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I bought a late 2011 MacBook pro for parts. The computer turns on and functions but there is no lcd backlight. I can see there is video to the screen when shining a light through the back of the apple logo.

The lvds connector looks fine. The motherboard looks good. I've tried an SMC and a PRAM reset but those have failed.

I've heard that backlight fuses go bad but I don't have the right soldering iron, or confidence, to replace the fuse.

I see another board beneath the LCD clutchplate. Is that board an inverter? If so, maybe the inverter is the cause of the problem?

I have a couple mid 2010 mbp lcd assemblies sitting around but it appears those have a different cable layout. Before I try to dismantle these LCDs to find any cross-over parts, does anyone know if the 2010 mbp LCDs are compatible with a late 2011 board?

What do you suggest trying next? How can I isolate this problem?

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    It's easy to test a fuse - check for continuity with your multi meter. As far as the component in question (inverter), please post a picture - a "clutch plate" is automotive term (there's no "clutch" in a laptop) so I am unsure to what you're referencing. – Allan Mar 31 '18 at 16:35
  • @allan I don't have a multi meter at the moment. I meant to write "clutch cover". When I searched for it on eBay, all the listings had "clutch cover" in the title. I might have the wrong term. It is the black, plastic cover at the base of the display assembly. Does the LVDS cable provide backlight power and video data or only video data? If it's the former, I have isolated the problem to the motherboard. I tried a 2010 display assembly and it received video but no backlight. – www139 Mar 31 '18 at 20:35
  • @allan Apparently, LVDS provides backlight power and video (as suspected). The problem is with the motherboard. – www139 Mar 31 '18 at 20:43
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Thank you @allan for helping me move forward through the isolation process. Through deduction, I found the problem to be with the motherboard.

This is the entire process I used to isolate the issue...

  • Power on and shine a light through the Apple logo or examine the LCD closely to see if it is receiving video. The other option is to connect the computer to an external display.
  • Perform SMC and PRAM resets.
  • Remove back cover and examine the LVDS connector (it's the gold connector located near the hinge facing the display assembly. Look for any broken pins or corrosion on the motherboard in case of liquid or prior repair damage.
  • Try using another, working, display assembly. Also, check the backlight fuses on the motherboard. If the working LCD still doesn't have backlight power, the problem is isolated to the motherboard. All the A1278 MacBook Pros use the same LVDS cable (and pinout) so it is safe to connect. The other cables are for the camera and wifi connectivity. Leave those disconnected. Also, unlike older laptops, the display inverter is integrated onto the motherboard so it is nearly impossible to repair it

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