XP Won't Boot Up
Posted 09 February 2011 - 03:55 AM
Posted 09 February 2011 - 06:01 AM
Posted 09 February 2011 - 02:09 PM
Posted 10 February 2011 - 07:25 AM
Wikipedia: Power supply unit (computer)
Posted 12 February 2011 - 01:16 PM
Posted 12 February 2011 - 02:03 PM
Does the HDD led register any activity.
If you have the manual for the computer have a look at it.
If you do not go to the Compaq site and read it there.
If it does not even post and there is NO HDD light then you have without doubt an internal hardware problem
It is NOT an accurate check by any means, as some PSU only deliver voltage across certain components of the PSU when a load is seen, however as a start check the voltages on the molex connectors of the PSU to see if they are showing a 12v supply., using a multimeter.
You don't need to take apart your computer, you just need a basic multimeter to test voltage. Just plug the leads into a spare molex - black lead to black wire, red lead to red, yellow, and orange wires (orange is actually on your aux/atx connectors)
these will give you 12v, 5v, and 3.3v ratings
After taking anti-static precautions
Disconnect from the motherboard, all except the main power connection to the motherboard, normally 20 or 22 pin and the 4pin connector if present for CPU power.
If there is a green led, normally there is on the motherboard and that is NOT lit, then it is either a motherboard or PSU problem.
It MAYBE the power switch on the case., ie at the front. Test that with a muti-meter on resistance setting and operate the switch - ON circuit. 000 on multi meter. 1 on meter no circuit -
I presume if there is a 0/1 rocker switch on the PSU, normally below the AC cord that it is ON.
Edited by Macboatmaster, 12 February 2011 - 02:24 PM.
Posted 15 February 2011 - 07:29 PM
YOU started this thread on the 12 February
You never replied to the last post on it.
Yesterday the 15 February - YOU started this thread
which again appears to be the same issue,
YOU have also started this one
PLEASE do not start other threads on the same issue.
Edited by Macboatmaster, 15 February 2011 - 07:32 PM.
Posted 15 February 2011 - 10:03 PM
Posted 16 February 2011 - 07:12 AM
Check the voltages again on the power connector to the hard drive as shown on the above link.
CAUTION - Please be careful, I would not advise shorting out pins on the 20./ 22 pin main connector to the motherboard. One mistake and you will NOT have a Power supply. It will immediately be damaged beyond repair.
Disconnect the cable to the CD drive.
Disconnect the cable to the hard drive.
If you have disconnected the 20pin and the four pin to the motherboard reconnect.
Power up and see if the fans spin. If they DO NOT, then the PSU or the motherboard is faulty. If they DO SPIN
Power down , connect the keyboard and monitor. and power up again.
Will the computer now post if so press F2 normally, on keyboard. to enter BIOS
Will it then display the BIOS screen.
It will do this without the Hard drive in.
If it will not power up., switch off mains power.
Disconnect keyboard, monitor etc.
Taking static precautions
Locate the connection from the power button on the front of the tower to the motherboard. Normally connected to the lower right hand edge of the board as you look at it with the front of the computer to your right.. CAUTION if you disconnect any wires from the motherboard headers ensure you know which way they go back on and where. - note the colour of the wire. DO NOT rely on colour only, as there will be more than one wire of that colour.
I realise it an old computer, about 2002 I think, but if you are NOT sure of what you are doing, please do be aware that removing the wires and then connecting some of them incorrectly could destroy the motherboard. Particularly the USB headers.- although you do not need to touch those.
There wil be two wires from the switch most likely labelled on a very small black coloured connectors "Pwr Sw +" and "Pwr Sw -" or similar.
If these show open and closed circuit as the switch is pressed, it is working. YOU DO NOT NEED POWER CONNECTED TO TEST THIS.
If you do not have the knowledge to work this out, THIS area is the easiest to make a mistake.
If this is OK and the conmputer will not post you are back to PSU or motherboard.
Post results of test.
Edited by Macboatmaster, 17 February 2011 - 04:41 AM.
Posted 16 February 2011 - 02:11 PM
Posted 16 February 2011 - 06:41 PM
Posted 17 February 2011 - 04:38 AM
DC 50 volt scale and they all read 5 volts DC.]
As is always the case in matters of this nature, the next step depends very much on what resources you can acquire by borrowing etc.
I would simply try a known good PSU.
I do however appreciate that if you do not have one, that is of little assistance.
If you most certainly have only 5v on the yellow of the molex that is a reasonable indication that the PSU is faulty.
HOWEVER it is not quite as simple as that, as the main connection to the motherboard from the PSU has two pins, that receive a signal from the motherboard circuitry to open the PSU. ie: various aspects will only work on load.
If you examine the previous link I sent you,the details are in that link, hence my caution on the thread, do NOT short the pins., as if you short the wrong ones, you will certainly NOT have a power supply.
If the main 20/24 pin connector is on the motherboard and the 4 pin connector to supply power to the CPU and the motherboard is OK, then the circuitry in the motherboard, when it is powered up, will short the ground to power on pin. - normally 14 and 15.
This will then activate the power supply and IF YOU then have only 5v on both the red and yellow wires of the molex to the HDD and on the other molex connectors - there will be a number of them - then it is either the PSU or the motherboard.
IF YOU DO THIS TEST ENSURE that the CPU fan spins, otherwise you will fry the CPU.
If you cannot get your hands on another PSU and you wish to proceed then disconnect ALL PSU connectors from the motherboard and everywhere else and using the info on the link short the black and green nest to it which is Com and Power on. SEE the link for details.
Then test the molex. black and red, black and yellow. If still 5 volts it is NOW certainly the PSU, as you have now eliminated the possible motherboard fault.
CAUTION - at your own risk of course.
Edited by Macboatmaster, 17 February 2011 - 04:45 AM.
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