Member Avatar for Nucleartiger

Another poster seems to have a similar problem below but I didn't want to hijack his thread so here goes.

The power to my subdivision cycled off and on rapidly about 15 times the other morning. Afterwards my computer (HP a530n) wouldn't start. it gives no lights on the front and you don't hear anything inside happening (no fans spin up) on the back of the Computer the PSU LED is flashing.

I went through the online troubleshooting guide from HP and got to the point where you disconnect the PSU from everything to give you a solid green (if PSU is good) and then plug in things until the LED flashes again showing the fault. Well the first thing I unplugged after removing from the PSU was the Motherboardand decided I would go ahead and check the PSU LED as I disconnected things. Sure enough the PSU LED went solid green. So I decided to check out the PSU just to be sure by swapping it out with another that I had nearby in another desktop (call it computer #2). The PSU from Computer 2 went into Computer 1 and I get the fans to spool up for about a second before it powers back down. So I took the PSU from Computer 1 and placed it in Computer 2 and it started right up with no problems whatsoever.

So here is my question:
To me it looks like I have a bad Motherboard. Do you agree?

Or could it be one of the cards attached to the motherboard that is bad and that I need to unplug the individual cards from the motherboard to check them?

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Given the tests already posted by and the discharge/backup notes from and , the symptom pattern — a PSU that will run a different PC but only spins briefly in the affected chassis — most often means something on the system (motherboard, wiring or a short) is forcing the supply into protective shutdown. The goal is to isolate the motherboard from everything that can drag the rails down and verify the power‑delivery path step by step.

Actionable checklist (do these in order):

  • Safety first: unplug mains, ground yourself, and work on a non‑conductive surface.
  • Bench the board: remove the motherboard from the case and place it on cardboard. Connect only the CPU (with cooler), one known‑good RAM stick, the main 20/24‑pin and the CPU 4‑pin/ATX12V lead (use a PSU that actually has it). Power the board by shorting the two power‑switch pins briefly with an insulated screwdriver (this rules out a bad front‑panel switch).
  • Remove case wiring: disconnect HDDs, optical drives, front‑panel USB/audio, and the case power/reset harness completely and try again. Standoffs, misplaced screws or a damaged header can short the board.
  • Visual and tactile check: inspect for bulging/leaking capacitors, scorch marks, or broken components around the CPU VRM and power area; smell for burnt components. On AMD boards check for bent/shorted CPU pins if the CPU is removable.
  • Verify PSU rails under load: a paperclip test is not enough — use a cheap PSU tester or a multimeter to check 12V/5V/3.3V while the board is being powered. A PSU that starts unloaded but trips with the board is unstable under load.
  • CMOS/reset: if the board is otherwise stable, try clearing CMOS (remove battery and wait) and reseat memory and CPU cooler carefully.

If the problem persists after benching with a known‑good, properly‑equipped PSU and with the board off the case, the likely culprits are motherboard VRM/shorts or CPU damage and replacement is the next practical step. Because this is an OEM HP a530n, be aware some HP parts are proprietary — match connectors or source OEM replacements. If the machine ever runs long enough, copy critical data immediately.

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Member Avatar for Nucleartiger

Well I went ahead and disconnected all cards except the video card and tried to start it up with both PSUs. As before the computer does not respond at all with the original PSu and only respond for a bout a half second with the PSU from my old computer.

One thing that I forgot to mention before was that the motherboard has a 4 pin power point and the old psu that I was using for testing does not have that connector. Everything that I have read says that AMDs don't require that 4pin power connected to startup just that it will be unstable.

So If someone would please help me out here that would be great.

What do you think the problem with my computer is?

a) the motherboard/cpu is bad

b) the psu is bad

I think it is option a but any thoughts or suggestions before I go out and order a new mobo would be greatly appreciated.

Member Avatar for dcc

Pardon me if I snicker here, but what do you suppose they mean by being unstable. You will need a PSU with the P4 connector if the motherboard has that connector.

Member Avatar for Nucleartiger

I was afraid of that. Although like I said above I have seen multiple things online from people saying that the AMDs WILL work without that 4 pin connector.

I am just trying to figure out what the problem is without having to go out and buy stuff that I don't need.

Any other helpful responses are appreciated.

Member Avatar for dcc

There is an adaptor that will allow you to use the 20 pin connector type PSU. It still won't have the p4 connector which can be a problem with some motherboards. I built a new machine recently that had the 24 pin connector and the p4 connector and had been advised from the tech support that there may be an issue with the system fully powering up without the p4 connector.

What motherboard and CPU are you using?

Member Avatar for KevinTaute

Well I went ahead and disconnected all cards except the video card and tried to start it up with both PSUs. As before the computer does not respond at all with the original PSu and only respond for a bout a half second with the PSU from my old computer.

One thing that I forgot to mention before was that the motherboard has a 4 pin power point and the old psu that I was using for testing does not have that connector. Everything that I have read says that AMDs don't require that 4pin power connected to startup just that it will be unstable.

So If someone would please help me out here that would be great.

What do you think the problem with my computer is?

a) the motherboard/cpu is bad

b) the psu is bad

I think it is option a but any thoughts or suggestions before I go out and order a new mobo would be greatly appreciated.

I have a simular problem just about everytime the power goes out.
Try this. Remove the power cord from the computer. Open up the box and disconnect the power supply from the mother board. Wait till the light on the power supply stops flashing (total discharge), then plug the power cord back in - the light should stay green after a second or two. Once the light is green - plug the power supply back into the mother board. If you see a solid green light on the mother board, turn the machine on RIGHT NOW!!

It will run till you turn it off.

Yes, something in the mother board is dying, but if your machine still runs, MAKE A BACKUP!

Member Avatar for mechbas

those on and off voltage cycles also meant POWER SURGES, bad news for any system board. a new or reprogrammed BIOS is fairly cheap. if that doesn't work then it's time to consider another board, seems to me you've tried everything else.

Member Avatar for KevinTaute

I have a simular problem just about everytime the power goes out.
Try this. Remove the power cord from the computer. Open up the box and disconnect the power supply from the mother board. Wait till the light on the power supply stops flashing (total discharge), then plug the power cord back in - the light should stay green after a second or two. Once the light is green - plug the power supply back into the mother board. If you see a solid green light on the mother board, turn the machine on RIGHT NOW!!

It will run till you turn it off.

Yes, something in the mother board is dying, but if your machine still runs, MAKE A BACKUP!

After about a year, the power supply died on this machine (HP a530n). Replacing the power supply resulted in the problem going away.

Member Avatar for NullPointer

I'm having a similar problem. I took apart my computer to clean some of the dust out (something I've done in the past). Once I put everything back together I wasn't able to get it to start.

The LED on the motherboard is lit, but when I press the power button nothing happens.

I tried the method mentioned above (unplugging the power, unplugging the power supply from the mobo, plugging the power back in and then plugging the motherboard back in). Using this method, as soon as I plug the motherboard in the fans spin for a second or two then stop. The power button still does nothing.

I've tried jump starting it, switching the reset and power buttons (ie using the reset button as the power button), and I've triple checked that everything is connected correctly. Anyone have any insights into whats wrong? I don't think the motherboard is bad, as I mentioned the LED lights up indicating the motherboard has power.

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