Sign in with
Sign up | Sign in
Your question

Red light error on my computer?

Last response: in Components
a b ) Power supply
September 27, 2010 2:42:38 AM

hi my names trish
and i have a rebuilt computer.
it was working great but one day when i disconnected it; and when i plug it back in
the screen would not turn on it would go into standby mode, and my mouse nor keyboard lights turned on.

so iturned the tower around to make sure i plugged everything in right. and i did
but noticed
4 red circle lights in the shape of a square were on.
usally thous lights are all green.
can u please help me...

i need figure out why it doesnt work.

sincery, trish
san antonio texas
a b ) Power supply
September 27, 2010 8:43:25 AM

Where are the 4 red lights? On the back of the computer?
a b ) Power supply
September 27, 2010 9:49:58 AM

can you take the side off, and tell us what the motherboard is? it'll help us to determine what those lights mean, as they are unique to each motherboard manufacturer, and most boards do not have them
a c 144 ) Power supply
September 27, 2010 4:29:28 PM

This will be involved for you ...

We have developed a troubleshooting procedure that works pretty well. And along with some other instructions, it should help.

Work through our standard checklist and troubleshooting thread:
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

Breadboard - that will help isolate any kind of case problem you might have.

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.

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.

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.