Lenovo Legion 5 15ARH05H, NM-D281 Rev: 1.0 not work with the battery

[dhs6512]

Hello. Lenovo Legion 5 15ARH05H, NM-D281 Rev: 1.0 board
Initially dead. Inspection: the board was not touched, on EC IT8227E-192 2101-CXA there is a mini-burnout.
Replaced with the same one, flashed the EC with the official firmware (had to solder to the pins), left the main firmware (Gigadevice 25LB128DSIG) original.
When connecting the charger, the device started, gave picture and works, checked all the functions - ok.
Connected the original battery. Only on the battery the device starts for a second, lights up the keyboard backlight and turns off.
When connecting the charger (with the battery connected) lights up orange charge LED, AutoStart (as it should be without an RTC battery), lights up the keyboard backlight, turns off, AutoStart again and then repeats the cycle, that is, it does not want to work with the battery. I looked to see if the charger (BQ24780S) gives a PWM signal, there are pulses on the PL101 charge coil and they disappear in time with the above cycle. I think the battery is from 2020 year and threw in a new battery - same behavior. There is an EC exchange with the battery. I checked the charging circuits - I did not find anything criminal. The input mosfets PQ101, PQ102 are ok. The charger, batfet PQ103 is ok, I changed it - same behavior. Power supply original 230 watts, tried external power supply with the corresponding 4.65 kOhm resistor from ID to ground, same behavior. Please advice

[mon2]

Carefully measure the voltage to ground of each pin on the battery connector (JBATT1).

Interested in:

EC_SMCA ; pin 5
EC_SMDA ; pin 6

voltage measurements.

[dhs6512]

JBATT1: 1-4pins VMB +14,1v, 5pin EC_SMCA pulses (photo), 6pin EC_SMDA pulses (photo), 7pin BATT_TEMP_IN 0v

[mon2]

So the SMBUS lines are not shunted and are not at fault.

Disconnect the power adapter. Attach only the battery. Measure the voltage to ground on pin # 28 (Vcc) of the charger IC @ PU101.

Carefully also measure the voltage to ground on each pin of PD101 (dual common cathode diode). We are confirming if this dual diode is working properly to power the charger IC.

[dhs6512]

Charged battery (in this unnormal cycle mode) to about 15v and now voltages at PD101: 1pin 780S_VCC_R 14,74v, 2pin VIN 0,002v, 3pin BATT+ 14,93V

[dhs6512]

Measured all signals on the charger BQ24780S, comment please. Thank you.

[abobek zum]

HI,

would like to bump this topic even if its quite old. Was that issue solved ?

[mon2]

abobek zum - each case is different. Post the full details of your issues.

[abobek zum]

abobek zum - each case is different. Post the full details of your issues.

Thank you for your prompt answer.
In fact I have exactly same issue with the specific behavior included as OP so rather to create new topic I just want to ask about the status from this one. Tested on 2 different batteries ( one replacement and second one looks line original but have very few Charge/discharges count so probably is also not the original from that laptop - check by SVOD) - same effect. On other forum I found that solution was to use the Original battery.

[mon2]

Attach the pre-charged battery only; disconnect the power adapter.

Meter in DC volts (30v or higher) scale.

Measure the voltage to ground of the following points of interest:

PQ103 (battery mosfet) ; source - drain - gate pins are of interest
PQ102 (DCin mosfet) ; source - drain - gate pins are of interest
PU101 pin 28

[abobek zum]

Hi Mon2,

Here are the measurement"
PQ103 D: 16.34V, S:16,34V G:22,42V
PQ102 D: 16,34V, S: 0V G: 0V
PU101 Pin28: 16,16V

[mon2]

These are ok measurements.

Still with only the battery, review the REGN pin on the charger IC.

Next, attach the adapter and measure these points again:

PQ103 D: 16.34V, S:16,34V G:22,42V
PQ102 D: 16,34V, S: 0V G: 0V
PU101 Pin28: 16,16V

[abobek zum]

Battery only:
REGN is floating from 0.2V - 07V. If your press the PWRBTN, the MB is coming ON for split second and turining off. During this time REGN goes to 6.1V (same voltage as with charger only)

Battery plug in + charger:
PQ103 D: 20,54V, S:16,41V G:16,40V
PQ102 D: 20,44V, S: 20,44V G: 26,33V
PU101 Pin28: 19,19V

Here the boot is cycling - MB is coming ON and OFF. When I diconnected the SDA and SCL from battery (remove the PR205, PR206). I can boot this MB in this configuration, unplugin the charger and MB remains ON but if turned off it will not start with battery only. You need repeat the sequence with the charger. RTC battery is awlays not connect during this tryouts

[mon2]

RTC battery MUST be connected and must be ~3V else needs to be replaced. This is the first required step of the power on cycle on most motherboard designs.

