820-2915-A Wont power on with battery connected

[beogeek]

Ok so this doing my head in and hopefully someone more knowledgeable will be able to assist.

I've got a MacBook Pro 820-2915-A it will power on without the battery connected, but when the battery is connected it will do a 2,3-second fan spin when pressing the power button and then nothing.

After measuring and probing around I found that R7051 was bad, reading high instead of 2.2Ω so I replaced it. Still the same issue, I have the green light on the charger but it won't power on or charge the battery.

So to cut the long story short I've replaced U7000, R7051, Q7035, Q7030, and finally U4900 (SMC). Now when I connect the battery and adapter, the battery is charging with an orange light, in fact after waiting for 2 odd hours the BIL is indicating fully charged and the adapter changed to green once fully charged. But still, the same issue persists, when I try powering it on I get a slight fan spin and nothing, remove the battery and it powers on fine.

I've tried by-passing the SMC but it will not power on with the battery, by-pass works without the battery connected as I can see the FANS run at full speed.

I'm not sure what it is now, could it be the battery is bad? I've tried turning on the board with just the battery and the same thing, slight spin, and stop. So I checked Q7055 and it has 12.57v on all pins when the battery is not connected, with it is connected pin 4 is 12.54v. Also checked R6950 which is measuring fine.

I've ordered a new battery which is on the way as I need one for myself for testing, measuring the current battery reads 12.37v.

Any help or pointers are greatly appreciated.

[mon2]

Re: 820-2915-A Wont power on with battery connected

Post the voltage readings of the i2C (smbus) esd diodes at D6950 with the battery connected.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

Hi mon2 appreciate the help.

With only the bat connected
D6950
pin 1: 1.196
pin 2: 1.197
pin 3: 0

with dc adapter connected & bat connected
D6950
pin 1: 2.7-3.4 fluctuating
pin 2: 2.7-3.4 fluctuating
pin 3: 0

[mon2]

Re: 820-2915-A Wont power on with battery connected

Post the voltage readings of D6990.

First with only the power adapter ( no battery ).

Then remove the adapter, use only the battery.

Post the readings.

The PP3V42_G3H is not correct with only the battery.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

D6990
with charger only
pin 2: 16.70
pin 3: 16.41

with bat only
pin 2: 0.010
pin 3: 2.952

[mon2]

Re: 820-2915-A Wont power on with battery connected

D6990 is with 3 pins.

Please also post the voltage of pin #1 of D6990 for each case.

Is the battery charged? What is the voltage on the battery being tested ?

[beogeek]

Re: 820-2915-A Wont power on with battery connected

sorry my bad

with dc
pin 1: 12.57

bat only
pin 1: 12.38

bat voltage 12.38

[beogeek]

Re: 820-2915-A Wont power on with battery connected

prior to charging the battery it was indicating about 3 leds on the BIL, charger was amber, once charging was completed the BIL indicates full battery and the charger changed from amber to green.

Board runs fine without the battery connected, boots the OS etc. Only when the bat is connected it wont boot, I connect the charger, the fans quarter spin and that's all it does.

[mon2]

Re: 820-2915-A Wont power on with battery connected

What is the voltage on both sides of R6990 ? Measure with the battery connected.

Post the voltage of PP3V42_G3H with only the battery.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

R6990
Bat only
0.010 both sides

bat & dc
16.62 left side pin 2
16.79 right side pin 1

[mon2]

Re: 820-2915-A Wont power on with battery connected

Remove all power.

Multimeter in DIODE mode.

Check & post the readings of:

Red meter probe on pin # 1 & black meter probe on pin # 3.
Red meter probe on pin # 2 & black meter probe on pin # 3.


Red meter probe on pin # 3 & black meter probe on pin # 1.
Red meter probe on pin # 3 & black meter probe on pin # 2.

We want to confirm that D6990 is not damaged.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

Red meter probe on pin # 1 & black meter probe on pin # 3. 1.094
Red meter probe on pin # 2 & black meter probe on pin # 3. 0.253


Red meter probe on pin # 3 & black meter probe on pin # 1. OL
Red meter probe on pin # 3 & black meter probe on pin # 2. OL

[mon2]

Re: 820-2915-A Wont power on with battery connected

Remove D6990 off the logic board.

Then measure again the voltage on both sides of R6990 with the battery only.

Post the readings.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

R6690 0.001v on both sides with bat only

[mon2]

Re: 820-2915-A Wont power on with battery connected

Post the voltage readings on Q7055 mosfet with only the battery.

Voltage readings of:

pins 1-2-3 (Source)
pin 4 (gate)
pins 5-6-7-8 (Drain)

Please confirm that you are measuring the voltage of resistor R6990 (I had a typo in the earlier post - now corrected).

[beogeek]

Re: 820-2915-A Wont power on with battery connected

F6905 0.0 both sides

[mon2]

Re: 820-2915-A Wont power on with battery connected

1) Post the voltage readings on Q7055 mosfet (with only the battery).

2) Then, remove all power. Meter in resistance mode (2k scale).

Measure & post the readings of the same Q7055 battery mosfet for:

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

Checking for any low resistance readings which will likely be due to the mosfet being defective.

[beogeek]

Re: 820-2915-A Wont power on with battery connected

Q7055
source (1-2-3) & drain (5-6-7-8) 0.4Ω red probe on source, black on drain
source (1-2-3) & gate (4) 171.3Ω red probe on source, black on gate
gate (4) & drain (5-6-7-8) 165.7Ω red probe on gate, black on drain

[mon2]

Re: 820-2915-A Wont power on with battery connected

Q7055 is defective and needs to be replaced.

You can remove off the logic board and check the resistance again to confirm the readings. The resistance is too low for this mosfet.

If possible, replace with the same part but many parts can work as a replacement, if needed. Maybe you have a donor board ?

[beogeek]

Re: 820-2915-A Wont power on with battery connected

I'll remove it now and report back in a jiff