Msi gs66 charging issue

[shahnld]

Good Evening Masters..

My msi gs66 has a weird issue. It had a shorted mosfet on vram rails and 1x current sense to gpu or vram was melted,. I replaced the mosfet and currenr sense resister and the laptop started to work,

but When plugged in it says battery is 99% and as soon as i remove the charger the laptop shutsdown.. beside this issue laptop is fully functional.

So i opened it and i checked voltage on battery +. Without charger in MV's, when i plug in the charger then voltage on battery+ connector goes to 19.75v and then starts to drop until MV's. This happens with and without the battery,.

3.3v is present on clk, data at bat connector,. I replaced both input mosfets. Input mosfets has 9v and 8v on gates.. bq24780s is also replaced but same issue..

voltage measurments on bq24780s are as follows, any help is much appreciated.
Pin, voltage
1, 20v 2, 20v
3, 20v
4, 26v this voltage is not present on input mosfet gates.)

5, 3.3v
6, 2.6v
7, 0v
8, 0v
9, 0v
10, 1.027v
11, 12, 3.3v
13, 0v
14, mv
15, 0v
16, 3.3v
17, 2.5v
18, 2.5v
19, 2.5v
20, 2.4,v
21, 1.6v
22, 0v
23, 0v
24, 6.085v
25, 5.76v
26, 2.33v
27, 2.24v
28, 20v

Kind Regards

[mon2]

Input mosfets has 9v and 8v on gates.
4, 26v this voltage is not present on input mosfet gates.)

Pin 4 = ACDRV and often, this pin will mate with the gate pin of the DCin mosfets through a 4k series resistor. Respectively, the gate pins should also have the same boosted ~25v to enable each mosfet.

Remove all power. Meter in resistance mode. Measure the resistance from the gate pin of the first mosfet to the ACDRV pin. Is there ~4k resistance? Repeat for the 2nd DCin mosfet.

Is there a schematic available for your logic board? Link it in the schematic forum for a review. Hunt for this expected 4k resistor.

Perhaps this expected 4k resistor is no longer ~4k ohms in resistance or is missing off the board? Basing these assumptions off the reference design schematics.

[shahnld]

Thanks alot for your reply.. i will trace down this resister and replace it. Will report back once that is done.. Cheers

[shahnld]

Pin 4 = ACDRV and often, this pin will mate with the gate pin of the DCin mosfets through a 4k series resistor. Respectively, the gate pins should also have the same boosted ~25v to enable each mosfet.

Remove all power. Meter in resistance mode. Measure the resistance from the gate pin of the first mosfet to the ACDRV pin. Is there ~4k resistance? Repeat for the 2nd DCin mosfet.

Is there a schematic available for your logic board? Link it in the schematic forum for a review. Hunt for this expected 4k resistor.

Perhaps this expected 4k resistor is no longer ~4k ohms in resistance or is missing off the board? Basing these assumptions off the reference design schematics.

Hi.

I have checked. Both acFet and BatFet has 2 resisters which has 9v and 8v on it connected to gates. And both gates are also not connected togather.. Idea's...?

[mon2]

Share the silk screen details of your logic board. From random internet searches, the logic board should bear a silk screen like 'MS-16V1' which is one of many permutations used by MSI for the G66. Another is MS-16V31, etc.

[shahnld]

Good Evening..

I just replaced the battery from another msi laptop, batteries were identical in measurements, wire count and wire color location so i just installed it and to my surperise it worked in it. Its charging now and laptop works without charger. So conclusion is that the battery was dry dead due to not being charged for 7 months..

Appreciate all the help and time.. 👍👍⚘️