Macbook A1534 820-00244

[Instafixx]

Hello,
Namaste.

Have a Macbook A1534 Completely dead.

PPBUS_G3H is at 0.1V.
Drawing 5V on the charger.

Any help?

[mon2]

Re: Macbook A1534 820-00244

Remove the fuse on ppbus_g3h. Power up again. What is the voltage to ground now of ppbus_g3h ?

[Instafixx]

Re: Macbook A1534 820-00244

Remove the fuse on ppbus_g3h. Power up again. What is the voltage to ground now of ppbus_g3h ?

Removed F8400.

PPBUS_G3H is now 8.7V
The Machine is also drawing 20V but not getting on.

Should we replace this fuse?

[mon2]

Re: Macbook A1534 820-00244

Should we replace this fuse?

No fuse is fine but the ISL regulator is shutting down due to an excessive consumer side load on the logic board.

By removing the fuse, the load was removed so the PPBUS_G3H rail is operating as it should. Your ISL regulator is working fine.

Fault is on the consumer side of the fuse.

Remove all power. Meter in resistance mode.

Check the resistance to ground on the side of the fuse where the load exists. That is, the fuse pad where you measured the PPBUS_G3H is OK.

Check the resistance to ground of the other fuse pad.

What is the resistance ?

Removed F8400.

Wait. You actually removed the wrong fuse but interesting on the results.

You have removed the LCD display backlight fuse. Can you confirm this?

[Instafixx]

Re: Macbook A1534 820-00244

No fuse is fine but the ISL regulator is shutting down due to an excessive consumer side load on the logic board.

By removing the fuse, the load was removed so the PPBUS_G3H rail is operating as it should. Your ISL regulator is working fine.

Fault is on the consumer side of the fuse.

Remove all power. Meter in resistance mode.

Check the resistance to ground on the side of the fuse where the load exists. That is, the fuse pad where you measured the PPBUS_G3H is OK.

Check the resistance to ground of the other fuse pad.

What is the resistance ?



Wait. You actually removed the wrong fuse but interesting on the results.

You have removed the LCD display backlight fuse. Can you confirm this?

Yes Indeed.
The Pin#2 F8400 is PPBUS_S0_LCDBKLT_FUSED.

Meter set in 2k Mode the reading is .505 at Pin#2.
Should we put in a new Fuse ?

[mon2]

Re: Macbook A1534 820-00244

No. The resistance is too low after this fuse.

What is the current draw from your 20v power adapter?

Can you toggle the key caps led?

That is, the missing backlight should not stop the logic board from booting.

[Instafixx]

Re: Macbook A1534 820-00244

No. The resistance is too low after this fuse.

What is the current draw from your 20v power adapter?

Can you toggle the key caps led?

That is, the missing backlight should not stop the logic board from booting.

This is weird. Last day with only board and charging port connected had got 20V. Now with everything packed its again back to 5V.

Can the LCD be the issue ?

[mon2]

Re: Macbook A1534 820-00244

Remove it to check if it is at fault.

Rotate the power head by 180 degrees and test again.

[Instafixx]

Re: Macbook A1534 820-00244

Remove it to check if it is at fault.

Rotate the power head by 180 degrees and test again.

What do you mean by rotate the powerhead ?

[mon2]

Re: Macbook A1534 820-00244

The A1534 uses Type C connectors so this implies there is a TOP SIDE and BOTTOM SIDE contacts.

One side is with the CC1 communication line.

Other side is with the CC2 communication line.

If you remove the power adapter connector and flip it upside down, you will test if the other side of the connector is working or not.

[Instafixx]

Re: Macbook A1534 820-00244

the a1534 uses type c connectors so this implies there is a top side and bottom side contacts.

One side is with the cc1 communication line.

Other side is with the cc2 communication line.

If you remove the power adapter connector and flip it upside down, you will test if the other side of the connector is working or not.

without the lcd connected i get steady 20v.
The amps rise from .6 to 1.5 gradually.

No caps key light. The trackpad clicks. No switch on chime.

[mon2]

Re: Macbook A1534 820-00244

What is the voltage to ground of PPBUS_G3H in this setup?

[Instafixx]

Re: Macbook A1534 820-00244

What is the voltage to ground of PPBUS_G3H in this setup?

It is tough to check that in this setup because of the design of a1534. But bare board PPBUS_G3H is 8.7V

[mon2]

Re: Macbook A1534 820-00244

It is a good voltage.

Can you attach a USB hub and a USB thumb drive with a led to check if there is usb access on booting? Checking for led flickering to indicate USB activity. To confirm if CPU is ok.

[Instafixx]

Re: Macbook A1534 820-00244

It is a good voltage.

Can you attach a USB hub and a USB thumb drive with a led to check if there is usb access on booting? Checking for led flickering to indicate USB activity. To confirm if CPU is ok.

Dont have a USB with LED. But no video output on the External as well. Caps Lock toggle also not working.