Pinball display clock

A clock using ex-pinball six digit neon gas plasma displays

These displays were used betwen from 1987 until 1980 on a variety of Bally and Stern pinball machines.

I bought a large quantity of displays, still on their driver PCBs. Condition unknown - I had to assume most had faults of some kind.

Six digits - ideal for hours, minutes and seconds. My artwork separates them into sets of two digits. The artwork is sandwiched between two sheets of glass and it can be changed for custom artwork if someone wants to have a display to match a machine they own.

I intend to make a batch of these clocks available for sale shortly, so please enquire if you wish to be added to the waiting list.

Testing displays using a plasma ball proved to be a quick and easy way to establish if there was any gas left in the display. This weeded out some of the junk so that I could concentrate on the rest of them.

After making a simple test circuit, I was able to start fixing any faults. There were some common faults that I soon learned to recognise. Others were trickier. On one I found a shorted copper track on the circuit board that must have been there since it was manufactured.

I wanted to make my clock board completely non-destructive of the original display. As all the connections to the display were on one set of sturdy pins, I decided my board could simply plug on top of these. There are two main types of these boards and fortunately the connector is the same on both, although the position is different.

12 volts in. My clock driver board provides the necessary 5 volts and 180 volts out to the displays. The existing Bally boards already have seven segment decoders and digit select lines as well as all the high voltage and keep-alive circuitry. It was easy to interface directly to them from the microcontroller.

A fun little project and one that seems to have impressed those in the pinball community that I have shown it to.