Lenovo Yoga 510 no power!

[Ariu]

I have a problem with a lenovo Yoga 510 that is not turning on.
The dc jack is taking power (20v) and no short to the first and 2. mosfet.

The first mosfet has 20v on source but no voltage on drain and gate.
Replacing the mosfets didn't resolve the problem



Please help.

[mon2]

Re: Lenovo Yoga 510 no power!

Post the resistance to ground of +19V_P2. Remove all power. Meter in resistance mode (2k). Check these s location first. In general, check the resistance of each coil to ground. Looking for very low values.

[Ariu]

Re: Lenovo Yoga 510 no power!

Post the resistance to ground of +19V_P2. Remove all power. Meter in resistance mode (2k). Check these s location first. In general, check the resistance of each coil to ground. Looking for very low values.

The resistance of +19V_P2 is not really readable, is changing permanent his value between kohm and mohm.

Coil PLI1004 is showing 6,3ohm and PLI1003 (9ohm)

[mon2]

Re: Lenovo Yoga 510 no power!

Ok. Post the voltage readings of pins 1, 2, 3, 4 and also 18 of the charger ic @ PU301.

[Ariu]

Re: Lenovo Yoga 510 no power!

Ok. Post the voltage readings of pins 1, 2, 3, 4 and also 18 of the charger ic @ PU301.

Pin 1 -> 2,3V
Pin 2 -> 3,1V
Pin 3,4 -> 0 V
Pin 18 -> 20,21V

[mon2]

Re: Lenovo Yoga 510 no power!

Pin 3,4 -> 0 V

Not good. This implies the +3VALW rail is not working which is required to pull-up these open-drain I2C bus interface lines.

Post the voltage @ PL402. See attached.

If this voltage is 0v or not +3v3 then remove all power -> meter in resistance mode (2k is ok).

Red meter probe on PL402 coil (either side is ok); black meter probe to ground.

What is the resistance ? This part of the circuit appears to be a very common failure on the logic board. Often one of the caps in the attachment fails but confirm the resistance to ground first.

[Ariu]

Re: Lenovo Yoga 510 no power!

Not good. This implies the +3VALW rail is not working which is required to pull-up these open-drain I2C bus interface lines.

Post the voltage @ PL402. See attached.

If this voltage is 0v or not +3v3 then remove all power -> meter in resistance mode (2k is ok).

Red meter probe on PL402 coil (either side is ok); black meter probe to ground.

What is the resistance ? This part of the circuit appears to be a very common failure on the logic board. Often one of the caps in the attachment fails but confirm the resistance to ground first.

The resistance on PL402(32,92 kohm) is to high for the 3,3V Rail. and the voltage is 0V.

[mon2]

Re: Lenovo Yoga 510 no power!

Resistance is good so no bad cap on PL402 rail.

Post the voltages @

ENLDO_3V5V
5V_3V_EN
PL401
+3VL (pin 17) of PU401

[Ariu]

Re: Lenovo Yoga 510 no power!

resistance is good so no bad cap on pl402 rail.

Post the voltages @

enldo_3v5v
5v_3v_en
pl401
+3vl (pin 17) of pu401

enldo_3v5v -> 0,72 v
5v_3v_en -> 0v
+3vl -> 0v

[mon2]

Re: Lenovo Yoga 510 no power!

What about PL401 ?

Remove all power. Check the resistance to ground on enldo_3v5v.

See attached. Post the voltage at the request point of interest.

You may have a bad cap or the resistor is damaged that should just pass the voltage to enable the LDO rail.

Confirm the resistance (NO POWER to the logic board) for:

PR407
PR408

These resistors form a voltage divider to lower the rather high 19v from the DC adapter to a safe voltage to act as the ENABLE signal. Presently the voltage is too low to enable the LDO of PU401 PU402.

[Ariu]

Re: Lenovo Yoga 510 no power!

What about PL401 ?

Remove all power. Check the resistance to ground on enldo_3v5v.

See attached. Post the voltage at the request point of interest.

You may have a bad cap or the resistor is damaged that should just pass the voltage to enable the LDO rail.

Confirm the resistance (NO POWER to the logic board) for:

PR407
PR408

These resistors form a voltage divider to lower the rather high 19v from the DC adapter to a safe voltage to act as the ENABLE signal. Presently the voltage is too low to enable the LDO of PU401 PU402.

