[SOLVED] Red light flashes next to barrel-port

[Carl]

Update: Leaved the pinebook charged overnight (10+ hours) and battery is still just 21%.

Update: Yesterday I booted the pinebook 3 times after every other hour to check the battery status and if it's actually charging when the red light flashes. I noticed that the battery dropped about 5% after every boot (power supply connected through the entire day. It was down at 8% after the 3rd boot. Leaved it charging for another 12+ hours without touching the pinebook, wakes up to 20% again - it seems to be charging but abnormally slow.

I will try to leave the pinebook charging for at least 24 hours to see if it can bypass 20%.

[rimaille]

Voice of god, i don't know, he's presented as a founder, and he say 'Red LED blink means charging circuit not able perform charging. '
Which does not help us on the causes that can lead to this malfunction. Heat could be probably one, too much power drawing as well...

https://forum.pine64.org/showthread.php?...6#pid63316

[FreeRangeRon]

My PBP isn’t charging the battery at all, unlike Carl’s which seems to be trickle charging, so our faults might be slightly different. Anyway, I took a look at the resources available.

From the schematic (page 11) you can see the LED next to the power socket is connected to the 'STAT' pin of the BQ24171 battery charger IC.



From the BQ24171 Datasheet:

"Open-drain charge status pin with 10-kΩ pullup to power rail. The STAT pin can be used to drive LED or communicate with the host processor.It indicates various charger operations: LOW when charge in progress. HIGH when charge is complete or in SLEEP mode. Blinking at 0.5 Hz when fault occurs, including charge suspend,input overvoltage, timer fault and battery absent."

My interpretation (the interpretation of a novice) of the fault conditions are:

Charge Suspend - Disables battery charging when the temperature of the battery pack is below 0 °C or above 60 °C 
Input overvoltage - If (my math is correct and) the input increases over 6.5v or drops below 2v charging will terminate. 
Timer fault - If the battery voltage is too high or low it won't be charged. I can't quite get my head around how to work out the values that trigger this, I’m sure someone with experience could work it out easily. 
Battery absent - There’s a little dance here where the BQ24171 applies a discharge current and then monitors the voltage to determine if a battery is present. I won’t pretend to understand anymore than that.

When I realised that my PBP wasn’t charging I removed the battery and charged it using an external charger (TP4056). The battery charged without issue and it was cool to the touch, although it was only slow charging which took about 10 hours to go from 3v to 4v. The point being the cells themselves seem to be fine. However, I haven’t been able to test the thermistor, if that’s faulty it could cause a ‘charge suspend’ condition. Additionally, with the battery charged to 4v it’s in the accepted voltage range and should not cause a ‘timer fault’.

I’ve used a number of different charging sources (different USB wall plugs, the provided barrel plug adapter) but all have been 5v, give or take 10%, which means they shouldn’t be causing an ‘overvoltage’ fault.

At the moment I’m hoping this is a bad thermistor, that would be the easiest fix. If it’s a board-level component then I don’t think I’ve got the skills or tools to be able to find the bad part.

I hope that information is useful to anyone else having this problem. Happy to try any other tests that might narrow this fault down. 

Cheers,
Ron

[wdt]

From the schematic and data sheet, if thermistor is right,
between FB (14) and GRD (25) should be 2.1V, or 2.05 if a bit hot or 2.025 if hot
And, obviously R53 should be roughly 10K, depending on temp, so 5-12K
GRD is not a pin, the foil under chip, any good grd will do I think (or pin 23)
pin diagram on pg 4 of datasheet

[Carl]

OP updated

---

My PBP isn’t charging the battery at all, unlike Carl’s which seems to be trickle charging, so our faults might be slightly different. Anyway, I took a look at the resources available.

From the schematic (page 11) you can see the LED next to the power socket is connected to the 'STAT' pin of the BQ24171 battery charger IC.



From the BQ24171 Datasheet:

"Open-drain charge status pin with 10-kΩ pullup to power rail. The STAT pin can be used to drive LED or communicate with the host processor.It indicates various charger operations: LOW when charge in progress. HIGH when charge is complete or in SLEEP mode. Blinking at 0.5 Hz when fault occurs, including charge suspend,input overvoltage, timer fault and battery absent."

My interpretation (the interpretation of a novice) of the fault conditions are:

Charge Suspend - Disables battery charging when the temperature of the battery pack is below 0 °C or above 60 °C 
Input overvoltage - If (my math is correct and) the input increases over 6.5v or drops below 2v charging will terminate. 
Timer fault - If the battery voltage is too high or low it won't be charged. I can't quite get my head around how to work out the values that trigger this, I’m sure someone with experience could work it out easily. 
Battery absent - There’s a little dance here where the BQ24171 applies a discharge current and then monitors the voltage to determine if a battery is present. I won’t pretend to understand anymore than that.

When I realised that my PBP wasn’t charging I removed the battery and charged it using an external charger (TP4056). The battery charged without issue and it was cool to the touch, although it was only slow charging which took about 10 hours to go from 3v to 4v. The point being the cells themselves seem to be fine. However, I haven’t been able to test the thermistor, if that’s faulty it could cause a ‘charge suspend’ condition. Additionally, with the battery charged to 4v it’s in the accepted voltage range and should not cause a ‘timer fault’.

I’ve used a number of different charging sources (different USB wall plugs, the provided barrel plug adapter) but all have been 5v, give or take 10%, which means they shouldn’t be causing an ‘overvoltage’ fault.

At the moment I’m hoping this is a bad thermistor, that would be the easiest fix. If it’s a board-level component then I don’t think I’ve got the skills or tools to be able to find the bad part.

