How to repair Nokia e71 cannot power on

Here is tips how to repair nokia e71 can't power on :
1. Check batteray first (replace batteray if needed).
2. If batteray normal, check batteray connector (replace batteray connector if needed).
3. If batteray connector normal, check power switch (replace power switch if needed)
4. If power switch normal, check R2512 and R2511 (replace resistor if needed).
5. If all above working normally, upgrade firmware/software.
6. If the problem still not solved, check main processor.

note: upgrade need flashing tool.
Replacing main processor is high risk and need upgrade firmware.