Hi, I recently got a pirate version of Ayrton Senna's Super Monaco GP 2.
I know that the original game has an SRAM + battery backup system.
This PCB had space for the SRAM, battery, and a backup circuit, but they aren't populated, as it can be seen in the pictures:

Ayrton Senna's Super Monaco GP II pirata - Solda - 150dpi.jpg Ayrton Senna's Super Monaco GP II pirata - Componentes - 150dpi.jpg Ayrton Senna's Super Monaco GP II pirata - montado - 150dpi.jpg

Slightly better resolution pictures can be found on my Google Drive here.

The problem is: I don't understand this backup circuit!
Not that I'm an electronics expert, but I think that this circuit simply won't work.

Is my assumption correct?
If it is, can someone help me to add a good battery backup circuit, preferably made of discrete parts?
Thanks in advance.