I can't imagine the compensator has failed as you would either have no drive or nasty noises when you do.
The symptoms are of a failed rectifier only. A common problem on the early cars due to vibration and poor earthing, most people with early cars change to a Harley Davidson rectifier which is a plug and play replacement for the CE unit, is more reliable and about a quarter of the price. Search TM for the part number or the Morgan Three Wheeler Club site for the alternative parts list.
