palokiller, just some more food for thought:"
Power, but no video (computer begins to start up, fan and hard drive spins, Caps
Lock key lights up when pressed, but there is no startup sound or video)
Note: Examine the display carefully. An image may be barely present on the screen, but with no backlight clearly illuminating the image. In this case, the system is working properly except for the backlight. Refer to “No display or dim display” troubleshooting symptom to resolve this issue.
1. Reseat memory cards. Try known-good memory.
If you or the customer do not fully seat the memory, the computer will not start up. See
Knowledge Base articles 303083, “Intel-based Mac Power On Self Test RAM error codes”, and
303721: “MacBook: How to install memory.”
2. Reset the SMC. See Knowledge Base article 303319, “Resetting MacBook and MacBook Pro
System Management Controller (SMC)”. Resetting the SMC means you will also need to reset
the date and time (using the Date & Time pane of System Preferences).
Warning: Make sure you do not hold down the “fn” key when resetting the SMC.
3. Press F2 (with the fn key pressed and not pressed) to increase the screen brightness setting.
4. Try connecting an external display to check for intact video signal. If external video appears, check the system for any pending software or firmware updates and update accordingly.
5. Verify that the LVDS cable connection is properly seated to its connector on the logic board
and that the cables are not damaged.
6. Reseat inverter cable.
7. Replace the display assembly.
8. Check all cable and flex connections to the logic board. Try restarting.
9. Replace the logic board.
No power, no video (no sleep light, no fan movement, no hard drive spin, no Caps
Lock LED when pressed, and no display illumination)
Note: After each step, check that the system is not supplying power to the logic board. If you see the sleep LED come on or the Caps Lock LED illuminate when the key is pressed, then the system is indeed drawing power. In this case, hold down the power button for six seconds to ensure the system is shut down before working on the computer. At this point, the issue is no longer a ‘No Power, No Video’ problem. Move on to the “Power, but No Video” troubleshooting section.
Note: Examine the display carefully. An image may be barely present on the screen, but with no backlight clearly illuminating the image. In this case, the system is working properly except for the backlight. Use the “No display or dim display” symptom to resolve this issue.
1. Remove any connected peripherals.
2. Check that the battery has enough charge to start the computer by pressing the button
next to the LEDs on the battery (on the bottom of the machine). At least one LED must light
continuously (not flashing). Make sure the battery is fully seated.
3. Connect a known-good Apple 60W MagSafe Power Adapter and power cord to a known-good power outlet. If the cord is properly inserted, the LED should light up; if not, go to the “MagSafe
power adapter” symptom.
4. Check for damaged pins or magnetic debris on MagSafe power adapter. If pins are okay,
reseat power adapter connector and make sure it is fully inserted. Refer to Knowledge Base
articles 303566 “MacBook Pro: Troubleshooting MagSafe power adapters with stuck pins” and
302461 “Portable Computers: Troubleshooting power adapters.”
5. Try powering up without the battery installed. If it starts up, try a known-good battery. If it does not boot, replace the battery connector cable.
6. Press Caps Lock key to see if light on key comes on. If it does, hold power button down for
six seconds to shut down the computer and restart.
7. Reset PRAM. Restart the computer, then hold down the Option-Command-P-R keys until you hear the startup sound at least one additional time after the initial startup sound.
8. Reset the SMC. See Knowledge Base article 303319, “Resetting MacBook and MacBook Pro
System Management Controller (SMC)”. Resetting the SMC means you will also need to reset
the date and time (using the Date & Time pane of System Preferences).
Warning: Make sure you do not hold down the “fn” key when resetting the SMC.
9. Try to power up the system and check the sleep indicator. If the LED lights up solidly and
turns off, the logic board is getting power and completing the boot cycle. Go to the “Power,
but No Video” troubleshooting section.
10. Verify that the power button cable is connected properly to the top case flex cable assembly and that the flex cable is connected correctly to the logic board. Try turning on the system.
11. Disconnect the top case. Inspect the connectors. With the top case removed, restart the system using the on-board startup jumper pads, as shown below. If it starts up, replace the top case.
Caution: Use a jeweler’s flat-blade screwdriver that is just wide enough to short the two
small solder pins (jumper pads) located directly below the power symbol.
12. Test each RAM slot individually with known-good RAM. (The computer should still start with only one known-good DIMM.)
13. Try removing the AirPort Extreme card from its socket and start the computer. If it starts, shut it down and check the flex cable connector and the connector on the logic board and replace the damaged parts.
14. Reseat these cables:
• Hard drive flex cable (will start up to flashing folder if not connected or corrupt)
• Optical drive flex cable
• Trackpad flex cable
• LVDS cable
• Battery connector with sleep switch cable
15. If computer starts on battery power only, replace MagSafe board with a known-good MagSafe DC-in board.
16. If computer starts up, inspect any suspect flex cable connectors and their terminals on the logic board for damage and replace any damaged parts.
17. Replace logic board.