The letters under each LED relate to where they should be positioned on the dice.
Connect all the arrows on the transistors to the positive supply rail.
HOW IT WORKS
The 555 timer IC is connected for Astable Operation, the clock pulses are fed to the 4017 IC via the
10K resistor. The 4017 is a 10 stage counter, output 6 (pin 5) is connected to RESET (pin 15), thus giving us a 6 stage counter
, outputs 0 to 5.
6 of the LEDs are connected as 3 pairs, thus requiring 4 different signals, these signals come from the 4 transistors, which in
turn are connected to the nescessary outputs of the 4017. Where a transistor is operated from more than one output, diodes are
used to avoid a short circuit situation between outputs.
Pin 13 of the 4017 (INHIBIT) is connected to +ve via a 100K resistor to stop the counter from advancing, however pressing the
ROLL button will connect pin 13 to -ve and allow the counter to advance, hence, throwing the dice.
on the transistors to the positive supply rail.