Question on using TIU and MTH HO Plus O guage

The AUX input is only to power the TIU's innards, not to provide power to the track. 

I would say the track serving the HO should be kept separate, and not connected to the terminal block at all--connect directly to the desired pair of TIU output posts, with DC being fed to the corresponding input posts.  Note that this cannot be done with a Rev G TIU, since the black terminals are internally connected.

Thanks RJR.   How do I determine which TIU I have?

Robert,

Actually, thsi should work with a Rev. G (as well as later TIUs). I use DC for trackside accessories and regularly connect the DC - to track Common with no ill effects. However, the DC + c annoy her commingled with the AC Hot so a separate TIU  channel must be used.

Further, this must be a Fixed channel since the Variable channels (in variable mode) will not pass DC current. However, I don't recall if a Variable channel set to Fixed mode will, or will not, pass DC.

If a Fixed channel is not available, one could use a Variable channel with an AC input and rectify the output of the channel to DC. 

How do I determine which TIU I have?

Look on the bottom for a heat stamp or sticker with a Rev. identification.

The TIU models are REV. H, I and L, possibly followed by a number, or a number and a lower case letter. No REV. designation at all indicates a Rev. G TIU.

This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site!

CLICK HERE go to MTH's web page for the book!

Thanks! 

I'm at work but had the wife check.   Its Rev L.

I have of course a second fixed channel but how do I make sure it runs off the DC input and not the AC?

I have of course a second fixed channel but how do I make sure it runs off the DC input and not the AC?

Just connect a DC power source to the other Fixed Channel inputs, + to Red and - to Black, then connect the output of that Fixed Channel to the 2-rail track.

It makes no difference which output terminal goes to which rail.

Gotcha.

Thanks Barry.

I keep taking for granted the banana adapter for the power supply and just need to pick up another.