Hi, all. Finally got around to building a DDT16 from the kit. Unfortunately, it is not operational. No smoke or flames, but entering the monitor and typing, e.g. C700G, just hangs. I've tried a couple of different slots with no better luck. The EPROM verifies fine against the binary and I've double and triple checked for bad or missing solder connections, misaligned chip pins, etc.
Where do I start trying to figure this out? From the Apple side, the slot ROM appears in the correct place and data looks correct. I'm guessing that it's going south when the CPU bank register is hit. What part of the hardware deals with this? Any tips appreciated!