Fuses in Macbook Pro 2019 A2159

[mp844]

Hi, would anyone have a boardview / listing of all the motherboard fuses on A2159, please?

I made the mistake of connecting up another LCD (quick & dirty, for testing) without disconnecting the battery correctly, and now the laptop is bricked.

It does take charge and I can see +12V line at numerous fuses on the board but I must be missing something (hoping it is a fuse!). Any help would be greatly appreciated..

Happy New Year!
Martin

[Simplebeans]

Re: Fuses in Macbook Pro 2019 A2159

Hi, would anyone have a boardview / listing of all the motherboard fuses on A2159, please?

I made the mistake of connecting up another LCD (quick & dirty, for testing) without disconnecting the battery correctly, and now the laptop is bricked.

It does take charge and I can see +12V line at numerous fuses on the board but I must be missing something (hoping it is a fuse!). Any help would be greatly appreciated..

Happy New Year!
Martin

Whats the board number usually it's found on the board?

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

Whats the board number usually it's found on the board?

Hi,

FV9945202
VZKRGYB0
1. 4G 742

I hope this helps? If not, please let me know and I will have to extract the board first.

[piernov]

Re: Fuses in Macbook Pro 2019 A2159

https://logi.wiki/index.php/Board_Nu...Book_Air_13.22

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

https://logi.wiki/index.php/Board_Nu...Book_Air_13.22

Thanks, it's seems to be the one below, can anyone help with a complete fuses listing/boardview please? Or perhaps you know which fuses in your experience are likely to go when another display is plugged in to mainboard?

A2159 MacBook Pro 13" Touch Bar Two USB C
820-01598 2019 MacBook Pro 13"

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

See attached.

Start with fuse F8400 which is the INPUT fuse to the backlight boost circuit.

Meter in DC volts mode; 30+ volt scale should be fine.

Red meter probe on F8400 & black meter probe to ground.

Check & post the voltage reading on BOTH sides of this fuse.

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

Check & post the voltage reading on BOTH sides of this fuse.

Firstly, many thanks for your time.

I get 10.8V on both sides of this fuse.

Remarks: laptop was off for nearly a month (I was away); so initially I was getting 0V on this and other fuses. Plugged in charger, I was able to see up to 40W draw on USB-C charge monitor. CPU heatsink got a bit warm. I can see the same 10.8V across other fuses on board and numerous capacitors. Laptop will not turn on though.

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

What is the voltage that is negotiated on the USB Type C connector ?

Is it 5v or 20v after a few seconds of connecting the Type C power adapter ?

Are you using the original power adapter ?

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

What is the voltage that is negotiated on the USB Type C connector ?

Is it 5v or 20v after a few seconds of connecting the Type C power adapter ?

Are you using the original power adapter ?

It's the 96W Apple charger.
It has negotiated 20V and draws around 2A, has been for the past half hour, however this is not a steady draw and goes up and down a little, I saw 58W on it for a moment a few times. It fluctuates but definitely charges.

I'm sure it starts at 5V but then it must quickly negotiate 20V because my charge monitor does not pick it up.

CPU heatsink is warm, about 40degC, screen and keyboard are dead, no response to long press of power button.

edit: CPU fan spins a few rotation when CPU sink gets too warm. It still appears bricked. Thi swas hard to notice.

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

The 20V negotiations is good. This implies the USB power delivery controllers are functional and they are chatting with the external power adapter to select this power contract.

The PPBUS_G3H rail looks low for the Macbook Pro.

Reference:
https://www.logi.wiki/index.php?title=PPBus_G3H

1) Meter in resistance mode (2k is ok).

Remove all power.

Check the resistance to ground for F8400. What is the resistance ?

2) Meter in DC volts scale (30v+ is ok).

Check the PPDCIN_G3H_CHGR voltage. This should match what the USB Type C meter is reporting and should be ~20VDC.

See attached on a cluster of caps that can be used for this measurement.

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

The 20V negotiations is good. This implies the USB power delivery controllers are functional and they are chatting with the external power adapter to select this power contract.

The PPBUS_G3H rail looks low for the Macbook Pro.

Reference:
https://www.logi.wiki/index.php?title=PPBus_G3H

1) Meter in resistance mode (2k is ok).

Remove all power.

Check the resistance to ground for F8400. What is the resistance ?

2) Meter in DC volts scale (30v+ is ok).

Check the PPDCIN_G3H_CHGR voltage. This should match what the USB Type C meter is reporting and should be ~20VDC.

See attached on a cluster of caps that can be used for this measurement.

Board removed, capacitors drained. I get around 12 MOhms (Mega) at F8400 in ref to GND. I plugged in USB-C daughterboard, charger with monitor, it negotiated 20V again and I measured 20.3V at the capacitor cluster.

n.b. I left it to fully charge overnight, and voltage at F8400 rose to 12.43V (remained at 12.4V after unplugging charger).

Will be happy to go through next steps, the board is out. Many thanks.

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

Hi.

See attached.

Measure and post the voltage for PP3V3_G3H.

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

In addition to the above measurements, check & post the voltage readings for each of the coils on the logic board (see attachment).

Each coil is linked to a local switching regulator. The coils are 2 pin devices, you can measure either side of the coil with the red meter probe (DC 20V scale should be fine).

Black meter probe to ground (shield is ok).

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

In addition to the above measurements, check & post the voltage readings for each of the coils on the logic board (see attachment).

Each coil is linked to a local switching regulator. The coils are 2 pin devices, you can measure either side of the coil with the red meter probe (DC 20V scale should be fine).

Black meter probe to ground (shield is ok).

01 = 0V (MegaOhms in ref to GND)
02 = 5V
03 = 3.3V (PP3V3_G3H)
04 = 12.6V
05 = 0V (50 Ohm in ref to GND)
06 = 0.66V
07A= 0.66V (hidden under connector tape, to the left from inductor 7, R22)
07 = 0.72V
08 = 0.7V
08B= 0.8V (to the right from inductor 8, smaller one marked R47)
09 = 0.95V
10 = 1.2V
F8400 fuse = 12.6V

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

01 = 0V (MegaOhms in ref to GND)
* this rail is for the LCD backlight which is not working so makes sense to be @ 0V

05 = 0V (50 Ohm in ref to GND)
* L7702 on the logic board
* for the 1v0 rail required for the EDRAM
* the resistance @ 50 ohms is not a bad reading

Check & post the voltages linked to Q7702 (dual mosfet), pin # 1. You can use one of the capacitors shown in the top right of the schematic.

Use C7752 with red meter probe (20v scale) & black meter probe to ground.

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

+12.6V between that cap and GND.

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

This is a good voltage.

See attached. Measure and post the voltages on the Q7702 mosfet.

Be very careful on measuring pin # 3 on the mosfet with the meter lead.

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

This is a good voltage.

See attached. Measure and post the voltages on the Q7702 mosfet.

Be very careful on measuring pin # 3 on the mosfet with the meter lead.

Used a needle and a few measurements to be sure;
Pin 3 of Q7702 = constantly fluctuates between -500mV...+200mV with momentary spikes up to 1V

Pin 5 at the inductor/pad = 0V

[mon2]

Re: Fuses in Macbook Pro 2019 A2159

See attached. Measure & post the ENABLE voltage for this switching regulator.

[mp844]

Re: Fuses in Macbook Pro 2019 A2159

See attached. Measure & post the ENABLE voltage for this switching regulator.

0V at the pad, about 46kOhms, both in ref to GND.