I was playing with Rich Cini's Altair32 emulator and noticed that the status LEDs change when I single step. According to the theory of operations manual, the Altair stops and steps only at instruction fetch cycles. So the status LEDs should always be the same after a step, reflecting the status for an instruction fetch: MEMR is on, M1 is on, WO is on.
This video shows this behavior:
http://www.youtube.com/watch?v=vAhp_LzvSWk
It looks like the emulator doesn't handle the status LEDs correctly.
Anyone with a working Altair care to confirm this?