KT3 (8th generation) battery charging problem

[dom123dom]

I've ordered some replacement USB sockets, going to take a few weeks to arrive, more waiting.

In the meantime I'm going to see if I can find a reasonably priced microscope.

Would something like this 2MP one be good enough for working on a kindle or do I need to spend a bit more for the 5MP version?

https://www.jaycar.com.au/2mp-wi-fi-...stand/p/QC3752

[knc1]

I have a very similar device.

When working on a Kindle, there isn't enough distance to the support post to allow you to reach at least halfway on some of the boards.

The tablet I was using (Some of the pics posted here where taken with it) had an HDMI output.
I hooked that to a 53 inch TV/Monitor.
Now that is a lot of magnification.

[dom123dom]

Originally Posted by knc1

I have a very similar device.

When working on a Kindle, there isn't enough distance to the support post to allow you to reach at least halfway on some of the boards.

The tablet I was using (Some of the pics posted here where taken with it) had an HDMI output.
I hooked that to a 53 inch TV/Monitor.
Now that is a lot of magnification.

Hmm, interesting idea, I have a hdmi adapter with Micro B connector which should fit my Tab S2 and connect up to my 28" monitor. Thanks I'll give that a try.

[caner4ever]

Originally Posted by dom123dom;38[IMG

https://imgyukle.com/i/ZxIAt[/IMG]18199]Hmm, interesting idea, I have a hdmi adapter with Micro B connector which should fit my Tab S2 and connect up to my 28" monitor. Thanks I'll give that a try.

i have 6 this model kindle and same problem. Sometimes boot ok , but drain battery . Sometimes no boot no start.can you contact me please caner4ever@gmail.com
Whatsapp: +905547379324

https://imgyukle.com/i/ZxIAt

[knc1]

Originally Posted by caner4ever

i have 6 this model kindle and same problem. Sometimes boot ok , but drain battery . Sometimes no boot no start.can you contact me please caner4ever@gmail.com
Whatsapp: +905547379324

https://imgyukle.com/i/ZxIAt

Looks like a business for profit, not a hobbyist.
If so, you should offer to hire someone, perhaps from here.
Our purpose here is to help the end-user, not the OEM or Refurbisher.

[caner4ever]

Originally Posted by knc1

Looks like a business for profit, not a hobbyist.
If so, you should offer to hire someone, perhaps from here.
Our purpose here is to help the end-user, not the OEM or Refurbisher.

Hello,

In Turkey we dont have any customer service for the Amazon products and i can help the users who need technical supports, as part time. i have 6 device same problem , and i want to learn how i can fix this problem . Sorry for my english

[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:

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:

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.

[dom123dom]

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:

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:

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:

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.

[dom123dom]

Looking at the datasheet here: https://www.rohm.com/datasheet/BD71815AGW

I can see what you mean it talks about:

Embedded Coulomb Counter for Battery Fuel
Gauging
- 15-bit ΔΣ-ADC with External Current Sense
Resistor (10 mΩ, ±1% or 30mΩ, ±1%)
- 1-sec cycle, 28-bit accumulation
- Coulomb count while charging/discharging

and

15-bit ΔΣ-ADC measures the battery’s charge and discharge current by means of an external current sense resistor
(10mΩ, ±1% or 30mΩ, ±1%).

So should it be 10mΩ or 30mΩ for the Kindle? You mentioned 30 above.

Is this the right one?
https://www.digikey.com.au/product-d...RCT-ND/2003876

EDIT:
With a magnifying glass I can see 030 printed on the chip so I just bought the ones below, I hope they are the right model!
MCS1632R030FER - Ohmite - Current Sense Resistor

I think this will be very challenging soldering for me, it looks tiny.

[Bembela]

Sorry for late reply. It is definitely 30mΩ. I´ve never tried 10mΩ but it should work as well.
Meanwhile I was playing around with another piece with same issue. I tried only to reheat the resistor and it has been working for 13 days till now.

I think about 2 possibilities. 1)Change of the resistivity to right value because of the heat(hardly possible but I´m not an expert). 2)"Reset or recalibration" of values in BD71815AGW after soldering. There is significant time gap (5-10min) after soldering. Heat protection I guess. Could be the heat a side effect of values reset in IC?

[dom123dom]

Originally Posted by Bembela

Sorry for late reply. It is definitely 30mΩ. I´ve never tried 10mΩ but it should work as well.
Meanwhile I was playing around with another piece with same issue. I tried only to reheat the resistor and it has been working for 13 days till now.

I think about 2 possibilities. 1)Change of the resistivity to right value because of the heat(hardly possible but I´m not an expert). 2)"Reset or recalibration" of values in BD71815AGW after soldering. There is significant time gap (5-10min) after soldering. Heat protection I guess. Could be the heat a side effect of values reset in IC?

Interesting, thanks for the feedback. I received the resistors in the mail today and was about to try to solder a new one. Maybe I will try some heat first. Did you use a heat gun or a soldering iron?

[dom123dom]

I tried to warm up 030 resistor to remove it, I'm finding it extremely difficult, tried tweezers, tried a small screwdriver to pry off, tried my soldering iron. In the end I set my heat gun to 250 and tried to heat up the solder a lot. Still not really working.

So anyway I warmed it all up and thought i may as well try charger and see what happens.

I still get the same boot, it stops at the same point...the output tells me 46 degrees.....but now I have an orange charge light!

@Bembela What method did you use to remove the shunt?

[Bembela]

Soldering iron station. It consumes a lot of heat especialy one side of resistor. I tried also heat gun but after that there were black stain on the display. Eink is sensitive to heat. So be careful. I`m using notebook cooling pad to avoid screen damage.
So where are you now?Can you post log?

[dom123dom]

Still same as before (as below), but the difference is now I get an orange charging light which I was not getting before. I've seen a few reports here that leaving the kindle on a long charge on wall charger can fix errors so I'll probably leave it overnight and see if I get a charged battery with green light in the morning (10pm here now).

I also bought a USB charging lead that shows the AMps and volts draw. Do you know what it should be charging at? I'm getting 5.02volts and between 0.27 to 0.3 Amps.

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

[knc1]

and if that does not work, freeze it.