Quote:
Originally Posted by Bembela
Hi guys.
I suggest to look around Rohm PMIC BD71815AGW because I have experience with simmilar errors in log and behaviour. Let me explain. I found also KT3s with fast battery drain. Depleted in 2 hours. So I opened it and found out with voltmetr that battery is still almost fully charged (4.09V).
After battery reconnection I booted device again to saw that now it shows 85% and the percentage of battery went down as fast as before.
Kindle only „thinks“ that voltage goes down.So why fake draining?
Connecting to serial line I saw in protocol some coulomb counter errors(and also those mentioned by dom123dom - DEBUG:keypad.c:105:keypad…..) . I booted to bist and tried folowing:
Code:
bist > vni batt vol
FG voltage =4044mV
bist > vni batt temp
FG Temperature = 31C
bist > vni batt curr
FG Current = -1351mA
bist > vni batt cap
FG Capacity = 85 Percent
Voltage mesuring and capacity was ok but the current consumption was not real. In datasheet for BD71815AGW I found Coulomb counter block and current sensing 30mOhm resistor (shunt).
After replacement of shunt is everything allright. After 2 months there is no fake draining and no more DEBUG:keypad.c….. errors.
Second device with fake draining I was playing finished exactly in same point as experienced dom123dom. But I messed it up during soldering and I removed tiny cap next to shunt. I was able finaly to put it on place but something went wrong and it got stuck here:
Code:
CPU: Temperature 37 C, calibration data: 0x5a45255f
Reset cause: POR
FRED::: EXTCSD177=0, 179=48FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
Board: Heisenberg
Board Id: P00118xxxxxxxxx
S/N: G000K90xxxxxxx
I2C: ready
DRAM: MR5=0x1,MR6=0x4 512 MiB
In last 2 months I have replaced successfuly another 4 shunt resistors. I wanted to wait some time to confirm that this repair is reliable and post it here. Hopefully it can help to someone. I am not offering any paid services. My apologies for english errors or rule violations if I commited some. |
This is very helpful thanks. What did you do to fix the device that ended up with this:
Code:
CPU: Temperature 37 C, calibration data: 0x5a45255f
Reset cause: POR
FRED::: EXTCSD177=0, 179=48FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
Board: Heisenberg
Board Id: P00118xxxxxxxxx
S/N: G000K90xxxxxxx
I2C: ready
DRAM: MR5=0x1,MR6=0x4 512 MiB
Did you manage to fix that one?
I have spent a lot of time and effort (and enough money to buy a new kindle!!) replacing the USB connector port and the battery, it has not resolved the charging problem.
It was a good experience to learn how to do it but I'm disappointed it didn't fix it!
I'm learning slowly...where did you get a replacement shunt from and how do you replace it?
Thanks again for sharing your experience.