rjorge
asked on
Can a computer not boot due to low power supply?
Hi,
I have bought (second hand) a Abit N68SV with a AMD X2 7750 processor on it. I tried to start up my system using a old 300 W power supply. The result is that I don't get anything on the monitor, when I start the computer. So I am wondering whether the problem could be with the power supply just not being strong enough to start the system. However everything seems to be ok when I start, as the CPU fan is running all the time, while powered.
Cheers.
r
I have bought (second hand) a Abit N68SV with a AMD X2 7750 processor on it. I tried to start up my system using a old 300 W power supply. The result is that I don't get anything on the monitor, when I start the computer. So I am wondering whether the problem could be with the power supply just not being strong enough to start the system. However everything seems to be ok when I start, as the CPU fan is running all the time, while powered.
Cheers.
r
It's certainly possible, though if the fan is running normally a problem with the 12V is not likely. The easiest way to find out is to use a DVM to check the actual voltages at the power supply connector on the motherboard. This site has a pinout of the 24-pin ATX connector.
If you have a PCI POST 4 card, by all means install it and see if the system is POSTing. If the POST 4 card is counting BIOS stages as the system is powered on, there is at least an indication that the machine is not entirely dead.
If you have a PCI POST 4 card, by all means install it and see if the system is POSTing. If the POST 4 card is counting BIOS stages as the system is powered on, there is at least an indication that the machine is not entirely dead.
you can calculate how much power you need : http://www.antec.outervision.com/
and did you connect the 4-pin aux CPU power cable?
ASKER
@nobus. There is no 4-pin aux CPU pin in the board that I remember. Only the 24 in power supply pin. I think.
You can try to remove connection for CD/DVD drive, remove off any other device and do a test.
The intiial bios flash should be seen on the screen at least. If you cannot see the bios flash
it could be the video out put to the screen need to be checked.
Check also that your RAM is connected correctly. If you have two or more RAM sticks remove them all off and test the machine with just one. A faulty RAM stick could also give weird results.
The intiial bios flash should be seen on the screen at least. If you cannot see the bios flash
it could be the video out put to the screen need to be checked.
Check also that your RAM is connected correctly. If you have two or more RAM sticks remove them all off and test the machine with just one. A faulty RAM stick could also give weird results.
did you calculate the needed power yet?
ASKER
@all
I've calculated the load. With the CPU+2Gb DDR2+SATA HD+ATI RADEON 5670 the calculation is 219w recommended wattage. I've even tried using it without the graphics card and it still doesn't boot.So indeed the 300w should be enough.
I've calculated the load. With the CPU+2Gb DDR2+SATA HD+ATI RADEON 5670 the calculation is 219w recommended wattage. I've even tried using it without the graphics card and it still doesn't boot.So indeed the 300w should be enough.
are you sure you have the 4-pin +12v connector plugged in?
have you tested the PSU on another system or tested another PSU on this mainboard?
Are you doing all your testing with the mainboard outside of a PC chassis? As to ensure nothing is shorting out.
have you tested the PSU on another system or tested another PSU on this mainboard?
Are you doing all your testing with the mainboard outside of a PC chassis? As to ensure nothing is shorting out.
Are you sure the PS is OK? test it on another system to be sure, or test with a KNOWN good one
>> I've even tried using it without the graphics card << difficult to see if it boots..
if you have a V-meter, you can check +5V and +12V on molex connectors
>> I've even tried using it without the graphics card << difficult to see if it boots..
if you have a V-meter, you can check +5V and +12V on molex connectors
ASKER
@all
I have noticed that I only had the main 24 pin PS cable connected. So there was a problem. The board has a 4 PIN ATX 12V slot but the PS only has a 2 PIN cable that fits in half the slots. Can that be the cause?
I've tested the PS on a older system, with a M811 motherboard and a Athlon 3000+ CPU. The system booted well, got image on the screen, although once or twice did not boot well due to the awkward position of the graphics card hanging in the air.
I've performed the tested with the MB on top of a bubble wrap, using my case's board connectors. The board was also out of the case.
I have noticed that I only had the main 24 pin PS cable connected. So there was a problem. The board has a 4 PIN ATX 12V slot but the PS only has a 2 PIN cable that fits in half the slots. Can that be the cause?
I've tested the PS on a older system, with a M811 motherboard and a Athlon 3000+ CPU. The system booted well, got image on the screen, although once or twice did not boot well due to the awkward position of the graphics card hanging in the air.
I've performed the tested with the MB on top of a bubble wrap, using my case's board connectors. The board was also out of the case.
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
Hi all,
a small correction. The connector on the board is a 8 PIN, but the cable I had is just 4 pin. Still, I think what nobus said applies. I'll get teh adapter cable and if that doesn't work will simply change the PS.
a small correction. The connector on the board is a 8 PIN, but the cable I had is just 4 pin. Still, I think what nobus said applies. I'll get teh adapter cable and if that doesn't work will simply change the PS.
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
here you have one 8-pin : http://www.directron.com/ad202.html
ASKER
Final outcome. I've tested with a newer power supply and the MB did not boot. It was crooked.
tx for feedback
With the X2 7750, the CPU fan should spin up full speed for a moment then slow down to the regulated speed during post. If it stays full speed when you get no pic, it indicates a M/B or PSU problem. If you can get a system speaker attached to that M/B it will help determine any problems via the audible POST beep codes.