Computer switches off and on after a few seconds

Hi folks,

Apologies for me possibly asknig the obvious here, but I think its best before going out and purchasing more good to kits my machine out.

I have just assembled a new piece of kit, which when I boot up switches off after about 4 seconds and then back on after 3 or 4 seconds. With no clear activity on my monitor. Occationally I do get activity on the monitor and goes into my install windows process, however usually hangs in process.

I am sure its my PSU as I only have a 425W. But I would like to get some ideas incase anything else might be causing the problems (specs listed below).

Abit IP 35 Mobo
Intel Core 2 Duo E6750
nVidia 8800GTX
4GB GeiL DDR2 800mhz
1 500GB Sata plugged in (2 not)
1 Sony 8x DVD Burner

Can someone tell me its my PSU or make any suggestions? Seems like a no brainer 420W is not enough, but just wanted to confirm thats what is causing the issues.

Thanx in advance folks

UPDATE: I have tried the 425W PSU in my older machine with the 8800GTX and works fine. Old sys specs

AMD Athlon64 3500+
2GB DDR 400
500GB SATAII HDD
8800GTX

Does the Intel CPU + Abit board seep that much more power than the AMD here? (excuse my ignorance if thats a stupid thing to say!)

Please help :(

Have you tried running one stick of RAM? It might be struggling with 4GB if you havn't changed the voltages in the bios. 2.1 - 2.2v is needed for the geil ultra if thats what you are running.

Thanx for the speedy reply, I have tried with 1 stick of ram (running at single channel) to no avail, same issues apply. Have tried voltage at both 2.1v and 2.2.

As Staffsmike says - you could also try just one stick of ram, Graphics and mobo/cpu to see if it will post to bios if that fails. Sometimes your pc will turn off due to overheating (thermal throttling) but it appears to be turning off a little quickly for that maybe ?

I guess it could be the PSU.. it is a bit risky running it on a 425w PSU.

Colossous point about heat might be worth checking. If you can get in the bios check the cpu temps.

I thought at first you were just reporting the old P35 double boot but they function normally when they come back to life..

Its wierd, sometimes it will post to bios, mobo does the usual "I'm on and happy" beep and go through the post process, however say 4/5 times it will just run for a few seconds, power down for a few seconds, rinse and repeat!

It might be worth adding that when I got to a point of being able to install windows, after completing the format, blue screen of death appeared, causing me to reboot.

On the times it has been in bios I have left it running for a while to monitor temps on the mobo and cpu, they appear normal.

Another Note, might be that I have the 24 pin connector in ok, but the mobo has a further 8 pin slot, of which I am only have a 4 Pin connector on my PSU.

That would do it .. lol

I keep forgetting to ask that.

I think you can get a molex to 4pin connector I shall have a look.
EDIT: found one here Molex 4 Pin Square Connector - Aria Technology


If you need a cheap(ish) PSU the Corsair VX 450W is very good.

520w HX model is even better and modular :)

The next thing i would check would be the Psu then, do you have a spare or know someone who could loan you one for a test ?

I dont have a spare, however will buy a 600W PSU and give it a go as to be honest could do with more meat than 425W to deal with the my new machine.

Quote:

---

Originally Posted by GavinW

I dont have a spare, however will buy a 600W PSU and give it a go as to be honest could do with more meat than 425W to deal with the my new machine.

---

Cool, again - Staffsmike suggested Corsair and they are great Psu's - Seasonic and Enermax too - good brand models ftw, too many components get ruined by cheap and nasty Psu's !!

Thanx for the help guys, will try a molex 4pin square connector as suggested my staffsmike (thanx a lot for that) and if that works, I will invest in a better PSU.

I will update on how it goes (fingers crossed!)

Quote:

---

Originally Posted by GavinW

Another Note, might be that I have the 24 pin connector in ok, but the mobo has a further 8 pin slot, of which I am only have a 4 Pin connector on my PSU.

---

Quote:

---

Originally Posted by staffsMike

That would do it .. lol

---

Surely you just plug the 4 pin connector into the first four pins on the 8 pin slot? Using all 8 pins is usually optional unless it's a server board with two CPU sockets.

I do have a 4 pin plugged into the first 4 pins on the board.

If this isn't the issue then, what would be causing these symptoms?

Well it might be the issue, but if that's the case it should clearly say in your motherboard manual that you must use an 8 pin EPS connector.

What components have you definitely tested in the other computer - psu, gfx, hdd?

My first inclination would be that you have a faulty power button on your case - short the power + and grnd jumper on your motherboard (either with a jumper or paperclip) and see if that works. If not, unplug everything and just use the 20/24pin connector between the motherboard and PSU and do the same - the PSU should stay on. If it doesn't then your problem is probably either the motherboard or quite possibly the CPU - try begging a compatible CPU from a mate to test the latter.

Just aim to get the power supply constantly on at first, once that's sorted you can add in components one at a time.

I have tried PSU, GFX and HDD in other comp and works fine. I would have thought that the AMD 64 chip with the 8800GTX connected would use more power than my Intel E6750 chipset.

I will try your suggestions of getting it staying switched on, even if nothing is plugged in except CPU.

I will also have a lookie at the power jumpers, in case perhaps I have + and - round the wrong way, would that make a difference?

I would just like to find out which is the offending component, hopefully it will be the cheapest to replace! At least I know its not the GFX card as that is working fine, and is the most expensive to replace!

Sorry! Missed this one earlier.

Dead simple really, it's a quirk of that motherboard (and in more general terms the chipset).

Just update the BIOS to a newer version and the problem should go away because it really does sound like the standard aBit P35 double boot problem (check their forums for more details on this). In the mean time, just be patient with the second boot, let it complete it each time it asks because it's a self-test facility.

------

The hanging during install is possibly down to the RAM voltage or the PSU quality as a whole. Vista and XP also do not like to install with 4GB RAM. Put 1GB in and install using that, then add the rest when the install process is complete.