Fujitsu Siemens RX300 S4 server won't boot after battery replacement, how to fix it?

Question

System administration

There was a problem with the Fujitsu Siemens RX300 S4 server, after replacing the battery, it stopped loading correctly:
1. The “welcome” Fujitsu Siemens logo appears for three minutes, after which the server turns off and the “Costumer Self Support” light flashes in the “Part may be replaced urgently” mode »
2. What exactly needs to be replaced is not clear
3. I can’t enter the BIOS
4. In those. They refuse to help support, referring to the fact that the server is old and those. support for it has ended
5. Documentation is thin and useful information could not be found in it
6. Please tell me, maybe someone faced a similar problem and have thoughts on solving it?
7. Who doesn't know what the Indicate CSS button on the motherboard is for?

Answer 1

7. The model is not yours, but it may be useful https://www.manualslib.com/manual/713151/Fujitsu-P...