BleepingComputer.com: cpu or mobo dead?

Hi, I took out an old computer to play with as my new computer is in novatech getting a new mobo.

When I turned on the computer all fans turned on and led lights on the front of the case, there was no display or beeps to indicate anything wrong.

I opened up the case and noted that all cables where in place and the hard drive was running.
I tested the vga cable and monitor on my laptop and they worked fine.
DVD rom works fine.

So I disconnected all devices, hdd, dvd rom and pci card. The mobo has on board graphics. I reseated the ram modules, took them out, tried booting with one module etc. I noticed that the usual long beeps happen when I boot with no ram modules. Does this indicate that the mobo and cpu are fine?

I reseated the cpu, but did notice that the cpu did not heat up as expected after 5 seconds of powering up. I had my finger on the cpu, normally I thought I would be going to hospital with third degree burns ?

I had a device yeaturday, mobo analyser, but I dont know how it works and think its bad and Im sending it back to get a refund. Could this has caused a problem. It usb powered and not the older pci slot ones.
You can also use the printer port to run the mobo anaylser but, there was no power when I did this. Obviously the printer port has no power. I dont understand though, three month ago the computer was running fine.

It as e system, celeron d, with 2 gb of ram and a foxcon mobo.

(Moderator edit: post moved to more appropriate forum.jgw)

This post has been edited by jgweed: 28 July 2011 - 10:20 AM

Hi I.Tstudent

Sounds like your motherboard and CPU are working to some extent at least, does not mean they have not got a problem of course

Have you tried resetting the BIOS I.Tstudent. Just in case you do not know how, make sure you unplug the power supply, then flip the battery out for 10 seconds or so (Judging by what you have tried already suggests you are probably experienced enough to know this already).

If that does not work, I would probably start by seeing if I could get hold of a VGA graphics card to try out if you could borrow one of someone (PCI etc if you do not have a VGA slot) to help eliminate on board graphics chip.

I am not a big fan of motherboard testers, they are a bit cryptic to use and I have never really benefited from experimenting with them at all.

Good Luck,
jodav

Cheers mate, yeah I already jumped the cmos with no joy, Theres just no display at all. I thought mobo testers would be like code 01 is displayed, and you look in the manual and see that code 01 means the hard drive is banjaxed. But no its just makes thing worse.
I have a psu tester coming tomorrow (I like my gadgets) just to make sure the p1 connector is giving the correct voltage.

I should be able to borrow a graphics card next week, I will update then.

It seems to be very tricky to point to the cpu or mobo as the point of failure.

Can you see whether the mouse and/or the keyboard are getting any power? A good candidate for these kinds of symptoms would also be the power supply unit (the fact that the fans go on doesn't mean much, since they need pretty low voltage, compared to other devices). If you have an alternative PSU, that might be worth a try.

Well good Luck I.Tstudent, the symptoms would suggest the CPU is unlikely to be the problem. Keep us updated buddy
jodav

I.Tstudent, on 28 July 2011 - 08:11 AM, said:

usually it's took more than 5 second's to heatsink fan to get heat from processor.
try to leave it over 30 second's and try to touch fan (plastic) area on heatsink fan first and try to feel does you feel any heat, if not you could try to touch metal area on heatsink fan, if still no heat shown up leave your hand on that metal area for a couple of minute's until you feel some heat.
no heat in heatsink fan for a couple of minute's means 3 thing, mainboard / processor / heatsink fan failure.
on mainboard you could check tiny pin on processor slot (PLEASE BE VERY CAREFUL WITH THAT TINY PIN), check does any pin have sideways (DO NOT TOUCH IT, JUST SEE IT)
on processor, maybe it's dead, you could try to plugged it on a another mainboard.
on heatsink fan, some people forget to check does any plastic that cover thermal paste on bottom plate at heatsink fan.

