Power Outlet ... not engaging?

Haven't used this in awhile but tried to the other day and nothing. Fuse good and when I push the button, the lights go on ONLY if I hold it in for a few seconds then they go off. Any simple or complicated ideas before it goes to the doctor? Thanks.

 

Do you have something plugged into the outlet that is loading the circuit? Unplug it and activate the inverter, THEN plug in your device.

You asked for simple ideas

I had a similar issue when my air compressor was plugged in and turned on - had to unplug it, turn on 400W, then turn on the compressor.

 

I did simple first thing, guess I should've mentioned that. I actually used a small Porter Cable compressor last year on it. It wouldn't build full pressure but I had to try it. It's run all kinds of things and just went to test it and had the issue. Looks like time to use my warranty.