Issue 02 September 1992 . Top board redesigned using LM339 modulator. Issue 03 March 1993 . Issue 04 July 1994 . Mk IV, new circuit.
Main change is to the acceleration and deceleration ramp circuits.
Issue 05 October 1994 . May 1995 . Without this the high pedal lockout could take a long time to reset, as the controller internal demand speed could be at full speed and had to ramp down to zero before resetting. Issue 07 November 1996 470p on demand speed line. Some controllers had a small high frequency instability problem.