Quote Originally Posted by daverob View Post
Thanks for the vote of confidence, but I'm no expert on this era of machines so I'd only be making guesses and your description makes enough sense to me.

BTW my guess would be that the switches activate the lamp and relay, and the relays are used to 'latch' the switch contacts. ie the switch is closed which activates and closes the contacts on the relays, one of the relay contacts is also wired across the switch, thus effectively holding the switch closed even after the ball has passed through. There will be another set of relay contacts (or a push to break switch) which will remove the power to these relays, thus resetting the 'latches' and turning the lamps off.


Another thing that I thought of was that you can't put a single resistor in the 'ground' connection as the voltage drop would vary depending on how many LEDs are lit, but you could do it with a zener diode, as the voltage drop across the diode would always remain constant even with the changes in current due to the number of lit LEDs. You'd have to figure out the power ratings of the LEDs and how much power the zener diode would have to dissipate if all the LEDs were on at the same time, but it could be feasible and would be easier to wire in than rewiring all of the wires going to the edge connector via a resistor.

It's not the conventional way of using a zener diode to set the voltage in a circuit. But I use zener diodes in a similar way in my dongles as the voltage supplied to the dongle by the pachinko machine is too high to feed directly to the voltage regulation circuitry.


On the other hand if I was going the individual resistor route, then I'd probably use a scalpel or craft knife to cut the tracks on the lamp PCB near the edge connector and solder a surface mount resistor across the cut in the track. While surface mount components are a little bit fiddly to work with, it's got to be easier than soldering a resistor into a wiring harness.
the balls that land in the pockets do not "pass through". A trap door retains the balls in the pocket. The 1st ball in the pocket holds the switch closed until a coin is inserted and the START SOLENOID opens the trap door, releasing the balls into the track behind the window.
I never thought of a zener diode...because I am more mechanical inclined than electrical inclined. What value (is that the correct term) diode would be required...based on the information I will provide in my next post when I perform the tests you taught me to do.
I had considered cutting a trace, drilling 2 holes per circuit, and mounting a traditional resistor thru the board, soldering it to the traces. I rejected that idea because, splicing into the wiring harness is easier to reverse if I make a mistake. Once I start hacking the bulb board...it becomes HARD to reverse. As far as the surface mount resistors...I did not expect them to have enough wattage (correct term?) to handle such a voltage drop. i could be wrong.