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Need Help Diagnosing Strange PC Issue Please


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#1 thebondservant

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Posted 05 October 2009 - 01:08 AM

Greeting experts. Client is a friend (aren't they all sometimes).

HP Pavilion, about a year old. Vista Home Premium.

Pre-crash info (I wasn't present), BSOD with a hardware failure notice. Rebooted to the desktop once after that, within minutes the screen went dark... the end.

The PC won't boot to post, no video (it's integrated), keyboard won't function either. I've reseated everything.
Haven't slaved the HDD but it "sounds" fine, the CPU & Case cooler fan work fine. The CD goes in and out but doesn't "sound" like it's attempting to read any data.

What's bugging me is my inability to cause any diagnostic beeps. Ram out, nothing, HDD disconnected nothing, (did plug into powered speakers to make sure I wasn't missing something)... No Beeps.

I haven't swapped out the PSU or tried to throw in a video card yet. My limited experience with this combination of issues suggests either a dead bios or motherboard and I'm leaning toward that strictly upon the lack of beeps. There is no explanation for that I can think of.

Any experienced direction would be helpful. Thanks in advance for your time.

Edited by thebondservant, 05 October 2009 - 01:11 AM.


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#2 garmanma

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Posted 05 October 2009 - 01:44 PM

Check the voltages at the motherboard plug


Caution: There are electronics inside the case that are very susceptible to electrostatic discharges. To protect your computer, touch the metal of the case to discharge yourself of any electrostatic charges your body may have stored before touching any of the components inside. As a safety precaution you should unplug the computer to avoid electrical shock.
-----------------
The purpose of this procedure is to bypass the motherboard to test the PSU.

Caution:
This procedure will involve working with live 12VDC electrical potentials which if handled improperly may lead to electrical shock. Proper precautions should also be taken to prevent electrostatic discharges (ESDs) within the case of the computer. For safety purposes please follow the instructions step by step.

First, shutdown your computer. Then unplug the power cable going into your computer.

Once you have opened the case, touch the metal of the case to discharge any static electricity.

The connector of the PSU which connects to the motherboard is readily recognizable by the number of wires in the bundle. To disconnect it you will need to press on the plastic clip to disengage it and then pull the connector up and away from the motherboard. Please take notice of the location of the locking tab and the notch on the socket of the motherboard, this will only connect one way as it is keyed. This wire bundle will have a memory of the way it has been installed and will want to bend back that direction, you may have to play around with it to find a position that the connector will stay in the same position while you run the test.

Posted Image

From the top left to right the pins are 13-24, the bottom from left to right are 1-12.


Please notice that there are PSUs with 24 pin and 20 pin connectors, the location of the green wire in the 24 pin connector is #16, and the green wire in the 20 pin connector is #14. If you look at the connector with socket side facing you and the clip on the top the number one pin will be on the bottom left corner. This makes the pin out for the 24 pin connector from left to right 13-24 on top, and 1-12 on the bottom. The pin out for the 20 pin connector from left to right is 11-20 on top , and 1-10 on the bottom. If you look at the connectors you notice that these are sockets that fit over the pins on the motherboard where the PSU cable attaches, this is where you will place the jumper. For a jumper you will need a piece of solid wire about the size of a paper clip (20-22 awg), preferably a wire with insulation. It will need to be large enough to fit firmly into the socket so that it will not need to be held in place while testing. You are at risk of electrical shock if you are holding the jumper when you power up the PSU. Insert one end of the jumper into the socket of the Green wire, and insert the other end into the socket of any Black wire.

Once the jumper is in place plug the cord back in. If the PSU is working properly the case fans, optical drives, hdds, and LEDs should power up and remain on. I would suggest that you not leave this connected any longer than is necessary for safety purposes.

To reconnect the 20/4 pin connector unplug the power cord, remove the jumper, and reconnect the connector. Take a moment at this time to make sure that nothing has been dislodged inside the case.
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At this point you can use a DC Voltage meter to read the different rail Voltages. You will want to insert the black probe into any of the Black (-) sockets, and insert the Red (+) probe in the five different colored sockets, one at a time. Below are the five different colors and their corresponding rail Voltages. The Voltages should be within about ten percent of the given values.

Yellow +12VDC

Blue -12VDC

Red +5VDC

White -5VDC

Orange +3.3VDC
Mark
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why won't my laptop work?

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#3 thebondservant

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Posted 05 October 2009 - 06:50 PM

Thanks Mark. Will do and post back result.

By the way. Below is so true....lol... thanks

Ray

Having grandkids is God's way of giving you a 2nd chance because you were too busy working your butt off the 1st time around

#4 thebondservant

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Posted 06 October 2009 - 01:15 AM

Test results using the jumper were free from any anomalies. This particular model doesn't have a hard drive light, but, the psu light, the power button light, hard drive, cpu & case fan, these all stayed on once power was plugged in. The Multi-Drive searched for media like it always does and stop searching but that's normal boot behavior. So, using the jumper, identical to pushing the power button.

The Voltages were all within acceptable ranges also.

Would you suggest a next step?

Thanks

Ray

#5 garmanma

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Posted 06 October 2009 - 04:45 PM

You say it gives you a black screen and no BIOS beeps, but does it continue to run? I mean the power supply
With everything reinstalled, remove the CPU only and turn it on
If it turns and remains on, most likely the CPU is bad

a dead bios

If it is a removable chip, you can reprogram them for twenty bucks
I'd be more inclined to believe it's the mobo
Mark
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#6 thebondservant

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Posted 06 October 2009 - 06:51 PM

You say it gives you a black screen and no BIOS beeps, but does it continue to run?
I mean the power supply

Yessir, it purrs like a mustang with no transmission. No video, no beeps. PLUS the
hard drive doesn't sound like she's trying to load the OS at all, not enough activity.




With everything reinstalled, remove the CPU only and turn it on
If it turns and remains on, most likely the CPU is bad

I'll remove the CPU next up.

a dead bios

If it is a removable chip, you can reprogram them for twenty bucks
I'd be more inclined to believe it's the mobo


Well, I'd have to concur even with my limited experience. The only time I've had bios
issue was my own bad flashing. The box just reminds me of my first ASUS laptop, I killed it
with a bios flash before I even had it on the net... Never had a bios commit suicide.

Will post back once it's running again with the solution. Thanks for the guidance. There's
no substitute for experience.


Ray

#7 thebondservant

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Posted 17 October 2009 - 05:28 PM

Update... Darn Flu, that was fun. Okay I installed a new CPU last night. When I removed the CPU as suggested everything remained on so there was no change I behavior, so, I made the decision to purchase a new CPU. Turned the Power on. No change at all. Disappointed, but, there were no guarantees that the CPU was bad and it could have been based upon all the diagnostics.

I went back through the diagnostic process. While the hard drive does spin up, the CD searches, the PSU.... PSU's, and the fans
spin... The Lan LED is dark, NO BIOS beeps and the keyboard flashes all lights then doesn't respond. I missed the LAN LED the first time around and
I think that's probably significant. Since we narrowed it down to the CPU and maybe the MODO I'd have to say it's latter now. Is it common from your
experience to have a "part" of the circuitry on a MOBO go bad or not get power? Feels like I've missed something obvious but maybe not.

If it's the MOBO I'm thinking it becomes complicated now since NO OS CD's were supplied when it was new and from what I understand a complete O.S. install is required with a new MOBO installation... Correct?

Thanks in advance.

Ray

Edited by thebondservant, 18 October 2009 - 04:39 PM.





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