I hope that information is useful to anyone else having this problem. Happy to try any other tests that might narrow this fault down. 

Cheers,
Ron

Hi Ron,

Thank you for the insightful information. Have you managed to make any progress?
Our symptoms sound similar since my PBP also completely stopped charging from the barrel-port - however I managed to solve all my symptoms by using a USB-C power supply (updated OP). For some reason the power supply that came with the PBP and or barrel-port appeared to be damaged/faulty for me. Have you tried charging using the USB-C port?

Kind regards,
Carl

[FreeRangeRon]

From the schematic and data sheet, if thermistor is right,
between FB (14) and GRD (25) should be 2.1V, or 2.05 if a bit hot or 2.025 if  hot
And, obviously R53 should be roughly 10K, depending on temp, so 5-12K
GRD is not a pin, the foil under chip, any good grd will do I think (or pin 23)
pin diagram on pg 4 of datasheet

Thanks for the info wdt, i've made some measurements:

Voltage between FB (14) & GRD:
Battery: 1v
Battery & charger: 1.8v

These are not within the range you mentioned, do you think that's why the battery isn't charging? I'll need to look over the charging IC's datasheet again to understand this relationship for myself.

R53:
No Battery: 18.7K
Battery but no charger: 6.7K
Battery & charger: Out of Range

I also checked the resistance on the battery side, the reading between the thermistor (white lead) and ground seems to be bang on 10K so that looks fine. To be extra sure I connected the battery without the thermistor lead and replaced it was a 10K resistor. It didn't make any difference, I still got the red flashing LED, and the voltages across FB & GRD were the same.

When I was searching around I noticed that there was, what looked like, a short between pins 14 & 15 on the BQ24171:

Checking the datasheet it doesn't look like it should have caused any problems on the IC, the SRN pin is rated up to 20V but I don't know what other strange behaviour that could've been causing elsewhere in the circuit. I went ahead and fixed it anyway:

But, still red flashing light and no battery charging.

Perhaps the BQ24171 is damaged? Although I've tried a few things I don't think I've made much progress yet. Back to the datasheet tomorrow I think, where hopefully I'll have more luck.

Thanks in advanced for any further suggestions.

[FreeRangeRon]

OP updated

---

Hi Ron,

Thank you for the insightful information. Have you managed to make any progress?
Our symptoms sound similar since my PBP also completely stopped charging from the barrel-port - however I managed to solve all my symptoms by using a USB-C power supply (updated OP). For some reason the power supply that came with the PBP and or barrel-port appeared to be damaged/faulty for me. Have you tried charging using the USB-C port?

Kind regards,
Carl

As above Carl, still stuggling with this one. Yes I've tried the USB-C port but also gives me the red blinking LED.

I'm gald to hear it was just a faulty power supply that was causing your issue, I hope your PBP serves you well on battery power.

Cheers,
Ron

[belfastraven]

OP updated

---

Hi Ron,

Thank you for the insightful information. Have you managed to make any progress?
Our symptoms sound similar since my PBP also completely stopped charging from the barrel-port - however I managed to solve all my symptoms by using a USB-C power supply (updated OP). For some reason the power supply that came with the PBP and or barrel-port appeared to be damaged/faulty for me. Have you tried charging using the USB-C port?

Kind regards,
Carl

As above Carl, still stuggling with this one. Yes I've tried the USB-C port but also gives me the red blinking LED.

I'm gald to hear it was just a faulty power supply that was causing your issue, I hope your PBP serves you well on battery power.

Cheers,
Ron

I have seen this when I first got the pbp in the fall.  In my case,  I had taken out the battery and had  the connectors reversed when I reinstalled it.  Assuming that you didn't do that,  is it possible that  one of the connectors is damaged,  or that the battery did have the connectors reversed?   IF that were the case, though,  you still should be able to boot with the battery out and the bypass connected.

[wdt]

>further suggestions.
Again, pg4&5, data sheet
2,3,4 = 5V
12 = 3.3V (reference)
18 = 0.5 to 1.6 V
These are input, but not 12
My guess is that the short has damaged it (but only a guess),
too bad you didn't check if it was really shorted (continuity)
If 14 is out of 2.025-2.1 V range, charging is shut down (pg22)
If the battery is too low it may fault too, pin 15 (should be 3.6 or >),
may slow charge down to 3.0

[FreeRangeRon]

OP updated

---

Hi Ron,

Thank you for the insightful information. Have you managed to make any progress?
Our symptoms sound similar since my PBP also completely stopped charging from the barrel-port - however I managed to solve all my symptoms by using a USB-C power supply (updated OP). For some reason the power supply that came with the PBP and or barrel-port appeared to be damaged/faulty for me. Have you tried charging using the USB-C port?

Kind regards,
Carl

As above Carl, still stuggling with this one. Yes I've tried the USB-C port but also gives me the red blinking LED.

I'm gald to hear it was just a faulty power supply that was causing your issue, I hope your PBP serves you well on battery power.

Cheers,
Ron

I have seen this when I first got the pbp in the fall.  In my case,  I had taken out the battery and had  the connectors reversed when I reinstalled it.  Assuming that you didn't do that,  is it possible that  one of the connectors is damaged,  or that the battery did have the connectors reversed?   IF that were the case, though,  you still should be able to boot with the battery out and the bypass connected.

I've ruled out the battery as the cause, all the connections are fine and it's charging on an external charger without issue. The thermistor resistance is also within the expected range. The machine boots with the bypass cables inplace, but without the bypass I get the red flashing led.

I'm leaning toward the charging IC being damaged.

Thanks for your response,
Ron