BTTF Time Machine Build Questions - Ask Me Anything

[Mark D]

So I’m guessing that all the indicator lights were converted to 12 volt (as they are Neon high voltage as stock), maybe LEDs? Also, for the bottom button, did you take a lens from one and just fit it over the push button?

When the original cars were being built the keypads were found pretty much as you see them on screen as a complete assembly. They only had to be modified slightly to fit in the car below the time circuit displays. The keypad didn't actually function in any way other than the indicators being wire to light up when the TCD drive switch was turned on. All of the numeric displays were controlled by a separate box off camera to operate as you see on screen.

The stock TRW keypad assembly has a circuit board inside that has a push button soldered into it along with the LED's that are behind each indicator indicator. Production on the film just tapped into the circuit boards to make the lights work.

For the restoration we used a real keypad assembly and wired the lights and the actual keypad to function so it works like you see in the movie. You can actually enter dates into the keypad and the displays work based on the input.

All of the real TRW keypads are now long gone so most people building a replica need a casting of the green housing and a source for the rest of the internals. Luckily the lenses for the indicators used by TRW were an off the shelf component so today you can buy them as a separate indicator light. It doesn't matter what bulb type you get for the indicators since you throw away everything but the lens. The white keypad was also an off the shelf part made by GTE, and I believe TRW just assembled these components using their own custom circuit board to create the keypad assembly.