Here is a photo of the clock powered on and running, nothing like a warm glow of Numitrons....unless its Nixies!

The nice thing about the RCA DR-2000 Numitrons is that it uses a standard 9 pin tube socket.

This clock is using a MM5314 multiplexed clock ic. With Numitrons and multiplexing,  you are required
 to solder a diode to each segment to prevent ghosting the number to the tube next to it.

Since this is a multiplexed clock, all the displays are wired parallel to each other except the common to each tube.

The top side of the circuit board. The components are layed out with plenty of room.

The bottom side of the circuit board, the only wires are that are not connected is the transformer and display.

This is what makes it all worth it. Now I have to build the case for it. The case will be veneered with walnut.

Here is the case I am building. I was going to make it angular but I want to finish this clock soon
so I can start with my next one which will be using Vacuum Flourescent tubes. Now its time
to veneer it with Walnut.

I made a modification to the original design. The Numitrons were a little to bright for my taste so I wired a
LM317 adjustable voltage regulator (bottom left) and a variable resistor (top right) and now I can the
adjust the brightness of the Numitron displays, plus they will last a lot longer.

It's finally finished. Here is the clock with 2 coats of stain. I used brass screws to
hold the sockets to the case.

The rear of the clock. The white pushbutton switch is the slow set, the green is fast set
and the red switch is to stop the clock.

Thats all folks!

Back to Homepage

Updated 05/30/2005