Powers on but will not boot until after several tries

[dariem]

My desktop will power on but it will not boot until I’ve powered it off and on between 5-20 times. No beeps, no blinking lights. When this happens the power lights are on, the fans are on, the amber light under the hard drive icon comes on but just for a second, the hard drive “clatters” for a couple of seconds, then nothing else happens – no boot. Like I said, after powering it off and on 5-20 times, it finally boots. Once it’s running I don’t shut it down. But another problem occurs: eventually it freezes for no apparent reason and I have to power it off. And the cycle starts again.

Here’s what I’ve done to try to resolve it. I tried the troubleshooting steps on HP’s support site for “Computer Does Not Start”:

• Removed discs and devices – only monitor, keyboard, and mouse connected
• Performed hard reset
• Cleared CMOS
• Ran hardware diagnostic tests (F10) – all passed. Could only run this when I got it to boot.
• Checked for hard drive detected in BIOS - detected. Could only run this when I got it to boot.

In addition I cleaned out dust inside of computer – heat sink and fans had a lot of dust. I also reseated RAM and hard drive power & data cables. 

None of these fixed the problem. Any suggestions on what else to try?  Thanks!

[old_geekster]

@dariem, welcome to the forum.

I had a situation very similar to what you are experiencing.  The outcome was a failing power supply unit (PSU).  I suggest that you test the PSU to see what happens.

Please click the Thumbs up + button if I have helped you and click Accept as Solution if your problem is solved.

[dariem]

old_geekster,

Thank you.  I will test the PSU as soon as I can and see if that's the problem.

[dariem]

I'm looking for a pinout diagram to test my PSU.  Haven't been able to find one on the Internet.  The PSU is:

Manufacturer: LITE-ON Technology Co, LTD

Model: PS-5301-02

HP Part #: 667893-001

Anyone have or know where to find one?

Thanks!

[dariem]

I tested the PSU and the voltages were all correct.  But is it a valid test without any load on it?

Any other suggestions?  Thanks!

[old_geekster]

Thank you for the additional information, @dariem.

Here is a guide that should help you properly test the PSU.

[Grzwacz]

Hi

I concur with OG. It appears to be a power supply problem.

You did your due diligence in all the test you performed.

I usually connect a known good power supply to the MB. Disconnect all internal drives, internal USB devices such as card readers, mouse, and keyboard. Run with only a monitor. A bare bones config to eliminate variables.

Also connect a spare reset switch and power on. You could also short the PS pins on the MB with a screwdriver to power on.

This will tell you if it is a power supply or mainboard problem.

Grzy

[dariem]

old_geekster and Grzy,

Thank you for the info.  It's apparently not the PSU.  I tried a known good PSU in the computer and it did the same thing.  Do you have any other suggestions?

Thanks!

[Grzwacz]

Hi dariem

You are welcome

I can only guess, and am sure old_geekster may have some additional thoughts.

How does the motherboard look? Any bulging capacitors?

Maybe the MB VRM is on it's way out. That can cause the symptoms (problems with the POST and random freezing).

Grzy

[dariem]

Motherboard looks fine as far as I can tell - no bulging capacitors.  Is the VRM something that can be tested or changed out easily?  Or if it is the VRM does that mean I need a new motherboard?

Thanks!