Aspire 4820TG BIOS password problem

I recently dismantled my old Aspire 4820TG laptop in order to clean the fan. This operation involved removal of the motherboard. I was able to successfully clean the fan and replaced the thermal paste on the CPU and GPU chips. The operation went well. The computer works well and boots up my Linux OS perfectly. The problem arose when I tried to enter the BIOS. My supervisor password is no longer recognised.

I read that I can remove the CMOS battery to reset the BIOS but having tried that on an old machine that I have for spares I broke the battery holder. I don't want to risk this on my working machine. I know that I can short the CMOS jumpers to clear the BIOS but cannot find them on the motherboard.

Could anyone help me please?

Accepted answers

Oliverjames

I've found a solution. I stumbled across this video https://www.youtube.com/watch?v=scpy4jH6HY4 and decided that the given software solution was the way to go. On another machine I opened a Win10 session, downloaded Rufus, used that (as root/administrator) to create a bootable FreeDOS usb stick. Having found and downloaded clnpwd.exe from the Web I then copied it to the bootable FreeDOS usb stick. I suspect this could done using a Linux OS, my usual toolbox.

I was able to boot my Aspire 4820TG from the FreeDOS usb stick. I then opened clnpwd.exe, selected option 2 and the job was done. Upon reboot of my Aspire, F2 brought up the BIOS window.

All comments

billsey

Shut it down, remove the charger then open it up and remove the battery and HDD. The two jumpers are near the CMOS battery:

Short those both, plug the power in and boot it through POST. Once POST is complete you can shut it back down and stop shorting the jumpers. Reassemble and the password should be cleared. Modern machines don't make it quite this easy, for security reasons, but these old W7 machines are a bit simpler.

Oliverjames

https://community.acer.com/en/discussion/comment/1153248#Comment_1153248

This image is of the motherboard of a 4820T. The 4820TG is different.

Oliverjames

20221017_090928.jpg

This is a photo of the 4820TG motherboard showing the CMOS battery holder. This is from a second machine that I kept for spares. The battery holder is fragile and broke when I removed the battery. I read that, on laptops, the password is generally saved to an Eeprom chip and hence the battery removal method doesn't work.

billsey

Yeah, I only have the one image covering both the 4820T and 4820TG, so can't give any other help on this one. :(

Oliverjames

I've found a solution. I stumbled across this video https://www.youtube.com/watch?v=scpy4jH6HY4 and decided that the given software solution was the way to go. On another machine I opened a Win10 session, downloaded Rufus, used that (as root/administrator) to create a bootable FreeDOS usb stick. Having found and downloaded clnpwd.exe from the Web I then copied it to the bootable FreeDOS usb stick. I suspect this could done using a Linux OS, my usual toolbox.

I was able to boot my Aspire 4820TG from the FreeDOS usb stick. I then opened clnpwd.exe, selected option 2 and the job was done. Upon reboot of my Aspire, F2 brought up the BIOS window.

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