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For you guys who got a timing circuit board from me a while back:
As I mentioned before there is risk of the mag voltage generated on the primary (P-lead) blowing something on the board.
Yesterday I accidentally snapped my coupler while positioning the crank to check timing: blew the circuit board for sure, almost 100% is the 555 chip as it proceeded to get very hot before I could disconnect the battery. Amazing how much energy is stored in a little 9 volt battery.
Failure mechanism is the magneto generates a pulse of several hundred volts on the primary when it snaps through and that is more than enough to take out a chip and or other components designed for 15 volts max.
As I have used mine quite a lot before this happened, you can protect it some by moving the crank slowly, backwards when you can, and don't let the coupler snap through. I'm sure there is a circuit modification that would protect it, likely with protection diodes, but that would probably be more trouble than just buying a commercial unit.
Fortunately 555 chips are cheap and easy to replace, hope it didn't take out any of the caps.
Darryl
As I mentioned before there is risk of the mag voltage generated on the primary (P-lead) blowing something on the board.
Yesterday I accidentally snapped my coupler while positioning the crank to check timing: blew the circuit board for sure, almost 100% is the 555 chip as it proceeded to get very hot before I could disconnect the battery. Amazing how much energy is stored in a little 9 volt battery.
Failure mechanism is the magneto generates a pulse of several hundred volts on the primary when it snaps through and that is more than enough to take out a chip and or other components designed for 15 volts max.
As I have used mine quite a lot before this happened, you can protect it some by moving the crank slowly, backwards when you can, and don't let the coupler snap through. I'm sure there is a circuit modification that would protect it, likely with protection diodes, but that would probably be more trouble than just buying a commercial unit.
Fortunately 555 chips are cheap and easy to replace, hope it didn't take out any of the caps.
Darryl