I.Tstudent, on 28 July 2011 - 11:32 AM, said:

that depend's on what BIOS in your mainboard, please read your manual again and make sure you read it carefully, usually code 01 is not hardrive, but that depend's on what mobo tester that you use. I doesn't know what mobo tester that you use but I think you have read at wrong section on that manual book.
please watch every code that shown up right after you turn your computer, every code that shown up show what process that have been passed and the last one is the process that have been stuck.

have you try to turn your computer on without keyboard, mouse, printer, usb device plugged in? only PSU, mainboard, memory, monitor, VGA Card (if you dont have any onboard VGA).
if still no POST, leave it and make some coffe or find another activities just to make sure that you not frustating because your doesn't get POST.

check your heatsink fan position will be a good idea, sometime's the problem lies on that, the reason why I hate LGA 775 slot is the heatsink fan position must be at right position or your doesn't get POST, on a several heatsink fan brand you need to make one foot not at locking position.

You won't believe this, was just going to check if the keyboard and mouse lit up when I powered on. The keyboard and mouse flashed once, but I heard the post beep once to indicate everything was fine, so I looked up at the screen and I have bios wtf?

Key board does npt work though, no light when I hit caps etc. Im going to reboot and see. (this is real time) Rebooted, back to square one (no beep, no display). Defo soemthing fishy going on. Must be psu. Psu checker coming tomorrow

abauw. I actually took the heat sink off and put my finger to the back of the metal zero insertion force lock. No notice of heat for 5 to 10 seconds. Also, sorry the code for hdd was just an example of how I thought the mobo checker worked, the manual says 01 is a cpu test. But im getting the mobo checker replaced as it says 01 ff for all my computers, even when they are on and working perfectly, also it doesnt go through any codes, like I thought and what you said. It just lights up as 01 ff and thats it.

Up-date, psu tester reads that everything is fine and enough power is being emitted. After a few mintues the heat sink on the cpu becomes luke warm (I can keep my finger on it after 5mins). I will have to wait to see if I can get a graphics card next week to test.

I dont understand though that last night the post beeped and the display came up, but the keyboard would not work and when I rebooted it would not display. I just changed the power cable (just in case) no joy, chnage the cmos battery and tried another psu. The other psu is from a computer that must be 12 years old, the psu only powerd the fans slightly, they turned very slow, I tried out my new psu checker and low and behold the older psu is dead (at least my new gadget works).

Early conclusion is that the mobo is part dead, as the printer port will not power the mobo checker. New mobo checker should come tomorrow.

Hi I.Tstudent,

I am in a bit of a rush at present, but from experience do not discount anything, ELIMINATE all you can including the Keyboard by attaching another one (remove the mouse). Create a list of what you have eliminated like the hard Drive\memory\PSU\VGA cable\monitor etc as you slowly home in on the Motherboard and CPU.

Good Luck I.Tstudent
jodav

Ok people. Just had time to play about with the machine. Everything started to work fine. All drives and PCI cards are in and the post beeps, the mobo checker states 0000, which must mean good as the manual does not say . Windows loads!

I will put this weirdness down to the computer not been turned on for some time and then being powered. I recall that older machines may hold a charge that could knock the sync between machine and mobo. I know in college some are machines need to have the power cable pulled out for up to 15mins before the monitor and machine sync correclty.

This does not answer the post problem though. Maybe it does?

out of curiosity what kind of mobo tester did you buy?

This sort of weirdness can be caused by failing capacitors on the motherboard. As they fail the capacitance drops until the amount of capacitance becomes marginal and you start having problems just like you are describing.

BTW they can fail even when sitting unused for a period of time. The voltage applied to them helps keep the insides in the proper condition.

The mobo tester is a klm4, £13 out of ebay.

Rotor123, so if a computer is left unused for like a year or so. The capacitors could fail?

Thanks

Yes they can go bad sitting. I've pulled used computers that have been sitting for a while and were working when put away, and when tested did not work. My best guess is that the capacitors were starting to go and finished up on the shelf. There is a electrolyte in them as well as aluminum

http://www.badcaps.net/ Tons of information and how to's

Bad brands can even fail with no outward sign. I've seen bad capacitors on Dell, HP, ASUS, MSI, Gigabyte etc. There was a period of time 2 or 3 years I believe it was that a good brand had a manufacturing defect that wasn't caught for until they started going bad prematurely. A lot of brands got caught in that one.

Sort of like the manufacturing defect from NVidia that caused HP and other brands a lot of grief.