There is a small condensor on the board, close to the machine front edge. It is a yellow colour, and devellops cracks along the sides with age. When faulty,the machine will not start most times. Sudden rapid pressing on the pedal will make the machine jerk into action, perhaps two times in ten depressions. I use a .01uf 630 v condensor to replace it in our 230v New Zealand system. Another common jerkey running fault comes from one of the two black three legged transistors. They are usually positioned together and are quite small. The boards are easily broken when removing the two light wire pins. Standard mechanical pedals can be fitted by a skilled mechanic, and the boards can then be discarded altogether.
Regards... mansrobe...Trademe NZ
robert, May 2009