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820-3115 in special and a smc question 12.22V -> 12.54V for all boards

Dozer

Dozer

Member
hi everyone.

i worked on a 820-3115

the board is running good.

the problem was, no charging. possible to turn on with power cable only and with power cable and accu. not possible to turn on only with accu. if running with power cable and accu it is possible to disconect the power cable board is running on accu. in osx no accu "to see"

i found out the i2c lines had 3.41V and 0.87V so here is no communication.

unfortunalty i replaced first the smc, the problem was after that still the same. after replacing u7000 it was solved.

now the question.
How u7000 can adjust the voltage from 12.22V to 12.54V without to communicate over i2c with the smc. the board was running correct with power cable.


next question is in the boardview i found on the right side of the smc the component c5349. But on all boards i hvae here there is a resistor. How that can be??
 
Paul Daniels

Paul Daniels

Super Moderator
C5349 and R5349 are right next to each other on the board, are you sure you're looking at the right one?
 

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aprendiz

Moderator
If there is no communication between SMC and ISL voltage will be 12.2xV, ISL cant regulate to 12.56V without this communication, it does power on because it is enought voltaje to power on, but will not power on from battery because it dont know if there is a battery present because of the lack of this communication and of course will not charge the battery....
 
Dozer

Dozer

Member
aprendiz , thanks.
i looked a video from louis rossmann and there he explained that after power on the u7000 generates 12.2x V, then he "ask" via i2c the smc what voltage needed, 12.54 or 8.xx, depends on the board where he is.

i had some boards there was 12.2xV and no power on, no way. after replacing the smc there was 12.54v and it started, so i still confused a little bit.
 
Paul Daniels

Paul Daniels

Super Moderator
dukefawks said:
Mistakes in the schematics and BV. There are many, this is just the first one you found.....
Click to expand...

Working on FlexBV at the moment with features to let us modify the BV files for these sort of situations, though right now I'm mostly using it to fix up the iPhone boards.
 
D

dukefawks

Administrator
How u7000 can adjust the voltage from 12.22V to 12.54V without to communicate over i2c with the smc

It can't. If the SMC or the ISL has a problem on the i2c bus then output voltage will remain 12.23V.
 
Dozer

Dozer

Member
yes, duke i thought the same way and thats why i am confused that the board was working. accu was not to "see", i replaced the smc and after that i replaced the u7000. to be shure i replaced the old smc back.

before i replaced u7000 on the data-line i measured 0.87V on the clock line 3.41V, is it possible that the 3115 board can work with 12.22V ?
 
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