Ted

You're getting light, so your backlight is working. The led's behind the keyboard are wired in series, so the circuit itself seems to be fine. So it would seem that the thin sheet of polycarbonate that diffuses the light and spreads it across the whole keyboard has either gotten misaligned with the side-emitting led's, or, something is blocking the light from the led's from entering the medium. You could try turning your laptop upside down and flushing whatever debris might be stuck under the keyboard with a can of compressed air. (Though I can't imagine how it would have gotten there in the first place) If a liquid spill is the cause, it would have to be some kind of opaque liquid (milk, coffee, etc.), and you could try to take the whole backlighting sheet-assembly off the keyboard. It is attached with adhesive. Be warned that you can very easily snap one of the smd led's that are on the circuit in the middle, which would destroy the whole thing in the process. They are very fragile. If you can manage to...

Any significant events before the issue started? For example, liquid getting into the keyboard will usually fry at least one led; the keyboard backlight circuit on your MacBook model has 4 (or 6, I can’t remember) led’s wired serially, and fed by a ribbon cable supplying ~5vDC, modulated by a single chip that handles most things low current DC. If the lights are fried, you could probably pick up a keyboard backlight replacement off Amazon or the like for maybe twenty bucks. It’s pretty much a drop in replacement, though you will have to gut the case fairly thoroughly to get at it. If it’s the controller, the only real practical option is to replace the logic board, which really isn’t that practical, economically speaking. If you have a nice smt repair station setup and can find the chip (which you probably won’t be able to do, probably Apple proprietary, so perhaps a donor logic board) then you could replace the chip, but this is easier said than done, to put it mildly. Dan’s solution will give you a...

I realize that this is like 3 years too late but its’s for the 10gbps (sort of) point-to-point ethernet connection you can make by connecting two Macs together via thunderbolt.

I don’t understand, when do you need to remove this if it’s not broken already? Are there components underneath that can be replaced/fixed?

You gotta wonder though, with the vents on the other side of the driver, doesn’t this mean that the ferrofluid would degrade that much more quickly? Maybe it’s only meant to be used for 5-7 years, which is reasonable for laptops, etc, but if I’m going to buy a speaker, I’d want to get one that sounds great, and keeps sounding great for a long time…

Ohh, right that makes more sense… It would sound horrible if it was solid the way it’s so thick and uneven on the coil. Scratch what I said about “potting epoxy”

Also I’m baffled by a sentence in the post linked about diamond tweeters, what does “accurately reproducing audio above and beyond the limits of human hearing” even mean? Isn’t that a little paradoxical?

I think what you’re referring to might be the potting epoxy. The golden brown liquid-looking stuff on the coils?

In this step, you are cleaning the keypad while it is removed from the calculator, and the photo should reflect that. someone should update this with the correct photo!