No Dcs signal from TII

Do they turn on ?

Have you checked for shorted fuses or tvs suppressors ?

A model/rev # would also help.

Yes they turn on, one unit is probably 20 years old doesn't have any fuses, tvs is good there is power to the track. Other 2 units are rev L fuses are good tvs as well, power to the track.

1. Have you tried changing channels to see if that helps ?

2. What happens when you try to run a train ?

3. Are you able to check signal strength with the remote ?

4. Happens with one engine or multiple ones ?

5. Have you checked voltage at both the channel inputs and outputs and on the track ?

Tried all channels, no dcs output, the engines come on as soon as power is on the track, can't check signal strength, happens with all engines, checked all voltages in and out.

Took millivolt readings on the transmitter chips, all seem to be about the same, the 5 volt regulator is getting hot, all I can figure is there is some kind if internal short in the tiu.

Have you tried doing a feature or factory reset ?

Yes

Menu, System, DCS setup.    DCS "ON" in either your Fixed or variable channels.

Yup I have done this as well

1. Any error messages ?

2. Do the engines run properly in conventional mode ?

3. Do you have access to a known, good TIU that you can swap in ?

Richie, I have talked to Jon about his issues, and I can tell you he's well beyond what you're asking.  He indeed has a working TIU, and there's nothing wrong with the engines.

A while back on OGR someone reported they can "hear" a TIU sending out DCS packets using an AM radio (not FM, only AM).  Does anyone even have a pocket AM radio anymore?

Additionally, there is this DCS Port Tester tool.  The info is embedded in a long project thread in the Electrical Reference section.

Both of these are meant to indicate DCS "activity".  It doesn't tell you if the high-frequency DCS signals are correct or mean anything...just that there is something that appears to be more than the AC track voltage.  And something you can't detect/measure with a meter.

If you have a known good TIU you might be able to do a side-by-side and confirm that indeed nothing is coming out of any DCS channels.  And even without sending TIU commands, when you first turn on a DCS channel you should get DCS Watchdog activity which should have an activity "pattern" that can be recognized.

Note that the DCS signal tester requires a pure sine wave transformer feeding the channel to properly function.  However, it's a great go-no go tool for checking DCS output levels.  The only issue is that it's a lot harder to check input DCS signal reception functionality.

Given that all 4 generators are apparently not operating correctly, which to my way of thinking is not normal, what is common to them? Are all 4 powered from one source? Is that source operating correctly?

Chris

LVHR

It could also be the receiver circuitry as it's all in one place.  AAMOF, it's probably more likely to be a common element when all the channels fail.  Remember, we haven't actually looked at the output signals from the channels.

The receiver chip has been replaced,  no change.