I built this BCD (Binary Coded Decimal) clock back in 1977 at the genesis of the PC era. I will not publish a detailed instructable since this is made out of obsolete ICs. The concept may still be viable. In the first image, the clock time reads 11:12:34. It is a 12-hour clock.

I used a 125V to 8V AC AT&T phone transformer to power the clock. The full-bridge rectifier and filtering circuit are built on the circuit board. These components were state of the art at the time.

The face is made from 1/8" dark plastic plate with white dry transfer labeling.

The clock was mounted on the wall, in a shadow frame box, behind my desk. It always got plenty of comments

Step 1:

The actual circuit board is one-tenth inch spaced 1970 era prototype board. I used 24 ga solid wire for the actual circuit. There are a clock IC and a buffer IC with 2N3904 transistors driving the LEDs. The buttons on the back are used to set the clock.

The face is made from 1/8" dark plastic plate with white dry transfer labeling.