ASUS P7P55D-ELX MB, Kingston 4 gig Hyper X T1 RAM, Intel i5-750 Lynnfield, MSI Twin Frozr 1 gig NVidia Video Card all in a Cool Master Case. Using prior 1T HDD and 650W pwr supply.
Installed everything and powered up. All fans turn on but no POST beep and nothing happens after turn on. I have re-seated CPU, RAM and reconnected all cables to make sure all is correct. Even changed SATA cables to HDD. Still nothing. I was told some new systems do not beep on start up POST so I do not know if I should or should not hear this. Others systems I have built in the past have all beeped.
Don't know where to go from here. Purchased all new items from Newegg.
The ASUS MB has four slots and two are designated for single RAM sticks. I put one at a time in each and tried to turn on without any luck. Made sure to turn off PC each time to change out stick. Still no luck.
I have built at least four PCs before without any problem. Still don't know is there should or should not be a POST beep on this build. There is still something missing from the normal PC startup sounds. I have a bad feeling I have overlooked a simple cable connection. But all power cables are connected from the pwr supply and the system cables have been double checked. SATA cables to the HDD and DVD are double checked. The only big difference with this machine is I am using my HDD and pwr supply from the old machine since they are fairly new. The other difference is the case has lots more going on in the front like USB slots like most modern machines.
My big problem now is I do not know how to diagnose the problem or direct cause like a bad component. I don't know enough to understand the process of start up. If I were to take components out to take it down to the most basic, what would I absolutely need? is the CPU and RAM enough to know it is working well at that point and then add a component at a time to see where the problem lies?
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.
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.
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.
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.