This modification was fitted as a modification to late issue 15 control boards (after August 2004) and is incorporated in Issue 16 and later boards.
The modification is only of possible relevance to board issues earlier than 15 and to any issue 15 not already modified. You should however check with support before fitting this modificatiosn: very few controlles suffer the problem this fixes!
At power-on, an internal reset pulse occurs. This pulse hoods the motor outputs in an off state. If, at the end of the pulse, the High Pedal LockOut is clear, the controller starts up.
Some controllers show a tendency not to start up, even though the HPLO is clear. The fault appears to be to do with a certain batch of ICs and as a result we modified the circuit to raise the threshold at which the reset pulse clears.
The modification involves fitting a 47K resistor to the control board as shown in the diagram below. A subminiature (CR16) size is ideal but a standard (CR25) can be used.
4QD, in publishing this modification here, accept no responsibility for the results of any do-it-yourself modification. Only you, the potential engineer, can be aware of your own abilities.
The power must be totally disconnected from the circuit board and the controller left to discharge for at least 15 minutes before handling it.