[Fran] demonstrates the display running with a CD4511B BCD-to-7-segment decoder, hooked up with a bunch of 3904 power transistors to get the chip working with filament bulbs instead of LEDs.

What is the 4511 IC? The 4511 datasheet specifies that this IC is a BCD to 7-segment latch/decoder/driver with four address inputs (DA to DD), an active LOW latch enable input (EL), an active LOW ...