Information for troubleshooting was gathered from PowerBook 165c Service Manual
PowerBook Will Not Turn On
When you press the power button, the computer does not respond
Drained or Defective Battery
First, try holding down the power button. If the computer still does not respond, the battery may be drained. Try inserting the power cord into the power supply and pressing the power button once more. If the computer still fails to turn on, the next solution will be to replace the battery.
If the computer will not turn on after replacing the battery, the internal wiring may be faulty. Access the motherboard and ensure that none of the ribbon cables are loose or damaged. If damaged, the cables will need to be replaced.
Defective Hard Drive
The next potential source of the problem is a defective hard drive. First make sure that the hard drive is securely seated and that no connections are loose. If the problem persists, the hard drive may need to be replaced. For instructions, refer to the hard drive installation guide.
First, check to make sure the motherboard is securely seated and that no connections are loose. If the problem persists, the motherboard may need to be replaced. For instructions refer to the motherboard installation guide.
The computer turns on, but the cursor does not respond when trackball is moved.
First, try restarting your computer to test for a simple software malfunction.
Check Control Panel
Within the control panel, there are several settings relating to the trackball. Review these settings to ensure that the appropriate boxes are selected and that the trackball is properly installed.
Check Another External Mouse
Use an external mouse that is known to be working. If the cursor responds to the external mouse, the problem relates to the internal components of the trackball assembly.
Expose the internal wiring of the mouse and ensure that no wires are damaged and that all connections are secure. Refer to the trackball instillation guide for assistance with accessing the internal wiring.
The final solution for repairing a defective trackball is to replace it. Refer to the trackball instillation guide for instructions.
There is no response when the keys are pressed
First try restarting your computer to ensure that the problem is not related to a simple software malfunction.
Check Control Panel
Within the control panel there are several settings relating to the keyboard. Review these settings to ensure that they are configured appropriately and that the keyboard is properly installed.
Check Another External Keyboard
Try connecting an external keyboard to the laptop. If the computer responds to the external keyboard, then either the internal keyboard or the wiring is faulty.
Remove the keyboard to expose the internal wiring beneath the keyboard. Review the condition of each wire and check for loose connections.
The final solution to a malfunctioning keyboard is to replace it. Refer to the Keyboard instillation guide for assistance.
Defective Floppy Drive
A floppy disk is in the drive but the computer does not recognize it is there.
Floppy drive is unresponsive after disk is inserted
First try a different floppy disk that is known to work. If there is no response, proceed by checking the floppy drive connection. If there are no visible flaws, try replacing the floppy drive cable. If the problem persists, the computer may need a new floppy drive, daughterboard, or motherboard.
Floppy disk will not eject
Start by shutting down the computer, and hold down the mouse button when you turn it back on. Next try inserting a small, opened paperclip in the pinhole next to the drive. The pinhole is the manual override to the eject function. If there is no response, check the floppy drive cable connection. If the problem persists, the floppy drive, daughterboard, or motherboard may need to be replaced.
Disk initialization fails or read/write/copy error is displayed
Start by trying a different disk that is known to work. Next, install the inverter shield if it is absent. Inspect the floppy drive cable connection. If the problem persists, the floppy drive cable or floppy Drive may need to be replaced.
Screen Not Working
The PowerBook turns on but the screen is unresponsive
The computer appears to be functioning normally, but the screen is blank
Start by connecting the computer to a power source and restarting the device. Next, try adjusting the display options including brightness, contrast, and backlight intensity. Check the connections with display cable, inverter, interconnect board, daughterboard and motherboard. If there is still no response, the display, daughterboard, or motherboard may need to be replaced.
The screen suddenly goes blank
Start by connecting the computer to a power source and restarting the device. Next, try pressing any key to wake the computer if it is asleep. Try adjusting the screen contrast, brightness, and backlight intensity. If the problem persists, remove the lowercase and make sure the display cable is securely connected and undamaged. Also, check to see if the daughterboard is properly seated. If the screen still fails to respond, the daughterboard may need to be replaced.
The backlight is not working
Start by connecting the computer to a power source and restart the device. Next check the connections with the display cable, converter, inverter, interconnect board, daughterboard, and motherboard. If the problem persists, any of these components may need to be replaced.