Alienware m15 r6 not charging.

[flyhotstuff]

I bought this laptop sometime ago with an issue of it not detecting the battery but would work only with the charger, eventually, I found the problem was a missing resistor and replaced it and fixed the trace to it, it would detect the battery, but it would still not charge, it would detect the charger but fake charge. I recently moved so I did not have my regular microscope, I used a digital microscope I had to reflow/retouch the contacts of PUB1 which is an ISL95522A. I did not realise that I had bridged pins 16 and 17 and when connected to the charger, it blew the IC and the 10a (PRB13) resistor next to it. Replaced resistor and ISL95522A, laptop turns on with battery but not with charger. The charger is detected but not charging.

I have 19v at the first two MOSFETs at VIN but only 3.7/8 volts after them and to the next two MOSFETs. I have 4.7v at the gate. I replaced the MOSFETs, but there has been no change. I can't find any shorts. with the battery inserted, I get 10.5 volts at the 2nd MOSFETs.

attached is the link to the schematic and board view

https://www.badcaps.net/forum/troubl...la-k452p-gdp50
https://www.badcaps.net/forum/troubl...ll-la-k455p

[mon2]

Attach only the power adapter. Meter in DC volts mode (20v or higher scale if manual meter type).

Measure the voltage to ground on each pin of PDB2. Post each measurement.

[flyhotstuff]

Attach only the power adapter. Meter in DC volts mode (20v or higher scale if manual meter type).

Measure the voltage to ground on each pin of PDB2. Post each measurement.

on PDB2 I have:

Pin 1= 19.12v
Pin 2= 19.48v
Pin 3= 175mv

and my bad, I bridged pins 17 and 18 on the ISL95522A. not 16 and 17. I have 5.1v on VDD_CHG on pin 18 and 19V on pin 17 DCIN_CHG

[flyhotstuff]

Attach only the power adapter. Meter in DC volts mode (20v or higher scale if manual meter type).

Measure the voltage to ground on each pin of PDB2. Post each measurement.

Well it is "fixed" it was the ISL95522A itself. Bought on AliExpress lol. I had a known working ISL95522H that i tried into his laptop in the past and when i put it on all the voltages came back. Now it still appears to be fake charging. I am getting 11.75V out the output to the battery. Battery is at 10.94v at 88%. Where should I start looking?

[mon2]

Which part is onboard now? Is it the original part # or the 'H' version? Not sure of the differences between the 2 at this time but it could matter.

The dual diode appears to be ok and not leaking.

Now if you attach both the power adapter AND the battery, measure this dual diode again but interested in the voltage to ground on each pin. Red meter probe on pin # 1; black meter probe to ground. Interested in the DC voltage here.

What is expected is that the higher of the 2 input voltages to this diode will appear on pin # 1 (output).

So one leg will be the battery voltage as input; other will be the power adapter input; pin # 1 will be the higher of the 2 voltages.

Likewise, if you use ONLY the battery, the adapter leg should not have a voltage on this diode since the diode is expected to reverse block the power path (ie/ BA_PWR to pin # 1 but no reverse feed onto +19V_VIN).

[flyhotstuff]

Which part is onboard now? Is it the original part # or the 'H' version? Not sure of the differences between the 2 at this time but it could matter.

The dual diode appears to be ok and not leaking.

Now if you attach both the power adapter AND the battery, measure this dual diode again but interested in the voltage to ground on each pin. Red meter probe on pin # 1; black meter probe to ground. Interested in the DC voltage here.

What is expected is that the higher of the 2 input voltages to this diode will appear on pin # 1 (output).

So one leg will be the battery voltage as input; other will be the power adapter input; pin # 1 will be the higher of the 2 voltages.

Likewise, if you use ONLY the battery, the adapter leg should not have a voltage on this diode since the diode is expected to reverse block the power path (ie/ BA_PWR to pin # 1 but no reverse feed onto +19V_VIN).

finally to around to doing this. So the battery does charge. But very slowly, like 10-15 percent per hour. maybe that's why I thought it was fake charging previously. So I figure a charging voltage of 11.3v-11.75v is too low.

on the Dual Diode with the adapter plugged in:

Pin 1- 19.08v
pin2- 19.46v
pin3- 11.35v (mirrors voltage to the battery)

[mon2]

What is the voltage markings on the battery pack that is for this unit? The charge volt should be slightly higher than the battery voltage.

[flyhotstuff]

It's an 11.4v battery pack. It was at 62 percent earlier and now at 81% after charging for almost 3 hours.

[mon2]

3 hours is too long.

Remove all power. Meter in resistance mode.

Locate PQB1 and PQB3. These 2 mosfets dial down the main power rail voltage to the charging voltage.

Measure PQB1 first to see if it is defective.

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. Repeat for PQB3.

What is the history of the battery under test? Is it old or a known good one for this unit? Test with a known good unit. This battery may have too many charge cycles already. I would expect the charge voltage to be higher than the battery voltage and matching the schematic value of ~12v6.

[flyhotstuff]

PQB1- Source to Drain- 3.3MΩ
Source to Gate - 19.08 KΩ
Gate to drain- 3.3MΩ

PQB3- source to drain- 3.1MΩ
Source to gate- 97kΩ
gate to drain- 3.3MΩ

battery is good. I actually charged it in a m15 R4 I owned and it charged normally without issue, which is how I realised that the laptop would turn on with just battery power.

[mon2]

Source & gate resistance is very low on both mosfets. Start with carefully fluxing and removing PQB1 off the board. Allow the part to cool down.

Confirm if the removed part is leaking in the source & gate measurements.

Also measure the 2nd mosfet again without power. Post all measurements.

[flyhotstuff]

Source & gate resistance is very low on both mosfets. Start with carefully fluxing and removing PQB1 off the board. Allow the part to cool down.

Confirm if the removed part is leaking in the source & gate measurements.

Also measure the 2nd mosfet again without power. Post all measurements.

OL on source to gate on removed MOSFET PBQ1 in resistance mode

PQB3 measurements
PQB3- source to drain- 3.29MΩ
Source to gate- 97kΩ
gate to drain- 3.5MΩ

[mon2]

To confirm, you are now measuring PQB3 while it is removed and on your workbench?

If yes, replace PQB3 as it is defective. The source / gate measurement should be hundreds of k ohms or higher like the other measurements for a good mosfet.

The mosfet can be replaced by many others but you can also check donor boards / other motherboards that may offer a drop in replacement.

The criteria is to start with the same type of mosfet as the original. We can review the datasheet for this mosfet, p/n AON6354.

https://www.aosmd.com/res/datasheets/AON6354.pdf

We know that the replacement must be:

5*6 mm in size
DFN 5x6
N-channel type
Source / drain support for 30v (or higher)
As high current as the original or better

Option #1 - replace with the same part. One can argue that it has died so select a better rated part.
Option #2 - replace with a higher grade part.

Original part:

https://www.digikey.com/en/products/...ON6354/7690189

Replacement (better) part:

https://www.digikey.com/en/products/...56-RLG/7360047
https://www.digikey.com/en/products/...CR-RLG/7360029
* can handle higher current loads

PS: Purchase some spares since PQB1 is also the same part and if required, you can replace it as well. At this time, PQB1 looks to be ok from the resistance measurements.