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Computer Building problems

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Bob1234234

Technical User
Jul 1, 2003
1
US
I am building two comptuers and am having problems.

With the first, when I turn it on the fans start but nothing comes up on the screen!? I have tried 3 video cards, 1 AGP and 2 PCI and they all have the same thing happen.

Where is the problem? Is it the motherboard, do I need a new one or do I have to do something else to get it working? The power supply is a switching power supply, what is a switching power supply?


With the second computer, again nothing happens but the fans start to turn but then quickly stop. There is a LED light on the mother board that stays on after the fans stop.

One other problem though it is minor compared to these first two, the power buttons don't work so I have to use the switch on the power supply to turn on and off.

Both computers have:
D875PBZ Motherboards
768MB of RAM
80GB Serial hard drives
2.8GHz PIV proccessors
400-430W power supplies

Thanks for any help you can provide.
 
Hi Bob,
One more thing that you might try is this:

With the PS plugged in and turned on, cause a short between the two pins that go to the power button on the case (i.e. emulate the power button being depressed momentaraly)
Some motherboards will not power up properly unless you use the pins meant for the case switch. Just make sure you are crossing over the right two pins!!!
Cheers,


Matthew Janes

Everything in its right place...
 
1st computer:
If the USB connected to your System Board then try starting up without the USB connected. Always start with fewer card on the slot (PCI).



 
Use extreme caution if you try this. The power supply has full 110 volts on the input side when it is plugged in. The voltage of a power supply is about 12Volts, but the amps can be very high. A power supply can not normally hurt someone if handled with care.

Another way to test a motherboard is kind of radical. Many technicians use a variation of this before they put the motherboard into the case. They simply set the motherboard on a non-conductive surface and hook up a power supply and see if the card will boot up noticing the beeps.

You should initially get the beep code for no memory or no CPU, or no video card, or no drives if you try to start it without those items attached. Normally there are 2 pins that are used to start the motherboard by pressing a screwdriver up against them, it should try to start. It is possible to keep an extra ATX power button to turn a computer on if this scares you. I removed one out of an old case to use at home. This is actually very interesting to do or watch.

If you attach a video card and a monitor you should get some output assuming you have a CPU (With Cooler and fan) and some memory. This tells you if the motherboard is good before you place it in the case. If you have problems at this stage you dont have to remove the motherboard to send it back.

Do not assume the static free bag is non-conductive!!!

Cardboard works great.

They sell different types of testing equipment at online stores like and some other places like An extra floppy would be nice too.

If you do not like my post feel free to point out your opinion or my errors.
 
Make sure the CPU fan is plugged into the CPU fan header.

If you do not like my post feel free to point out your opinion or my errors.
 

With the second computer, again nothing happens but the fans start to turn but then quickly stop. There is a LED light on the mother board that stays on after the fans stop.

One other problem though it is minor compared to these first two, the power buttons don't work so I have to use the switch on the power supply to turn on and off.


1. The green light is the light telling you that there is power in the ATX powersupply and that the motherboard is in standby mode.

2. The switch on the back of the power supply will NOT turn your system on and make it boot. IF the power button on the front of your PC is broken, hook your RESET button up to the DC SW prongs on the motherboard and just hit RESET to turn the PC on.

ATX requires that a wire be hooked up to the motherboard (or at least have the circuit collapsed) in order to power on and boot up.

Try that and let us know.

Cheers!

 
Hello,

I just joined in after searching the web for answers to my problems connected to the latest PC I am trying to build. I have had many experiences in upgrading and actually building PCs from parts I buy and/or are given to me but this present one has stumped me. This latest one will run on an AMD Duron 1gig on an K7S5A MoBo, which gives an option of using either DDR or SDRAM RAM chips. I am using SDRAM @ 256Mg. It has a 300w PS, with the following peripherals: one CDROM drive, a DVD drive, FDD, and two HDDs, one for 3gig and another for 30gig.

