I have finally revived the last of the three N500s. The battery was completely dead and I didn't want to spend money on a spare one as I have two other working N500s.
I finally found a used LiPol battery that fits into the body. I disassembled the original battery and took the control board with the connector out. I soldered the new LiPol battery and tried it. The thermistor is possibly on the board as there is a pin on the board that needs to be soldered. I did not need to connect any resistors and the phone boots and works without any problems.
So now I have three of the same device working. The last one just needs to be jailbroken. Then I would like to run some tests and compare these "same" phones. Even at first glance, the systems look completely different, so I am wondering what I will find on them.
Jan "Jenkings" Škoda - blog
Simplifying IT, Amplifying Knowledge