PC worked fine: then no beeps, no boot, no video

[Crakatoa]

Hello everyone, my problem is similar to that which others have posted, but I've tried the remedies associated with those other posts without success. The problem began when I was working on the PC as usual, and the screen froze. Tried a soft and hard reboot and nothing happened. Unplugged it and replugged it, and the computer has never worked since. Precisely: when I plug it in and turn the power on, all the fans start spinning, I can hear the optical drives spin as they would on a normal start-up, the led light on the front which indicates when the hard drive is spinning lights up, and the green power light on the motherboard lights up. But I get no POST beeps, and no video. The monitor, which works because I tested it on another computer, stays blank and the power light on it blinks yellow as if it's not getting a signal.

I've tried staring it in various configurations of parts: only cpu, cpu and ram, cpu ram and video, etc., and the result is always the same. Powers up fine, but no beeps and no video. Manufacturer (it's no longer under warranty) suggested motherboard burn out so I bought and replaced the mobo with a new one of the exact model (Asus A7V8X-X). Result is exactly the same. Now they suggest it must be the CPU. Maybe, but there's been no burn smell, the CPU looks unblemished and without scorch, and the chip housing on the old board shows no sign of warping or melting. One guy suggested I run the computer without the heat-sink and my finger on the CPU for a few seconds to see if it heats up--anyone have any opinions about that? It sounds risky, so I'm not doing it unless everyone thinks it's OK.

Oh yeah, I've done the whole CMOS clearing thing. No luck.

And I've swapped the ram stick with the ram that used to be in their, but which has been in storage since I upgraded, and either they're both cooked or they're both fine and that's not the problem. I don't know. I'm really broke and can't afford a technician repair: the $50 for the innefectual mobo replacement was like a punch to the stomach. Any help would be appreciated. I'm going to do the last thing I haven't tried--the HAL9000 build out of case instructions--but I'm not optimistic. Does anyone have any insight based upon this data as to what the problem might be?

I appreciate any and all responses...thanks!

[Crakatoa]

OK, for whatever it matters I've done the HAL9000 out of case build (http://forum.pcmech.com/showthread.php?t=12753) with no success. Same problems from above post persist: no POST, no beeping sounds, no video. But fans are spinning A-OK so power is flowing.

[Cricket]

Are you getting an image on the monitor? If you are, did you replace the IDE cable yet?

If you aren't getting an image on the monitor, try another power supply.

If the same thing occurs even with a new power supply, try to start the system with just the CPU and heatsink installed...no RAM or video card. Any beeps?

Cricket

[Crakatoa]

Hi Cricket, thanks for the reply:

>>Are you getting an image on the monitor? If you are, did you replace the IDE cable yet?<<

Nope. Nothing. The monitor stays in hibernation mode, or whatever you call it when the indicator light on the monitor blinks yellow instead of green.

>>If you aren't getting an image on the monitor, try another power supply.<<

Unfortunately I don't have another power supply sitting here. I'm typing this on a little laptop. All the fans spin, the mobo LED light comes on, and the optical drives are powering up too. As well, the computer worked perfectly with this set-up and power supply for over a year. With that said, could it still be a psu problem?

>>try to start the system with just the CPU and heatsink installed...no RAM or video card. Any beeps?<<

I tried as you suggested. I even took the mobo out of the case, put it on cardboard, and started it with only the CPU, heatsink, and internal speaker (to hear if it beeps). I also tried this with the video card to see if anything would show up. Nothing. No beeps. Just spinning fans. And this is in a brand new mobo. Out of frustration I also took the heat sink off and powered up the computer for a few seconds with my finger on the CPU to see if it was hot. Yep. Almost blistered my finger in only one second. I understand that to mean the CPU is working? No beeps at all doesn't suggest a RAM problem, right?

This is really baffling. But I appreciate the help.

[Cricket]

Originally Posted by Crakatoa Unfortunately I don't have another power supply sitting here. I'm typing this on a little laptop. All the fans spin, the mobo LED light comes on, and the optical drives are powering up too. As well, the computer worked perfectly with this set-up and power supply for over a year. With that said, could it still be a psu problem?

Yes. The power supply provides several different voltages to the system, not just 12v. If any of these voltage rails are bad, the system either won't boot up or will exhibit very unstable performance. For problems like this I always swap in a working power supply to test with.

