<VV> Condenser, triac AND transistor failure

[David B. Neale]

Thanks for the 'tip', Seth! Installation of the Delta T-707 transistorised ignition unit, ( it isn't a capacitive discharge unit; it's too early; it is just a big transistor switch ), does indeed make me subject to transistor failure, whilst still leaving me with a condenser to go on the fritz, as that remains in place. Double trouble .... you might well grin! It certainly made me laugh ....

I am intrigued by Dennis's scheme of triggering a Mark Ten CD unit by a Pertronix .... I know that the latter units fail sometimes, ( of course ), and I did wonder how many of those failures are down to Triac failure in the Pertronix. I may follow your plan, Dennis, and retain my Pertronix, and use it to trigger the new unit.

The killer for earlier transistor ignitions wasn't generally the current through the transistors, ( certainly not with CD units, as the transistors formed an inverter, and a large ..... capacitor ..... stored the inverter's output and, discharged by a triac or thyristor, 'zapped' the coil ). I suspect the culprit was the very high voltage spike caused by the coil, exacerbated by semiconductor switching.

David 

'65 Monza 140 HP convertible, sparking furiously