couple of questions

[aji12_17]

Hello!

Got a few questions for ya. I recently cleaned out my PC, took it all apart and all that, put it back together, and upon turning it on, it went through POST, hit the windows loading screen, then a quick BSOD flash and it rebooted. i went into BIOS and didnt see anything off, so I saved and exited, rebooted, windows boot screen, went to safe mode, and the BSOD flashed and rebooted. the next time it hit POST, started detecting hard drives, rebooted to nothing....no POST, no alarms, no video signal, no smoke, no joy. just spinning fans.

I've been tinkering for a while now and have it narrowed down pretty well. However there are a few things I'm not 100% on.

1. Does a computer POST without RAM? I was under the impression that with bad RAM it will freeze during POST, but with no RAM you got the scary beeps. When I boot with no RAM there is no difference from when the RAM was in.

2. If you have a faulty CPU, would it still POST? I have the P6N Diamond and its got the 4 light indicator, however nothing ever lights up, so I thought it was the motherboard that was borked, however- If I remove the CPU and attempt to boot, it detects that there is no CPU and shuts off...soo....does that mean the MB is fine? (even though there are still no lights on the bracket, no beeps..just a shutdown.

I'll give my system specs in case there is anything else im not thinking of...

MB- MSI P6N Diamond
CPU-intel C2duo E6700 (OC to 3.2ghz)
RAM-mushkin pc2 8500
vid- MSI 8800gtx
PSU- PC power and cooling silencer 750w quad

It was an assembled and working setup for the last 2 months (stable OC the whole while).
Tested the PSU and all voltages are good,(plus the CPU and NB heatup so ya know SOMETHING is churning em). Tested with different known good RAM, in every slot, to no avail.
reseated everything again and again. checked all pins and nothing was bent.
Tried it in and out of the case, no shorts(that are visible..stupid tin whiskers...).
Went back to the stock cpu cooler, still nothing.
cleared CMOS via CMOS CLEAR button
Removed battery and let it sit unplugged for 20+ hours (went to bed and then to work)
Powered on with every combination you can imagine. just CPU, CPU+RAM, CPU+RAM+VGA...ect....no luck
the whole time I had the diag bracket and the system speaker plugged in and neither of them did anything.
one thing to note- it is a possibility since sometimes I go into superman mode and dont properly ground myself that I fried something, or a cat brushed up against it..or walked on it...or whatever it is cats like to do to MB while you sleep.

as I said im thinking its either the MB or the proc, and im leaning towards the MB, but before I buy a new one, I'd like to be as positive as possible and exhaust all ideas. one possibility is maybe (BIOS is a little unknown to me) there is a way to flash the bios. If it got corrupted thought the CMOS reset should have done the job, right?

OK my apologies, I'm babbling. Thanks for takin the time to read this, sorry for the ugly formatting, and thanks in advance for any help you can give me.

 

[cfvh600]

How did you clean your pc? You sure your mobo can POST without RAM or a CPU?You shouldn't be able to see anything on your screen without any of those 2 components.

 

[aji12_17]

took it out and blew it off with canned air, mostly to get the cat hair out of it (just got some new filters for the case)

and no i didnt hold the can upside down.

without the ram your comp wont post but you should get a series of beeps i think. not sure..thats one of my questions. as is the "can it post without a cpu" question.

 

[jsc]

Definition: POST - POwerup Self Test. (I know. But it makes sure that we are all talking about the same thing.)

Will a PC complete the POST with a faulty CPU? I am inclined to say, "Probably not." But it would depend on the nature of the internal failure of the CPU.

Will a PC complete the POST with no RAM? Yes. But here, we are getting really fussy about definitions. My Box #1 and Box #2 both generate a series of long beeps and a blank screen when I try to boot with no RAM. Any audible sound other than a single short beep indicates that the PC completed the POST, but failed.

Most people interpret a failed POST as not POSTing, and technically, that's not accurate. Functionally, they are also two different indications. A classic "new build" problem - you turn on your PC and nothing happens (well, maybe the fans spin up). Assuming everything is properly cabled, you probably have either a bad PSU - most likely, a bad motherboard or CPU, or something improperly installed in the case that is shorting out the PSU.

If you hear any kind of beeps, you know your CPU is probably good, the motherboard and PSU are at least somewhat working, and you have no major shorts.

How did you test the PSU?

Here's a link to my "Troubleshooting a New Build" article:

http://www.tomswiki.com/page/Troubleshooting+a+New+Build

Although you have tried a lot of things that are in it, it may give you some more ideas.

 

[aji12_17]

Definition: POST - POwerup Self Test. (I know. But it makes sure that we are all talking about the same thing.)

Will a PC complete the ...
...http://www.tomswiki.com/page/Troubleshooting+a+New+Build

Although you have tried a lot of things that are in it, it may give you some more ideas.

your kinda my hero right now.

As far as testing the PSU I used my trusty multimeter and the specs according to PC Power cooling.

Thanks for stating tha about the POST. thats exactically the problem. if it failed POST I'd be happy really. but no...nothing....

The only pins I have are on the psu connectors(CPU is flat bottomed) and the ram is seated well(as well as I can, but i suppose i can do a continuity check on the back pin by pin....oi )

Thanks for the link also...read it over, not a bad guide at all.


heh and no i didnt use soap and water.

thanks again, ill update if i find anything. prolly gonna buy a new mb soon. first..off to poke small pins and listen for the beep.....

 

[jsc]

Nothing pretty much means PSU, CPU, or motherboard.

Don't forget the PSGood signal on pin 8 (of 24). Yo can have all of the outputs, but without PSGood - should go to 5 volts within 1/2 second of powerup , the CPU stays reset and nothing happens.