Salvaged computer giving me issues.

[Tethandros]

Hey all, long time lurker here. I recently came into the possession of an old HP Pavilion 762n. Plugged it in, pushed the power button... heard fans spinning and nothing else; no beeps, no hard drive clicking, no signal to the monitor, nothing.

I decided to open it up and apart from copious amounts of dust, nothing seemed to be awry. The video card fan looked like it was grinding a little, but that shouldn't cause the POST to fail.

Anyway, I started disconnecting equipment to isolate the problem. Out came the videocard, RAM, hard drive, CD-ROM drives, floppy drives (one at a time, of course, then all at once).. Still nothing. I even tried running it without a CMOS battery in.. nothing.

So, should I be looking into a new motherboard? Is there anything else I can try? This isn't going to be my main computer and it can't get any deader than it already is, so extreme measures are not a problem. Thanks!

[DonT-FeaR]

lol
did you test the hdd on the pc you have now???


was it all plugged in propperly? (sounds stupid but its not)

and does the psu work?

if yes to all above new mb i think....

[Luke122]

I suspect the PSU isnt giving 12v to the mobo. I had a similar problem with the same symptoms. Try a different PSU if you have one, or a PSU tester to see what's up.

If you arent getting any errors or beeps when you try to boot it with no ram, then it's either a dead board or no power.

[Tethandros]

Alright, I just checked the 12v rail, and it came back at 11.71v. Now, I believe that 11.7v is within the acceptable range for PSUs, but I may be wrong. Thanks for all your help guys.

[nevermind1534]

I got an HP that did something similar, and it was the power supply. It doesn't have a bestec power supply, does it?

[Tethandros]

Nope, it's a HIPRO power supply, whoever that is..

[nevermind1534]

I think that's what mine out of the trash had. If it's not a bestec, everything else should be ok, if it's just the PSU. I think it's only emachines that used bestec.

[FuzzyPlushroom]

Some HPs did, too - got a Celeron 566 and Athlon 1700+, both HP systems, which both had 'em. Nasty.

Hipro PSUs are fine unless the capacitors inside have failed - this is an easy visual check, usually, if you pop it open. Any of them bulging or leaking?

http://static.flickr.com/42/120329818_0e20370795_m.jpg

[Tethandros]

http://img241.imageshack.us/img241/7428/0817081650pi9.jpg

I don't think any capacitors are leaking, but that white stuff under the plastic shroud and on some of the caps could be leakage, or just thermal paste. None of the caps are bulging, so other than the white stuff, the PSU looks fine.

Sorry about the crappy pic btw, all I had available was my cell phone's camera.

[FuzzyPlushroom]

The white stuff is just glue. Nothing to worry about there.

You don't have a friend who has a multimeter you can borrow, just in case, do you?

(I'd bet on it being the motherboard, a Micro-Star Int'l [MSI] MS-6579 - I'd check the capacitors on that as well, for similar symptoms, since quite a few MSI 'boards up until the early P4 era had these problems, and an unrelated 'bad batch' of capacitors from an otherwise reputable company [Nichicon HM/HN series] brought down quite a few 'boards from the P4 Northwood/Prescott era. Of course, there's a good chance it's not the capacitors at all, and static electricity, for example, killed off the 'board. Do you have a known-good stick of DDR RAM you can try in it?)

EDIT: 300... woo.

[Tethandros]

I've got a multimeter myself, which is how I got the voltage on the 12v connector. Also, I know the sticks of RAM are good because i tested them out in another computer and it booted fine. I just put one of them into my home server, in fact, and it's been running fine for about a day now.

As for the capacitors on the motherboard, they all seem fine also.. I guess the next step is to measure all the voltages.. Yay. Once again, thanks for the help.

[Luke122]

I read somewhere yesterday that power supplies dont put out the exact voltage unless there is some load on them, so 11.71v on the 12v may be normal for your psu.

Can you try another psu with this mobo?

[Tethandros]

Grr.. I would, but the thing is that I have only two other PSUs; one is in my main computer right now, and one is in my home server.

I suppose I could disconnect the server for a minute, since it's not doing anything terribly important at the moment. I'll post with the results.

[nevermind1534]

If it is the PSU, you can get one for like $5 off of newegg.

[FuzzyPlushroom]

A $5 PSU?

Would you get a heart transplant from some guy on the street?

Yeah, I didn't think so.

The lowest you can go, unless they're on sale, is around $20-$30, and only for selected units - the only worthwhile PSUs that cheap are FSP/Sparkle units, with occasional exceptions - this (http://www.newegg.com/Product/Product.aspx?Item=N82E16817104210), for example, is OK, as is this (http://www.newegg.com/Product/Product.aspx?Item=N82E16817174011) and probably this (http://www.newegg.com/Product/Product.aspx?Item=N82E16817103149). (I'd get the Hipro, if it'll fit.)

EDIT: This Antec (http://www.newegg.com/Product/Product.aspx?Item=N82E16817371013), for a few bucks more, would be an excellent choice. I'd make sure it was the PSU (test with another first) and, if it is, pick this one up.

[Tethandros]

Alright, I tested it with another power supply. This one put 12.1v out on the 12v, so that's out of the equation. Nothing. I then noticed that the fan on the video card wasn't turning, so i switched it out with another known-good card. Still nothing. Therefore, I am forced to conclude that it's probably the motherboard that went kaplooey.

If anyone has any groundbreaking ideas, I'd love to hear them, but while I'm preparing for all eventualities, is this (http://www.newegg.com/Product/Product.aspx?Item=N82E16813130178) a good buy? Thanks, guys.

[nevermind1534]

Maybe it was ebay that I was thinking of. I think I did get my a hipro 370W for $7 on sale, though.

[pbturner]

had the same situation....did all the same things to test....as a last thought, removed the front of the PC case and checked the power switch. turns out it was stuck in the IN position. by pulling it out, i was able to get the PC to come on, and STAY on. used a small amount of electrical contact cleaner to lubricate the switch, and it now functions as expected.