cruncher down, need help

[Philippart]

One of my computers won't start up anymore: when I press the power button both the hd and power light keep blinking and the cpu fan tries to start up but fails to do so and tries again and again, making a pulsating sound (spinning up and down the fan).

I can't reset the CMOS: taking out the battery doesn't fix it.

Does anyone know what this could be? PSU? CPU? Motherboard?

Thanks

 

[Rudy Toody]

Sounds like the PSU.

If you have had the box apart and the mobo is Gigabyte, check the polarity of the front panel power switch.

 

[theAnimal]

If you have a DMM test the voltages on the PSU.

 

[Ken g6]

My computer did this for awhile. I think I finally narrowed it down to an old DVD-ROM drive! So try unplugging all unnecessary accessories.

 

[petrusbroder]

Any beep-signals?
If none, then probably the PSU.
If any, check them out here: http://en.wikipedia.org/wiki/Power-on_self-test which also can lead you to further reading.

 

[Rudy Toody]

If you have a DMM test the voltages on the PSU.

If you're an old-timer like me, use your VOM.

 

[Philippart]

no beep at all it retries starting up before even the fan spinup and beep!

 

[dajeepster]

no beep at all it retries starting up before even the fan spinup and beep!

even i can't decipher that.. well.. i'm not even going to try... don't know if this is one idea or four different ideas. do it in bullet points or something, writing in continuous like this makes it difficult to figure out what you are trying to say, which makes it harder for the rest of us to assist you.

I would go with ken_g6's idea and petrus's idea.. and then go with the power supply being bad if neither of those ideas work.

And going with Rudy Toody's idea.. just disconnect the power switch and reset switch from the motherboard, and just momentarily short the two pins for the power switch on the motherboard together to turn the computer on. I normally just use a phillips screwdriver to do this....
I had a gigabyte case once that displayed similar problems. The case itself had a circuit board for front panel controls that started to go bad.

oh.. and does the fan in the power supply spin up? (any power supply worth anything has a fan)

 

[WhiteFireDragon]

actually, if the fan keeps trying to start and fails in an infinite loop, it's most likely a mobo problem more than the PSU. this same thing happened to my gigabyte board when the mosfet got fried. next culprit would be the PSU, then the memory.

 

[Philippart]

actually, if the fan keeps trying to start and fails in an infinite loop, it's most likely a mobo problem more than the PSU. this same thing happened to my gigabyte board when the mosfet got fried. next culprit would be the PSU, then the memory.

I removed the hd and unplugged any external stuff, I removed the RAM and exchanged the PSU:
same problem.

So it must be the mobo since a bad video card would result in beep tones and a broken cpu would result in a message like "cpu error" as far as I know. Am I right?

 

[petrusbroder]

Yes, you probabaly are.
Broken CPU gives probably no signal at all ... that has happened to me once.
A message "CPU-error" requires an at least partially working CPU - without at least some CPU-functionality you won't get any messages at all.
Check the capacitators and the MOSFETs - look for buldging tops and/or signs of overheating or burns.
If it is the mobo, lets hope the CPU, RAM and cards survived ...

 

[dajeepster]

So it must be the mobo since a bad video card would result in beep tones and a broken cpu would result in a message like "cpu error" as far as I know. Am I right?

sometimes bad video cards don't result in beep tones... but flames and char marks instead.

http://s850.photobucket.com/albums/ab68/dajeepster/crashNburnSapphire3650/ D:

http://forums.anandtech.com/showthread.php?t=2041400&highlight=

 

[biodoc]

sometimes bad video cards don't result in beep tones... but flames and char marks instead.

http://s850.photobucket.com/albums/ab68/dajeepster/crashNburnSapphire3650/ D:

http://forums.anandtech.com/showthread.php?t=2041400&highlight=

Saffire is definitely off my vendor list!

Tom, did you figure out the problem yet?

 

[Philippart]

I tested everything and it's indeed the motherboard. But I don't see any physical damage and no flames either

I think running it way too much overclocked for 3.5 years 24/7 was too much for it...
It was rated FSB1066 (266Mhz real) and I ran it @FSB1500 (375Mhz real)

it was this one: http://www.asus.com/product.aspx?P_ID=YwIVDOTcvIMHZdTy&templete=2

I ordered this one to replace it: http://www.asus.com/product.aspx?P_ID=URA00A6u0GrUqHiH&templete=2
It is rated FSB1600 so I won't push the board too hard this time

Thanks to everybody for your precious help!

 

[petrusbroder]

I have both - the P5B ist still going strong after more than 3 years of 24/7 @ 350MHz and the P5Q is sweet (don´t remember how long I have had it - less than a year ...).

 

[Philippart]

sounds great so we have approximately the same setup

 

[dajeepster]

sounds great so we have approximately the same setup

I've got that motherboard in my sister's computer.. it's currently running an E6400 with no OC. I don't OC my families computers, just mine.

Her computer has been running 3 years now.