4366 Views 5 Replies Latest reply: Dec 5, 2010 4:16 PM by Merged Content 1
Welcome to Apple Discussions!
Before taking anything apart, you might try resetting the SMC or LabTic:
If no joy, then it's time to try taking apart your Mac and see if you can spot the cable and see if it is broken or not well seated.
Thanks for the suggestion but it seems to be a hardware problem. First, I took the Mac apart because of a little drinky spill that would not be covered by the extended warrantee. This is the aluminum model and replacing the keyboard is not an option, the whole top needs to be replaced at $250. I would do it if I knew that would fix the problem. The LED backlight string is probably controlled by an LED driver circuit and this may have overshot and killed the LEDs. I measure 4.95 volts at the connector for the light string no matter what the brightness setting is. Not having information as to how the driver works (is probably current sensing) I have no way to know if the driver (part of the m-board) is fried or not. So, I want to diagnose the LED string but I want to do the least disassembly possible until I know that I can fix it and put it back together. I don't know how many times the various fine pitch connectors on the m-board can be connected/disconnected without failing.
What I really need is some detailed information. Just a photo of the LED assembly (it is stuck to the black plastic that covers the keyboard) would help a lot. I need to know if it is just a series string of LEDs that connect only at the connector that is near the left side fan. If I can determine that it is failed I can get some new chip LEDs and or fix a bad solder joint or cracked circuit trace. Apple does not sell the little stick on LED string but makes you buy the whole top cover.
Does anyone have a late model Macbook Pro (the kind with the keys fitting in individual holes in the top cover, not the one with the easily removable keyboard) with the motherboard removed that they can photograph? I can certainly take it all apart again but that will mean three disassembly/assembly cycles before I get it working and I am afraid of the possibility of screwing up one of the many fine pitch connectors.
Also, if anyone has a schematic or description of how the LED driver works that would help me determine if it is working or not. My guess is that the driver overshot because of a temporary short and that it killed the LEDs.
I have the same issue after having installed an MCE Optibay adapter removing the Superdrive and the factory HD and inserting a 1T SATA drive + a 128 GB boot SSD. i was following the instructions with absolute care...
Now , for some strange reasons, my backlight is dead: by pressing the keys f5-f6 the onscreen software indicators seems to work but no lights from Leds comes on.
I checked and rechecked the flat cable for backlit, reset the SMC many times, redid all the unmounting and remounting of the Optibay, but no success........
Any ideas ? Any progress from your side ? Should we run out to a service center ?.. With no apple care sounds expensive..... sad that there is no pictures of all the complete cabling....any more detailed informations ???
I actually did this MCE optibay mod back in May 2009 and had the exact same LED issue.
I poked around and then gave up.
I'd buy a new top case if I thought that would fix the issue, but with you all having the same issue I'm beginning to wonder.
Any ideas? I'd like to have the backlight working again.