Dell Inspiron 7567 LA-D993P odd charger issue

[Johndill]

Hi, I have a Dell Inspiron 7567 LA-D993P that I've just got running.
There was corrosion around PU1503 which shorted PC1518 & blew PL1504. (Reference pictures attached)
I've replaced PC1518 & PL1504 & the laptop is now running however I now have another issue.

Here are the tested scenarios:

1. With the laptop running on battery, I plug in the 150W charger & the charger shuts off (no LED, protection mode) but the laptop remains running on battery.

2. With the laptop off, plug in charger (LED says on) & the front charging LED says it's charging. Turn laptop on & open bios battery settings, charger is detected & says charging (but it's not charging).
Unplug charger, switches to battery, plug charger in, charger LED goes out (protection mode).

3. Same test but with a 240W charger, laptop turned on, plug in 240W charger, laptop says charging but percentage does not move over time, the 240W does not trip out.
4. Any charger can run the laptop without the battery connected.

It seems as though the charging circuit has a partial short drawing too much Amps or something & tripping the lower wattage chargers?

Any ideas what could be happening?
I've just read @piernov "Laptop battery charging circuit" thread which is amazing but I'm not quite sure where my case fits. Thanks :-)

[mon2]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Remove all power. Meter in resistance mode.

Check the resistance across the mosfet pins.

Review mosfets pq301, pq302 and pq306.

Source & drain
Source & gate
Gate & drain

Post each measurement of each mosfet.

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

PQ301:
Source & drain - 0.4 ohm
Source & gate - 0.425K ohm
Gate & drain - 0.425K ohm

PQ302:
Source & drain - 11.5M ohm - 120K ohm with probes reversed.
Source & gate - 8.6M ohm - 120K ohm with probes reversed.
Gate & drain - 0.430K ohm

PQ306:
Source & drain - 0.4 ohm
Source & gate - 0.434K ohm
Gate & drain - 0.435K ohm

[mon2]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

At least one of these mosfets is leaking. The resistance values are low.

With care, remove mosfet pq306 and take the measurements again of the removed mosfet.

Also measure the mosfets again that are on the board for the dcin side. Are the readings higher now that pq306 is removed?

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

PQ301:
Source & drain - 0.4 ohm
Source & gate - 7.1K ohm
Gate & drain - 7.1K ohm

PQ302:
Source & drain - 220K ohm
Source & gate - 220K ohm
Gate & drain - 7.1K ohm

PQ306 (off the board):
Source & drain - O.L
Source & gate - O.L
Gate & drain - O.L

[mon2]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Still with low resistance readings.

Remove mosfet at pq301 and measure the resistance again.

[mcplslg123]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Resistance on PR302??

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Still with low resistance readings.

Remove mosfet at pq301 and measure the resistance again.

Q301 (off the board)
Source & drain - 0.2 ohm
Source & gate - 7.6K ohm
Gate & drain - 7.6K ohm

PQ302 - all in the M ohm range

Resistance on PR302??

PR302 - 0.1 ohm

[mcplslg123]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

You have a clear cut short to ground on CLR(PR302).

Remove the CLR and verify both the pads for resistance again. The side which is shorted, inject 1V there. You may increase the amps but voltage should'nt exceed 1V. Observe the amps consumed and look for hot component after injecting 1V for few minutes.

You need a dc supply/shortkiller to do this.

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

You have a clear cut short to ground on CLR(PR302).

Remove the CLR and verify both the pads for resistance again. The side which is shorted, inject 1V there. You may increase the amps but voltage should'nt exceed 1V. Observe the amps consumed and look for hot component after injecting 1V for few minutes.

You need a dc supply/shortkiller to do this.

Sorry, that's a mistake, PR302 to ground is 30M ohms. :-)
I mistakenly measured across as I was with the mosfets.

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

PQ301 (off the board)
Source & drain - 0.2 ohm
Source & gate - 7.6K ohm
Gate & drain - 7.6K ohm

PQ302 - all in the M ohm range

Does this mean PQ301 is the fault? :-D

[mon2]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Pq302 readings are now ok.

Q301 (off the board)
Source & drain - 0.2 ohm
Source & gate - 7.6K ohm
Gate & drain - 7.6K ohm

These are the measurements of pq301 while it is off the logic board and on your work table? Or these are the measurements of the pcb pads where this mosfet was removed?

The readings are very low and indicate a short.

[mcplslg123]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Sorry, that's a mistake, PR302 to ground is 30M ohms. :-)
I mistakenly measured across as I was with the mosfets.

Ok, so no question of voltage injection. PQ301 readings looks bad. Confirm what @mon2 has asked.

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Yes, measurement of PQ301 component itself on my workbench. :-)

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

I have an LA-C912P doner board (schematic attached). Is PQ707 on the doner board a good replacement for PQ301? :-)

[mon2]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Thanks.

Pq301 is for sure defective. Replace it and check the resistance again for these mosfets.

Datasheet for the donor mosfet pq307 is attached.

Yes, the donor mosfet is suitable and actually a better part than the original.

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Thanks.

Pq301 is for sure defective. Replace it and check the resistance again for these mosfets.

Datasheet for the donor mosfet pq307 is attached.

Yes, the donor mosfet is suitable and actually a better part than the original.

Thanks, PQ301 is replaced with the donor & PQ306 re-installed. All mosfet mesurements are in the Mega ohms. Good to test? :-)

[mon2]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Confirm the clr resistance to ground is not super low. This is the main power rail that powers the logic board.

After this test, yes, power up to test again.

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

PR302 is around 15M ohms. :-)

[Johndill]

Re: Dell Inspiron 7567 LA-D993P odd charger issue

Yes! It is charging & the percentage is going up! :-D
We did it! Thank you so much for your assistance. Another laptop saved. :-D
It currently at 42% now.