Data East / Sega PPB-1 - High Voltage Transistor Coils Saver - Version 1

Data East & Sega - PPB-1 High Voltage Transistor Coil Saver - V1.0

Data East, and later Sega used a separate circuit board to manage the High-voltage coils.  Other pinball manufacturers used "Snubber" boards.  On the PPB-1 circuit board, the 50V coils are driven by those beefy "TIP36C" power transistors.  They held up pretty well, but if they did short out, there really isn't much fusing them.

The 50V starts off the transformer as 48VAC, where it is rectified on the PPB-1 board's BR1.  There is a fuse on the 48VAC input, and that's it.  When one of the TIP36c shorts out, and the corresponding coil locks on, it has to draw enough amps through BR1 to blow F5.  This will kill the coil, and strain BR1.  This board fuses the individual TIP36C and provides an LED indicator for each one

Easy to install.  Simply remove the plug(s) from J8, and connect this board onto the J8 header on the PPB-1.  Then plug the connectors to J8 on the HVTCS.  Connect the wire to any convenient Ground for LED indicators

The HVTCS fuses the power to each coil.  Populate with 1-1.5 Amp fuses (I have personally had good luck using 1A SB fuses in these).  The next time a drive transistor on this circuit were to short, the 1A fuse will blow before more damage occurs. 

Each fuse has an LED indicator.  With a ground wire attached, the HVTCS will show which fuses are good.  Note:  not every game uses every HV transistor.  DE The Simpsons only uses two, and one is the knocker - which is missing on my game!