General discussion

Power Supply Discrepancies

So my computer recently started displaying no picture on its monitor. However, when I turn on the computer it sounds like not every device is powering up. So I opened up the computer and tested every connector on the power supply with a multimeter. I read that when I short out pins 15 and 16, the fan is supposed to start to spin, but it does not. However, with these two pins shorted out, I was able to take voltage measurements of the pins on every other plug, and the measurements fell within the tolerance ranges. Once I plug the 20-pin plug back into the the Mobo and power on the computer, the fan starts to spin but the CPU is so quiet that I feel like everything is not powering up. What does this mean? Where do I stand?

Discussion is locked
Reply to: Power Supply Discrepancies
PLEASE NOTE: Do not post advertisements, offensive materials, profanity, or personal attacks. Please remember to be considerate of other members. If you are new to the CNET Forums, please read our CNET Forums FAQ. All submitted content is subject to our Terms of Use.
Reporting: Power Supply Discrepancies
This post has been flagged and will be reviewed by our staff. Thank you for helping us maintain CNET's great community.
Sorry, there was a problem flagging this post. Please try again now or at a later time.
If you believe this post is offensive or violates the CNET Forums' Usage policies, you can report it below (this will not automatically remove the post). Once reported, our moderators will be notified and the post will be reviewed.
- Collapse -
I suspect....

You gave no details of your system, just what is it and OS, etc.. You gave some details but even that leads only to guesses. In such cases when it comes to PSU issues, just replace it. A 20-pin PSU connector suggest an older system. If in fact it is an older system, then more than likely it saw better days. PSU do age it may have given up the ghost, so replace. remove and/or read the decal sticker on or look by your system info what is available for your model#, if OEM, like Dell, Gateway, etc.. The cost is far cheaper than you think but again you may what to think replacement of the whole is more than a PSU problem, it maybe the mtbrd. and thus again replace. I wish I could offer more but its limited with the details you offered. For now, that may cover what is need to fix your problem.

tada -----Willy Happy

- Collapse -

Sorry for the lack of details.

The power supply is a NPS-250KB and I am running Windows XP on a Dell DHM. I am just wondering how I know that the Power Supply is the problem and not the video card.

- Collapse -
PSU, common problem

Since you thought the video portion, then swap out the monitor to another system and see if works.-OR- place another monitor in place of old one and if display returns. If sameo-sameo, then think PSU as cause. As I stated, an older PSU plus being 250W unit is weak or kaput. I tend to lean towards bad PSU as its almost 2nd nature just to replace it and check results. You can reduce power slightly if you remove any extra drives and keep it simple to include anything that may reduce demands for now as a quick check. If not a bad PSU, then the other half, the mtrbd. is a cause, provided no extra beeps, warning, etc. get sounded.

tada -----Willy Happy

- Collapse -
With that fan running.

With the PSU in the system and that fan running, what voltages did you measure?

CNET Forums