The PS2/PS3 boards operating in conventional provide insight but I don't think a practical (cost) alternative for the matter at hand. Granted, if the OP cannot find a LocoSound board gathering dust at a reasonable price, then the intrigue vanishes.
@gunrunnerjohn posted:I don't know about easy, but if I wanted to disable PS/2, I'd probably lift the leg of the little inductor that couples the DCS signal into the board, that would turn it into a conventional locomotive.
Of course, if you're running conventional with no DCS, you don't have to do anything, there is no WD signal. If you're running on a DCS layout, why in the world would you want to run a DCS locomotive in conventional mode?
GRJ's last comment got me thinking - a dangerous thing! 
Again, my tunnel-vision is on the conventional-only operator and what options are out there for an E-unit that has cruise/speed control. Of course one logical "feature" of an E-unit with cruise/speed control would be ability to turn it on/off. Another would be traditional direction lock (e.g., forward only).
The LocoSound manual suggests you can use conventional Whistle/Bell controls on the transformer to turn speed control on/off...likewise for directional lock. Of course this means you need a train transformer with Whistle and Bell or some ability to generate both conventional control signals.
OTOH, if I understand the ERR Cruise Commander instructions, you need command-control capability to turn conventional speed control on/off. I'd think this could be sort of a chicken-egg situation. 
The above manual snippets also suggest there is a selection of large vs. small motor which might have to do with the tach-less feature (?). And there's a speed step selection which I'd think might affect speed control operation (?). Both selections apparently also require command-control.
I still think there is cause to issue a BOLO (Be on the Lookout) for a LocoSound Steam board!
