My girlfriend's computer died recently after having been unplugged for a few days (it worked before being unplugged). When I plugged it back in and hit the power... nothing. I went to make sure the power switch was on in the back, and I caught a whiff of burnt electronics coming from the power supply, which was much stronger when I stuck my nose in it. I assume that's what the problem is...

However, I was wondering if a dead PSU can still power the LED on the LAN port, because when it's plugged in, it does light up. The MOBO looks fine - no apparent shorts or blown caps, and the CPU smells fine though I haven't checked the chip visually. All signs point to the PSU, but I wanted a second opinion before I ordered another one.

Her old one was a generic 420w PSU... would either of these be okay to replace it:

http://www.newegg.com/Product/Prod [...] 6817153023
http://www.newegg.com/Product/Prod [...] 6817159040

Thanks.

Makes no sense to me. How would you know that? Check the chip. While you're at it, check EVERYTHING.

No, neither of those would be good. Coolmax is on tier-5 ("Do not buy" ) of the PSU listing at http://www.tomswiki.com/page/Tiere [...] ngs?t=anon, and that particular Thermaltake is on tier-4. Choose one from tier-3 or better. If your budget is limited, check out a model from FSP. They're on tier-3 and you can get a 450-500W model for around $60.

$60 is a bit out of her price range, and her PC isn't exactly top-of-the-line. She wanted something for $25, but she grudgingly accepted my advice to go up to $50 with shipping + taxes included if I found a good one. Not that PSUs aren't important (I learned that lesson the hard way with 3 blown PSUs in a previous build), but surely there is a good, cheap solution. She already owes me about 4 months of back rent and about the same amount in loans I gave her for school, so it's a situation where she's broke and I'm barely getting us by until she gets her nursing degree.

Her computer would probably fall in line with tier 4 on that list, actually:

Thanks for the link, though. I'll go back to newegg and see if I can locate anything better that's in my price range. PSUs are one area I'm not very comfortable with, so it'll also be helpful as a reference for future builds. However, it's a bit odd to me that a PSU with 1300+ customer reviews and a 5/5 rating on newegg would be in tier 4 (not recommended), as usually a bad product would show its true nature in the face of so many opinions. I'm actually using a tier 5 PSU (Rosewill) on this machine and have been for a while. Who knew? Runs fine...

The reason I didn't check the chip visually is that the smell of burnt electronics is definitely not localized there. It would be a pain and further risk to the CPU to remove everything and freshly install the fan/HS, and the circumstances surrounding how the computer died don't really fit with a blown chip. There were no warning signs - it was just plain dead when I plugged it back in and hit the switch. It seems it would have at least powered on for a split second, or perhaps even beeped to let me know the cause of the issue... I suppose anything could happen, though.

Thanks MrsBytch. It seemed obvious, but I needed someone else to say that. So I assume a PSU can be blown and the LAN light still comes on? That was the main cause of my doubt.

The LED on the ethernet port is fed from the 5 volt standby output. On every PSU schematic diagram that I have seen, the 5vSB output is electrically separate from the main power outputs.

For that matter, every PSU outputs a control signal called something like "PSGood" or "PwrOK". Without this control signal, nothing will happen, even if all the power outputs are present.

Here is a cheap, good PSU for $30:
http://www.newegg.com/Product/Prod [...] 6817153023