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#HOW TO REPAIR APPLE MACBOOK AIR CHARGER CABEL SOFTWARE#The software may be trying to reset the bus. The SMB_BC_ACOK command is stable, with some regular high to low transitions. Looking at the MAX9940 supply, it is really noisy too. Looking at the one-wire bus, there is a weird noise on it. But when the communication is messy, then it keeps on retrying to communicate, and never allow computer power. I assume that when there is no one wire communication at all, bios enter a downgraded mode that power the MacBook Air without charging the battery. Worst: in this state, the MacBook refuses to boot. Maybe the pull-up just wake up the one wire chip in the AC adaptor, and it turns on the green LED. So… The communication with the AC adaptor exists but is not OK. Looking at the battery voltage, it remains at a dreadful 7.3volt, not rising at all. Now, the LED on the MagSafe connector turn green! But… It should be orange, charging, as there is just a few percent left in the battery. This kind of bus has a pull-up, but obviously, it was not powered. With the battery and AC adapter connected, looking with an oscilloscope, there was no life on this bus. In nearly all the brands, it is the central pin of the barrel connector. The AC adapter, like every other laptop brand, is talking to the motherboard through a one-wire bus. This man has obviously gathered all the schematics available on the internet, his repair shop is well-equipped, but he has not the left I/O board one. This is the most useful video I found on the subject. But don’t expect to find the ribbon cable schematic, or the left I/O board schematic. You will find the motherboard schematic easily. It is really easy to find high-end audio amplifiers schematics, but hard to find apple schematics. ![]() Looking for documentationĪpple is not fond of open hardware, or easy to fix hardware. But no, the AC adapter MagSafe light kept off. Changing this connector is possible, but it is a pain.Īfter the corrosion cleanup, I thought the job was done. But do not expect to have something clean at the end, gold is gone. I used a 0.7 mm flat screwdriver + flux off to remove most of the corrosion. The first thing is to carefully clean this connector. The first obvious culprit was the connector: just look at the corrosion! Corroded pins on the left I/O board connector This small board has the MagSafe connector, a USB connector, and an audio jack connector.īetween the motherboard and the I/O board, there is a flat ribbon cable (it is a shielded multi-layer FPC, no a straight simple cable that connects pin 1 of the motherboard connector to pin 1 of the I/O board). Mainboard on the left, I/O board on the right, flat ribbon cable connectors in between.Ī1466 MacBook Air has a mainboard, and a small daughter board called “Left I/O board” by Apple. Tiny, isn’t it?Ī good iron solder, flux, tiny 0.3 mm tin solder, solder wick, tweezers, flux-off (I really like the Chemtronics one, but if you’re comfortable with pure isopropyl alcohol, keep it). ![]() This is the size of component you’re going to look at. Images below are VLC screenshots of this kind of hardware. Your eyes won’t be really useful with 0.35 mm pitch component and 0.1 mm PCB tracks. Fix a A1466 MacBook Air charging circuit. In this situation, if you are the only electronic engineer in the company, there is a very high chance that your colleague asks you to look at the problem. (If you know a good waterproof backpack, tell us!) This happened after water damage on a rainy day: the computer was in a colleague’s backpack, and the rain was strong enough to wet everything inside, including the computer.Īfter letting the MacBook dry up during the night, it is not charging anymore. The battery is slowly dying… just a few percent remaining.
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