Wolfgang1960 wrote on 2023-06-23, 08:27:

Hello, I got this laptop with a totally empty Cmos-Batterie which I want to replace. But I have no idea how to open the case. There are some screws, but I am not sure about the right procedure. Can someone help me? Is there a manual? Thanks a lot. Wolfgang

According to an old post by user @Alan on Zenith Google Groups...

"A Bulletin ZDS sent out at the time!.

Computer Models: Z-STAR 433 vl and vlp

Problem: When you start your machine, you get the message of an RTC failure.

Cause: The RTC battery is out of charge

Solution:Remove the battery, open the coprocessor cover, change the jumper JP1 from
mid position to position 1-2, reconnect the battery and the power supply, restart the
computer and let it pass the POST tests. Reput the jumper in the original position,let
the computer charge for 3 hours and upgrade to the latest BIOS.

This problem will not occur with a BIOS rev 2.23C* or higher"

*As you're on 2.22C, this might happen again - not sure if 2.23C is available online anywhere or if someone on Vogons may have it

Edit - pic added