PSU won't go on

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I've tried to figure this out myself but gave up, so I hope someone can give me a hint. I hope this has a simple answer.

I was given a not too old m/b (Intel D845WN) and was thinking to make a whole computer out of it. But before I invest too much I want to check it out. So I put it on the bench and connected a PSU (the kind with the extra P4 connector). I turn on the PSU and the stand-by LED goes on. I shorted pins 6 to 8 on the front panel connector (2-row header) and --- nothing happens. The PSU doesn't go on. I'm pretty sure I've got the correct power switch pins, from a diagram I found on the Intel's support site.

I did the same thing with a different M/B, and the PSU does go on, so I'm pretty sure it's not the PSU. Also, I measure the voltage on the green wire from the PSU, and it is about 4 volts, whether or not the power switch pins are shorted.

I'm hoping the M/B is not bad, and that I'm overlooking some trivial thing that everyone except me knows.

BTW, there are no cards plugged in. I tried with and w/out memory, and no difference.

I also tried removing the battery for a while, then replacing it, but no help.

TIA.

-- Joel

 

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Stupid question . . . there IS a processor on this board, right? -Dave

They say there are no stupid questions.

I think you win the prize Dave, for the first right answer! I thought I was told, or maybe I assumed, that under the honking heatsink and fan was a processor. I opened it up and don't see anything that looks like a CPU package, just a socket with a lot of holes. I knew it was something simple. (I take it from your question that, absent a CPU, the PSU won't go on.)

Well, I'm glad I didn't pay a lot of money for the board. This was very educational.

Thanks for your help. I'll be back if and when I get a CPU for it.

-- Joel

 

[Dave]

I've tried to figure this out myself but gave up, so I hope someone can
give me a hint. I hope this has a simple answer.

I was given a not too old m/b (Intel D845WN) and was thinking to make a
whole computer out of it. But before I invest too much I want to check it
out. So I put it on the bench and connected a PSU (the kind with the extra
P4 connector). I turn on the PSU and the stand-by LED goes on. I shorted
pins 6 to 8 on the front panel connector (2-row header) and --- nothing
happens. The PSU doesn't go on. I'm pretty sure I've got the correct power
switch pins, from a diagram I found on the Intel's support site.

I did the same thing with a different M/B, and the PSU does go on, so I'm
pretty sure it's not the PSU. Also, I measure the voltage on the green
wire from the PSU, and it is about 4 volts, whether or not the power
switch pins are shorted.

I'm hoping the M/B is not bad, and that I'm overlooking some trivial thing
that everyone except me knows.

BTW, there are no cards plugged in. I tried with and w/out memory, and no
difference.

I also tried removing the battery for a while, then replacing it, but no
help.

TIA.

-- Joel

Stupid question . . . there IS a processor on this board, right? -Dave

 

[Dave]

Stupid question . . . there IS a processor on this board, right? -Dave

They say there are no stupid questions.

I think you win the prize Dave, for the first right answer! I thought I
was told, or maybe I assumed, that under the honking heatsink and fan was
a processor. I opened it up and don't see anything that looks like a CPU
package, just a socket with a lot of holes. I knew it was something
simple. (I take it from your question that, absent a CPU, the PSU won't go
on.)

(my reply)

I honestly don't know. In reading your earlier post, I kept thinking, "what
CPU?". You didn't mention it, which was really odd. I know that the CPU is
required to run POST. Without the CPU, it would make sense that the
mainboard would never signal the PSU to switch on. (Because if the PSU did
switch on, nothing would happen anyway.)

BUT, I never would have tested a mainboard like that (without a CPU), for
the simple reason that I know that the CPU is required to run POST. So
before NOW, I had no idea that a mainboard without a CPU would prevent the
power supply from switching on. It was just one of those things I never
would have thought to try.

It eventually occurred to me that (strange as it may seem) the board might
not have a CPU. So I thought I'd ask. It was a lucky guess. -Dave