Hi, a few years ago I bought an xps 7590 and about a year ago the motherboard on it failed. I've been trying to diagnose the issue for the past few days.
The things I have noticed that seem relevant are that ALWON is 0.0v, and ACAV_IN is 1.6v. Tracing back to PU1901 seems to show that the logic gate there is receiving the appropriate inputs and VCC. If I short VCC to the output with my probe, the other side of the gate will rise to 3.0v, and then RTC voltage will rise to 2.2v. The MEC will then get quite hot, and after about 20 seconds, the RTC voltage will fall to 0.4v, and the other side of the gate back to 1.6v. I don't get any response from the power button while it's in this state. The resistance from ground on the RTC+ on the connector is about 1000ohms, which doesn't seem right, because that's simply the resistance between the RTC rail and the battery's pin. I suspect the MEC is short to ground, but I'd rather that not be so as I have no means of replacing it.
If anyone has any ideas on where to go from here (or simply wishes to confirm my fears), I'd be happy to hear them. Thanks!
The things I have noticed that seem relevant are that ALWON is 0.0v, and ACAV_IN is 1.6v. Tracing back to PU1901 seems to show that the logic gate there is receiving the appropriate inputs and VCC. If I short VCC to the output with my probe, the other side of the gate will rise to 3.0v, and then RTC voltage will rise to 2.2v. The MEC will then get quite hot, and after about 20 seconds, the RTC voltage will fall to 0.4v, and the other side of the gate back to 1.6v. I don't get any response from the power button while it's in this state. The resistance from ground on the RTC+ on the connector is about 1000ohms, which doesn't seem right, because that's simply the resistance between the RTC rail and the battery's pin. I suspect the MEC is short to ground, but I'd rather that not be so as I have no means of replacing it.
If anyone has any ideas on where to go from here (or simply wishes to confirm my fears), I'd be happy to hear them. Thanks!