Sorry

PL401 ->7,64V

[mon2]

Re: Lenovo Yoga 510 no power!

PL401 ->7,64V

That is very low. Remove all power & battery. Use only the DC adapter.

You should see ~19V here. Can you confirm ? This is the B+ rail so it should be ~19V.

[Ariu]

Re: Lenovo Yoga 510 no power!

That is very low. Remove all power & battery. Use only the DC adapter.

You should see ~19V here. Can you confirm ? This is the B+ rail so it should be ~19V.

I know that is to low, I'm using only the adapter no battery connected.

The Resistance of pr407 and pr408 are ok, the voltage on pr407 is not always the same between 2,4V-3,1 V, its the same voltage as on +19V_P2

What can be the reason of that non constant Resistance on +19V_P2 , i think because of that the first mosfet is not passing the voltage to drain ...

[mon2]

Re: Lenovo Yoga 510 no power!

the voltage on pr407 is not always the same between 2,4V-3,1 V

Which pin on PR407 shows this voltage ? @ pin # 2 ? That is a good voltage if on pin # 2.

But then it is 0,72 v on PU401 & PU402, pin # 11 (enldo_3v5v)? Confirm it.

its the same voltage as on +19V_P2

Is this comment on PR407, pin #1 ?

Remove all power. Check the resistance to ground on enldo_3v5v.

[Ariu]

Re: Lenovo Yoga 510 no power!

Which pin on PR407 shows this voltage ? @ pin # 2 ? That is a good voltage if on pin # 2.

But then it is 0,72 v on PU401 & PU402, pin # 11 (enldo_3v5v)? Confirm it.



Is this comment on PR407, pin #1 ?


Remove all power. Check the resistance to ground on enldo_3v5v.

Yes the voltage on pin #1 pr407 is between 2,4V-3,1V

[mon2]

Re: Lenovo Yoga 510 no power!

Remove all power.

Meter in resistance mode (2k scale is fine).

Check and post the resistance for each of the first 2 mosfets as follows:

Source (1-2-3) & Drain (5-6-7-8)
Source (1-2-3) & Gate (4)
Gate (4) & Drain (5-6-7-8)

Measure and post the resistance readings for PQ302 and also for PQ303.

[Ariu]

Re: Lenovo Yoga 510 no power!

Remove all power.

Meter in resistance mode (2k scale is fine).

Check and post the resistance for each of the first 2 mosfets as follows:

Source (1-2-3) & Drain (5-6-7-8)
Source (1-2-3) & Gate (4)
Gate (4) & Drain (5-6-7-8)

Measure and post the resistance readings for PQ302 and also for PQ303.

PQ302

Source (1-2-3) & Drain (5-6-7-8) -> 1,2Mohm
Source (1-2-3) & Gate (4) -> 4,9Mohm
Gate (4) & Drain (5-6-7-8) -> O.L

PQ303

Source (1-2-3) & Drain (5-6-7-8) -> 1,1Mohm
Source (1-2-3) & Gate (4) -> 4,8Mohm
Gate (4) & Drain (5-6-7-8) -> O.L

[mon2]

Re: Lenovo Yoga 510 no power!

Good readings.

What is the voltage on pin # 4 (GATE) of these mosfets ?

Apply the external 19v power adapter and check the voltage on the GATE. They share the connection so will be the same on both devices.

[Ariu]

Re: Lenovo Yoga 510 no power!

Good readings.

What is the voltage on pin # 4 (GATE) of these mosfets ?

Apply the external 19v power adapter and check the voltage on the GATE. They share the connection so will be the same on both devices.

yes they share the connection and on both gates no voltage 0V...
sometimes only 0,1V on both pins

[mon2]

Re: Lenovo Yoga 510 no power!

1) Check and post the resistance (no power to the board) for the other mosfets. See attached. Still checking to see if there are any damaged mosfets.

2) For the first 2 mosfets (N-channel), the GATE voltage needs to be higher than the voltage being passed through to enable.

3) Suspecting that the charger IC is damaged and needs to be replaced but check for possible mosfet damage.

This Intersil charger IC is available from Digikey (and a few other vendors):

https://www.digikey.ca/en/products/d...ource=octopart

https://www.findchips.com/detail/isl...ion?quantity=1

4) Do check the voltage on the OTHER side of PR307 which is driving the gate. Is the voltage there also ~0V ?