lenovo yoga 2 13 Check this Out?

[dj_ricoh]

Re: lenovo yoga 2 13 Check this Out?

Remove pu301 and do a resistence check on pads.
If there is no short replace it.

[lorins_core]

Re: lenovo yoga 2 13 Check this Out?

The voltage injected needs to be 1.5v or lower

Would you Teach me. where parts To inject the 1.5V nor

Which on the PU301 nO of PIN. i put or Inject the 1.5V

Thanks

Although. I have BQ24727 IC. It is Compatible?

[lorins_core]

Re: lenovo yoga 2 13 Check this Out?

I have BQ24727 IC. It is Compatible?

[dj_ricoh]

Re: lenovo yoga 2 13 Check this Out?

Lift pu301
Then use dmm and do a ohm check on each pads.
Not on IC on the motherboard pads.

[lorins_core]

Re: lenovo yoga 2 13 Check this Out?

Lift pu301
Then use dmm and do a ohm check on each pads.
Not on IC on the motherboard pads.

Thanks Man. I Try it later...

[flankerzo]

Re: lenovo yoga 2 13 Check this Out?

Thanks Man. I Try it later...

hi, have you solve problem? i have similiar problem, but my blown cap was filtering LCD backlight voltage C1159, 4u7 25v. and i came to similair conclusion about PU301 / BQ24715.
I can see voltago on VIN to ACDET pin6, but no voltage on pin5 ACOK, ic is getting power on VCC. On bad mothebord, there is 10V on PQ101 pins 2and3.

I also have secon motheboard that is OK but with lover HW specs, and on that board on PU301 pin 5, there is 2,5V, and i dont have voltage on PQ101 pins 2and3.

im gonna atempt transplantation

[flankerzo]

Re: lenovo yoga 2 13 Check this Out?

i transplant P301 from good board to bad, well, it started heating PU401 , i have it on bench supply with current limiter to 300ma, nothing blow, but it started clipping. after 30 sec it stopped clipping and PU301 is dead again.
I traced 10ohm short on +3VLP, i tried remove reset circuit, L38 coil, and after removing KB9012QF A4 short was gone, yeah, this one needs programing .... ordering supplies from aliexress

[stingerchamp]

Re: lenovo yoga 2 13 Check this Out?

Hi ,

i have seen this fault in many boards , if mosfets are OK out of board then

, this occurs due to sensing resistor value (resistance value) increases to
OL( out of range)

We have 3 sensing lines in this motherboard

ACP
ACN
CMSRC

whether you are getting REGN6V out but ACDRV will be generated when you get signal from CMSRC and in CMSRC mid way we have a resistor. check resistance of that resistor you will get high resistance even OL, change that resistor and you will get high voltage at gate for ACDRV signal.

[flankerzo]

Re: lenovo yoga 2 13 Check this Out?

Hi ,

i have seen this fault in many boards , if mosfets are OK out of board then

, this occurs due to sensing resistor value (resistance value) increases to
OL( out of range)

We have 3 sensing lines in this motherboard

ACP
ACN
CMSRC

whether you are getting REGN6V out but ACDRV will be generated when you get signal from CMSRC and in CMSRC mid way we have a resistor. check resistance of that resistor you will get high resistance even OL, change that resistor and you will get high voltage at gate for ACDRV signal.

i didnt foresee this witchcraft, i will check them and report thanks for tip
i still need to wait for two IOs from china

[flankerzo]

Re: lenovo yoga 2 13 Check this Out?

checked resistors, they are okay

[flankerzo]

Re: lenovo yoga 2 13 Check this Out?

It ended on no signal from CPU leg, well ..., i tried, i got voltages on everything, i may messed up and shorted it

[REpairAT]

Re: lenovo yoga 2 13 Check this Out?

Hi,
got the same notebook, same problem.
Faulty parts replaced so far:
- this blown cap (replaced by 10µf 25V)
- PU301 BQ24715
- PQ306 AON7508
All of them were clearly faulty. Now, notebook runs on battery but does not charge. If I disconnect the battery and try to power on with charger only, power light comes on for around 1sec but goes off again. So clearly the 20V power rail is present also on charger only. MOSFETs all fine, also resistors around PU301 have right value. Any more suggestions?

