820-00165 Charging Problem

[Instafixx]

Hello,
I have a Macbook Air A1466 820-00165 which has a weird problem.
The Macbook came in for a charging problem but we put the charger and it started charging. We suspected that it maybe a charging issue but the Macbook intermittently charges from different chargers.

One Observation : Whenevr we connect it to a DC power Supply (Input 15V) it charges and post that it will charge from a normal charger too until one day it wont charge and then again have to plug in the DC Power Supply.

Anyone can guide me on this?

[reformatt]

Re: 820-00165 Charging Problem

I've seen this with genuine magsafe chargers. Non genuines work fine though because they don't use any load sensing to switch through the power.

Check R7012 value, then check for residual voltage here with battery connected and no charger connected. Usually it's a leaky Q7180 allowing battery voltage back into this area, which messes up the load detection of the genuine Magsafe chargers.

[Instafixx]

Re: 820-00165 Charging Problem

i've seen this with genuine magsafe chargers. Non genuines work fine though because they don't use any load sensing to switch through the power.

Check r7012 value, then check for residual voltage here with battery connected and no charger connected. Usually it's a leaky q7180 allowing battery voltage back into this area, which messes up the load detection of the genuine magsafe chargers.

currently not charging with a genuine magsafe charger

battery out

meter in 2k mode

resistance at pin #1 of r7012 is .648.

What should i do now?

[mon2]

Re: 820-00165 Charging Problem

How many charge cycles on the battery ?

Is the battery the original?

Test with another known good battery.

[Instafixx]

Re: 820-00165 Charging Problem

how many charge cycles on the battery ?

Is the battery the original?

Test with another known good battery.

battery cycle count is 294.
Yes it is an original battery.

Right now its charging well even with the original chagrer.
So how do i swap any part and be sure that it is a part issue? Because the charging issue is intermittent.

Only thing which i am sure of is that whenever it doesnt charge from a genuine magsafe charger, we have to connect it tohe dc power supply post which it is back to normal for sometime.

[mon2]

Re: 820-00165 Charging Problem

Measure the voltage to ground of ACIN pin #3 of U7100.

What is the voltage when using the original adapter that is flaky with the charging?

What is the voltage when using the working dc power supply?

Also post the voltage of PPDCIN_G3H_ISOL.

[Instafixx]

Re: 820-00165 Charging Problem

Measure the voltage to ground of ACIN pin #3 of U7100.

What is the voltage when using the original adapter that is flaky with the charging?

What is the voltage when using the working dc power supply?

Also post the voltage of PPDCIN_G3H_ISOL.

Pin # 3 of U7100 is 3.3V

Voltage of PPCDIN_G3H_ISOL is 15V.

On both the flaky charger and the DC Power Supply.

[mon2]

Re: 820-00165 Charging Problem

See attached.

Measure the voltage to ground of:

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

pins of the battery mosfet @ Q7155 when:

a) using the non-working / flaky original charger - interested in the voltage readings when the battery is NOT charging

b) the battery is charging with your DC power supply

[Instafixx]

Re: 820-00165 Charging Problem

See attached.

Measure the voltage to ground of:

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

pins of the battery mosfet @ Q7155 when:

a) using the non-working / flaky original charger - interested in the voltage readings when the battery is NOT charging

b) the battery is charging with your DC power supply

So somehow it is working till now from the Flaky Chagrer too hence cannot measure the Voltage when it is not charging. Hence checked with the charging ON.

with Flaky Charger
Q7155
Pin#1 8.58V
Pin # 2 8.57V
Pin # 3 8.58V
Pin #4 7.87V

On the right side there are 4 Points but the schematics has only 1 hence posting voltages of all 4 from top to bottom. Top Point is close to the battery connector
A Cycling from 0.3 to 8.58V
b 8.58V
c Cycling between 0.3 to 8.58V
d Cycling between 0.3 to 8.58V


All voltages on the flaky charger while its charging. Battery Not Connected.

[mon2]

Re: 820-00165 Charging Problem

Now add the battery and measure these points again.

[Instafixx]

Re: 820-00165 Charging Problem

Now add the battery and measure these points again.

With Battery On and Charger On (Flaky) and charging.

Q7155
Pin#1 8.58V
Pin # 2 8.57V
Pin # 3 8.58V
Pin #4 1.2V

On the right side there are 4 Points but the schematics has only 1 hence posting voltages of all 4 from top to bottom. Top Point is close to the battery connector
A 8.58V
b 8.58V
c 8.58V
d 8.58V

Note that the battery is at 100 charge and the charger is showing a green light.

