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#1
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How can i reset CMOS ???
First of all, sorry for my english !!!
The pc can't start. Led are ON, but the pc doesn't start. The monitor is off, no signal. THe pc doesn't make any beep. I think there is a mb problem and i want to reset the CMOS setting. I try to remove the battery fro one day, but these action have no result. I try to change the position of the jumper near the battery (with pc off) but nothing change. There is anyone that has had the same problem and he has resolved it. The pc is an ACer Aspire m3640, the motherboard i think is a Foxconn (but i'm not sure) Thanks !!!!! |
#2
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How can i reset CMOS ???
Francesco wrote:
First of all, sorry for my english !!! The pc can't start. Led are ON, but the pc doesn't start. The monitor is off, no signal. THe pc doesn't make any beep. I think there is a mb problem and i want to reset the CMOS setting. I try to remove the battery fro one day, but these action have no result. I try to change the position of the jumper near the battery (with pc off) but nothing change. There is anyone that has had the same problem and he has resolved it. The pc is an ACer Aspire m3640, the motherboard i think is a Foxconn (but i'm not sure) Thanks !!!!! Did you check the battery voltage ? Either replace the battery, or check the battery with a multimeter. A CR2032 should read at least 3.0V when it is new, and if the voltage drops below 2.4V it should be replaced. Also, verify that you haven't pulled loose the power switch cable leading from the front panel of the computer, to the motherboard. There are a number of cables, that plug into the PANEL header, and one pair of wires goes off to the power switch. Since you've removed the CMOS battery, with the power cord of the computer unplugged, you've already cleared the CMOS. If the computer has all power removed, and the CR2032 battery is removed as well, the CMOS settings would be lost. And that is what resetting the CMOS does as well. So you've already done it. And that is why I suggest checking the CR2032 battery voltage next, in case that battery is flat (zero volts). Some computers (but not all) will not start if the battery is dead. Paul |
#3
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How can i reset CMOS ???
"Paul" wrote in message ... Francesco wrote: First of all, sorry for my english !!! The pc can't start. Led are ON, but the pc doesn't start. The monitor is off, no signal. THe pc doesn't make any beep. I think there is a mb problem and i want to reset the CMOS setting. I try to remove the battery fro one day, but these action have no result. I try to change the position of the jumper near the battery (with pc off) but nothing change. There is anyone that has had the same problem and he has resolved it. The pc is an ACer Aspire m3640, the motherboard i think is a Foxconn (but i'm not sure) Thanks !!!!! Did you check the battery voltage ? Either replace the battery, or check the battery with a multimeter. A CR2032 should read at least 3.0V when it is new, and if the voltage drops below 2.4V it should be replaced. Also, verify that you haven't pulled loose the power switch cable leading from the front panel of the computer, to the motherboard. There are a number of cables, that plug into the PANEL header, and one pair of wires goes off to the power switch. Since you've removed the CMOS battery, with the power cord of the computer unplugged, you've already cleared the CMOS. If the computer has all power removed, and the CR2032 battery is removed as well, the CMOS settings would be lost. And that is what resetting the CMOS does as well. So you've already done it. And that is why I suggest checking the CR2032 battery voltage next, in case that battery is flat (zero volts). Some computers (but not all) will not start if the battery is dead. Paul Consider that there is a problem with the power supply. PS's quite often can fail partially so that you can still have LEDs lit or a cpu fan running, but have other sections of the PS fail to not give enough voltage to allow the cpu, graphics, hdd, etc to function. -- Jan Alter |
#4
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How can i reset CMOS ???
