System shuts down after 3 seconds

[Deeno]

Ive had a Pentium II 450mhz (At least I think its 450, why dont Intel mark it on the chip ?) machine with built in sound & video on the board. It recently went dead, would not boot at all, no beeps, no display at all, I could hear the processor fan running and the hard drive, but nothing happened.

After a bit of thinking I was fairly sure it was a motherboard problem and since I was never that happy about having onboard sound & video, I
purchased a new motherboard that supported both Pentium II & III processors, so that I could upgrade easily later. Ia also got new sound & video cards some new memory and a new ATX case
So basically bar the drives and the processor I have replaced everything.

I put it all together very carefully yesterday, but when I plug the mains into the unit It only boots for about 3 seconds and then cuts out. Note that I can only get this to happen when I physically plug the main lead in, then take it out and put it back in again. It will not boot at all from the on off switch.

Because Im not 100% sure what speed the CPU is, I have had to try a number of the jumper settings, but it does the same thing on every setting.
(If anyone knows how to tell what the speed is please let me know)

As the on off button seems to be playing up could it have anything to do with the LED leads ? I didnt think they mattered that much.

Im starting to think that the cpu is dead, as this might account for my last system not working, If I had another I could swap it, but I dont.

I read a post from another guy who had the same problem and he was advised that it may be a shorting problem and to try and boot up with the motherboard out of the case, Is it worth trying this?
I havn't checked the CMOs jumper yet, could that have anything to do with it?

Any help would be much appreciated.

Regards


Deeno

[sea69]

not an expert in this area.. but sounds like a possible BIOS problem.. it still thinks you are on your old (everything?)

others here will know how to direct you to proceed, if this is the case.



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pending

[Randy_tx]

Regretfully, it sounds like the CPU is the problem. I'm not a Pro on Intel chips, but everything else is new.....which leaves it as the culprit. Most new motherboards "Autodetect" the cpu chip and are jumperless.......is yours? If so, the only reason it booted for a few seconds and went dead would be a dead short or the cpu being defective (unless you have the ram in wrong or one of the devices in wrong)...If you havent already, try plugging ONLY the keyboard, video card, memory & cpu into the sytsem and try to post up[which is to get a ram count and the ability to go into the bios].....IF YOU HAVE A JUMPERED MOTHERBOARD, MAKE CERTAIN YOU HAVE THE CORRECT CORE VOLTAGE SET!!
By the way......the Lead from the on/off switch should be pretty easy to plug in correctly by looking at the motherboard book to see where it should be plugged in.......that could have an effect on it turning off in three sec. also.

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Will XP save Me ?

[This message has been edited by Randy_tx (edited 04-23-2001).]

[tjaymadison]

Welcome, Deeno! http://www.PCGuide.com/ubb/biggrin.gif There are a few things you might try. Some motherboards ship with a thin plastic insert preventing the CMOS battery from making contact until you're ready to use it, with a small tab sticking out so you can remove it. If this is not the case with your board, the battery may well be dead. Depending on the actual date of manufacture, your board may have a drained battery. Some also have a jumper that may be marked "Clear/Run" to clear a BIOS password, and it should be on "Run". Does your power supply have a slide switch on the back to select voltage (115/230), and is it set correctly? Does your mobo also have jumpers for selecting bus speed? If so, PII's are "locked" and a 450 will only run at an FSB speed of 100.

There was quite a flap about mis-marked Pentiums a few years back, but a "real" PII is normally marked along the top edge of the SECC or SECC2 plastic housing. Unfortunately, Celerons at the time were produced in the same package, providing an opportunity for fraud. If you post back with all the numbers, maybe someone here can help. Or you can investigate yourself at Intel's web site.

As far as running the mobo outside the case, this can be a worthwhile strategy. Just be sure that you put it on something non-conductive like a piece of cardboard. I'd recommend just the mobo with RAM and CPU on board, video card in place and hooked up to the monitor, and the keyboard and mouse plugged in. Check your manual so you're prepared to press the key(s) that will start the BIOS setup program. If it does successfully start, then you could well have had a short. When you put the mobo back in the case, make sure you use fiber or plastic washers at the mounting points to isolate the mobo. Let us know how you make out. Good Luck! http://www.PCGuide.com/ubb/biggrin.gif

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"When I nod my head, hit it with the hammer."
(Moe, holding nail, to Curly, holding hammer)

[Randy_tx]

Your computer should be set at 2.0 volt core voltage.......if indeed it's a 350-500 PII. If anything else, it could be 2.8, 1.65, 2.05 etc....so It's VITAL to know which chip you have! The multiplier factor is LOCKED on a PII......so you shouldnt be able to change it effectively anyway + the Front Side Bus should be 66 mhz [nothing else will work if it's a PII-300-450].

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Will XP save Me ?

[This message has been edited by Randy_tx (edited 04-23-2001).]

[gossamer]

I thought PII's had a 100 MHz bus?

[Randy_tx]

Here is one of the most complete settings pages I've seen: http://www6.tomshardware.com/howto/00q2/000412/index.html
You are CORRECT......sorry!!! The 100 BUS speed came out with the 350 & up it looks like to me.......YIKES!
Sooooo........setting the Bus @ 100 is what needs to be done!
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Will XP save Me ?

[This message has been edited by Randy_tx (edited 04-23-2001).]

[Deeno]

How do I set my core voltage to 2.0 v ?
How do I know what the voltage is at the moment

[Randy_tx]

Deeno.......I REALLY believe it's time to take the unit to a qualified technician. In order to get your system to "Post-up" you really need to have some knowledge of motherboard jumpers & motherboard book information as it translates into actual setting changes. You have indicated a strong willingness and eagerness to try to do it yourself; however, I know you dont want to ruin your system, and more "things to try" at your knowledge level could cause you even more problems than solutions at this point.

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Will XP save Me ?

[Deeno]

I was beginning to think that myself

Thanks anyway