ALB-Repairs
Member
Hi, although im not very active on this forum i have something that i think people may find useful.
You need to take a genuine Magsafe cable and connect it to a bench power supply. Use it as your charger. You can set voltage, easily turn it on and off, but most importantly:
You can measure current. Mine has a Magsafe 1 and magsafe 2 cable attached, Gets a green light, acts like a normal charger, and can be set up to 20V for 15" retina's
To give you 3 examples:
2015+ apple laptops dont turn on the fan automatically, so how do you know if its quater fan spinning without measuring a bunch of crap? (as far as you know its stuck in S5) Look at the current, it will literally show you that its power cycling.
Something has an SMC related issue (No S4/3) you will see a different current being drawn by the board, In my case when i get 8.1V or am missing SMC_Reset_L, i will have 0.0031A vs 0.0036A.
If you have a bad U1950 but all S0 your current should be around 0.2A rather than 0.5-0.6A, The CPU wont be getting hot, In the same case, if you have a bad S0 rail, you will get a simalar reading and instantly know to check ALL_SYS_PWRGD and U1950.
I fixed a 2915 with a 5vs0 short recently, but at first glance it was stuck in S5, no fan spin, no s4, but i was able to see the machine was trying to turn on, the current would jump from 0.036A to 0.1A or so, This meant rather than searching the SMC related or S5 related stuff, i knew it was trying to boot but shutting down, probably some current sensors somewhere, therefore probably a short circuit, I started looking at the rails and quickly found a bad cap on 5v_s0
It was a quick fix that would have taken much longer if i wasn't observing the motherboards current draw.
If you have a short circuit somewhere you will be able to identify it without having to measure stuff.
Essentially this will give easily accessible information to help pinpoint diagnosis, its similar to using diode mode to figure out what part of a backlight circuit isnt working (but more useful IMO)
If this becomes commonly used it should (in theory) become far easier to pinpoint complex issues.
P.S: I havent bothered figuring out how to connect USB C macbooks to a bench supply as a charger.
I hope this is adopted by not only learners but people who know what there doing. It will make your life allot easier.
You need to take a genuine Magsafe cable and connect it to a bench power supply. Use it as your charger. You can set voltage, easily turn it on and off, but most importantly:
You can measure current. Mine has a Magsafe 1 and magsafe 2 cable attached, Gets a green light, acts like a normal charger, and can be set up to 20V for 15" retina's
To give you 3 examples:
2015+ apple laptops dont turn on the fan automatically, so how do you know if its quater fan spinning without measuring a bunch of crap? (as far as you know its stuck in S5) Look at the current, it will literally show you that its power cycling.
Something has an SMC related issue (No S4/3) you will see a different current being drawn by the board, In my case when i get 8.1V or am missing SMC_Reset_L, i will have 0.0031A vs 0.0036A.
If you have a bad U1950 but all S0 your current should be around 0.2A rather than 0.5-0.6A, The CPU wont be getting hot, In the same case, if you have a bad S0 rail, you will get a simalar reading and instantly know to check ALL_SYS_PWRGD and U1950.
I fixed a 2915 with a 5vs0 short recently, but at first glance it was stuck in S5, no fan spin, no s4, but i was able to see the machine was trying to turn on, the current would jump from 0.036A to 0.1A or so, This meant rather than searching the SMC related or S5 related stuff, i knew it was trying to boot but shutting down, probably some current sensors somewhere, therefore probably a short circuit, I started looking at the rails and quickly found a bad cap on 5v_s0
It was a quick fix that would have taken much longer if i wasn't observing the motherboards current draw.
If you have a short circuit somewhere you will be able to identify it without having to measure stuff.
Essentially this will give easily accessible information to help pinpoint diagnosis, its similar to using diode mode to figure out what part of a backlight circuit isnt working (but more useful IMO)
If this becomes commonly used it should (in theory) become far easier to pinpoint complex issues.
P.S: I havent bothered figuring out how to connect USB C macbooks to a bench supply as a charger.
I hope this is adopted by not only learners but people who know what there doing. It will make your life allot easier.
