Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Hi Fullrace,..my external connected surge protection circuit consist of a standard non-polarized .047 uf > 100 vdc capacitor, a 5.6 Volt Zener diode & a fast Recovery Rectifier  diode 600 vdc 1 amp 
  all of which are wired across the 2 wire Hall sensor wires. The 2 diodes "Cathode" leads should be marked with a black stripe & Must be connected to the + polarity hall sensor wire lead. In the ET1-ETX all silver H&M engines, both sensor wires are black colored & i had to power up the ignition module & verify with a dv voltmeter to determine the voltage polarity. I also wited an identical circuit across the + & - battery holder leads. All Black striped end diode Must be connected to the voltmeter verified +  sensor & battery holder wires. The p/n 1N4937 600 volt diode & p/n  1N4734  5.6 volt 1 watt Zener Diode componets are available at Parts Express. I wired my protective circuit  up before any ignition spark was activated & powered up with trigger magnet on far side away from the sensor. So far, 30+ engine runs have been factory supplied (black, all potted sealed ignition system trouble free.