Internal Video Cable to VGA?

Question

Does anyone make a cable or daughter card that will convert the internal video connection to a VGA connector?
With my LCD all gray and the sleep switch not working, I thought I'd see if there was a away to test the internal video before I take the screen back off.
Thanks

Answer 1

Hi, Severian. I gather that you are trying to determine 1) whether or not the video circuitry on your logic board is generating usable display data, and 2) if it is, where that data is disappearing: at the connection between the video data cable and the logic board; somewhere in the cable; or in the display itself.
Step one is to verify that the video signal from the video processor is usable for display purposes. Since the Video Out port is also soldered to the logic board, there is no place save in the LB itself for that signal to go missing between the video processor and the port. Therefore, connecting a known-good external display to the port with a known-good cable will quickly tell you whether there's a usable video signal being generated. I gather that you've done that test and verified that your on-board video circuitry is working.
Since the external display works normally, the most likely suspect is the data cable from the LB to the built-in display; the other possibility is the LCD display itself. First, verify that the cable is properly connected: disconnect and reconnect it securely and test again. If the connection is OK, the cable may be damaged either outside or (far less likely) inside the display bezel. It's a complex and delicate cable, actually a bundle of separate tiny coaxial cables. Pinching, sharp bending or twisting, stretching or abrasion can destroy it very easily. All of these things are most likely to happen where the cable passes through the display hinge. Inspect it very carefully with a hand lens, but be mindful that the actual damage may not be visible even if its probable location is.
The cable connects to the LCD inside the display bezel, of course, and the bezel is glued together, with the expectation that it will never be disassembled. If something goes wrong with the cable (or the other two cables that run from the computer into the bezel, one for the backlight and one for the sleep light), an Apple technician's remedy is to replace the entire display unit, including all three cables ($$$). Some bold do-it-yourselfers, reluctant to pay for a new LCD when a bad cable or backlight may be their only problem, have figured out ways to dismantle the display bezel while keeping the inevitable cosmetic damage to a minimum. One such procedure is nicely documented here. The disassembly is not for the fainthearted.
I should also point out that my sleep switch is bad on the laptop so that is why I'm so determined to get the internal video to work.
Sorry, but I don't follow. What is the relationship?
As it stands right now, the login in screen is being diplayed on the laptop screen so I can't even login in to change the video over.
My understanding was that you had nothing but gray on the built-in display. Please clarify.