The mosfet readings are correct. From the details so far, to me, the battery is the root cause and should be replaced with a known fresh one. If done already, test with another brand. There are many bad batteries on the market. The specs of the batteries can be faked with simple I2C tools from TI, etc. There are at least 2 companies selling devices to 'unseal' batteries, etc. To me, it is illogical to pimp up a dead battery. If the BMS locked out the battery pack, it did so for safety reasons. Forcing the BMS to come back to life again with hack tools is dangerous.

[MTT97]

I have pretty much the same issue as OP. Laptop is legion y540 15irh, boardmodel NM-C221. The EC was bad causing the +3VLP on PU601 to short to ground. Replaced EC, short gone, laptop comes back to life. But i'm now seeing a warning message on each boot that You are using a lower-wattage adapter and when battery is connected with the charger, it wont boot at all. The charger led blinking orange and power button blinking white. I removed the PD203 diode for the Adapter_ID and the low wattage adapter warning is now gone but i still cannot get the laptop to boot with battery and charger plugged in. There are voltage fluctuation when the battery and charger plugged in at the same time, i've done a lof of measurement, including some here:


Battery + charger:
780s_VCC = stable 20v / internal resistance when everything unplugged 500ohm

BQ24780S_VDD = stable 5.7v / internal resistance when everything unplugged 430ohm

PC216 780S_LX = unstable 4.3-1.6v

PC216 780S_BS_R = unstable 8-3v

PR211 780S_BS = unstable 9-3v


Battery only:
780s_VCC = stable 11v

BQ24780S_VDD = stable 5.9v

PC216 both pins = stable 11v

PR211 both pins = stable 11v


Charger only:
PC216 780S_LX = 0.2v stable

PC216 780S_BS_R = 5.6v stable

PR211 780S_BS =5.6v stable

Everything else seems to be stable

[abobek zum]

Small update. Battery is not the solution for my case. I tested with 3 different batteries.
MTT97, is your laptop starts only on battery ? Your desciption when you plugin charger and battery is the same as main.

About the warrning, you should measure the resistance on adapter pin and ground on your charger. How many Watts you should have there ?
Here are few values.
170 W ~ 1,9 kΩ

230 W ~ 4,6 kΩ

300 W ~ 8,6 kΩ

P.S you have diffrent laptop/ MB so you should probably start your own thread.

[mon2]

but i still cannot get the laptop to boot with battery and charger plugged in.

MTT97 - this usually implies that you have leaky mosfet in the power path.

Remove all power -> meter in resistance mode -> review the measurements across the 2nd DCin mosfet @ PQ102:

source / drain
source / gate
gate / drain

Post each measurement. Each should be hundreds of k ohms or higher else is likely defective and should be replaced. If found to be ok, review the other mosfets linked to the charger IC. Suggest to review PQ103 next (aka battery mosfet).

As per the charger article by piernov (see above for this sticky), often the 2nd DCin mosfet becomes defective and raises such issues. If available, flux and replace PQ102 for quick testing. These are common N-channel mosfets and may be available on assorted motherboards.

[MTT97]

Small update. Battery is not the solution for my case. I tested with 3 different batteries.
MTT97, is your laptop starts only on battery ? Your desciption when you plugin charger and battery is the same as main.

About the warrning, you should measure the resistance on adapter pin and ground on your charger. How many Watts you should have there ?
Here are few values.
170 W ~ 1,9 kΩ

230 W ~ 4,6 kΩ

300 W ~ 8,6 kΩ

P.S you have diffrent laptop/ MB so you should probably start your own thread.

The battery doesn't have enough charge to test it if the laptop works on battery only and i have no bench power supply at the moment to charge it manually. The laptop wont charge the battery either, it's just blinking orange light.

As for ADAPTER_ID, the resistance to ground measured 950ohm which was low, i then removed the PD203 diode as mentioned before and now ADAPTER_ID is measuring 6k ohm to ground.

[abobek zum]

The battery doesn't have enough charge to test it if the laptop works on battery only and i have no bench power supply at the moment to charge it manually. The laptop wont charge the battery either, it's just blinking orange light.

As for ADAPTER_ID, the resistance to ground measured 950ohm which was low, i then removed the PD203 diode as mentioned before and now ADAPTER_ID is measuring 6k ohm to ground.

I meant to measure resistance of ID pin on your charger, not on your MB. To eleminate charger.

[MTT97]

I meant to measure resistance of ID pin on your charger, not on your MB. To eleminate charger.

Two original Lenovo chargers has already been tried, 180W & a brand new 230W charger. Same result.

Edit: 180w & 230w both measured 4.6k