I'm using a Binary to BCD system using this double-dabble decoding device. It all seems pretty good, but it doesn't work properly. If you are unfamiliar with double-dabble, it should take an input, and if it's higher than 4, add 3. I've seen this device used in another video, but this one doesn't work 100% correctly.
Even after downloading the schematic and opening it in CircuitSimulator, putting in a 5 gives a 7, not an 8 like expected:
Anyone good enough to identify the problem?