BTO/CLEVO P950ER repair help needed :)

[revex666]

Goodday,
I have a BTO/CLEVO P950ER. The laptop is not powering on and no lights are burning when the adapter is plugged in.
Since I'm new to motherboard repairs (I did a few basic MOSFET replacements and capacitors that were obviously broken) Fault finding and identifying which components might be broken is quite difficult jet. I took the motherboard out of the laptop and started measuring this is what I found so far:
- Power in = 19V
- No voltage to battery pins
- ACDRV no voltage
- REGN no voltage
- ACN and ACP shorted to ground
- PC62 PC63 PC64 shorted to ground
- PC48 no voltage
- PR82 no voltage
- PD16 (C) was at first 19V and later 1.5V
At a certain moment, I realized that something else was going on. I measured PD16 again and here was only 1.5V (not stable). I went back to pin 1 of the DC_Jack and here there was no voltage anymore (fluctuating between a few mV's), while, when plugged out the adapter is giving 19V also PQ19 and PQ20 are getting warm. Drain PQ20 no continuity to ground. Am I right to assume PQ20 is faulty and should be replaced or is something else going on?
looking forward to hearing/learning more

[Techtiger]

Re: BTO/CLEVO P950ER repair help needed

Check the resistance to ground Diode mode PQ 19 PQ20 PQ25

[mon2]

Re: BTO/CLEVO P950ER repair help needed

- PD16 (C) was at first 19V and later 1.5V

So most likely PD16 is now damaged due to an excessive current draw.

Remove all power. Meter in diode mode.

Red meter probe on back of the arrowhead (anode); black to the front common cathode (cathode). The meter should show a low voltage reading = conducts.

Reverse the meter leads and the meter should show 'OL' to block in this direction.

Repeat with the other side of the dual diode for similar tests.

Do check the RESISTANCE to ground of the common cathode on this part. This cathode is used to power the battery charger IC and should be ~19v since it is a raw feed from the DC power adapter.

[revex666]

Re: BTO/CLEVO P950ER repair help needed

thanks for the quick reply:
PQ19 = drain to ground 2,8
PQ20 = OL
PQ25 = i can not find since i dont have a boardview. However i suspect it is the one in the attached picture and that one is 2,7 for drain to ground

[revex666]

Re: BTO/CLEVO P950ER repair help needed

So most likely PD16 is now damaged due to an excessive current draw.

Remove all power. Meter in diode mode.

Red meter probe on back of the arrowhead (anode); black to the front common cathode (cathode). The meter should show a low voltage reading = conducts.

Reverse the meter leads and the meter should show 'OL' to block in this direction.

Repeat with the other side of the dual diode for similar tests.

Do check the RESISTANCE to ground of the common cathode on this part. This cathode is used to power the battery charger IC and should be ~19v since it is a raw feed from the DC power adapter.

thanks for your help/response. Attached is a picture of how i measured on PD16 and 17. in both directions and on both diodes there meter gives OL. When switching meter to resistance and measuring to ground the reading starts around 1.3Mohm and is increasing

[revex666]

Re: BTO/CLEVO P950ER repair help needed

i made a stupid mistake PD16 = 0.605V and OL and PD17 = 0.610V and OL

[mon2]

Re: BTO/CLEVO P950ER repair help needed

Connect the power adapter and then carefully measure the voltage to ground of each pin on pd16. Post the measurements.

[revex666]

Re: BTO/CLEVO P950ER repair help needed

thanks again for your response. I measured on anode site 0.2 to 1.6V, it is jumping around. on cathode stable ~1.5V

[mon2]

Re: BTO/CLEVO P950ER repair help needed

As per post #2, meter in resistance mode.

No power to the logic board.

Measure the resistance to ground on pq20 drain pins.

If the resistance is low, the power adapter is being shorted. If the resistance is ok, check the voltage to ground at the pq20 drain pins. Also direct at the adapter connector.

