Running PS1 engines through my DCS system

Are you using the TIU to control the track power through a variable channel to run your PS1 engines with the remote or are you running those engines with a transformer with the power passing through the TIU?

DCS has a specific PS1 start-up command when using the remote to control those engines.

Flat out, some PS1 engines are known to be very picky about power source and want near perfect sine wave variable power.

A TIU variable channel yes, can vary the AC power, and yes, MTH did try to design it to be compatible with many engines, but that said, it's still an electronically modified wave form and thus not true sine wave output- and thus possibly not compatible with older and sensitive PS1 engines.

Also, you kind of left out some information- the above assumed you were using the variable channel to vary the power, but let's say you are using the fixed channels, or even using a variable channel as fixed- and using your input transformer to modify the voltage for conventional running of PS1 engines.

In that case, a TIU channel could have a damaged TVS (Transient Voltage Suppressor) diode (there is one on all 4 outputs) and say that TVS has partially shorted in one direction- they are normally bi-directional for AC. Well that could be giving a DC bias and distorted waveform. This is one possible answer why bypassing the TIU in a fixed voltage situation could apply.

@Vernon Barry posted:

A TIU variable channel yes, can vary the AC power, and yes, MTH did try to design it to be compatible with many engines, but that said, it's still an electronically modified wave form and thus not true sine wave output- and thus possibly not compatible with older and sensitive PS1 engines.

Vernon,

You nailed it.  I agree fully.

I have some additional and related observations though.  I don't have any of the oldest releases.  My PS-1's are later-issue models, and as a result they do work acceptably well when controlled by the thumbwheel on the DCS handheld (which in my case is raising or lowering the output voltage of a TIU variable channel).

But, having said that, they growl something terrible (electromechanically; not from their sound systems) while they're rolling along -- due to the chopped sine wave that they're receiving with this approach.

Also, if I'm not mistaken @H1000 is referring to the soft keys that are built into the DCS handheld for more easily activating PS1 functions with one or two button pushes (rather than pushing Whistle/Horn and Bell numerous times).  These are quite handy and also work well for me.

Mike