SIEMENS NIXDORF PCD-4NCsx - Reset BIOS password

[paoolica]

Hello,

I recently bought an old SIEMENS NIXDORF PCD-4NCsx/25 with Award BIOS and just discovered that it has a BIOS password.
The previous owner provided one, but is not working, probably he forgot it.

Does anybody know how to reset the password, please? Could it work by removing the clock battery (seems like a soldered DALLAS chip)?
I tried with some AWARD BIOS master passwords but with no luck...

 

[GiGaBiTe]

The CMOS battery is potted inside the Dallas RTC module, there's no way to disconnect it without destructive means. Though, it's probably long gone flat, and isn't holding settings anymore.

BIOS passwords on laptops are generally stored in NVRAM somewhere, and aren't affected by the CMOS battery at all. Unless there's some hidden master password, you're stuck unless you can figure a way to clear that bit of NVRAM that holds the password, wherever it is.

 

[paoolica]

Thank you for the response! I could try to desolder the Dallas chip, and see if it works. The Dallas chip seems that still have some juice in it because I don't receive any CMOS error. Problem now is that I can't manage to disassemble this laptop (perhaps without breaking it), it seems it has a screw right under the left hinge which I simply can't reach. Does anyone has a service manual for this laptop or have an idea how to proceed?

 

[GiGaBiTe]

Laptops are almost never intuitively designed to be taken apart. There's probably a hidden clip or screw somewhere holding it together. Manufacturers like hiding them under labels, rubber plugs and feet.

It looks like you have some hex posts holding part of the case on in two of those pictures, those need to come out to remove whatever bit of plastic they're holding down.

 

[ventzel]

I have an identical laptop that i'm trying to repair. When i power it up it have a continuous speaker tone but doesnt do anything else.
So far i have examined the signals and it have activity only around ku80c51slbg (keyboard controller). When i have read U64 eprom (27C256), witch hold the program of ku80c51, i have noticed that all locations are filled with zeroes.

@paoolica do you have means (a EEPROM programmer, knowledge etc) to make a backup of U64 EPROM? Or, if anyone else can provide me a copy of the content of U64, i will appreciate it. I searched for a couple of days for the content of this EPROM but no luck yet.

On topic:
CMOS clock/RAM bq3287amt is a bq3285 with integrated lithium battery and crystal. To reset CMOS RAM content you need to bridge pin 21 (/RCL) to ground when bq3287 is powered (Vcc pin is at 5V).

I have traced pin 21 and is connected to JP5 so you need to bridge this jumper. It's not clear for me if you need to bridge this jumper with laptop powered on or you need to power off (removing battery and power adaptor), bridge JP5 and then plug in power adaptor and power on the laptop to clear CMOS RAM so you need to try both methods.

 

[georgiamark]

Hello,

I recently bought an old SIEMENS NIXDORF PCD-4NCsx/25 with Award BIOS and just discovered that it has a BIOS password.
The previous owner provided one, but is not working, probably he forgot it.

Does anybody know how to reset the password, please? Could it work by removing the clock battery (seems like a soldered DALLAS chip)?
I tried with some AWARD BIOS master passwords but with no luck...

It sounds like you've got quite a vintage system there! Resetting the BIOS password by removing the clock battery might be worth a try, but be cautious with any soldered components. I think Nick Squires will help you. He has years of experience in dealing with BIOS password recovery and offers some guidance. Good luck!

 

[ajacocks]

Welcome to the forum @georgiamark .

- Alex