[mon2]

Re: 820-00165 Charging Problem

Yes, right side of this mosfet has the drain pins = pins 5-6-7-8. Any of these pins can be measured since these block of pins are mated together. See the datasheet or the bottom side of these mosfets. You will see a solid connection between these pins.

The gate voltage defines if this mosfet is on or off. Being a P-channel mosfet, the gate voltage must be lower than the voltage it is passing between the source and drain pins.

So if gate is a high or same voltage as the source / drain pins, the mosfet should be off.

Of concern is that you do not have a lower voltage on the gate pin when the battery is removed, yet drain has the same voltage as the source??

That is, the drain pins should be at 0 volts for this case.

Remove all power. Remove the battery. Meter in resistance mode.

Measure the resistance across this mosfet's pins:

Source & drain ; select any of the pins (1-2-3) and (5-6-7-8)
Source & gate (4)
Gate & drain

Post the resistance of each measurement. If the resistance is low on any of the above checks, the mosfet is leaking and should be replaced.

Suspecting that this mosfet is defective from your measurements without the battery.

[Instafixx]

Re: 820-00165 Charging Problem

Yes, right side of this mosfet has the drain pins = pins 5-6-7-8. Any of these pins can be measured since these block of pins are mated together. See the datasheet or the bottom side of these mosfets. You will see a solid connection between these pins.

The gate voltage defines if this mosfet is on or off. Being a P-channel mosfet, the gate voltage must be lower than the voltage it is passing between the source and drain pins.

So if gate is a high or same voltage as the source / drain pins, the mosfet should be off.

Of concern is that you do not have a lower voltage on the gate pin when the battery is removed, yet drain has the same voltage as the source??

That is, the drain pins should be at 0 volts for this case.

Remove all power. Remove the battery. Meter in resistance mode.

Measure the resistance across this mosfet's pins:

Source & drain ; select any of the pins (1-2-3) and (5-6-7-8)
Source & gate (4)
Gate & drain

Post the resistance of each measurement. If the resistance is low on any of the above checks, the mosfet is leaking and should be replaced.

Suspecting that this mosfet is defective from your measurements without the battery.

Meter in 2K Mode
Black Probe on Source and Redon Drain .367
Black Probe on Source and Red on Gate .705
Black Porbe on Gate and Red on the Drain 1


i hope gave the right measurements.

[mon2]

Re: 820-00165 Charging Problem

Can you post a pic of your meter face?

Appears that the same button may be also with diode mode?

If yes, keep pressing the mode button till you see the omega symbol. Post a pic to clarify.

[Instafixx]

Re: 820-00165 Charging Problem

Can you post a pic of your meter face?

Appears that the same button may be also with diode mode?

If yes, keep pressing the mode button till you see the omega symbol. Post a pic to clarify.

Its a Analog Meter.

[mon2]

Re: 820-00165 Charging Problem

No, meter is digital. The 2k scale also is the diode mode scale.

Press the yellow button to switch to the resistance mode scale.

Then measure again. If you do not get a proper reading, switch to the next higher resistance scale.

Post your readings again.

Check resistance between,

Pins 1 & 8 = source & drain
Pins 1 & 4 = source & gate
Pins 4 & 8 = gate & drain

[Instafixx]

Re: 820-00165 Charging Problem

No, meter is digital. The 2k scale also is the diode mode scale.

Press the yellow button to switch to the resistance mode scale.

Then measure again. If you do not get a proper reading, switch to the next higher resistance scale.

Post your readings again.

Check resistance between,

Pins 1 & 8 = source & drain
Pins 1 & 4 = source & gate
Pins 4 & 8 = gate & drain

The Yellow button just switches on the Backlight.

Used another Digital Meter. Pressed the button till i got the Omega Sign on the screen . Picture attached.

Black on 1 and Red on 8 = 2.12
black on 1 and Red on 4 = 8.31
Black on 4 and Red on 8 = 8.82

[mon2]

Re: 820-00165 Charging Problem

Can you a pic of the meter face with one of these measurements?

Is the reading in M ohms? That will be then (for example) 2.x megaohms but we need to confirm each.

When you short the meter probes, the reading should be ~0 ohms.

[Instafixx]

Re: 820-00165 Charging Problem

Can you a pic of the meter face with one of these measurements?

Is the reading in M ohms? That will be then (for example) 2.x megaohms but we need to confirm each.

When you short the meter probes, the reading should be ~0 ohms.

Yes its M Ohms.

One strange thing is that while taking the measurements again i am getting

Black on 1 and Red on 8 = 848 k
black on 1 and Red on 4 = 8.33 m
Black on 4 and Red on 8 = 6.2 M

[Instafixx]

Re: 820-00165 Charging Problem

Also sometime 4 and 8 is =0 ohms~