weird PSU problem

[QueBert]

installed a 500gb HD + new video card in my GF's box. Put the card in and it was fine, she had 2 200 HD's, was going to remove 1 and put the 500 in.

I unhooked one of the 200's and hooked up the 500, powered on, after about a second it shut off. tried again, same thing, unplugged the 500 same thing, unplugged the 200 and plugged the 500 in, it worked. Thinking it might be a molex issue I unplugged the power from her DVD and same thing, but plugging the same molex back into the DVD it powers up. It seems like a short but I can't figure out why the DVD works and the 200 gig HD won't. The drive was working fine 2 days ago. I swap one out for the 500 and now this.

anyone have a suggestion for me? I don't want to run out and get her a PSU unless I have to, it's a Vantec 350 I believe, the model # has 350N in it. Her system...

AMD Sempron 3300+
Ati Raedon 1950 pro AGP
2 gigs DDR
2 HD's

I know that PSU isn't much for that card but it seems to be working fine, played Bioshock for a a few hours with no issues.

 

[GalvanizedYankee]

This is confusing.

All I know is that the 500 & 750 gig HDDs take alot more wattage at spin-up(BOOT) than the smaller drives.

Let us know what the resolution is.

 

[mindless1]

It is most likely that the surge current for spinning up the drives is pulling the PSU voltage too low due to insufficient PSU current capability.

A multimeter reading when it's turning off would probably confirm this, but basically you need a new PSU, most likely with more 12V current. It's possible the present PSU just has a part like a capacitor going out and this is causing a large enough ripple to trip the shutdown circuit. In case that's it you could disconnect PSU from AC for several minutes, open it and inspect the caps - if you had an inclination to solder in replacements that is.

 

[QueBert]

to GalvanizedYankee the resolution was to buy a new PSU. I messed with it for an hour or so, after trying all the molexes in all the devices and having the same result I decided I wasn't going to be able to figure it out, if it was even possible. Bought a Thermaltake 430, not a really great PSU but GF paid for it and didn't want to spend much. Everything is good now.

Guess a 350 wasn't enough to power her system and the 2nd HD pushed it over the top *shrug*