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sillyeagle
01-07-09, 02:10 AM
The manual says to turn off PSU, move jumper to pins 1 2, then immediatly move back to pins 2 3 and power back on. Is that correct? I'm getting a C1 error so can't tell if it's been cleared.

Any other board I've used requires it to be powered on once the jumper is moved, which triggers a message indicating it has been cleared. I don't see how it can clear simply by placing on pins 1 2 for moment, especially after all power has been drained from the board by pressing the power button with the PSU off.

qube
01-07-09, 04:42 AM
thats the correct way you describe it :cool:

Muppet
01-07-09, 06:06 AM
The manual says to turn off PSU, move jumper to pins 1 2, then immediatly move back to pins 2 3 and power back on. Is that correct? I'm getting a C1 error so can't tell if it's been cleared.

Any other board I've used requires it to be powered on once the jumper is moved, which triggers a message indicating it has been cleared. I don't see how it can clear simply by placing on pins 1 2 for moment, especially after all power has been drained from the board by pressing the power button with the PSU off.

Don't power on the PC with the jumper set to clear Cmos. You very likely will damage the board.
When clearing I usually leave the jumper for 10 seconds after changing it. If you want, you can also remove the battery.

weevil
01-07-09, 06:47 AM
The manual says to turn off PSU, move jumper to pins 1 2, then immediatly move back to pins 2 3 and power back on. Is that correct?

It is yes.

I don't see how it can clear simply by placing on pins 1 2 for moment, especially after all power has been drained from the board by pressing the power button with the PSU off.

The reprogrammable chip maintaining BIOS settings uses the battery to maintain power when the machine is off. This much you know, the chip is probably EEPROM, electrically-erasable programmable ROM (so not really ROM then but that's another story) :)

If you remove the battery to clear BIOS there is still a voltage present with the battery removed. This voltage is maintained by a smoothing capacitor (storage device similar to a battery) which guards against voltage spikes getting at the chip by way of the DC voltage rails

The jumper when set to the active position probably short-circuits the DC power supply, which knocks out the BIOS chip's maintaining-voltage by discharging the smoothing capacitor and crowbarring the plus and minus power rails- and so the BIOS chip is effectively reset. With the jumper not moved and the battery out, BIOS settings will be held for a time while the smoothing capacitor (across the battery's plus and minus terminals) slowly discharges to zero volts

You can use a pair of pliers to short out the battery terminals for a moment with the battery removed, that would be quite as effective as moving the jumper if you can't get at it with hardware in the slots - although I wouldn't recommend that if you're currently learning about the ins and outs of the hardware

Peter

sillyeagle
01-07-09, 04:34 PM
Thanks for the info.

ViN86
01-07-09, 04:46 PM
i typically unplug the computer, remove the battery, then move the jumper to short the pins. i usually leave it for 5 min, then replace the jumper and the battery.