820-00165-A No Power

[speggio91]

Hello everyone,

I've got this macbook air 2017 A1466 which initially was working good exept for the wifi adapter not being detected by the OS.

After inspecting the board, I discovered some traces of liquid damage around the area of R3558, R3559, R3554 and the pin 1,2,3,4 of U3540 slightly dull.

I cleaned the area with alcohol, took some measurements on the resistors and in the process i accidentally knocked off R3554.
Also the test pads in those area and other resistor were a bit corroded.
By cleaning the corrosion, some of the board mask went off exposing the ground layer on the side next to R3559 R3554.

I soldered a new resistor of 200K in the place of R3554. I had to scratch some mask off cause the pad number 1 was gone.
I made sure that none of the pin number 1 of R3554 and pin number 2 of R3559 were getting in touch with the exposed ground layer. Measuring the resistance to ground of PP3V3_WLAN line showed more that 300K stable.

Upon reconnecting the magsafe board with the ribbon cable to the main board (connector J9500), I flipped that ribbon cable upside down by accident.

After attaching the magsafe, I came up with no led, no power no fan spin.

PPBUS_G3H line is 0V without shorts.
PP3V42_G3H line is 0V without shorts.
PPDCIN_G3H line is 0V without shorts.
PPDCIN_G3H_ISOL line is 0V without shorts.
CHGR_DCIN line is 0V without shorts.

The only voltage I've found is 7V on PPDCIN_G3H_CHGR line

Could be that I've blown up Q7180?

Any help will be well appreciated

[reformatt]

Re: 820-00165-A No Power

Pretty sure I've done that once or twice with the ribbon cable, it shouldn't create any issues.

Tests should be done without battery installed. If you are using a genuine Magsafe charger, the load provided by R7012 should trigger the charger to enable the full voltage. Sometimes I've seen leakage through D7005 or Q7180 from the battery interfere with the Magsafe turning on.

You can test for this by installing battery only (no magsafe) and check for voltage at R7012. If you have anything above 0 here, then you have leakage back from the battery.

[speggio91]

Re: 820-00165-A No Power

Hello reformatt, thanks for the hint.

All the previous tests was made with just the magsafe connected, without the battery.
I have 2 geniuine magsafe 2 charger and the results was the same.

I tried to connect just the battery and measuring on R7012 I got 0.090 mV.
Is that still considered an important Leak?

I noticed that with just the battery connected, now I see these voltages:

PPBUS_G3H = 7.6V
PP3V42_G3H = 3.4V
PPVRTC_G3H = 3.4V
PP5V_S5 = 0V no shorts to ground detected
PP3V3_S5 = 0V no shorts to ground detected

[mon2]

Re: 820-00165-A No Power

D7005 is a suspect.

With only the battery, measure the voltage to ground of each pin on D7005.

With only the official power adapter, perform the same voltage checks.

Post each measurement. If the MagSafe led is off then this important 3v42 power rail is not functional.

[speggio91]

Re: 820-00165-A No Power

Hello Mon, thanks for your message.

D7005 on battery only:
pin 1: 7,6V
pin 2: 51mv
pin 3: 7.4V

D7005 on charger only:
pin 1: 2V
pin 2: 44mv
pin 3: 1.5V

Some observations:

when i measured D7005 with the charger connected, those voltage were decreasing very fast on pin 1 and 2. Even after I unplugged the charger, those voltages were still there and eventually reached 0V after few minutes.
If i connected and disconnected the battery, and taking measurements right away on the diode, pin 1 is 1.7V and pin 2 1.5V both decreasing fast. So i guess the charger doesn't have any effect on those values and maybe the diode is faulty.

[speggio91]

Re: 820-00165-A No Power

I have an update:

I'm feeling misarable to say it but the culprit was the J7000 not being connected to the magsafe board

Not having experience on these boards before I didn't think of connecting it, I thought that J9500 flat was enoug haha

Now the macbook is powering on and loading the system. The wifi adapter is also being recognized. Everything seems to work well exept for one thing.

Maybe it's me, but I think now the system is running a bit slower than before, the apps are taking lot of time to load, even the system preferences took 10 seconds to show up. If I move the windows, the movement is smooth though.

I've connected every flat cables, sensors, camera, etc.
The model has 8GB of ram and an i5, 1.7Ghz Cpu.

[mon2]

Re: 820-00165-A No Power

Test after a pram reset.

[speggio91]

Re: 820-00165-A No Power

final update:
the general slow down of the OS got fixed apparently by plugging in the battery. The first tests after reassembling the machine was done without it.
I also did a PRAM reset and it did increase a bit more the loading speed.

Thank you all for the interest and support, you are a guarantee!