Chosen Solution
Hello, I have a Macbook Air A1466 (EMC2559). This machine had liquid damage from a large Gator Aid. After much manual cleaning I was able to get it to boot but no display. I further found that the fuse F9700 is blown. I also found that the lcd cable and connecter have been severely burned and both must be replaced. Further investigation shows there is a short at C9017. As I have been checking all the circuits I checked D9701 RB160M-60G (has a 76 on it). I did a diode test and found the following Forward bias multimeter reads 200 Ohms Reverse bias multimeter reads 470 Ohms Both measurements on a Fluke meter in Diode Test mode. I also did a resistance test Forward 8K Ohms, Backward 30K Ohms. Is it safe to say this diode needs to go too?
Diode Mode measurements are not Ohms but Volts. It’s an important distinction because the idea is to measure what the forward voltage is on a forward biased diode. Silicon based diodes have a 0.7V drop across them when properly biased however some diode types have slightly lower voltage drops (Schottky) and some multimeters don’t provide enough current in Diode Mode to fully bias the diode. In essence, you are supposed to see some reading between 0.2V and 0.7V when forward biasing the diode and OL or ~3V when reverse biasing the diode. It sounds like your diode is bad. However when measuring in-circuit, there is always the possibility that you are also measuring everything else that is in parallel with your diode so to be certain, remove the diode and measure it directly to see if the issue is caused by the diode or by the rest of the circuitry.
