Hi, sadly you're probably correct about the logic board failure. Generally issues with black screen, lines, white screen, etc. are caused by liquid damage, failing GPU or display fuse. I've heard of guys doung component level soldering & they say it's easy & a cheap part, but unless you have a rework station & know which one it is it's impossie. As for a work around, I've seen guys with LVDS cable extentions & other things, but they were hacked up & spliced DIY style. You're just going to have to use an external monitor or sell it & buy a new one.
I recommend NOT trying ANY 'shorting' of your logic board. Your board is currently good, so don't destroy it. The solution is simple, but takes a new keyboard/backlight & a complete removal of lower case components. If you can use a screw driver, have the correct tools, can follow directions & have patience this will cost about $100 US with parts (buy NEW on ebay) & tools (on iFixit). Good luck
I'm doing it now, will update on how it goes. Update: Mayer, no I can't find a part number on my keyboard, I saw one on the backlight 815-9996. On the keyboard I see the word "TOP" on the plastic circuitry & I saw some numbers but the were unreadable thought the circuit lines. Just search ebay they should have the correct models labeled with years & sometimes model numbers.
The Apple tech repair guide for this model of Macbook Air states that the flexures use Phillips #000 screws, but I didn't have good luck using #000 drivers on them. A high quality precision Phillips #00 driver worked a little better, but I'm wondering if this is actually a JIS cross point phillips #00 or #000 screwdriver? The screws look more like JIS (Japanese Industry Standard) instead of Phillips, anyone try a JIS with better luck on these?
The Apple tech repair guide for this model of Macbook Air states that the flexures use Phillips #000 screws, but I didn't have good luck using #000 drivers on them. A high quality precision Phillips #00 driver worked a little better, but I'm wondering if this is actually a JIS cross point phillips #00 or #000 screwdriver? The screws look more like JIS (Japanese Industry Standard) instead of Phillips, anyone try a JIS with better luck on these?