Cricket

[Crakatoa]

O-Kay. I'll try and find a power supply unit in the city on the cheap. Which is not to say crappy but to say inexpensive. I really don't know what else it could be unless this new motherboard was garbage straight out of the box.

[GerBa]

I'm sure glad i found this post, not that I am glad Crakatoa has the problem, but I have exactly the same problem with my computer. I moved recently and it worked when I packed it and didn't when I unpacked it. I'm down to checking the power supply now. I hope that is the problem.

[Crakatoa]

Well, I've got an update on this problem which might (somewhat) help others in the same fix. Unfortunately, I also have a consequent problem which I'm hoping someone (anyone! please!) might be able to solve.

So at the advice of this board and a tech-friend I went and bought an Antec psu as well as a new cpu (athlon xp 2200, the max my ASUS A7V8X-X can handle). It had to be one or the other, right? On a piece of cardboard outside the case I installed the old cpu into the mobo, along with the heat sink and some paste of course; powered it up with the new psu, and plugged-in the internal speaker. Still no POST, no beep. One last chance: I swapped in the new cpu...and...IT WORKED! So I guess the old CPU was fried--this despite no increase or change in my computer usage leadng up to the failure, no prior problems of freezing nor burning-smell, and with the chip showing no physical signs of scorching. Anyway...So I put everything back in the case, re-attached all the pci cards and components, and plugged all the drives and fans into the new psu which I decided to keep (just in case the old psu was somehow responsible for cooking the old cpu).

The computer powered-up on the first try and WindowsXP Home came up on the monitor as if there had never been a problem. The computer worked okay for one week, but froze from time to time and required hard reboots, something it never did in the past. I reduced the cpu speed in BIOS to reduce the heat and strain on the cpu, and kept the side of the case off to keep things cool. Still the system would freeze, but would re-boot. Then everything went kaput, again.

This second major-failure began as the first one had: me typing on the computer, then the system froze; I went to reboot and it refused to boot or POST; I got no beeps and no video, this despite that the fans spun and power was clearly juicing all the components. Sigh. I repeat the previous troublshoot, breaking down the computer outside the case to the point where I've got just the mobo, cpu+heat sink, speaker, and psu together on a piece of carboard. I sometimes add RAM and/or video card to this basic out-of-case config just to see if it will give me the correct warning beeps. The result is almost worse than the first major-failure because now the problem occurs intermittently:

SOMETIMES this configuration will start up fine, and I'll hear the tell-tale beeps warning of RAM problems (if I haven't installed RAM) or video problems (if I haven't installed video). Installing RAM and Video brings up the BIOS screen on the monitor. But OTHER TIMES while trying additional out-of-case test-starts this same configuration will entirely fail to produce any POST beeps. AAAARRRRRRRRGGGGH! (Again, all of this is occurring out-of-case on cardboard. I just don't get it.)

What could be causing this intermittent problem, where sometimes these few basic components work, and other times they don't?

I'm totally baffled, and desperate for help/opinions.......

[Alfie]

When you took off the heatsink and started the computer,you fried your 1st cpu,never do that!
If you did that on your new board,it could also be damaged as a result.
Ir the 1st power supply was faulty,it could've damaged your board.
If you have a new power supply and the board is new,rma the board,go from there.

[Crakatoa]

I appreciate the reply. Is it an absolute certainty that I fried the cpu when I tested it for a second without the heat sink? I think it was already ruined because (1) the computer had already failed and had been troubleshooted to the point where either the cpu, psu, or mobo were faulty. The mobo and psu eventually were tested and worked, leaving only the cpu. As well, the mobo has temperature-protection which shuts of the system at 80 degrees, so the cpu powered itself down after no more than 2 seconds. Anyway, that board and cpu are gone. This is a new board, new cpu, and new psu which are causing the sometimes POSTs/sometimes doesn't POST problem. Anyone else have opinions?

[Alfie]

Although there may be protection built in,this is for a cpu with heatsink attached and the fan may fail,for example.
As the cpu raises in temperature and it goes past the failsafe temp,it shuts down,but with no heatsink the temperature increase is so fast,by the time the system responds the cpu is cooked.
Have you tried another video card?