Computer not booting :P

[Guest]

Hi

First my computer shut down by itself randomly and froze randomly too (whatever was on screen wouldnt change). I cleaned all the doghairdustwateverballs from the fans and everywhere and it worked well for hours but then shut down again and i couldnt get it boot anymore. (All but psu fans spin, hdd and cpu work, start button light wouldnt come on it just showed the hdd activity light for a split sec when i press it like always)

I tried cleaning up more dust, cleared (tried to xD) cmos a few times to be sure, swapped and did some fancy eraser trick on the ram sticks like twice, removed video card, checked all the wires so theyre not loose, didnt have mouse and keyboard attached (no signal to them btw)

ummm... the disk thingy opens and closes.

the psu fan hasnt propably worked for a year -.-

Does it sound like its just the psu and not also some other component? I dont want to buy a new psu if theres more components broke...

the computer is like 3-4 years old, fujitsu siemens amilo pisomething

 

[T_T]

Unfortunately, there could be a number of reasons, PSU included, for your system to have these symptoms. The top reasons for boot, but no display are:

1. Bad RAM
2. Bad PSU (including supplemental power cable)
3. Bad GPU (video card)

Some uncommon, but not far fetched reasons are:

1. Monitor signal cable
2. BIOS setting
3. Bad mobo
4. Bad CPU

That said, with so many variables, other than PSU, there is no guarantee that replacing just the PSU will correct all the known symptoms.

 

[Guest]

Wait, i took the video card off, no beep. no beep with ram off either/ram in different slots. Also the processor does heat up when i start it (no i didnt let it heat to 200 degrees) so it should be working. So i think its either just the psu or psu AND mb... Can the mb get broken by the psu, and still have the cpu and fans working?

 

[T_T]

The absence of beeps could mean one of two things:

1. There is no speaker connected to the mobo; or
2. Your mobo is damaged

As far as the PSU damaging other parts, it is possible. The most common problem is that if a low quality PSU goes bad, it can send surges to connected devices, thus causing said connected devices to also fail due to severe overvolting. The unfortunate truth is, the only way to know if this has happened is to replace the PSU. My advice, get a quality PSU from one of these manufactuers, but also get one that's at least 80+ Bronze Certified:

1. Antec
2. Corsair
3. OCZ
4. Thermaltake
5. Cooler Master

Edit: To add to my advice, get the PSU to test in your current system, but with the premise that if the new PSU fails to boot your system, you can still use the newly purchased PSU to build a new system.

 

[jsc]

Try breadboarding your system.

The following is an expansion of my troubleshooting tips in the breadboarding link in the "Cannot boot" thread.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different, but they all use a single short beep for a successful POST.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboarding

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.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=youtube_gdata

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, long single beeps, or series of short beeps indicate a problem with the memory. If you get short beeps verify that the memory is in the appropriate motherboard slots.

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.