The main problem is similar to the 2nd PC problem of this thread and I am still in the stage of initial power up after putting all the parts together. When I push the power up button, everything starts to run, such as the fans, the drives, etc. Then in about 3 seconds everything stops. Sometimes there is a long beep, sometimes nothing. I read that a long beep could be a RAM problem, so I re-seated the chip. I have also re-seated all the cards such as the Video card and the DVD decoder (this is an older DVD drive). I have even used the RESET switch on the POWER switch pins, and reversed them every way which way, but no success.

Any recommendations or trials I need to try that might resolve this problem?

Any assistance is appreciated.
 
CPU fan plugged into the wrong fan header? or
You are using a low speed fan (70 or 80mm) that the motherboard is having difficulties picking up (sensing) most motherboard act like this if they cannot detect a fan connected to the CPU header pins.
Martin

Replying helps further our knowledge, without comment leaves us wondering.
 
Hi, Martin:

True, the CPU fan I am using connects directly to a connector coming straight from the PS. Thus, the on-board CPU fan pins are bare.

Should I then add another CPU fan that I should connect to the on-board pins?

Thanks a lot!

Amadeo
 
wow this could answer my question. SO on ATX boards you have to have a fan connected to the headers for the post to complete? Or did I understand wrong?
 
are you sure there isn't an additional single wire from your fan that should also go to the mobo fan header?
 
Hi, All:

I believe the answer lies in what the MoBo is featured to do as written in its manual. And in my case, the MoBo has features, among others, enabling it to monitor and manage CPU fan speeds and CPU temperature. Thus, I would then suppose that if the CPU fan header which has three pins, one pin devoted for the monitoring, is not connected to the fan itself then the power-up attempt will fail. The additional single wire question does not apply here.

I shall purchase an additional CPU fan that can be connected to the header and shall find out if this works.

Thanks for all the help.

Amadeo
 
Hi, ALL:

Was able to purchase a new CPU fan and was able to install it. The initial boot-up continued for about a minute. Then it stopped completely and power was cut off! The only clue the monitor gave was that system saw the video card installed.

Thus, my next question is (before I review everything again): What other factors would cause the power to be automatically cut off and stop the PS?

Bad or incorrectly-seated Peripherals/Cards? MoBo problems? Bad PS? What else?

Thanks for any assistance, from maybe similar experiences.

Amadeo
 
XP has to have 600 X 800 for video. Try booting in Safe mode by continually pressing the F8 until the same mode options come up on the screen. At first a boot screen for XP will come up and then press F8 and many options will be present. Try selecting enable VGA mode and see if that helps. Sometimes you have to change the configuration options to list 600 X 800 to get XP to work.

If you are installing a new motherboard you need to install the OS from the beginning. You may also need a patch CD fro the chipset that has additional drivers on it.

If you do not like my post feel free to point out your opinion or my errors.
 
Hi, All:

It seems I still have the same problem after all this time and after going through very many tests and trails.

To recap: This is a newly built PC from many different components gathered and put together. Mobo is K7S5A, CPU is 1.3AMD Duron, RAM is 256Mg SDRAM (although MoBo allows another option with two extra slots for DDR SDRAM).

At this point, I am able to initially power up the system and it recognizes the video card as reflected on the monitor. And then, it ends with a prompt. From then on, everything hangs, though all the fans and LED lights are on. Keyboard strokes are not recognized and no LED lights on the keyboard. A boot disk is on FDdrive from the start. And I have even put the Win98 CDROM on one drive and the MoBo software on the second drive, a DVD drive. But still nothing.

Cannot access BIOS since keyboard is not working.

Any ideas?

Thank you.

Amadeo
 
Do you get any beeps besides the one that means cleared past post. Make sure you are using the case switch instead of the psu switch. the psu switch turns of the psu the power button turns on the mobo. Fans some boards it matters and some boards it doesn't I have all mine going right to the psu without any problems at all. but I know alot do. try takeing out the ram. test for proper grounding and that things that are supposed to be grounded aren't. Disconnect everything and try from the start. with just the mobo attached see if you get beeps then go to video. If video comes up try your drives. If nothing helps chew on the peice and snap it over your knee.
 
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