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Heres a blast from the past, im not really doing this for profit as I cant charge anything decent for it so just doing it for curiosity. So what it did was not detect the charger at all. So I replaced Q4 and it now detects the charger, charges the battery enough to turn on, then current drops to 0.05a and then it'll turn back off again after a few seconds showing the battery is empty. Tried another battery also, have also tried jumping Q4 from B1 > B2 > B3 balls which works, but then when it turns on it has the same problem.
So im putting this one down to some kind of current sensing problem. Iv checked R173 which is on the line usb_pwr_sense and its fine. There is another line called vbus sense, not sure if thats current related. By the look of it though vbus sense goes to Q2 which appears to be a mosfet that then opens Q4, but as we have jumped Q4 that shouldnt matter if that works or not.
The thing about these is there doesnt appear to be any current sensing lines on the battery, there is just positive, negative and ntc and thats it. Im going to check the ntc line thermister in a moment, if its not that im pretty clueless now as the charge circuit is as basic as it comes.
So im putting this one down to some kind of current sensing problem. Iv checked R173 which is on the line usb_pwr_sense and its fine. There is another line called vbus sense, not sure if thats current related. By the look of it though vbus sense goes to Q2 which appears to be a mosfet that then opens Q4, but as we have jumped Q4 that shouldnt matter if that works or not.
The thing about these is there doesnt appear to be any current sensing lines on the battery, there is just positive, negative and ntc and thats it. Im going to check the ntc line thermister in a moment, if its not that im pretty clueless now as the charge circuit is as basic as it comes.
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