TMCC upgrade with MTH DCS TIU.

I would not run on more than 18 volts on the track.  Just curious, what locomotive do you have that requires that much voltage?  You will be running past the stated maximum voltage for the Lionel stuff, I sure wouldn't do it.

I haven't modified anything with the TIU, that is what it outputs. Is this wrong? I am running the 2 Z-750's on each input for 150 but the voltage is the same on both fixed outputs, is this bad for the MTH engines too?

did you measure the voltage with a load?

I've got a Z750 transformer powering my DCS layout and have run my Williams E7 with ERR Cruise Commander and 3rd Rail E7 with TMCC and Railsounds in Conventional mode for a while now.  I make sure I don't run them fast (high voltage) in conventional.

I would heed the warning about using in excess of 18 volts if you plan to run them in TMCC mode via DCS.  My Z750 transformer also puts 21+ volts on the track (as stated in the Z750 manual), I'm getting a Lionel PowerHouse 180 which should solve this issue.

I hate to spend more $$$, but I'd rather do that than suffer the consequences.

I don't know of a good way to lower the output of the Z750 brick.  The manual says NOT to use the controller, just the brick.

The brick is rated at MTH at 21 volts, IMO too much for TMCC/Legacy.  Here's a standard line from a Legacy User's Manual.

Increase track power voltage to full power (no more than 19 volts AC).

How does Lionel control track voltage if not with a controller? and if they do why not with a MTH controler? same idea right?

Bigdodge, I had an engine on the track but just on, not moving.

Lionel "controls" the track voltage by making the transformer have an 18V output!

I just got an email from Scott Mann and he stated the following:

DO NOT RUN ANY OF OUR ENGINES ON Z750, it is cut wave transformer that can send spikes of 110V thru the electronics.

Only use ZW, Z4000 or MRC Pure Wave.

So there we have it.  I guess even running my E7 conventionally is taking a risk, good thing I've run it just a couple of minutes at low speed.  A PowerHouse 180 should do the trick, but what effect will it have on MTH engines?

A bigger question I have is, if it's not good to run the 3rd Rail E7 on a Z750, how about my Williams E7 with ERR Cruise Commander installed?  Same thing as the 3rd Rail E7 as that's what's inside it, right?

Bob, note that the Z750 brick is just a pure sine wave transformer, it's the controller that hacks up the waveform.

It's not good to run ANY Legacy or TMCC stuff on 21 volts IMO.  You're exceeding the published specifications of all of them at that level.

First, who's Scott Mann? Second, if it's the controller (TIU) that cuts up the sine wave then it doesn't matter what brand you use? Now, I just read about the ALL Tracks setup to set voltage to 18 volts (I'm at work and haven't tried this yet) is this a viable solution to the too much voltage problem?

The TIU sets voltage based on the assumption that the input voltage is 18 volts.  If you connect a 21 volt transformer and set all tracks to 18 volts, you get 21 volts.

If I set a voltmeter on the output side will I be able to dial down to 18 volts?

The fixed outputs of the TIU are just a relay, so you can't "dial down" the voltage there.  You could run the variable channels at a lower voltage.

Why go to all this trouble for a cheap transformer?  I'd get a PH180 and be done with the issue.  I think you're going to way too much trouble for a $40 power brick.

PH180, You mean a powerhouse 180 right? For 40$? I have 8 Z-750 already, so if I can make them work it saves me buying new $80 transformers (X4).

John,

The TIU sets voltage based on the assumption that the input voltage is 18 volts.

Actually, that's not quite correct.

The Fixed channels make no assumption at all as regards the input voltage. As you correctly say, they pass voltage straight through. In fact, I have voltage-hungry subway sets and, when I run two sets on the same track, I increase voltage to 19-20 volts because they tend to reduce the voltage on the tracks by 3 or 4 volts.

The TIU's Variable channels, however, are a different story altogether. They assume an input voltage of 22 volts, the maximum output of a Z4000 handle. When they adjust voltage they do so by dividing the input voltage by 22. For example:

• With 22 volts input, setting a Variable channel's voltage to 16.5 volts multiplies the 223 volts by 16.5/22 for an output voltage of 5 volts.
• Similarly, with 18 volts input, setting a Variable channel's voltage to 16.5 volts multiplies the 18 volts by 16.5/22 for an output voltage of 13.5 volts.

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 on the link below to go to MTH's web page for the book!

How do you "increase the voltage"? What transformers are you using?

Thanks Barry, 22 volts.  I probably could have found that if I looked, I knew the fixed channels don't do anything to the voltage.

I'm just curious drodder, how did you end up with eight Z750 bricks?

I got 4 for the TIU and 4 with controllers to use on the conventional engines for the Christmas layout, a future Living room Ceiling train, a kids layout and a spare. Bought them on garage sales and e-bay in sets.

Personally, I'd put them up for sale in the for-sale forum and buy a couple of PH180's, but that's just me.  I regularly buy PH180's for $70-80, and you should be able to come close to that for two of the Z750 units.  Sell four and have two 180W transformers that put out the proper voltage for TMCC, problems solved.

My plan is run conventional: power TIU w Z500 and z1000 for each variable input.

Does this limit me to run only MTH? I was hoping to add a TMCC equipped engine.

Alan

First thing that Barry will tell you is you can't connect to different voltage transformers together, I'm still going to try a 750 and a 1000 but it doesn't sound good. You can run a Lionel on the 1000 brick as it is 18 volt already.

I didnt realize the z750 put out 21+ V. The z500 is just for powering the TIU.

Yea should be fine running Lionel TMCC with Z1000 brick.

Alan

Well, if you're paralleling them, he'd be right.  You can connect like transformers together, say two Z1000 or two Z750 to increase the current on a single output.  However, connecting transformers that have different output voltages in parallel is a bad idea.