macbook pro 820-3115

[mortito]

good morning
I need help I have this motherboard the charger light turns green it turns off and turns on again in a few seconds
and so constantly the motherboard does not boot

I did the following measurements in u7000
in DCIN I have oscillating values 18.1 18.3V
ACOK 3.2V
ACIN 4.4v
CSIN OSCILLATION BETWEEN 18.1 AND 20v
CSIP OSCILLATION BETWEEN 18.1 AND 20v
BOOT OSCILLATION BETWEEN 14.1 AND 20v
SGATE OSCILLATION BETWEEN 17 AND 20V
AGATE 004.2mV
VDD 5V
VDP 5V
R7020 OSCILLATION BETWEEN 18.1 AND 20 V
Q7085 SOURCE 18.6v DRAIN 18.6v

thanks in advance greetings

[mon2]

Re: macbook pro 820-3115

Hi.

1) study page 3 of the schematics to note the power on sequence shown in the circles.

2) voltage @ D6990 pin 1 ? pin 2 ? pin 3 ?

3) voltage @ L6995, pin 2 ? Must be 3v42 volts here.

4) if L6995 is not @ stable 3v42 volts then power down, remove the battery. Place your meter in resistance mode and check the resistance to ground for L6995, pin 2. What is the reading ?

5) If the reading is not super low, review the resistance to ground on each coil on the logic board.

Often the symptoms you are noting are related to bad / shorted caps. Usually the polarized tantalums. This is assuming there was no liquid damage that may be still on the logic board.

[mortito]

Re: macbook pro 820-3115

Thanks for the help I measured what you recommend and these are the measurements what I think is because q7080 does not have the gate in 7 v more or less I see that u7000 does not send pin 26 to ground to make the divider of the gate of q7080 I see that it is not switching

d6990
pin 1 has 15.14 and decreases to 11.24 and rises again to 15.14
pin2 18.54
pin3 18.26
L6995, pin 2 3.42 ok stable

[mon2]

Re: macbook pro 820-3115

pin 1 has 15.14 and decreases to 11.24 and rises again to 15.14

Not good. Remove F7040 = SMD fuse and then check the voltage rail as output from U7000. Check on F7040, pin # 1. What is the voltage reading ?

This rail must remain to be stable.

If not stable, power down and use the meter in resistance mode and check the resistance to ground on F7040, pin # 1. What is the resistance reading ?

Will be a good idea to remove the battery off the logic board and then test the voltage on F7040, pin # 1.

Also,

voltage reading @ R6905, pin # 1 ?
voltage reading @ R6905, pin # 2 ?

we need to be sure that R6905 is not defective and causing these fluctuations.

[mortito]

Re: macbook pro 820-3115

Thank you and sorry for not giving them to you before that machine I left it aside for the client when I touch it again I will communicate the tensions
thanks anyway for your help

[judamex]

Re: macbook pro 820-3115

I have the same problem, remove the fuse F7040 and pin 1 gives me 4V I think this voltage is not normal. replace U7000, check resistors and all seems fine.

[mon2]

Re: macbook pro 820-3115

Check the voltage of PP3V42_G3H_REG @ L6995, pin # 2.

What is the measurement ?


Remove all power. Meter in resistance mode.

Check the resistance to ground of the pin # 1 @ F7040 pcb pad for the fuse.

What is the resistance ?

[judamex]

Re: macbook pro 820-3115

Check the voltage of PP3V42_G3H_REG @ L6995, pin # 2.

What is the measurement ?


Remove all power. Meter in resistance mode.

Check the resistance to ground of the pin # 1 @ F7040 pcb pad for the fuse.

What is the resistance ?

voltage of PP3V42_G3H_REG @ L6995, pin 2= 3.49v

Voltage of F7040 pin 1= 3.58v

Measurement on F7040 pin 1 resistence mode is unstable = 1.1M to 600k and return to 1.1M

i check measurement whit the red to GND and black to pin 1

[mon2]

Re: macbook pro 820-3115

Resistance is fine. Voltage at fuse is too low.

Confirm the input voltage to the high side mosfet for this circuit.

What is the voltage?

Remove all power. Meter in resistance mode.

