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Question

I do not know why my pc will not boot - looking for ideas

by Oct 21, 2012 2:11PM PDT

I have an issue with my pc. Upon power up, it will not boot at all. There is power to the unit (power button is lit, green light on the back of the tower
is lit, and "system working" light under power button is constant on). The dvd/cd drive does it's usual start up noise. I get nothing on my monitor at all.
I opened the case and did a visual inspection as well as a thorough cleaning. While dusty, all fans were not clogged by any means. I removed the cooling fin/fan unit
from over the processor and that had about 25% blockage of dust in the fins. All capacitors looked normal (no bulging tops). I powered it back up and noticed that the fan
for cooling the tower ran briefly, then stopped (thermo controlled?). The power supply fan ran for about a minute then barely kept running (a slow sporadic rotation).
If I hold F8 during power up, nothing...nada. The "system working" light just stays on solid. I don't hear the usual noises of hard
drive activity. I'm at a loss here. Processor shot? Motherboard shot?

Windows Vista
HP Pavilion Media Center m8330f

Any insight would be helpful!!

Discussion is locked

7 Posts
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Clarification Request
since you see nothing ...
by Edward ODaniel Oct 21, 2012 2:19PM PDT

on the monitor have you tried the monitor on another computer to see if it is working or have you tried a different monitor on this PC? Even if the hard drive is dead you should get a Boot screen.

Prior to this failure to boot what happened? Did the PC start blue screening or shutting down?

Have you tried to access the BIOS - if you can't it is likely either the monitor or the graphics card although it could be the motherboard itself.

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Clarifiying hopefully
by barkinmarmot Oct 21, 2012 2:43PM PDT

I have not tried the monitor on another pc. I do have an older Sony Vaio laptop I am using which has a monitor output so I may try that. I do doubt it's the monitor though because upon powering up the whole system it does display analog/digital in the corner several times. That tells me it is not receiving a signal from the pc. And, I recently replaced the capacitors due to slow warm-up issues and it's worked great every day since.

Prior to this failure there were no symptoms. Used the pc on Saturday eve. and left it on overnight. Sunday morning I noticed the monitor was not active (no signal) and the pc was quiet (buttons lit as stated earlier, but no fan noise).

I'm not that advanced so I must admit I don't know how to access BIOS. I've only done safe mode before to be able to scan for a virus to quarantine.

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Answer
This sounds like a classic burn out.
by Former Forum moderator Oct 21, 2012 2:51PM PDT

But let's try the basics.

1. Perform the generic reset.

Unplug power, press and hold the power button for 60 seconds, release, apply power and try again.

2. Measure the CMOS battery. On this model any reading below 3.0 Volts is a goner.

3. You said you pulled the heat sink? That means you put on fresh compound? It's not the cause of the no boot but it's something you see new techs forget.

4. DOWNSIZE THE MACHINE SEVERELY. We go for BEEPS. Unplug HDD, CD/DVD, video card, all cards, unplug RAM, all USB things, keyboard, mouse, and see if it beeps. No beeps means what's left has failed.

5. If the power stays on, use the Volt meter to check +12V, 5V, 3.3V lines.
Bob

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Classic burn out? Aaarrgghh
by barkinmarmot Oct 21, 2012 3:06PM PDT

Ok. I hope not. But I like to tinker when it helps to narrow it down. I'll need some guidance.

1. I'll try a generic reset.
2. How do I measure the CMOS battery and where is that located? I do own a multimeter. "Less than 3.0 volts is a goner"....do you mean the whole pc?
3. I did pull the heat sink but did not apply any new compound. What compound is used?
4. Downsizing. Do I just unplug power harnesses or do I physically remove all that you list?
5. Lost me there

Thank you Bob and Edward for replying so quickly

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2. By measuring the battery with the Volt meter.
by r. proffitt Former Forum moderator Oct 21, 2012 3:20PM PDT

It means to replace it if under 3.0 Volts.

Sadly I think this means you are not into repair work. If measuring a battery needs tutorial write ups I have to write it's time to take it to the shop. Sorry but I don't want to ask folk to do more than they are comfortable with.
Bob

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A little more clarification
by barkinmarmot Oct 22, 2012 10:55AM PDT

Bob

I do know how to measure a battery. What I meant to say was is it measurable while installed, or must it be removed first. On my part I was not very clear. Yep, I've never measured a CMOS battery before, and that is why I don't know where it is located on the motherboard, thus the question. Google can help me with that. Please try to remember, I am not posting on an advanced repair tech forum. Many of us are not as skilled as you may be. Some may not know how to remove the access panel from their desktop, and that is perfectly ok. It doesn't mean they aren't comfortable doing it - they just haven't done it before. I actually am into a little repair work. I've soldered in new capacitors on my LCD monitor to give it new life. Not too shabby I think. When I am on auto repair forums and someone wants to know how to do a throttle body alignment, I'll answer in detail or give them a link to get them going. I appreciate that they have an interest in learning. Just my two cents.

Current status for anyone that might like to chime in:

Generic reset does not work. Upon plugging power cord back in, pc powers up to the same state without my even having to depress the power button. I now also see that the heat sink fan is NOT running. The fan noise I initally thought was from the heat sink is actually from the external video card fan. Monitor is confirmed to work fine.

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Answer
Looks like progress.
by Former Forum moderator Oct 22, 2012 1:24PM PDT

And I always measure the battery in the socket as I want to see the Volts reading there. Without the tiny load it may perk up and cross my off the cuff 3.0 Volts number I've used for decades for the Pass Fail line.
Bob

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