It might be that OC's were ok to start with. Then when you got 88.8 you walked into another issue, but most likely the display and heater are not working because of the thermal overload protection fuse - did you reset it and try again?
I have never yet seen a failed heating element on a Jobo machine (other then ones that were corroded to the point they broke in half).
It is common for more then one IC to fail at the same time, and often time, the problem is one of the IC partially failed on one of the upper boards and another failed one on the DC board. any other failed small element on any of the boards, or corrosion can cause issues with the thermostat control and display on the CPP2, though it does not sound like this is your problem.
Where are you getting your ATL+ from? we just finished refurbishing one, and will put it on the market as soon as we are set up in our new place...