OK Guys,
I tested voltage as the Clymer manual describes. Voltage at coils OK. Voltage at ICU not there, pulled out wire 5 and then tested current between pin 4 and the wire, reading was 1.2 mA, which according to Clymer manual means faulty trigger unit.
Interestingly my ICU did not have a wire to pin 7, yet I have read that is the tacho pick-up, so now I am puzzled how the tacho gets its signal, because it works, although I suspected it was reading slow.
Paul