820-4924 no battery

[andrew boren]

water damaged macbook, without a battery, works 100%, attach battery, battery % shows up and seams to be charging. randomly will shut down. if i measure the power pins on the battery while plugged in, the voltage jumps all over, leading me to believe there is a short but nothing seams to be shorted. i removed q7155 and the battery voltage was stable, replaced with spare, and same problem. i have tried 3 different batteries. anyone have a similar issue or have some way to force what ever is shorting out to fail so i can find it?

 

[dukefawks]

Checked resistance between pins 17/18, 27/28 of the ISL6259? It does shut down with AC and battery connected too?

 

[andrew boren]

ac + battery = crash. ac only no crash. battery only wont power.

 

[andrew boren]

and on pin 17/18 im getting almost 0 resistance, on 27/28 im getting about 20 resistance

 

[dukefawks]

That seems fine. Is PP3V42 present when on battery only? PPBUS voltage too?

 

[andrew boren]

pp3v42_g3h yes 3.41v ppbus_g3h is all over the place, from 12v down to 1 then back up

 

[dukefawks]

So PPBUS on battery alone is going up and down? ISL6259 is also suspect.

 

[andrew boren]

yeah only on battery, on ac its fine

 

[dukefawks]

I don't see how the battery voltage can be pulled low unless there is some serious current dragging it down. Also check if SYS_DETECT_L is staying low. Where was the liquid damage?

 

[andrew boren]

sys_detect_l is jumping between 1.7v to 2.7

 

[dukefawks]

sys_detect_l should be low. Is the 10K pull down resistor ok? Is there corrosion in the battery connector that is messing with it? You could short out the 10K pull down and see if PPBUS stabilizes.

 

[andrew boren]

the 10k resistor is measuring 10k ohm and yes its pin 2 is tied to ground so it should be pulling down

 

[dukefawks]

I asked to short out the resistor to make sure corrosion under the battery connector can not cause a pull-up effect. Short the resistor and see of PPBUS stabilizes.

 

[andrew boren]

yes ppbus stablized and so did the power pins, tho it won turn on. im guesing bc its shorted to ground battery wont work

 

[andrew boren]

sorry inm not to sure what to do from there, the 10k resistor is good, so why is it not pulling down. jumping pin 1 to ground workes to stabalize battery power,

 

[dukefawks]

I suspect corrosion under the battery connector or just another dead battery.

 

[andrew boren]

i ultrasonic-ed it once already, should i give it another go? and this happens with all batteries i put in, so it cant be a bad battery

 

[dukefawks]

Ultrasonic does not clean under connector/chips!!

 

[andrew boren]

ok so i guess im gonna ask a stupid question. how does one remove corrosion under the plastic battery connector if ultrasonic does not remove corrosion.

 

[dukefawks]

You remove it....