Thanks!

[mon2]

Re: lenovo yoga 2 13 Check this Out?

On PU301, measure (with care), the voltage of:

REGN
ACDRV

which are common to 'BQ' series charger ICs. Have the adapter connected (only) so we can confirm the BQ charger IC is being powered and able to boost the gate voltage to drive and enable the N-channel mosfets.

[REpairAT]

Re: lenovo yoga 2 13 Check this Out?

On PU301, measure (with care), the voltage of:

REGN
ACDRV

which are common to 'BQ' series charger ICs. Have the adapter connected (only) so we can confirm the BQ charger IC is being powered and able to boost the gate voltage to drive and enable the N-channel mosfets.

Thanks for the quick reply!
ACDRV looks fine with 25V, REGN measures 0.

[mon2]

Re: lenovo yoga 2 13 Check this Out?

REGN measures 0.

Not a good voltage. Check again as this must be ok since the ACDRV is a boosted voltage. Check at the IC pin to be sure. Should be ~6 volts.

[REpairAT]

Re: lenovo yoga 2 13 Check this Out?

Not a good voltage. Check again as this must be ok since the ACDRV is a boosted voltage. Check at the IC pin to be sure. Should be ~6 volts.

True, my mistake. Beautiful 6.00V straight.

[mon2]

Re: lenovo yoga 2 13 Check this Out?

Ok. So the charger IC appears to be ok (so far).

The boosted voltage will be used by the gate of the DCin mosfets to power the logic board.

Remove all power. Meter in resistance mode.

Check the resistance across the DCin mosfets that are driven by this ACDRV signal (often with a ~4k series resistor).

Check:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)


Post each measurement. Often the 2nd mosfet in the power path from the external power adapter gets damaged. The resistance checks will confirm this fault. Respectively, if the resistance is low, the mosfet should be replaced.

[REpairAT]

Re: lenovo yoga 2 13 Check this Out?

Ok. So the charger IC appears to be ok (so far).

The boosted voltage will be used by the gate of the DCin mosfets to power the logic board.

Remove all power. Meter in resistance mode.

Check the resistance across the DCin mosfets that are driven by this ACDRV signal (often with a ~4k series resistor).

Check:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)


Post each measurement. Often the 2nd mosfet in the power path from the external power adapter gets damaged. The resistance checks will confirm this fault. Respectively, if the resistance is low, the mosfet should be replaced.

PQ301 (Primary)
S/D 3,76MOhm
S/G 3,180MOhm
G/D 4,60MOhm

PQ302 (Secondary)
S/D 20MOhm
S/G 3,172 MOhm
G/D 10MOhm (rising)

[mon2]

Re: lenovo yoga 2 13 Check this Out?

Resistance is fine. Remove the battery. Does the logic board function ok with only the adapter ? That is, the DCin voltage should travel onto the main power rail since the mosfets are OK and the ACDRV is a good voltage to enable each.

After this confirmation.

Locate the other mosfets that will be nearby the PU301 charger IC.

There will be the HIGH & LOW side mosfets that are responsible to lower this ~19v down to a safe level to charge the battery pack.

Once these mosfets are found -> remove all power -> check resistance across each of the mosfets in the same way as above.

Each mosfet linked to the PU301 charger IC is a suspect and must be checked.

[REpairAT]

Re: lenovo yoga 2 13 Check this Out?

Resistance is fine. Remove the battery. Does the logic board function ok with only the adapter ? That is, the DCin voltage should travel onto the main power rail since the mosfets are OK and the ACDRV is a good voltage to enable each.

After this confirmation.

Locate the other mosfets that will be nearby the PU301 charger IC.

There will be the HIGH & LOW side mosfets that are responsible to lower this ~19v down to a safe level to charge the battery pack.

Once these mosfets are found -> remove all power -> check resistance across each of the mosfets in the same way as above.

Each mosfet linked to the PU301 charger IC is a suspect and must be checked.

Thanks for your assistance, job is done! In fact, the replaced BQ715 still had an issue, probably damaged again because I found the short battery mosfet only after the IC replacement. Ordered new BQ715, now all works like charm.