Check the resistance across the same 2x mosfets on this u7000 ppbus_g3h leg.

Check each mosfet with the usual

Source & drain
Source & gate
Gate & drain

[judamex]

Re: macbook pro 820-3115

Resistance is fine. Voltage at fuse is too low.

Confirm the input voltage to the high side mosfet for this circuit.

What is the voltage?

Remove all power. Meter in resistance mode.

Check the resistance across the same 2x mosfets on this u7000 ppbus_g3h leg.

Check each mosfet with the usual

Source & drain
Source & gate
Gate & drain

i remove F7040 and voltage its the same, mosfets are ok
resistence on F7040 pin2 1.1M ppbus_g3h

[mon2]

Re: macbook pro 820-3115

Post the resistance values for these 2 x mosfets.

Also measure when in dc volts mode, the voltage that is going into the high side mosfet.

It is possible that this regulator is not soldered properly.

[judamex]

Re: macbook pro 820-3115

Post the resistance values for these 2 x mosfets.

Also measure when in dc volts mode, the voltage that is going into the high side mosfet.

It is possible that this regulator is not soldered properly.

Resistance value for Q7030 pin 5 - 3.5M / pin 1,2,3 - 1.4M / If I check pin 4 of the mosfet it shows me a short circuit with respect to GND, but if I check pin 4 with the test point it tells me 1.4M

resistence value for Q7035 pin 5 - 1.3M / pin 1,2,3 GND .25 ohms / pin4 - 0.0


Voltage mode value for Q7030 pin 5 - 16.5V / pin 1,2,3 - 3.38v / pin 4 direct on mosfet 0.0V testpoint 4.5V

voltage mode value for Q7035 pin 5 - 3.37v / pin 1,2,3 - GND / pin 4 - 0.0V

[judamex]

Re: macbook pro 820-3115

Post the resistance values for these 2 x mosfets.

Also measure when in dc volts mode, the voltage that is going into the high side mosfet.

It is possible that this regulator is not soldered properly.

i resold Q7030 and check pin 4-gate now have 4.5V but pin 1,2,3 still same 3.4V

[mon2]

Re: macbook pro 820-3115

If I check pin 4 of the mosfet it shows me a short circuit with respect to GND

What is the resistance to ground of pin # 4 of Q7030?

On the resistance checks for these mosfets -> remove all power -> meter in resistance mode.

Check:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement and the meter scale used for these tests.

[judamex]

Re: macbook pro 820-3115

What is the resistance to ground of pin # 4 of Q7030?

On the resistance checks for these mosfets -> remove all power -> meter in resistance mode.

Check:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post each measurement and the meter scale used for these tests.

Meter on auto scale for resistance, model of meter "aneng AN8008"
resistence on Q7030 pin#4 - 2.1M
pin#1,2,3 - 2.7M
pin#5 - 3.3M
source (1-2-3) & drain (5) - 2.7M
source (1-2-3) & gate (4) - 2.6K
gate (4) & drain (5-6-7-8) - 1.5M unestable up and down

[mon2]

Re: macbook pro 820-3115

Source and gate resistance looks very low.

Confirm it again.

Mosfet looks to be defective.

[judamex]

Re: macbook pro 820-3115

Source and gate resistance looks very low.

Confirm it again.

Mosfet looks to be defective.

Source and gate resistance(RED terminal on gate, black terminal on Source) 21K
(Black terminal on Gate, RED terminal on source) 20.8K

[judamex]

Re: macbook pro 820-3115

Source and gate resistance looks very low.

Confirm it again.

Mosfet looks to be defective.

i remove Q7030 and check measurement, source (1-2-3) & gate (4) - 3.3M.
And check measurement on motherboard without Q7030 Pin#1-2-3 & Pin #4 - 2.3K

[judamex]

Re: macbook pro 820-3115

Source and gate resistance looks very low.

Confirm it again.

Mosfet looks to be defective.

i replace the mosfet and it still gives the same measurements

[mon2]

Re: macbook pro 820-3115

pin 1 has 15.14 and decreases to 11.24 and rises again to 15.14

Is this line pulsing between the 2 voltage values ?