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Power Supply

After finally figuring out those shift registers, my concerns turned towards my power supply needs.  Logic circuits work on either 3.3V or 5V so a PC PSU would be perfect.  On top of that, they are a dime a dozen.   Someone should have a spare one lying around.

Formally Functioning PC PSUs

Well, someone did have some lying around.  The permanent marker demarkation on the left one says it all.  At least they are useful for parts.  Not satisfied with the quality of my previous procurement, I set out to purchase the cheapest power supply I could find.  I purchased a Coolmax 500W power supply from Canada Computers, who happens to be a fantastic retailer for anything computer related.  I don't really buy from anywhere else anymore.

 My control circuit power supply needs are now furfilled.  Unfourtunately, the 12V rails of the PSU do not have enough voltage to actuate the solenoids that are used in 90% of the mechanisms in a pinball machine.  I discovered this after purchasing two brand new flipper mechanisms from http://www.actionpinball.com.  They came at the highway robbers discount price of $35 each along with the solenoids costing $13 each.  However, I justified this purchase in that the flippers were the main mechanism in the game and I wanted to maintain the 'feel' of a real pinball machine.  

Two Flipper Mechanisms

When I hooked up the flipper coil to the 12V for the first time all it could manage was too prevent the core from being pulled out by the spring. Turns out I had it hooked up wrong. You can see the 3 terminals on the flipper coil in the picture. There are 3 because there are 2 coils inside. The reason there are two coils is because the large one generates a lot of heat and having it powered for a long time would burn it out. This would be such a case when the flipper is held in the up position. So the flipper mechanism opens a leaf switch so that it only powers the secondary coil when open. This is called an EOSS switch, or end of stroke switch. Once I hooked it up properly it had more kick but not enough. I then read that the coils would run off of 24V. I tried used the +12V and -12V but the max current was only 1A so the circuit breaker would go in the PSU. The resistance on these coils is only 4.6 Ohm which means on a 24V supply they would pull 5.2A. This makes the PSU unhappy.
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