XPS 15 7590

[bosscharles]

Now when I connect the charger to the machine, the white light on the charger tip stays on for a few seconds and then goes off. I need to disconnect the charger from the power socket and then reconnect for the white light to come back on…with battery disconnected, I am able to turn the machine on and Bios detects the charger. If I connect the battery while in the bios, the charger is no longer detected light on charger tip turns off… machine runs off of battery…. Really weird behaviour! Any input welcome..

[bosscharles]

Battery is known working battery btw… so issue isn’t the battery.

[mon2]

Flux and reflow the charger IC. Review the DCin mosfets that are enabled by this charger IC. You may have a leaky DCin mosfet. To check, remove all power -> meter in resistance mode ( not diode).

Measure the resistance across the mosfet pins:

source (1-2-3) & drain (5-6-7-8)
source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

[bosscharles]

Removed and reinstalled IC. Charger detected and charging battery! That’s what it says in the bios but the battery is not being charged at all….. If I unplug the charger and then plug back in the light on the charger tip turns off and charger isn’t detected wtf…. About ready to throw this out the window

[mon2]

Which schematic matches your board? Which mosfets are close to the charger IC? These DCin mosfets need to be reviewed.

[bosscharles]

It is a LA-H331p i7 xps 15 7590 motherboard

[bosscharles]

Will work if ac charger is plugged in and battery is disconnected. Machine detects charger properly. Will also work off the battery if I charge the battery on another xps I've got. As soon as I plug in the AC charger, the light on the tip goes out and the machine keeps running off the battery. The only way to get the AC charger working again is to unplug it from the wall socket and then plug back in. Battery tested on other XPS and working fine. It's like somewhere something shorts the ac adapter when plugged in…

[mon2]

Review the DCin mosfet S5 (PQ209). Remove all power. Meter in resistance mode (not diode mode). Measure the resistance across:

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.

[bosscharles]

source (1-2-3) & drain (5-6-7-8) - 1.7k
source (1-2-3) & gate (4) - .03K
gate (4) & drain (5-6-7-8)- 1.5K

[mon2]

These are very low resistance readings for a good mosfet. Flux it well and remove this part. Allow it to cool and then check the same measurements while this part is on your work bench. Still the same measurements? If yes, it should be replaced.

[bosscharles]

Unsure if those readings where accurate, I had to change the batteries on my multimeter as they were low and giving erroneous readings. When I try to do the readings you ask, all resistance readings are fluctuating? Also, would this IC cause the light on the charger to turn off as soon as it is plugged in and the battery is also connected to the motherboard? It feels like that sort of thing is a short of some sort?