Francesco wrote:
I have tested the voltage. The only anomaly is the voltage o f the blue cable that is -11 instead of -12V. The other voltages are major than expexted. For example 3,37 ; 5,04 ; 12,01 I try to start the pc without any video card and after removed all memory banks, but again the fan start but no beep Mother Board ? Processor ? Power supply ? i think no after last test These are the various versions of the ATX power supply spec. The last one is for 24 pin power supplies. The first two are for 20 pin supplies. The first specification, is from the days when -5V was still included on power supplies. http://web.archive.org/web/200304240...12V_PS_1_1.pdf (page 27) http://www.formfactors.org/developer...X12V_1_3dg.pdf (page 30) http://www.formfactors.org/developer...public_br2.pdf (page 37) Did you check the PWR_OK signal ? It should be logic one (2V to 5V) when the power supply is running. If the signal is logic zero (0.8V or less), then the power supply is saying it isn't ready. The power supply may give the voltages, but not give PWR_OK. And that may prevent the motherboard from coming out of RESET state. So unlike your previous post, now you're saying the power supply is running. Or, did you start the power supply on your test bench, by shorting PS_ON# to COM ? If the power supply is now running, and the system won't start, that could be a stick of bad RAM. If there is bad RAM below 640K, it may affect the ability of the BIOS to do things. I had a problem here, were there were no beeps, and it was a stick of bad RAM. In theory, the BIOS should be able to start, without functional RAM, but that doesn't appear to be the case in practice. Paul |
#5
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How can i reset CMOS ???
Francesco wrote:
Did you check the PWR_OK signal ? It should be logic one (2V to 5V) when the power supply is running. If the signal is logic zero (0.8V or less), then the power supply is saying it isn't ready. The power supply may give the voltages, but not give PWR_OK. And that may prevent the motherboard from coming out of RESET state. I cheched the PWR_OK signal. The grey cable. ANd the voltage is little over 5V, 5.10 about. So unlike your previous post, now you're saying the power supply is running. Or, did you start the power supply on your test bench, by shorting PS_ON# to COM ? The power supply is running. I started shorting PS ON to COM only for testing power supply. The power supply is atrting even with the switch on the front panel. When I press the switch, the led on the front is lighting, the fan (all the fans, cpu fan, video card fan, pc fan) start, but the monitor say 'no signal' and the mb doesn't beep. I try removing vga card and using integarted vga but nothing. If the power supply is now running, and the system won't start, that could be a stick of bad RAM. If there is bad RAM below 640K, it may affect the ability of the BIOS to do things. Few weeks ago i changed one bank of RAM cause many blue screen under windows with one new bank of 2 GB memory that i think works well, until now I try changing bank but the pc doesnt' work again Maybe motherboard crash, or processor crash. I hope no!!! If you have any new idea please send to bewsgroup!!!! Thnks a lot for your help!!!!!!!! Try removing all the RAM (while the power is turned off on the back of the computer). Then, turn on the computer and listen for "beep" codes from the computer case internal speaker. If you hear "beeps", it means the CPU was able to read some BIOS code. If the computer is silent, with no beep codes, then the CPU cannot read the BIOS. Either the CPU is dead, or the BIOS is corrupted, or there is some other onboard regulated voltage which is not working properly. It could be a motherboard problem for example. CPU chips hardly ever fail and are very reliable. A good technique for troubleshooting, is to gradually disconnect unnecessary hardware, and watch for a change in the symptoms. For example, you can unplug the disk cables, in an attempt to get the BIOS working. The minimum configuration I'd use, would be motherboard, CPU, front_power_switch, computer_case_speaker, power supply That should be enough to test for "beeping" of the computer speaker, because of missing RAM sticks. If a motherboard and CPU won't work, then try another motherboard. You've already tested the power supply, so that might not be the problem. The motherboard could have a problem. But simplify the hardware setup, before taking the system all apart. Paul |
#6
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How can i reset CMOS ???
On 1/15/2010 9:37 AM, Francesco wrote:
First of all, sorry for my english !!! The pc can't start. Led are ON, but the pc doesn't start. The monitor is off, no signal. THe pc doesn't make any beep. I think there is a mb problem and i want to reset the CMOS setting. I try to remove the battery fro one day, but these action have no result. I try to change the position of the jumper near the battery (with pc off) but nothing change. There is anyone that has had the same problem and he has resolved it. The pc is an ACer Aspire m3640, the motherboard i think is a Foxconn (but i'm not sure) Thanks !!!!! Maybe you DID reset the CMOS but, because the computer does not POST, you cannot tell. As someone else wrote, your problem could be the power supply. If you have not changed anything else in the computer recently then the PS would be the first thing I'd try. |
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