Dell XPS 9550, Unknown Charger

[mptcultist]

Hi, I recently got an XPS 9550 that won't charge due to the "Unknown Charger" PSID issue.

I replaced PQ100 to no change, PR102 reads at 33 ohms, PR101 reads at 2.2k. When PQ100 is removed, the source pad reads at 3.3v, the gate reads at 5v, and the drain at 0v. When it is in place, both drain and source read at 1.4v, and gate still reads at 5v. PD100 is blown clean off and as such reads basically open.

I don't know what exactly to do from here, except maybe investigate PQ101.

[ktmmotocross]

Re: Dell XPS 9550, Unknown Charger

did u try another original charger?

[mon2]

Re: Dell XPS 9550, Unknown Charger

Yes, as suggested, test with another adapter.

The transient may have killed the MEC5085.

Remove all power. Meter in DIODE mode.

Red meter lead, yes red to ground.

Black meter lead to the MEC5085 pin used for the PD_ID communication.

What is the diode mode reading of the PS_ID pin?

PQ101 is a crowbar circuit that enables to disable the flow through mosfet if the adapter voltage is too high on the ps_id pin. The gate voltage of the mosfet is shorted to ground to disable it.

[mcplslg123]

Re: Dell XPS 9550, Unknown Charger

Hi, I recently got an XPS 9550 that won't charge due to the "Unknown Charger" PSID issue.

I replaced PQ100 to no change, PR102 reads at 33 ohms, PR101 reads at 2.2k. When PQ100 is removed, the source pad reads at 3.3v, the gate reads at 5v, and the drain at 0v. When it is in place, both drain and source read at 1.4v, and gate still reads at 5v. PD100 is blown clean off and as such reads basically open.

I don't know what exactly to do from here, except maybe investigate PQ101.

When PQ100 is removed, only drain can have 3.3V whereas you wrote source is 3.3V which i think you either misunderstood or its a typo. Just jumper between source and drain of PQ100(while pq100 is removed) and test again.

[mptcultist]

Re: Dell XPS 9550, Unknown Charger

Hi everyone, it appears that replacing PQ100 just fixed the problem. I didn't evaluate if I was actually still having issues after I replaced it because the multimeter reading didn't change, but it actually started working so, go figure.