Strange battery present behaviour in Lenovo Legion 5-15ARH05 mb model nm-d041

[ferah831208]

Hello guys, i need help with this problem, I have a NM-D041 mobo, it came with low impedance in 3v linear regulator rail, the cause was a damaged EC controller ITE8227e-192. I ordered a new one and replaced it. This laptop have a different chip for keyboard management and it8227e pins for programming ITE chips are not accesible through keyboard interface, I flashed it using i2c interface pins with vertyanov programmer because laptop was dead and SPI flash didn't have power (only 3v EC) so it couldn't access firmware stored in SPI memory. I read SPI and extracted it8227 firmware from original BIOS chip, and laptop worked perfectly apparently. The problem is when i connect the battery, i get an orange led solid, but every 1 second or 1 second and a half it flashes, in this model according to manual charging below 90% must be solid orange without blinking. The reason why led is flashing is everytime light goes off, 3VALW and 5VALW rails and their enable signal go to 0, cycling eternally as long as battery is connected, but it charges anyway, of course slower than it should. I checked in oscilloscope clk and data in EC, bq24780s charging IC and battery pins, all looks good, traces and resistors were measured. If i try to turn it on with battery attached it turns on and turns off immediately. I tried two batteries from similar lenovo legion models, one was 3 cells and the other 4 cells with same current and voltage as original (but different battery model). With both these batteries laptop turns on but orange led flashes quickly all the time and doesn't charge the battery, but it turns on and loads OS, both battery or AC mode. Maybe Lenovo implemented a battery model check and is not compatible? i guess that could be the reason. The problem is the original battery despite this weird behavior is charging, it was really discharged but now is charged.I tested this battery in the other lenovo i had different model, same led orange blinking all the time but laptop turns on and recognize battery wear level and percent, but cannot be charged (i guess this is caused by compatibility issues). Another detail, if i attach battery without AC plugged in, vdd pin 24 linear regulator from BQ24780s oscillates all the time (normally without acdet according to datasheet it should not be enabled). I replace chip but same behavior, This is really driving me crazy and i don't have any original battery to try but something tells me is not a battery issue (i might be 100% wrong). I flashed original bios from lenovo website hoping maybe after EC updated on startup something could change but same result. Any ideas? Sorry for the long talk but i wanted to provide every detail. thanks in advance

[ferah831208]

Update on this topic, I have tested 5 different batteries, four of them are from Lenovo legion laptops that have been repaired in my workshop. Another from a regular Lenovo model. All of them have been recognized in this laptop reading All data from BMS, with different percentages of wear. The original battery of this laptop tested in any of those laptops does not charge but is recognized and and turns on perfectly, only I get permanently the orange led flashing, in the only laptop that does not turn on with the battery is in the original one that gives the fault that I explained in previous post. With other laptops the battery from this Lenovo I'm trying to fix doesn't charge (same behavior orange led flashing permanently), but all laptops work both connected to the AC and disconnected. Does anyone have information about any battery model check that Lenovo may have implemented at EC level when there is i2c communication with the BMS? I don't know what else to think 🤔🤔🤔😔

[mon2]

REGN voltage to ground is not stable @ 6v? If true, then remove all power -> meter in resistance mode -> measure the resistance (not diode mode) to ground. What is the resistance in ohms?

Checking if there is a shorted part on this rail. In past chats with TI engineering group, the local cap on this rail is important to be present.

Also interested in the voltage to ground of the following pins of interest:

PU101 ; charger IC

VCC pin 28
ACDET pin 6
ACOK pin 5

[reformatt]

Have you checked your ADAPTER_ID logic line? I'm assuming the DC jack collapsed, shorting 19V into the ADAPTER_ID line, killing the EC in the process. There is a TVS diode PD102 that should have protected it, perhaps this is shorted and your adaptor ID isn't being recognised? This would be my line of thought. Pretty beefy charger for this model at 240W.

[ferah831208]

REGN voltage to ground is not stable @ 6v? If true, then remove all power -> meter in resistance mode -> measure the resistance (not diode mode) to ground. What is the resistance in ohms?

Checking if there is a shorted part on this rail. In past chats with TI engineering group, the local cap on this rail is important to be present.

Also interested in the voltage to ground of the following pins of interest:

