I had the same problems using a digital with my Futaba MC800...which is the same as a Quantam.
I soldered a power cap to a servo lead then plugged it into the batt slot on the receiver. Seems to have fixed my problems. I am looking for another ESC as soon as I have some extra money. I cant stand this Futaba. I have had it sent in twice because it wont reset or anything. Takes me 30 minutes or more usually to resset it or change profiles. I send it in and 3 or 4 weeks later they send me a new one and it works fine for about 2 months then starts all over again. Its like the buttons wear out or something and I dont even use them but maybe once every 2 months or something. I can usually set it once or twice before it stops responding to the set and mode buttons.
oh well, lesson learned