Here is diagram of Nokia N82 Power Switch ways, that explains show ON/OFF switch ways, helpful to reapir Power switch with jumpers if prints are broken/Damaged.
Problem: Nokia N91 speaker not working You can not hear other person while making a call Solution: Here is full speaker ways for Nokia N91. Observe carefully and make jumpers to solve the problem
Problem: White/ Blank Display Solution: Its better to change Display Filtersm (IC), In Case new Ic not available, remove red marked ICs and make jumpers as shown in picture below.
Turn off the phone Press upper side key ( Volume Up) While holding volume up key pressed, press power On button Keep both keys pressed, untill you will see a Menu with Reset /Format option Follow on screen instruction