Sign in with
Sign up | Sign in
Your question

Cannot set cmos default values

Last response: in Motherboards
Share
August 4, 2012 1:32:59 AM


Hello.
Hopefully someone may be able to shed some light on a problem that I am trying to resolve.

I recently was given an old HP Pavilion laptop (N3295) that had been sitting unused for years.
I have a planned home project that utilize this old computer. On this particular unit, the CMOS
battery had died and thus the CMOS was corrupt. However, the Bios (and User) passwords were
being requested even though none had ever been set by the original owner (co-worker friend).
I am also not able to boot the computer to an OS from any media. So... I stripped the unit and removed
the CMOS battery (bottom of motherboard - very hard to get to). With no battery, I rebooted and
noticed that the system detected a cmos checksum error (as expected) and restored default values. However,
this still did not resolve the problem.

Well, somehow, during my testing I *did* manage to get past the Bios password and was able to
get into the bios setup. I noticed that many if not most of the configurable items in the Bios setup
are grey'd out and are not configurable. Again, I decided to force the computer to reinstall the
default values and once again, I'm locked out with the password request.


It seems to me that the CMOS ram is NOT being reconfigured to the default values as claimed.
Does this imply bad CMOS memory? The RTC/CMOS is located in the National PC87570 Keyboard controller.
I find it hard to believe the CMOS ram is bad but that is what I am thinking. Does anyone have any thoughts
as to how and resolve this issue?

The way I see it, there really is NO password stored but the CMOS ram *thinks* that there is due to a
mis-configured bios bit.
Am I way off here? Sorry for the long drawn out explanation..

Any help is appreciated. Thanks
Jim
August 4, 2012 3:02:45 AM


It just dawned on me.. where are the DEFAULT CMOS values retained? Would these be hard coded
in the BIOS? The reason I ask is that I found a small 256 byte serial eeprom that has me
wondering. My guess is that this eeprom gets loaded at the factory with the default values.
I read back the data from the serial eeprom and saw what I thought was some configuration
data. So, what is the possibility that this eeprom has become corrupted and it is these
corrupted default values that are getting loaded when I reset the CMOS?

Again, your thoughts?







rfdes said:
Hello.
Hopefully someone may be able to shed some light on a problem that I am trying to resolve.

I recently was given an old HP Pavilion laptop (N3295) that had been sitting unused for years.
I have a planned home project that utilize this old computer. On this particular unit, the CMOS
battery had died and thus the CMOS was corrupt. However, the Bios (and User) passwords were
being requested even though none had ever been set by the original owner (co-worker friend).
I am also not able to boot the computer to an OS from any media. So... I stripped the unit and removed
the CMOS battery (bottom of motherboard - very hard to get to). With no battery, I rebooted and
noticed that the system detected a cmos checksum error (as expected) and restored default values. However,
this still did not resolve the problem.

Well, somehow, during my testing I *did* manage to get past the Bios password and was able to
get into the bios setup. I noticed that many if not most of the configurable items in the Bios setup
are grey'd out and are not configurable. Again, I decided to force the computer to reinstall the
default values and once again, I'm locked out with the password request.


It seems to me that the CMOS ram is NOT being reconfigured to the default values as claimed.
Does this imply bad CMOS memory? The RTC/CMOS is located in the National PC87570 Keyboard controller.
I find it hard to believe the CMOS ram is bad but that is what I am thinking. Does anyone have any thoughts
as to how and resolve this issue?

The way I see it, there really is NO password stored but the CMOS ram *thinks* that there is due to a
mis-configured bios bit.
Am I way off here? Sorry for the long drawn out explanation..

Any help is appreciated. Thanks
Jim

m
0
l
!