Specific Power Supply not working with system

[AlphaGamer46]

Hi.

 

If you have seen my older post, you'll understand that I've been troubleshooting my dad's old computer.

 

I have worked out that the issue is a dead power supply. I found one that seems to be pretty much the same, but more compatible with newer systems.

 

I hooked it up to the Leadtek Winfast K7NCR18D PRO with 1GB RAM and 2 80GB IDE hard drives, plus a 7800GT so I can get some video.

 

I plugged it into mains and when I pressed the power button, all of the fans inside spun for a very small time before they stopped.

 

I had this conversation with my dad about how some power supplies aren't compatible with all systems, but this power supply has identical connectors to those on the other PSU, beside the fact there is 2 4-pin connectors, one to turn the 20-pin connector into a 24-pin connector and one for something else. The board in this system only uses the 20-pin so that's all that I'm using, plus a lot of molex.

 

I know for a fact that this PSU works, I did the 'paper clip' trick and it works.

 

Is there a way to get this PSU to work with this system?

 

Thanks, Alpha.

[HalGameGuru]

Do you have the full model number to the machine or the old PSU? I know there were some for a while that had this weird little 6 pin linear power header in addition to the 20 pin. may have to get an adapter if it used one of those too.

 

Otherwise its hard to say, you may want to doublecheck the wattages of the different rails. Older PCs drew entirely different levels of power from modern ones. It may be overloading a rail.

[AlphaGamer46]

1 minute ago, HalGameGuru said:

Do you have the full model number to the machine or the old PSU? I know there were some for a while that had this weird little 6 pin linear power header in addition to the 20 pin. may have to get an adapter if it used one of those too.

 

Otherwise its hard to say, you may want to doublecheck the wattages of the different rails. Older PCs drew entirely different levels of power from modern ones. It may be overloading a rail.

The machine was an early Windows XP custom machine, the only model number I sorta have is the motherboard number above. The old PSU that is dead is an L&C Technology model LC-250ATX. The new one is a Numan model ATX-400WB&P4. I will have a look at the motherboard, making sure there isn't any power connectors that I'm missing.

 

Sorry, I sorta don't understand some of the electrical lingo like 'power draw' and 'rails'. If you're able to explain, that'd be amazing.

[HalGameGuru]

The rails are the individual circuits in the PSU that supply certain voltages of power. Nowadays the 12v rail is king, back then the 3.3 and 5 volt rails were often heavily taxed. And a lot of older PSU designs reflect this with HUGE wattages on those low voltage rails.

 

Power draw is just that, if there is a rail that is rated for a certain amperage/wattage and the system wants more it will shut it down to protect the PSU and PC

[HalGameGuru]

This claims to be a compatible PSU to the original you had and it DOES have a 6 pin aux power cable, I will check the mobo specs too real quick.

 

http://www.atxpowersupplies.com/300-watt-power-supply-fsp-atx-300-gu.php

[AlphaGamer46]

1 minute ago, HalGameGuru said:

The rails are the individual circuits in the PSU that supply certain voltages of power. Nowadays the 12v rail is king, back then the 3.3 and 5 volt rails were often heavily taxed. And a lot of older PSU designs reflect this with HUGE wattages on those low voltage rails.

 

Power draw is just that, if there is a rail that is rated for a certain amperage/wattage and the system wants more it will shut it down to protect the PSU and PC

Okay, I will have a look at the power draw of the motherboard and the rails.

[HalGameGuru]

I'm not seeing any reference to that board needing anything but the 20-pin, the paper clip trick lets you know it spins up but it doesn't let you know it puts out juice, do you have another PC you can install it in to make sure it works at all? It may still have an issue with the older hardware even if it powers up a newer machine.

[AlphaGamer46]

36 minutes ago, HalGameGuru said:

I'm not seeing any reference to that board needing anything but the 20-pin, the paper clip trick lets you know it spins up but it doesn't let you know it puts out juice, do you have another PC you can install it in to make sure it works at all? It may still have an issue with the older hardware even if it powers up a newer machine.

I do have another motherboard to test it with, just waiting for my dad to get home so he can give me the go-ahead. It can confirm that the CPU, RAM and everything else still works.