①2mm allen key
②cross screwdriver
③pointed-nose piler
a. Re-plug J12 in main board, re-plug J3, J4 in power & UPS board.
b. Unplug J12 in main board, measure the resistance via pin 4&5, it should be around 100KΩ @ 25°C indoor temperature (Figure 03-1). If it is lower than, then it’s temperature sensor issue.