No boot-up beep....sometimes

[MikeH]

Hi, I replaced my motherboard for an ASUS M4A78LT-M fourteen months ago, and all worked perfectly until about a month ago, when more often than not, after pressing the "On" button, the PC makes all the coming to life noises apart from the boot-up beep, and the monitor not finding a signal. Pressing the "Restart" button once seemed to initiate the beep. Lately, though, it can take up to three or four attempts at restarting before the beep is heard and the monitor comes to life. However, saying that, turning on the PC to access this forum, the beep was heard on the first press of the "On" button. Obviously a very moody motherboard!!! I've looked at other forums and done all the un-plugging and re-plugging of the RAM, drives and anything else that looks like it's plugged into something.
Do I try and sweet talk ASUS into replacing M/B nearly three months past the 1 year warranty period, or is there something else I can try.
Any advice would be welcome.
Thanks.

 

[Abarbarian]

You could try replacing the coms battery. It should not really need replacing as they last for quite a few years but you may just have a duff one.

Could be a faulty ON/OFF switch on your case.
I'm on my way out so must dash.
Good luck with the fault finding.

 

[Silverhazesurfer]

is it just the beep that is a concern? I'm slightly confused. Does the machine boot each time you try to restart, it just doesn't beep?

Typically, on hard boots, a motherboard will beep to indicate that it is operational. This can be a key troubleshooting tool. If the beep is not heard and the machine will not post, then there is a chance that hardware is failing and removing that hardware could re-instate the beep. Most of the time, the beep changes to a beep-beep beep beep-beep, and indicates a particular failure. Beep codes can be found by doing a search for your motherboard type.

A soft start, a reboot, may not cause the board to beep, as it does not need to go through the normal testing procedure. The system knows it has been alive previously and only needs to complete the "hey is this on" procedure rather than the initial testing.

I think you are making it confusing by focusing on the beep rather than the actual issue. It sounds like the machine will not POST, which is an issue. The beep is a troubleshooting tool.

 

[MikeH]

Sorry not sure what you mean by "post".
Every PC that I've had always gave one beep as it boots up. That's what my latest PC always did. About a month ago upon pressing the "on" button the PC made all the humming and rumbling turn on noises with lights flashing, but no single beep and no signal to the monitor, so I assumed it wasn't booting. Upon pressing the "restart" button, sometimes just once, but usually about three times, I would hear the single beep and the monitor would come to life. I've never heard more than one beep - ever.
Speaking to a friend of a friend, who is an alleged computer whiz and a network engineer, etc., he reckons it's either the 555 start-up chip or the start up capacitor playing up, and should be replaced. But doesn't working on a motherboard require one to have brain surgery skills???

 

[Silverhazesurfer]

POST = Power On Self Test

This is exactly that, a test that is run upon boot. The beeps you hear are supposed to indicate that the machine is booting. Some model motherboards do not have this. Almost every board I have seen has a piezo for that, some beep, some don't. If yours beeps and now does not, that is indicative of a failing board. Hence the reason you see nothing on the screen in situations where you hear no beep.

There are several ways to tinker with the board to see what is happening. If you remove a single device, such as all the memory, the system should give you a specific series of beeps indicating that there is no memory in the machine. The same with the graphics adapter. However, this is usually a bit more difficult since they are mostly all onboard chips now.

As far as the capacitor, that's possible. If you can identify which one it is and where it is located, you may be able to run a test with your buddy and see if it is functioning properly. The general failures of this type are lumped in under "CMOS Failures" as the BIOS is loaded on the CMOS chip and the POST runs from settings marked in the BIOS. Usually, if you cannot get to the BIOS, your machine is done, barring any component failures that could be causing your issue.

I would strip the machine down and see if you get a change in the behavior. Research the board and find the BIOS software type. Usually they are Award Energy Star over here in the states. Usually, there is a sticker on the chip. They are quite small now, 6mmx6mm approx, and are usually near one of the corners of the board. If you can find the beep codes for the machine, you can see if there is something causing an issue. If you have an all inclusive board, video/audio/lan/ on board, you will have a bit more difficult time as you cannot isolate the main circuitry from these chips. If removing the memory, CPU and disconnecting drives does not yeild results, you need a new board.

If you have a circuit board that connects the power and reset switches, this may be failing instead. You can troubleshoot this as well by checking the fans in the system. They should come on regardless of a failing system board when the machine powers up. This should prove your power switching to a certain point.