Custom PC won't post

Asus M4a785td-m evo
December 30, 2009 at 12:56:21
Specs: Windows Vista 32-bit
Started out buying an HP (a8ae-le Mobo) and, thinking I was smart, buying a discrete GPU (x1900xt 512) and 2GB Patriot DDR400 to complete the package back in Sept '06. Ran flawless if still slow for '06 due to the single core athlon xp 2400+.

Anyways, I went away for work over the summer this year and when I came back in late Aug I started havinging intermittent problems with it not being able to post. I would gut the innards, clean everything, reassemble, and all would work.

A month or so ago I noticed that, for no apparent reason, the power in the house would randomly go off mid-morning causing my computer to run into the unable to post problem. The first time this happened I did as before; gutted, cleaned, and all was well. However, the second time it happened... well, my beloved hasn't worked for about 3 weeks now.

What happens is everything is receiving power - HDD hums, chassis fans run, cpu fans on, PSU runs, LEDs on - fans usually run hard for 1 to 2 seconds on boot up, but they keep chugging with no monitor signal and no apparent signs of it even getting to load bios.

I finally ordered a new Mobo, CPU, and RAM (M4A785TD-M - ATHLON II X4 630 - 2GB GSKILL DDR3 1333), it arrived 2 and a half hours ago and wouldn't you know it, all the same as before. Lights on Mobo, fans whirring, HDD humming.

The only other 2 components it could possibly be would be, afaik, the PSU (BFG 650w)or the HDD (Seagate Barricuda 250GB 7200 SATA 1 yr old).

HDD was fine except for a rootkit that I contracted in Sept, but I got it taken care of. PSU is 2 years old and it's run completely flawless.

I would attempt to reinstall windows, but cant even get into bios.

The 2 other computers in the house is this, my mothers laptop, and a 6 year old compaq that doesn't have SATA connectors. So attempting to test either component is a no go.

Since I know it will come up, I've taken my computer apart so many times that I have either lost or cant remember which connectors go to enable the onboard sound for warning messages. So, there are no beeps.

Any advice is appreciated, especially, if I don't have to shell out for a new PSU or HDD which I believe to be good.

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December 30, 2009 at 13:40:55
Your powersupply provides power on 6 different rails and if any one of them is flakey your whole system can become unstable. Spinning fans and lit LEDs is no guarantee the unit is fully functional. The only way to know for sure if your PSU is OK would be to get it load tested. latest opinion on PSUs is that a single +12V rail putting out 40-60A is better than multiple 12V rail units like yours. Reason being if you have an unbalanced load you can overload one 12V rail while the extra capacity of the other rail remains unused as it's on a different circuit. In a single rail all the maximum output is available to meet peak load such as occurrs at startup.

You also mention a graphics card. How have you eliminated that as the cause of your problem? Since your motherboard does not seem to have an inbuilt peizo to give you POST beeps how can you possibly tell if the bios is registering either a ram or graphics fault? Here's a suggestion.
You got a new motherboard. Read the manual. It will tell you where the header is for system sounds.

Did you benchtest the new components outside the case first?

Goin' Fishin' (Some day)

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December 30, 2009 at 14:09:33
My graphics card is, and has been, out of the system eliminating it as a cause. Also, the system is currently hooked up to my flatscreen TV, elminating the monitor.

The system does/did have built in peizo but, as I said, I've taken the computer apart so many times, my multi-card readers and front panel sound inputs/usb inputs have been disconnected for some time as I do not require them.

The only connector I use from anything front panel, is from the power button from case, which is a 10-1 pin, new mobo has a 20-1 connection which I am only using the power and ground.

Also, for monitor/headset use with onboard audio I have what used to be the connector for the front panel which needs to be on so it completes the circuit, so I have that on as a jumper.

Now, could I use a jumper from say... well anything to complete a circuit on the mobo to get the post beeps since my case doesn't have a 20-1 pin?

No I did not bench first. No other system to test in.

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December 30, 2009 at 14:42:15
Benchtest means just that. Put the motherboard on a non-conductive surface ( Bench) connect only Powersupply, CPU with heatsink/fan. 1 stick of ram, keyboard and monitor to the onboard graphics. If the motherboard has an inbuilt peizo it will be connected and beep if the thing is able to POST.

You try to start up by using a screwdriver to touch the power-on pins momentarily. Do not use any kind of jumper as the contact is supposed to be only momentary. Holding the circuit closed causes the PSU to power off after a few seconds. Will it power up and give you any beeps and/or display?

Goin' Fishin' (Some day)

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Related Solutions

December 30, 2009 at 14:59:59
No sound. No beeps. HDD, cd/dvd drive, video card, network card all disconnected.

No video. Fan steady and constant. LED power light green on Mobo.

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January 13, 2010 at 05:35:44
Have the same a8ae-le mobo in a Presario with the same problem. HDD, fans, LED's ok, no post. Disconnected sata HDD, ide DVD, pulled modem & 1 stick memory. Nothing will show post or beep. Anybody have this problem?

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January 13, 2010 at 05:46:55

For best results you need to start your own thread here. I suggest you watch this one first and if your issues are not addressed THEN post yourself. Don't step on this thread.

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