know, it 'probably' is the mother board but how could it die just moving
out of the case and having it stored carefully away in the anti-static
bag. I have checked and checked the jumpers, the mounting, even the CMOS
battery-- I can't think of anything else to do. I don't want it to be the
motherboard, please, please <g>.

You have told us virtually nothing about your problem. Does anything at
all happen when you try to power it up? Have you made sure there are no
shorts between the motherboard and case? Have you tried shorting the
power-on pins on the motherboard to rule out the power switch? etc etc etc

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[Shoogle]

Sorry, I wasn't complete here.
When plugged in (mounted to the case), ATX plugged in all jumpers checked
as per manual, no peripherals, or just the monitor and keyboard. At
another time, m/board was isolated from the case. Neither time did
_anything_ happen, even the p/s fan doesn't start. And yes checked out
the 'start' switch for continuity and plugged into the right pins on the
header. Let's see that's all I can think of--I did a pretty close
inspection of the board and don't see any shorted jumper pins or anything
obvious. I even cleared the CMOS by putting the shorting jumper in
temporarily to clear it and then back to normal. Hmmmm...I guess that's
all.

 

[JAD]

remove the PSU . jump the green wire to a ground(black) on the mainboard
connector. plug in the PSU to outlet and power up using the rear switch. PSU
works?

 

[Shoogle]

I want to thank you guys, I've figured it out! JAD jarred my sluggish brain
into 'thinking'. The jumper was the key--thinking that it wasn't getting
the 'ok' to start. Well, I hate to display my stupidity for the world to
see but it was that I was reading the pin #'s on the header _backwards_,
i.e. pins 21,22 which are the POWER ON I was reading as pins 1,2.
Therefore I wasn't shorting the "Power On" pins but the speaker or
something. Am I ever blushing! <g>