Recently my computer has had trouble booting (to get the biip signal). When I press the power button, both cpu and psu fans runs, but computer want start. black screen, no signals on the keyboard. Sometimes after shutting off the power of the cabinet (on the backside) I sometimes can get my computer to start up. This problem has happened with increased frequency the last weeks.
My motherboard is 6 years old. Expet from that my other components are not older than 2 years.
Some things others may find useful when addressing this-
What kind of computer (CPU, video cards...
, and what wattage and brand of power supply
Although my first guess would be a power supply issue, try cleaning out the case. It's free and ought to be done every now and again anyway. Enough dust can cause shorting issues. You don't need it so clean that you could eat off of it, just spray it out with canned air or an air compressor. While you've got the case open, reseat ram, and tighten connections.
When it does start up, go into the bios and try turning the clocks back to stock (there should be a setting to return bios to default, or you should have jumpers or a battery to pull to accomplish the same), and check the power supply voltage. Over-clocking may be pulling too much power off of your supply. Even better, under clock your processor and drop it's voltage a tad. This should pull less lower off the supply. If this works, back up your data. You may be able to limp along on a bad PS for a bit longer by underclocking and removing nonessential devices, but it will eventually fail, and could take data (and other components) with it.
I have a 550w power supply. corsair. cpu athlon 64 dual core. integrated graphic card.
Low performance computer. 2 gb osz memory.
So I dont think there is a short of power in my system. I suspect motherboard or psu. maybe too much dust. I will clean and report back thanks
Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.
Make sure you plug the CPU power cable in. The system will not boot without it.
I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case once you are finished.
You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.
If no beeps: Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.
At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.
The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.
A way that might be easier is to use the main power plug. Working from the back of the plug where the wires come out, use a bare paperclip to short between the green wire and one of the neighboring black wires. That will do the same thing with an installed PSU. It is also an easy way to bypass a questionable case power switch.
This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.
If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.
Silence or long single beeps indicate a problem with the memory.
Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST. At this point, if the system doesn't work, it's either the video card or an inadequate PSU. Or rarely - the motherboard's PCIe interface.
Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.
ok I have now cleaned the components for dust. and I have unplugged and plugged in all the contacts. still not possible to make the machine boot. the power button on the case just got a orange light, instead of blue(which indicate that it will boot)
So next is to change the psu.
ok so if the change of psu doesent work, then it is definately something wrong with my motherboard. is it broken? is it possible to fix the motherboard? or do I have to buy a new computer?