I have a old build using an Asus a7n8x deluxe motherboard that has gone bad. The computer will start, all fans come on, hard drive sounds to be running, but computer does not post or have graphics.
I have tested the power supply in two other computers and has tested fine, however those other two PSU give same result in the machine in question.
I have moved the hard drive to two other machines. Due to major differences in the builds other machines will not boot from hard drive. Attempting to access data on hard drive allows me to see anything that is not password protected. Can not get into password protected files.
I have purchased a second Asus A7n8x deluxe motherboard as I thought the first one was the culprit and I am needing information off that hard drive.
After installing second motherboard I have the same issues. I have built a few systems but am no expert and surely am missing something simple (I hope).
I have attempted to bread board I get no beaps on either motherboard (case speaker is installed)
Green LED come on when PSU is plugged in
Upon pressing the power button all fans come on.
Shut down can be accomplished by holding the power button down.
I have removed power, battery, double checked for anything that could short out the board etc... simply have run out of ideas.
I understand this system is old and well outdated, however the information on my hard drive is the bigger concern. (the hard drive was backed up on an external drive, and that drive was stolen the day before this occurred. As for the hard drive, I have tried ghosting it but still can not access the password protected files. I have tried putting it in an external enclosure, same issue.
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, 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.
JSC, thank you for your quick response. I have gone through this list before posting in the first place (should have said that huh). No beeps, power supply proves good in two other machines... does that leave me at a video card?