[SOLVED]820-3115 battery charging issue

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jgraffis

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Ive got a 820-3115 that worked perfect at one time until i put a (killer) battery. this battery killed 2 machines in the same way. so after plugging in the machine wouldn't recognize the battery or run on battery power. i chased this back to a problem with in the SMC. i had a doner board it thought i would try to reball and if that went well maybe install in this board.

It in fact worked and the machine sees the battery now and runs on battery power but now it does not charge the battery.
Ive checked the current sensing resistors and all check out just fine. Saw one of louis videos about this and decided to check for bc_acok. it appears i have a short to ground on pin 4 of u6901, but only when battery is plugged in.

Any ideas on this?
 

dukefawks

Administrator
You cannot measure Ohms with power applied!! Also if ACOK would be missing you would not have a green light.

Is the battery fully recognized, like Cycles and full charge capacity displayed correctly? Does the light turn orange?
 

jgraffis

New member
it does show the cycle count, and charge capacity the light does not turn orange. I've checked with 2 different batteries that have different cycles and charge capacity.
 

dukefawks

Administrator
Get a better multimeter or replace the battery in it. 12.7 is too high. It should be 12.3 or 12.56V.
Measure resistance between pin 17/18 and 27/28, of course with no power.
 

jgraffis

New member
i checked it with 2 different multi meters just to double check with same result. maybe bad isl or trace?
 

dukefawks

Administrator
Please explain how this could be a bad ISL? I want you to understand what is going on. Look at the diagram and understand WHY you should measure 2.2 Ohm.
 

jgraffis

New member
it looks on the diagram to me that i should be 2.2ohms based on it being a current sensing circuit ? 2.2ohms on r7051. the others have very little to no resistance. Was thinking that when testing at R7051 and getting 2.2+/- couldn't really be that, could it?
 

dukefawks

Administrator
Come on how hard can this be, engage the brain.

Resistors are ok, but still OL between pin 17/18. What else is between the resistors and pin 17/18?
 
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