Complete Fix Solution

Heres the solution to repair Nokia 1616 and Nokia 1800 power ON/OFF switch problem.
This problem may cause the device unable to power up when hitting the power key. The problem may easily configured if the power ON and OFF switch key has no response, but the device is not totally dead for it shows a charging indication when you charge it up. Now, this solution simply shows the line paths (ON OFF ways)of the power key. Hints for repair: when the device will unable to power up when hitting the power key button but it shows charging indication when you plug-in the battery charger, the problem may possibly lies on the power key line paths. But before tracing the line paths, you must see to it that the keypad membrane is perfectly clean and free from dirt, corrosion and oxidation.

You can check the power ON/OFF voltage to the inner core of the switch key terminal pads, this voltage may range approximately  from 1to 3 volts. If there is no voltage reading you get on that spot, locate and trace the  test spots for the power switch, see the picture guide above, it is located just near the keypad LED. Make a continuity check by using a multimeter to those corresponding spots indicated on the picture guide, from the power key pads through to each corresponding component. The outer core is connected to a chip capacitor located near the clock crystal oscillator.