PU101 ; charger IC

VCC pin 28
ACDET pin 6
ACOK pin 5

Voltage to ground is stable when i plug ac connector, the weird thing is when battery is attached (without ac power supply), regn is cycling on off all the time, in theory regn only ia active when vcc is above UVLO, and acdet pin is above 0.6V, that of course it is not when ac is not connected, that's why i changed the bq24780s but same result. When i try to turn on the laptop with the battery it turns on and off quickly. With other batteries it turns on (but if i plug they don't charge), battery may be damaged but if i plug this battery in another model of lenovo, is not charged, but in those laptops battery only laptop turns on, only with the original laptop it turns on and off immediately. I checked all senses with this battery and the other ones and got same voltage readings. Im really out of ideas. If i connect battery and transformer, it charges but intermittent all the time (remember 3valw enable is cycling), but in this moment i have stable readings on acdet, regn, acok, and vdd. EC powers from 3vlinear regulator rail, so that's not the reason for enable 3alw intermittency. The schematic only provides power sequence for AC mode, not for DC mode, i know it changes and maybe have a power sequence issue when iin DC mode, not sure about this, only crazy thinking. I have another doubt, if pin regn needs acdet to be above .6v, why if i plug the battery from another laptop, it doesn't gets active, but after i press power button this rail is active, i guess that's logic because with laptop working this regn must be stable (or not, not so sure about this), but there is a weird difference from other batteries and this one with this pin behavior. Info u requested:
REGN resistance ----- 34K, cap is perfect i measured it.
AC mode not battery present:
ACDET---- 2.65V ACOK--.3V VDD --20V
Original battery attached without AC plugged:
REGN pulsing up to 2V
ACDET 0V ACOK 0V VDD 16.7V (Batery is charged in this same laptop)
AC plugged and Battery attached:
regn 6.08V stable, acok 3.3v, acdet 2.65V, 3vALW and 5Valw turns on and off responding to enable signal for this rails from EC.

I don't understand what happened in the first pace with this laptop, charger wasn't manipulated (typical in this plug technicians connect 19v rail to ID and EC burns, wasn't the case). Batery connector came with one plastic corner broken, somebody measured and disconnected the battery after laptop turned off, maybe they shorted data or clock pins to BAT++ ??? only thinking about why EC got damaged, and if this happened maybe battery also was damaged, but confusion is because t works in a diferent model at evidently is not compatible because is not charged. Don't have more ideas

[ferah831208]

Have you checked your ADAPTER_ID logic line? I'm assuming the DC jack collapsed, shorting 19V into the ADAPTER_ID line, killing the EC in the process. There is a TVS diode PD102 that should have protected it, perhaps this is shorted and your adaptor ID isn't being recognised? This would be my line of thought. Pretty beefy charger for this model at 240W.

was my first thought but negative, charger is ok, id line is perfect, i have a theory about why EC was damaged but it could be also bad luck

[mon2]

The ACOK is not ok when using only the power adapter. Measure this signal again with only the power adapter.

[ferah831208]

The ACOK is not ok when using only the power adapter. Measure this signal again with only the power adapter.

i think there was a misunderstanding , is not .3v (like 0.3v), it is 3v like in high level, that's why I meant. Sorry for the confusion.

[reformatt]

My inclination is to re-examine the EC, as it does communicate with the BQ chip via SMBUS. Quick look on Alixpress, there are two variations of the IT8227E with 192kb firmware, BXA and CXA. Confirm you have the right one and go over each pins soldering with a fine tooth comb. Check your SMBUS lines as well.

[ferah831208]

[QUOTE=reformatt;n3598658]My inclination is to re-examine the EC, as it does communicate with the BQ chip via SMBUS. Quick look on Alixpress, there are two variations of the IT8227E with 192kb firmware, BXA and CXA. Confirm you have the right one and go over each pins soldering with a fine tooth comb. Check your SMBUS lines as well.[/QUOTE
Hmmmm 🤔🤔🤔, haven't really noticed about the detail of BXA or CXA, only checked it was 192kb firmware version 😐😐😐, pins are tripled checked under the microscope and smbus communication looks OK on the oscilloscope, I will check about EC version and let u know, haven't noticed that detail 😔

[ferah831208]

Chip is it8227-192 CXA same as original 😐, of course always could be a faulty chip, I ordered it in AliExpress from a rated seller where I always order chips for repairs, but that can be a possibility, maybe I will order another one but I'm doubtful

[ledro]

I have the same problem after replacing it8227 on the same laptop model.
it would seem that it8227 bought from aliexpress is not ok,
I found on a forum that it doesn't read the battery temperature correctly, it says the battery is very hot and turns off.
with an it8227 taken from another functional laptop, it works without problems, only with the it8227 from aliexpress it causes problems

[ferah831208]

Uffff that's really not a good news 😔, but at the same time that's really enlightening , do u remember the forum?? Maybe I can dig for more info, I don't have a scrap for this, and now I'm doubtful about ordering again and having same issue. I will need to check again how temp batt is measured, but at the end if there is a microcontroller issue or incompatibility that's not something that can be fixed. It's definitely not a firmware problem, what u say I imagine is some misbehavior at registry level when reading battery BMS through smbus 😐😐. Do u know any other suppliers for this chip that maybe are guaranteed?? Thanks for the help

[ferah831208]

Update on this topic. I finally managed to fix the laptop after lot of research. I found the best info in Vertyanov's support telegram chat. For some reason nobody knows for sure, there is an issue with this series of ITE chips, but apparently they have this strange behavior in Lenovo laptops. The problem is related to a tag the chip must have (L005, L003, etc) at the bottom after all the numbers, I don't know if this is related to some special code or verification they include at the factory or what, but there is a table where u can find which tags are tested in specific motherboards so u can buy that chip directly without passing through this nightmare. Chips without that tag don't work with battery, other technicians had same problem, I ordered for this model it8227-192 in AliExpress, I spoke to the seller and he confirmed it had L005 tag and it worked perfectly. So if you don't find a scrap board you need to take notice about this specific detail (original chip had same L005 tag).