Nicole is correct about only SOME PS1 engines have issues with the Z-controller chopped wave output.
NOTE, The Z-4000 acts like a Sine but is in reality a stepped output simulating a wave. I forget how many steps but the Scope trace clearly shows it has digital steps in the wave. It's close enough that no engine I know of can tell the difference.
Ed is also correct, according to the posted updates, DCS Variable output now goes to 1.0VAC. (chopped tho, not sine wave)
RTR12, Correct the Fixed channels are straight thru, no voltage variation in the TIU for those.
Sounds like they put an inverter behind a smooth-performing DC throttle to get that "sine" wave on the Z4000. The Z500-Z1000 probably used phase limiters with some filtering capacitors on the output -- inexpensive to implement.
