Sign in with
Sign up | Sign in
Your question

Homebuilt PC isn't working correctly, only a few parts are functional.

Last response: in Systems
December 29, 2011 6:11:09 PM

Hello all,
A few weeks ago one of my friends and I decided to build a PC for my dad, we both have minimal experience but my friend has built PCs before, I've helped others design PCs but I've never physically built one. Anyway, I checked everything out to make sure it's all compatible, technically it should work but we've run into a few problems.

After connecting everything to the appropriate terminals and turning on the machine, I noticed that all of the fans, including the CPU fan, were in perfect working order, the case LEDs hooked up to the mobo work fine, and the mouse and keyboard light up when the PC is turned on. However, there is no response from the Disk Drive or Hard Drive, and the monitor claims there is "no incoming signal". All of the hardware is brand new, straight out of the box, so I'm not sure what the problem is. Any suggestions are most welcome, as I have four days to finish this thing.

Here are the specs.
There is no graphics card because my friend informed me that the particular CPU we picked out has HD graphics onboard meaning we wouldn't need a graphics card. The monitor is rather old and has a D-Sub connector, but it was working well last week and the mobo I picked out is compatible with D-Sub.
Intel Core i3-2120

GIGABYTE GA-H61M-DS2 Micro ATX Intel Motherboard

Disk Burner:
ASUS DVD/CD Player/Burner

NZXT Source 210 Elite White Steel

G.SKILL Ripjaws Series 4GB (2 x 2GB)

Hard Drive II:
Seagate Barracuda 250GB

Power Supply:
Corsair 430 "CX Builder Series"
a c 122 B Homebuilt system
December 29, 2011 6:27:54 PM

Start off by reviewing this thread:
Build it yourself:
If you overlooked something simple, this should help you find it.

Then, it is time for our standard "no boot/no video" thread. Work systematically 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 still no luck:
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.

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:

Check for line power at the PSU input. Extension cords, power strips, and power cords do fail.

If you have power and no beeps, suspect components in likely order are PSU, motherboard, and CPU.

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.

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.
December 29, 2011 6:54:48 PM

Though I should point out that I did use the aforementioned threads when building the PC, and everything in the first thread has been checked multiple times. This motherboard did not come with a case speaker, is this something that usually comes separately?