Hoshizaki ice machine

Hi, I have an hoshizaki ice machine IM-240dme, it fails to drop it's harvest in the harvest time, which has caused several actuator motors to burn out. Once the evaporator plate got so hot it melted the thermostat holder!
I was just wondering if any one had experienced this before as I'm stumped!
I have used ice machine cleaner- maybe I need to do it again for longer?
Refrigerant is R404 and correct charge.
Hot gas valve works.
New thermostat and holder.
It is in a hard water area and it has no filter on it, should it?...
Any help would be appreciated!

Many thanks

Had similar problems with these machines before,when it goes onto harvest does the ice get stuck in the tray and the door closes again?I ordered a new pcb from hoshizaki which I fitted and was also faulty.They sent another which was fine.Its worth checking the rotary switches inside on the pcb.1 of these controls the ice size and 1 controls the defrost time.I found that the board was out a few degrees which was causing these problems.

Yeah that's exactly what it does, I have tried adjusting/ increasing the harvest time but to no avail, I did notice however that when the cube size is on about 3, the cubes don't form properly, they are very very thin and broken, I think I'll give it a longer stint with the nickle free cleaner and if that doesn't work suggest the pcb.

Thanks for your help, it's much appreciated!

Hard water will mean calcium build up on HX. extra cleaning required and special filtration to soften water as well

The customer has had a hoshizaki engineer look at it, he has diagnosed it as needing as new water plate and evaporator? Do you think this could be the problem?