Odd power behavior

[jadfw007]

AMD Sempron 3000
WinPro DDR, 1 stick, 1gig
2 X SATA Western Digital Caviar, 80gig
Samsung dual layer DVD+RW drive
Silverstone SST-LC11 HTPC case w/ 300W PSU (also silverstone)
An extra 80mm fan I installed to improve air flow near the HDDs

In general, hitting the power button only works right after I switch outlets. Sometimes I can get it to power on by repeatedly pushing the power button, but this takes literally 20-30 tries.

However, when the thing powers up successfully, all hardware is correctly detected and I can even boot Linux from a live CD.

Also worth noting: I have a Foxconn wireless PCI card. If I stick this in the board, the machine won't start up at all.

This seems like an obvious PSU problem, but if that were the case I would expect that the machine would die or malfunction in some way after having been successfully powered on for some period of time. This hasn't happened yet. I've also never heard of anyone having a PSU issue quite like this so it makes me wonder. Any experience that any of you could share would be greatly appreciated.

[Sylvander]

Perhaps your on-button [switch] is faulty and not making the connection.

Disconnect the switch at the mobo and short the pins to see if that makes a difference.

[jadfw007]

Thanks for your suggestion. Here's an update on what I've tried
(and the result):

1) Disconnected everything but the CPU and RAM from the mobo: no
difference
2) Switched out the Silverstone PSU for another 300W PSU from an old
machine: system starts successfully every time
3) Re-connected SATA drives, DVD drive, extra case fan: system starts
successfully every time
4) Put the PCI riser back in: system starts successfully every time
5) Put the wifi card back in: system won't start for anything

This is the kind of behavior I'd expect if the PSU just didn't have
enough juice for all my components. I suspect the Silverstone PSU is
faulty or damaged.

[Sylvander]

"1) Disconnected everything but the CPU and RAM from the mobo: no difference
2) Switched out the Silverstone PSU for another 300W PSU from an old
machine: system starts successfully every time"
Logical reasoning suggests that this means the old PSU was faulty.

"5) Put the wifi card back in: system won't start for anything"
If you are saying that with this in place the PC won't run or complete the POST even with the new and functional PSU in place, then...
Surely this wifi card is the cause of a failure to POST [it's faulty].
Perhaps it damaged the old PSU, or vice versa, so that both the wifi card and the old PSU are now faulty.

[jadfw007]

Sure enough, when I disconnect the HDDs and plug the wifi card in, the machine powers on but doesn't boot. It's not the riser either. I switched out the wifi card with another, more power-hungry PCI component and the system boots fine.

[webbhost]

you say it worked fine when you placed things out of the PC and with new PSU, once you put the last component in (the WIFI) you get problems

Althrough it could be a faulty WIFI card, could it also be a power issue, as you did say its only another 300W PSU.. maybe 300W isn't enough to handle it?


Not "that" knowledgable about hardware but thought id bring it up as a thought

The reason i did say this is because you say it switches on with WIFI on and HDD out... hence you got 1 less component to worry about, so it can now handle WIFI too. (but of course it isnt gonna load cause the HDD is disconnected)