thomasbroche, start with this
"Video
No display, or dim display, but computer appears to operate correctly (if dim, display shows startup icon and/or desktop)
1. Remove any connected peripherals.
2. Try known-good power outlet, power adapter and power cord.
3. Make sure the F1 key is not stuck down.
4. Press F2 (with the fn key pressed and not pressed) to increase the screen brightness setting.
5. Open Display system preference panel and check brightness. If works, replace keyboard.
6. 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.
7. 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.
8. Connect an external display, and check for video on external display.
9. If video is fine on external display, troubleshoot LCD panel and verify cable connections to inverter and LCD.
10. If video symptom is same on external display, replace logic board.
11. Verify LCD panel cable and LVDS cable connections are seated properly and that the cables are not damaged.
12. Replace LCD panel.
13. Replace logic board. (wait with that until we get more clarification )
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thomasbroche, "inverter cable it sparked" just to make sure you checked your fuses as well as the LVDS connector? Give us the last four digits of your computers serial number or the 820-XXXX number of your logicboard. that will help us to identify your hardware.
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