Fuse is blown. To the best of my knowledge it can only be repaired by a technician which Ugears won’t do. Replacing the circuit board is not the fix. There are 2 “in line” fuses from the power cord to the circuit board. They are buried in the cord. I tried replacing them and failed. I’m not a electrical tech guy though ..: I did find them Though and they were blown…. Which is why the chair would not power on. If you can find someone to replace fuses it will power on and run.
The problem is not a blown fuse on the motherboard there is to in-line fuses coming from the power source to the motherboard that are completely covered under black shrink wrap, and those fuses were blown
Ugears Will send you a motherboard as a solution but that will not fix it. Inside the compartment where all of the parts are there are two wires that have in-line fuses on them and those fuses have blown which is why your remote will not power up. The in-line fuses are not marked. If you know somebody who is handy with electronics then you could cut the in-line fuses out and replace them and that should re-power your remote.
Sorry to hear you have the same problem. I never did get the chair fixed. I did find two porcelain fuses on two separate wires coming from the inverter to the circuitboard I bypassed those , and got the chair to power on enough to get it back horizontal but then it stopped functioning. I communicated back-and-forth with U gears and since my chair was only six months old they replaced it. They did stipulate that I leave them a positive review prior to them sending me a replacement chair. Hope that helps