I did also have problems with non working display segments of the Ice Tube.
It seems to be that there are some spikes coming from the microprocessor, corrupting the timing sequence of the display driver chip.
This problem is simlpy solved by placing some 1000 pF capacitors from the clock and data driver lines to earth. See the picture.
Adding these capacitors in this way solved the problem completedly.
Also the most right digit of the display was less bright than the others. This can be solved by adding another 22 Ohm resistor parrallel to the other (see picture).
Also the zvp3306 should be replaced by another FET a ZVP2110. The characteristics of this FET suits better the voltages of the circuit.
After all these modifications my Ice Tube is working fine now for some weeks without any problem.
I hope anyone else can make use of these suggestions.