Do I have a dead Motherboard? - no beep, no BIOS screen

[Swampfoot]

This machine ran beautifully for over a year. For several months now, this homebuilt machine would occassionally fail to boot or restart, but it's gotten to where it will successfully POST and boot maybe one out of 20 times. There's power - but no beep, no BIOS screen, just PSU fan, CPU Fan and case fan spinning.

 

This will be a sad loss if it's dead, since it took me so long to get 10.5.2 successfully running on this machine. I have the 10.5.2 install backed up as an image, though. So it won't be a total loss, but I will be surprised if I can find the very same motherboard for sale today. New motherboard means a fresh struggle. Bah.

 

If it is dead, any suggesstions what mobo to get that will let me keep my processor?

 

Here's the specs:

Processor: AMD Athlon 64 X2 4200+ Dual-Core - 2.2GHz

Motherboard: Asus M2NBP-VM

2gb RAM (two sticks, tried together and individually)

320 gb SATA Hard Drive

160 gb IDE Hard Drive

LG DVD-RW IDE optical drive

Primo P4 ATX Mid Tower Case with 500w Power Supply

Added a GeForce 7600 PCI x16 for OS X

Added a Realtek 8139 PCI ethernet card for OS X

 

I am NOT doing any overclocking.

 

Thing's I've tried:

 

-- CMOS Battery (CR2032) was dead, at least my tester showed it just in the red, right below the green, so I thought, "AHA!" and went to get a new battery today. Tested it before installing, it showed a full charge. Did the jumper thing on the motherboard that clears the CMOS cache or whatever it is. Put in new battery - no difference. Dammit!

 

-- Backside of motherboard shorted against the case? I pulled the motherboard, which has been stood-off correctly, completely out of the case, laid it on a dry towel, and connected only the power connector to the board, monitor to the on-board video connector, and one stick of RAM. Attempted to power up to see if I'd get the POST beep - it should POST and show me the BIOS screen even if no drives are connected, right? But nothing. Just the PSU, CPU and case fans come on. No beep, no BIOS screen.

 

-- Power Supply? Pulled the power supply motherboard connector. Using a paper clip, I jumped the green and black pins to power up the PSU while the connector was unhooked. The PSU fan runs fine. With a digital multimeter, I tested all pins on the 24-pin ATX power connector, plus the 4-pin CPU power connector. All the voltages are correct. the 3.3v, 5.0v, and 12.0v values are all spot-on. I realize that is with no load, but it is something.

http://www.pcpower.com/support/ATX_troubleshoot.htm

 

-- When the machine was running in XP, the ASUS motherboard monitoring app showed all voltages and temperatures to be normal. I rarely saw the CPU go above 45 Celsius.

 

-- Seating of RAM, Video Card, Ethernet? Pulled everything and re-seated it. Tried both RAM sticks, one at a time.

 

-- IDE Issue? Tried every possible permuation of Master/Slave, Primary/Secondary on the IDE chain with my IDE devices, plus every IDE cable I have lying around (which is quite a few). Also tried no IDE at all. No difference.

 

 

I'm at my wits' end! I am thinking the board is dead, since the PSU seems to test out, and on the rare occassion when the machine does boot normally, it runs with perfect stability for days and days in either XP or OSX, never had any uncommanded shutdowns out of nowhere.

 

Thanks for any help, all you Obi Wans out there.

[alicizmar]

Normally I'd say motherboard, too, but when my computer was randomly restarting itself, it turned out to be the PSU because it only showed troubles with a full load!

One way to find out is to dig up a PSU that works properly (as in from a computer that runs just fine or just a spare one will do for testing's sake). Plug it into the computer and see what effect it has. And don't just try one boot, either. Try two or three to be sure about it.

Other things to try...

-See if any PSU cables are touching metal. Just to be sure, get them secured away from any metal in the case (note that the part where they snake out of the PSU doesn't count). Sometimes one of them can have insulation or a cut in it where this itty bitty bit of wire's touching the case, causing a short.

-Make darn sure the CMOS is reset-yank out the battery, completely unplug the computer so there's no chance of it getting power from anywhere, and set the jumper to reset and LEAVE IT this way for 5-10 minutes. Then put everything back like it was and see if it boots.

-Still no go? Oh, dear. Try unplugging EVERYTHING except the power to the mobo and the RAM and proc and turn that on. That means no PCI cards, no SATA or IDE drives, not even the monitor or ethernet. Hey, you never know if some virus is stopping it from booting, right? (/sarcasm)

-For curiosity's sake, yank off the heatsink and make sure the processor isn't a charred black brick under there. If not, unclamp and remove the processor and blow the socket and proccesor pins off to get rid of any small things you can't see that may be interfering with the processor pins (dust, metal bits, hair, ant nests...etc.) and replace your thermal paste as air's nowhere near as good a conductor of heat as Arctic Silver (paste replacement optional).

-Still no? It's rare, but if you tried changing around the RAM with no success, you may have a bad RAM slot. Try putting a single stick into one slot at a time, seeing if anything different happens each time you try booting. Most likely, the mobo would give you a RAM beeping error if it were RAM, but you never know sometimes.

-If, after all this, you still can't get a POST, toss your machine out the window and buy a Mac. Just kidding, of course! But chances are your mobo's trashed.

The mobo I use is a Gigabyte GA-MA78GM-S2H (http://www.newegg.com/Product/Product.aspx?Item=N82E16813128090). Works well with OS X 10.5.2 as long as you don't need widescreen resolution on the integrated video (since you have a GeForce card, stick to that). Sound works after a simple AzaliaAudio kext installer I can fetch for you if you go forward with this and need it. LAN and video work out of the box, so the Realtek NIC card won't be needed anymore.

HOWEVER, I've read about issues with installation and the southbridge on it, especially in SATA mode. So if your OS X installation is on a SATA drive, tread carefully. I have mine on the IDE and it installed fine if you don't count that it took 3 hours (yawn, Windows takes longer).

Good luck and hopefully it isn't the mobo because changing those out is hell on any OS.