Fault with Riser Recliner Sherbourne?

My fathers recent purchase of a riser recliner from Sherbourne stops working when feet are raised up for a while. Sometimes unplugging all leads appear to correct, Sometimes the back goes down in stages but not smoothly so I can reset sometimes the green light on the power box will fade when the buttons are pushed. There is no logic. It has been repaired once but this has happened again. As if by magic it works after a while. There are no obstructions and all wires are in tact and pushed in. Any ideas what's doing it.