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Sudden strange phenomenon I can't figure out.

Running my trains. All going well. Sudden shut down of all engines (4 MTH PS2). Transformer (MTH Z-4000) shows 0 volts and amps to tracks when this happens, and no shorts or blinking red lights. Power remains on to the transformer.

If I start everything up again all seems fine for a few minutes, until all track power dies again.

Any thoughts?

Tony

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@romiller49 posted:

Sounds like you are maxing out the transformer. Try running just three engines  at once.

Thanks for that.  I just tried that - running 3 trains instead of four.  All was fine.  I think this is the first time I have experienced this problem because I rarely run my trains fast, and today I was really letting them fly.  Maybe too much juice required! 

The Z4000 has meters, what are they telling you when they're running.

Truthfully, I'd be looking for a loose connection that might be overheating and causing the disconnect.

Gunrunner…….something seems fishy here…….If Tony is running four PS2 engines….… and, I assume nothing else except the inherent headlight(s) and smoke unit(s), shouldn’t a Z4000 handle them no sweat?

Peter

Gunrunner…….something seems fishy here…….If Tony is running four PS2 engines….… and, I assume nothing else except the inherent headlight(s) and smoke unit(s), shouldn’t a Z4000 handle them no sweat?

Peter

You'd think so.  That's why I think it's a poor connection that's heating up with the load.  Add to that the zero volt indication on the Z4000, and I think it's likely something internal to the transformer.  It cools down and away you go again.

You'd think so.  That's why I think it's a poor connection that's heating up with the load.  Add to that the zero volt indication on the Z4000, and I think it's likely something internal to the transformer.  It cools down and away you go again.

I sure hope it's not the transformer.

Both meters on the transformer read 18 - 19 volts, and less than 5 amps when these engines are running.  When the shutdown happens they immediately drop to 0.0

I'm going to double check those numbers right now.

The draw bar connection between one locomotive and the tender was almost disconnected. I've reattached it, but have not run all 4 since.

I've been running all 4 engines without any troubles until today.

You'd think so.  That's why I think it's a poor connection that's heating up with the load.  Add to that the zero volt indication on the Z4000, and I think it's likely something internal to the transformer.  It cools down and away you go again.

My transformer numbers.

Made sure all engine A/B units are connected properly, as well as that suspect steamer/tender unit.

Been running all 4 at 30+ scale mph for 15 minutes now without a problem.

Do you think it could have been that loose connection on the steamer? 20240228_225616

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@Tony posted:

My transformer numbers.

Made sure all engine A/B units are connected properly, as well as that suspect steamer/tender unit.

Been running all 4 at 30+ scale mph for 15 minutes now without a problem.

Do you think it could have been that loose connection on the steamer? 20240228_225616

When you say you "start up again", exactly what action do you take, starting from seeing the voltage zero and everything stopped?  Truthfully, my top suspect is the transformer due to the fact that voltage drops to zero with no error indication.  Clearly, you aren't overloading anything with those numbers.  Hard to imagine a loose drawbar could do what you see.

When you say you "start up again", exactly what action do you take, starting from seeing the voltage zero and everything stopped?  Truthfully, my top suspect is the transformer due to the fact that voltage drops to zero with no error indication.  Clearly, you aren't overloading anything with those numbers.  Hard to imagine a loose drawbar could do what you see.

Well that's concerning!

All numbers drop to zero, as reported. I pull both transformer power levers back down to the start/no track power position, turn off the transformer, turn it back on, reset to 18 volts, restart engines with my DCS, and all fires right up again.

Do the voltages on both sides drop to zero?  How are the two sides connected to the track?  Remember, you should not parallel the two channels of the Z4000, that can cause issues.

I was just able to reproduce the issue. Just happened again. I noted that the voltage initially drops from 18 on both tracks to under 10v (more like 8v), then almost immediately to zero. Both sides. 

I'm such a novice at electrical issues that I'll need to research what you mean by running channels in parallel.

Tony

Do the voltages on both sides drop to zero?  How are the two sides connected to the track?  Remember, you should not parallel the two channels of the Z4000, that can cause issues.

Narrowing this down now. The issue is track #2.  When I repower track number one there's no problem. But when I begin to power up track number two I immediately getting overload red blinking light. There are no deralments.

Question: should I have insulating pins on my center power and/or common rails on my 4 way Ross switch?  That's the only spot I can see where power from Track 1 and 2 might be shorting out.

Well, I'm thinking this is the transformer. I'd try a different power source as my first choice.

If no alternative exists, how about you consider testing the transformer independently?  Failing any other load, see if you can find a few automotive headlights bulbs.  Wire them up in parallel as a load on both channels, two each.  You can get bulbs cheap on eBay.  You may have something around the house to provide a load on the transformer, I know I have some spare H7 bulbs in my garage for instance.

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@Tony posted:

Narrowing this down now. The issue is track #2.  When I repower track number one there's no problem. But when I begin to power up track number two I immediately getting overload red blinking light. There are no deralments.

Question: should I have insulating pins on my center power and/or common rails on my 4 way Ross switch?  That's the only spot I can see where power from Track 1 and 2 might be shorting out.

Insulate the two tracks from each other.  You need insulating pins between the two loops, that's likely one issue!  The Z4000 does not like it's two outputs connected together!  You only need to insulate the center rail.

Last edited by gunrunnerjohn

I slightly disagree, the transformer is doing it's job. When you trip overload for a long enough period, the Z4000 cuts both channels, and then you have to lower both handles and start again, the transformer is operating as intended (you can argue you don't like the way it works).

@Tony posted:

Narrowing this down now. The issue is track #2.  When I repower track number one there's no problem. But when I begin to power up track number two I immediately getting overload red blinking light. There are no deralments.

Question: should I have insulating pins on my center power and/or common rails on my 4 way Ross switch?  That's the only spot I can see where power from Track 1 and 2 might be shorting out.

Yes, you should have insulating pins, however because both are in phase from the same transformer- it should NOT cause a short circuit/ overload. EDIT- for clarity, what I'm saying is you would see the channels bonded together (might call that shorted) but not cause an overload indication- just when raising one handle the meter displays both channels rising voltage.

Again, you should not parallel 2 outputs of a Z4000, I agree with that 100%, however, if it does happen, it just looks like voltage bleed from one to the other channel and the voltmeter of both channels will show this happening.

What we have here is a true short or miswiring on the track, or some other condition shorting that output.

Testing:

#1 remove the wiring from the transformer on the offending channel (2) and raise the handle. If the transformer is still overloading then the short is internal (probably a failed shorted MOSFET on the powerboard). If it doesn't show overload and varies- then you have a real load short somewhere in wiring or track.

Last edited by Vernon Barry

From the Z-4000 manual.  Shorting the outputs together is not a good idea!

I strongly suspect this is what I was inadvertently doing it through my ignorance of how to hook things up electronically.

I have insulated the two sides of my four way switch. I've been running all four trains for the last fifteen minutes at high speeds. I have not had any shutdowns or problems. I suspect the reason why I could not reproduce the problem last night was that I need the right combination of engines hitting certain parts of the track to create the short/overload. I'm guessing I need two engines crossing the four way at the same time to reproduce the problem. Now that i've got it insulated I've had that combination multiple times and not had a problem.

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