[Techtiger]

Re: BTO/CLEVO P950ER repair help needed

Check the resistance to ground Diode mode PQ 19 PQ20 PQ25

What voltage do you get PQ 20 Drain side ? Is it fluctuating ? Based on the readings you have given
PQ19:
source (1-2-3) & drain (5-6-7-8) = 387k
source (1-2-3) & gate (4) = 8.7 OHM
gate (4) & drain (5-6-7-8) = 387k

PQ20:
source (1-2-3) & drain (5-6-7-8) = OL
source (1-2-3) & gate (4) = 4ohm
gate (4) & drain (5-6-7-8) = OL

I would recommend removing PQ 20 from the MB test it again Diode mode after
remove PQ20 do the same test don’t mix them important

[revex666]

Re: BTO/CLEVO P950ER repair help needed

i removed the MOSFET:
Measured resistance in DIODE mode
PQ19:
source (1-2-3) & drain (5-6-7-8) = OL
source (1-2-3) & gate (4) = OL
gate (4) & drain (5-6-7-8) = OL
drain to ground = 3.4ohm

PQ20:
source (1-2-3) & drain (5-6-7-8) = 0.3 ohm
source (1-2-3) & gate (4) = 4 ohm
gate (4) & drain (5-6-7-8) = 4.2 ohm

PQ20 drain pads to ground OL in diodemode

[Techtiger]

Re: BTO/CLEVO P950ER repair help needed

i removed the MOSFET:
Measured resistance in DIODE mode
PQ19:
source (1-2-3) & drain (5-6-7-8) = OL
source (1-2-3) & gate (4) = OL
gate (4) & drain (5-6-7-8) = OL
drain to ground = 3.4ohm

PQ20:
source (1-2-3) & drain (5-6-7-8) = 0.3 ohm
source (1-2-3) & gate (4) = 4 ohm
gate (4) & drain (5-6-7-8) = 4.2 ohm

PQ20 drain pads to ground OL in diodemode

Replace PQ20 and updated

[revex666]

Re: BTO/CLEVO P950ER repair help needed

what are the general rules in regards to replacing MOSFETS? Exactly the same specs (i presume yes)? Or are slight deviations also okay?

For now, i have an AON6372 with almost the same specs (Original MDU1512), is that oke or better order an identical?

[mon2]

Re: BTO/CLEVO P950ER repair help needed

The replacement should be ok.

1) same size = 5*6
2) same style (not Harry) = N-channel
3) same or higher voltage range source / drain = 30V
4) same or higher Id current support = 100A on original and is 47A-90A on the replacement. Should be ok.

[revex666]

Re: BTO/CLEVO P950ER repair help needed

I replaced PQ20 still the same problems in regards to Voltage. PQ19 was still getting hot so just to be sure i also replaced that one. here are the new measurements in diode mode tested

PQ19:
source (1-2-3) & drain (5-6-7-8) = OL
source (1-2-3) & gate (4) = 5.7 OHM
gate (4) & drain (5-6-7-8) = OL
drain to ground = 3.5 ohm

PQ20:
source (1-2-3) & drain (5-6-7-8) = 0.3ohm
source (1-2-3) & gate (4) = 1 ohm
gate (4) & drain (5-6-7-8) = 1.2 ohm
drain to ground = OL

[mon2]

Re: BTO/CLEVO P950ER repair help needed

These are very low resistance readings or the meter is in a different scale. Can you confirm the resistance scale on your meter used for these tests? Better if you post a pic of the meter face.

[revex666]

Re: BTO/CLEVO P950ER repair help needed

Hearby the pictures

[mon2]

Re: BTO/CLEVO P950ER repair help needed

These are low readings. Suggest to flux well and remove the mosfet. Wait till the mosfet is cool and then test the mosfet while it is off the logic board. If you see similar measurements then the mosfet is defective. Then measure the other mosfet without this one installed on the board. If you see low resistance on the other mosfet, then it too should be fluxed and removed to isolate the root cause of these low readings.

[revex666]

Re: BTO/CLEVO P950ER repair help needed

So MOSFET is of again and low reading are still present om pq20.
Pq19 when installed
drain source = 3.057mohm
Source gate = 3.888mohm
Gate drain = 5.87mohm

These readings seemed better so I replaced pq20 again with an other MOSFET and the power is back on the mainline.
So now the original problem remains

[mon2]

Re: BTO/CLEVO P950ER repair help needed

Remove all power. Measure the resistance to ground of ACN and ACP (as per post #2). If this main power rail is with a low resistance, someone is shorted.

Post the resistance measurement.