powering motherboard with no cpu

Kotu

Kotu

Kotu

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Joined
18 Oct 2002
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Ive got a dead PC, but the ram/psu work elsewhere, I have no way of testing the CPU or motherboard though (nothing to swap them with). At the moment the system powers up (fans come on, led on motherboard shows there is power), but there are no beeps to indicate post errors (does have a pc speaker attached), ive also tried plugging headphones into the green onboard audio socket to see if there is any output there (its an asus motherboard).

So im wondering if removing the cpu and powering it is likely to force any "no cpu" type errors. If the the motherboard can still produce errors then it might point to the cpu being the issue.
 
That's not going to work. From experience I'm going to say it is most likely that the mobo is fubar.

You can try running the mobo out of the case to remove shorting as an issue. What exactly is the spec of the system? Is this a new build? Or an "old" machine that has developed a fault?
 
its a second hand motherboard/cpu from a friend, they were replaced originally because the system stopped working but then the ram from this setup didn't work in the new one either so it was assumed the ram was broken instead.

I'm not sure about the exact CPU, a dual core 4000 something...
the motherboard is an asus M2NPV-VM which is AM2 (940pin).

Im hoping to rebuild the system for my dad seeing as hes still rocking a thunderbird 1GHz :P
 
Right well your choice of mobos will be limited as that is an old mobo but you should be able to find something reasonably cheap. Is the RAM DDR2? It probably is so make sure you look for DDR2 mobos!

You need to remove the cpu clean the paste off and see what the CPU is exactly. Then you can make sure you are buying a mobo that is compatible with the cpu.

If you are certain that the RAM and PSU are good, this makes sense. In my experience mobos fail long before cpus.....unless people overclock the hell out of the CPU ;)
 
Run the mobo outside of the case with only the ATX main 24 pin power supply connector, and the 4pin (or 8pin) power cord attached to it, put one stick of ram in (the correct slot for when you just run one, normally numbered 0 or 1), and then graphics card if it does not have onboard (powered correctly with PCI-e connector if it needs one) and the CPU. Plug NOTHING else into it. No audio, sata cables, drives or anything else, not even the front I/O buttons to the case. To attempt to turn it on rather than using the switch on the front of case, just short the two pins together using a screw driver. Check to see if it boots then.
If not, take the BIOS battery out and leave it out for a while and/or reset BIOS using jumper pins. Try to boot again.

Still no boot? More than likely it's the motherboard, especially if the CPU appears to not be physically damaged/altered.
 
Jaybee has just gone into more detail about what I said about running the mobo out of the case. You can do this but I think you'll find that the mobo is dead.

Seeing as you will need to remove and check the CPU anyway it doesnt hurt to try as it's all coming out of the case. If you are going to short the power pins on the header, you just briefly touch the two pins with the screwdriver and PLEASE ensure they are the +&- PWR pins!
 
I tried the breadboard approach before asking here :P Its part of the reason Ive asked such a strange question since even with the ram missing, it doesn't produce any error beeps. The CPU was inspected and all the pins were fine, no scorch marks etc, i just didn't make note of the exact cpu being used :(

Im just a little reluctant to get an old motherboard since another friend had similar issues and went through 3 motherboards replacements before finding out it was actually the CPU which was faulty.

I might just give it a go and see what happens, I don't really have much to lose at the moment, if it makes no difference then ill look for a second hand ddr3 system instead.
 
The mobo wont do jack without RAM installed!

Is really down to you fella. This is the hell that is troubleshooting, I do feel for you I do this practically on a day to day basis. Like I said I can't guarantee the CPU is good but in my experience its usually the mobo.

I don't know what the other parts are exactly on the system. Most "modern" mobos are dropping the IDE connector and I suspect from the age of the machine it has both IDE HDDs and DVD drives. I'll leave it with you to weigh up the pros and cons......good luck with it all
 
Had a quick skim though, so might have missed someone else mentioning it. Have you connected a case speaker to the mobo? I saw you mentioned you had PC speakers connected, however the beeps don't come through the standard speakers, it comes from a separate speaker usually built into the front of the case. You plug this speaker into a motherboard header in the same place that you plug in things like the power button, reset button, power LED etc.
 
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