How can i reset CMOS ???
in [Hardware]
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From: Paul on 30 Jan 2010 07:49 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/20030424061333/http://www.formfactors.org/developer/specs/atx/ATX_ATX12V_PS_1_1.pdf (page 27) http://www.formfactors.org/developer/specs/atx/ATX12V_1_3dg.pdf (page 30) http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_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
From: Francesco on 25 Jan 2010 19:41 > 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!!!!!!!!
From: Paul on 1 Feb 2010 12:55 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
From: John McGaw on 1 Feb 2010 15:59
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. |