Fix Your Stuff Community Store

Model A1224 / Mid 2007 and Early 2008 / 2, 2.4, or 2.66 GHz Core 2 Duo processor

549 Questions View all

Options

Blank LCD, external works - LCD,LVDS cable & video card are good

My iMac powers on and boots up but there is no image on the screen. Not even a faint image is visible, it's completely black. An external display does work. I also get a video signal when logging in via Remote Desktop. That all suggests the video card is good. I've also ruled out a bad display cable (LVDS cable) and a bad LCD panel. That leaves the inverter and logic board.

Does the inverter have any influence on whether or not the LCD panel is recognized? In other words could a bad inverter keep the logic board from supplying power to the LCD panel? My testing shows that there is no power being supplied to the LCD panel on pins 28,29,30 of the LVDS connector. (see LCD panel specs here for details on pinout http://www.50amp.com/imac/LM201WE3-TLF1....). Also diagnostic LED #4 is off (no comm between logic board and LCD)

Everything I've read about a bad inverter suggests that an image should still be visible, it just won't be backlit. Is that always the case with a bad inverter or is it possible the inverter is keeping the LCD from being powered on?

Answered! View the answer I have this problem too

Is this a good question?

Yes No
Score -1
Add a comment

1 Answer

Filter by:
Most Helpful Newest Oldest
Chosen Solution

Options

LED #4

Indicates that the computer and the LCD display panel are communicating. This LED will be ON (turn on and remain on) when the computer is turned on and video signal is being generated. If the LED is ON and there is no image on the LCD display panel, the LCD display panel or inverter might be installed incorrectly or need replacement. LED 4 will be off if the computer is turned off or if no video signal is being generated.

Was this answer helpful?

Yes No
Score 1

2 Comments:

When computer is on LED 4 is OFF. A video signal is being generated to the external display and also the virtual display via Remote Desktop. I replaced LCD with known working part and got the same black screen result. Inverter and LCD panel are installed correctly.

There is no video signal to the internal LCD nor is there 5v power to the LCD panel either.

by

Please give us the part numbers for both LCDs. Thanks

by

Add a comment

Add your answer

Chris will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 0

All Time: 1,401