You need 120VAC coming into main pcb, it supplies the 12 and 5 VDC to the UI display.

Do as much of this as you can by checking continuity on an unplugged machine. It is easy to get shocked or short a component out while working live.If you have any rubber or non-conductive gloves that would help protect you from a shock, use them. Believe me, you can get a bad shock from 120v.

That 120v first goes through the filter. That's my guess for your issue. Part # 241 on the diagram below. It's the small whitish plastic box under the console. It's probably upside down. The power cord will go to it. access it and verify that the fuse on it is closed (passing current) by checking continuity across the fuse built on the filter. It may have a layer of epoxy on it so try to make sure you are contacting the actual metal. If no continuity that is your issue, or at least the 1st issue as something may have caused it to blow. If you feel brave you can check this live by checking for potential across that fuse. Put a probe on both ends while the machine is plugged in, if the meter reads 0 the fuse is good, if it reads 120 it is not. It is not replaceable unfortunately.

If no continuity and you are feeling brave you can jump across the fuse with a short length of wire. Alligator clips are nice for this task. Once you are sure the wire is securely jumping the fuse plug it back in and see if it's alive. IF this gets action try to run and spin cycle or other test.

If no life at that point, unplug it again while you access the main pcb. Part # 60. It's the larger white plastic box and may also be upside down and have a cover. Make sure it is propped up securely then plug the machine in and see if the wires leading from the filter to it are delivering 120v. I think there should be a red led on the main pcb when it is powered up. If the main pcb is getting 120v from the filter and you have no lights on the User Interface (UI) you usually have a bad main pcb.

If you are truly motivated you can try to see if the DC transformer has failed by looking for 5 or 1 2VDC going to the UI or other components, but it doesn't matter as that isn't easily repairable unless you have some electronics knowledge.

Parts for GE WPGT9150H0MG: Controls, Backsplash & Top Panel Parts - AppliancePartsPros.com