Monitor trouble...please help?

Question

I am putting an old tower back together, and I cant get the monitor to come on. Its not the monitor, cause I tested both a Dell, and a Sony Flatscreen that both work on other computers. I dont have the original monitor anymore, but it worked just fine on this computer. The only thing besides the monitor thats different is the hard drive. It had windows ME before, and this HD has 98, but the HD does work. I tested two seperate video adapters also, one of which I know works. The motherboard works, and the fan and LED comes on like normal. The Dell monitor kicks into standby (or whatever the yellow light means) after about five seconds. The sony just stays on, and says No input. any ideas?

Answer 1

Make sure the internal speaker is correctly plugged into the motherboard (check in the motherboard manual). If yes, and there is no beeping it's more likely that the motherboard or cpu is actually not working correctly.

You might also want to swap out the power supply with a working one. The computer might be going on but the power supply could be faulty and is not suppling the correct voltages to the main parts of the motherboard. You should also check the connections of the Power supply as most motherboards require an extra 12V connection that runs from the PSU and plugs into a square 4 pin header somewhere near the CPU. If it's not plugged in the PC will give the same symptoms as you described as well. Check the motherboards manual to see if the motherboard needs such a connection.

If there is no internal speaker plugged in the solution is much more difficult as there could be beeping but you're not hearing it.

You might also then try this.
If there is more than one memory module plugged in, just have one of them in each time.

It would have been nice to know what motherboard it is. the motherboard could have onboard graphics and the CMOS settings might have been reset and it's booting from the onboard VGA. Some older computers don't have the VGA connector on the standard back panel, they plug into the motherboard using a cable.