Not posting after 18 months of stability

[adapa]

My home built system has been up & running for the last year +.

When I shut the computer down a few days ago, I allowed an install of a vista update.
When I started the computer the next day, it did not post. The fans & lights (on the front of the computer) cycled on & off at between 2 & 3 second intervals but no beep. I left the computer for an hour +, when I came back it was running normally.

I have had occasion to power down & start the computer a few times since, there has been no problems.

Until this morning when the same 'unable to post' situation occurred. Eventually it started after 15min's or so of trying.
I'm guessing the problem might be the mobo battery or Ram but I haven't' opened the case up yet. Do those two ideas seem logical to you guys?


ocz 600w psu
corsair xms 2GB + 2GB Ram (I think it is the same kind as the original)
WD Caviar SE16
Q6600 stock fan
EVGA 7900GS
ASUS P5B-e
Antec P180 case
Vista 32 bit Ultimate

 

[Proximon]

So you aren't having stability issues once it boots?

Sounds more like a PSU or MB issue.

 

[adapa]

yeah, the thought of a mobo issue had crossed my mind...<sigh>

the only thing that occurred after the second time the computer didn't post was a system hang which required a shutdown. Ctrl/alt/dlet didn't work.
And yes I should have included that bit of information in my OP.

I was under the impression that a psu issue would be obvious, ie. it works or it doesn't. I gather that impression is incorrect?

 

[Proximon]

Yep. This is no reflection on you, but ignorance about PSUs is rampant. It's a piece of hardware almost as complicated as your motherboard.

Unstable voltage under load can cause any number of issues. The voltage can be unstable in various way, dropping too low, over-compensating, or just extreme voltage ripple.

For instance, a PSU might only pass it's self-check when it's cold. It has to send a power-ready signal to the motherboard before it will boot, and a bad PSU might not be able to meet it's own requirements unless it's under, say, 25C. Once it has passed it's self-test, the motherboard might be able to handle the out-of-spec voltages, or it might crash.

Or, you could have some borderline voltage setting on your RAM, so that it sometimes boots and sometimes not... but this would result in a less stable system.

Or you could have some intermittent short on the board or even a loose wire.

http://www.tomshardware.com/forum/261145-31-build-post-checklist
not a new build, but there are a few things on there, especially the bit about building outside the box.

 

[qwazzy]

Sounds a lot like my problem. I have a P5B Deluxe though.

 

[adapa]

"Pull everything except the CPU and HSF. Boot. You should hear a series of long single beeps indicating memory problems. Silence here indicates, in probable order, a bad PSU, motherboard, or CPU - or a bad installation where something is shorting and shutting down the PSU.

I pulled every thing except the CPU & HSF. Most of the time I hear nothing- the HSF attempts to spin but no joy. Once I heard a continuous short beeps for 10 sec's. My mobo manual says that indicates a power error but quoted post by jsc indicates it might be a memory problem if the beeps are continuous.

Does this seem to indicate a PSU failure?

if so any recommendations on a cheap good 600w PSU?

 

[Proximon]

Not sure you need exactly 600W.

BFG LS-550:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817702008&Tpk=LS-550

Corsair 550VX:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139004&Tpk=550VX

PC P&C 610W
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703005

 

[adapa]

thanks again proximon
just pulled the trigger on the 550w corsair, with the 'bill me later' & rebates it's $60. I don't think I can do better than that. It seems like a dependable unit plus it's green too.

I agree the 600w was a bit over the top but when I built the system I thought I'd be adding more HD's.

Hopefully the new PSU will solve the problem.
Thanks you again for all your help!

 

[adapa]

posting to update;
Just before the new PSU arrived my old one died completely. I got the new PSU installed & it's working great. My old psu is still under warranty so I'm rma'ing it. I guess it'll be on ebay in a couple of weeks.
Thanks Proximon for all your help!

 

[Proximon]

When a 5-pound brick gets shipped around the country, there's always a chance of something getting knocked loose. Glad it all worked out.