Z 4000 Problem

We need more details on your system.

What do you have between the Z4000 output and your track?

A TIU?

A DCS silver Explorer box?

Again, what you said if I read it correctly, your Z4000 works if not connected to anything.

However, when you plug in your track system- and whatever DCS control device (TIU or Explorer) then the short happens.

Most likely, you have created a voltage spike event that killed a TVS (Transient Voltage Suppressor) that then is now shorted across the track wiring.

I have TIU and Lionel Cab 1.  So what canoe done.

I have a TIU and and Lionel Cab1.  So what can be done.  I assume this is in the TIU.  Not the track connection.

My transformer and all the apparatus is plug into a multi plug protector and I have a  surge protector for the house.

My transformer and all the apparatus is plug into a multi plug protector and I have a  surge protector for the house.

Yes, a surge protector works for power coming into your house.  However, every time your train derails, makes a spark, your track and power system can generate voltage spike on that lower AC voltage side of the transformer that a standard power strip or surge suppressor doesn't do jack squat for. That voltage spike can damage your engines, your control system, and even the Z4000 transformer.

Further, it appears you may have no circuit breaker or fuse protection between your Z4000 and TIU, and so when/if something inside the TIU fails, the amperage readout didn't lie, you can pass up to about 12Amps for several seconds before the Z4000 indicates a fault and then stops providing current. So what might be a minor issue with a small failure could become much worse damage and much more expensive repair or replacement problem. Given the fact that TIUs are in short supply and demand has driven the price to stratospheric levels, one would hope users would be more proactive

Root cause analysis:

Again, most likely, some derailment or other action at the track while powered generated a voltage spike high enough that the internal voltage suppressor TVS inside the TIU tried to clamp this spike and then was damaged. They fail shorted. Since this is on the output of your TIU where this TVS is placed, now that short is causing those 12+ Amps to flow through the TIU input, through the internal TIU circuit traces and components, and then be shorted by the blown TVS. Worse, you did not state what revision of TIU hardware you have and if it has fuses or not internally. Earlier revisions have no fuses, later revisions have fuses, but they are 20A rated, so by the time they blow, the TIU has taken serious abuse and more damage may have happened to the TIU beyond just a failed TVS.

What can you do?

#1 use a multimeter to check the TIU channel output with nothing connected is shorted. We already suspect this since when it is unhooked, the Z4000 was no longer shorted. Also you stated other TIU logic related problems that would happen with loss of power to the TIU.

#2 Most likely, this was fixed channel 1 of the TIU which is also used to power the TIU logic. In order to power the logic and use another channel- you then need to connect a power source to the AUX input of the TIU and then connect your track path and transformer input to a channel other than the one damaged. This effectively "works around" the damaged TIU channel problem. You didn't mention aux power when I asked about other components and how your system is connected.

#3 Alternatively, if you are comfortable with electronic repair, you could open your TIU, test and measure the suspected TVS diode shorted, then cut the leg of that TVS diode thus removing the short. The problem then is, there is a reason that TVS diode shorted. It did it's job and died in the process trying to protect your expensive TIU. It's not recommended to then run that channel without a TVS installed as now any voltage spike will just pass right on into the rest of the circuit unhampered and cause maybe even more damage.

Your fault is somewhat like what happened in this topic https://ogrforum.com/topic/28601350494762795

Also, this search produces dozens and dozens of similar stories. https://ogrforum.com/...agination.sort=SCORE

1. Just because I'm confused, if you remove the power from the problem handle of the Z4000 from the TIU and connect it directly to the track, does it still register excessive voltage or is it normal ?

2. Assuming that it performs normally when disconnected from the TIU and connected directly to the track, as VB suggests, first power your TIU through the AUX port with a correct wall wart (assuming you are not already doing this - you haven't given a lot of details).

3. Now connect the problem transformer handle to Fixed 2 Input and make your track connection from the TIU to the track from Fixed 2 Output. If Fixed 2 is already being used, then use Variable 1 Input and Output. You can convert Variable to Fixed later on if this works.

Please post your results.

@Missabe posted:

The power side of the Z 4000 when turn up to 18 volts a Overload comes up.  I unplugged the power side.  It powers up as it should.  I then tried slowly powering up and after 5 to 6 volts the amps went up to 11 to 12 amps.  On the other side the amps 1.5 amps at 18 volts.

Even tried removing all the engines & cars.  still read overload.  I checked all the track and even vacuumed it.  Still read overload.

I don't know if the the MTH Wifi has anything to do with this problem.  Know I have remote problems and App problem they won't let me choose a engine on phone or the 2 remotes.  I put new batteries in the remotes, still no change.

I had the same issue with a Z-4000....and i don't even own a TIU. I was told the there is an issue inside the Z-4000 on the side that is acting crazy. I bought it used and told the seller about the problem. He told me to return it and he sent me out another. He said that it came directly from MTH Warehouse layout and that he bought 8 of them.

Vernon,  You're right, I had a derailment.  I had a run-away.  The young man I was showing my layout to, he barely caught it before it smashed into another drag.  There were sparks.

The TIU REV L  any idea what a repair would cost?  I don't know if Scale Model Hobbies in St. Paul can fixit or they have to send it out.  Either way I will have a long ride or mail it.

Thank you,  Gerry

Did you try switching the problem side with the other handle?

I took the TIU apart and the only thing that looks like a TVS is brown & square with the word KDIE China.  Nothing looks burnt or smells burnt.

John,  yes I did and it worked fine.  I switched it back and still overload.

What TVS from Digi Key the Number do the recommend.

Gunners 1.5KE39CATPMSCT-ND  I can't find.

Sorry to hear your problem

but your description is not clarifying the problem

I would start simple

connect the Z-4000 throttle in question to an independent piece of track-see what occurs.

if you don’t have a track section, try swapping the throttles-see if the issues follow the throttle or stay with the track.

you don’t say what track you use-I had an issue I couldn’t find for months-turns out it was a fried MTH REALTRAX turnout.

I only found it because I moved some parked cars I hadn’t ran in a while-and I actually found 2 turnouts with the same issue-

i could run trains on other areas of the layout, but not at capacity I normally had.

Video would be helpful…

@Missabe posted:

What TVS from Digi Key the Number do the recommend.

Gunners 1.5KE39CATPMSCT-ND  I can't find.

First, what channel is the one shorted? I think Fixed1

The TVS diodes circled in RED are associated with the output of the 4 channels. The 2 ones in the middle area near the heatsinks are for the variable voltage circuits, and the other yellow circled ones near the serial port section are part of the logic power supply.

Technically, the TIU used 1.5KE33 for the Red ones, and 1.5KE51 for the variable section Yellow ones.

the 33 that was stock from MTH https://www.digikey.com/en/pro...inc/1-5KE33CA/688026

the 39 that Gunrunnerjohn has mentioned https://www.digikey.com/en/pro...inc/1-5KE39CA/688030

the 51 that is the variable channels https://www.digikey.com/en/pro...inc/1-5KE51CA/688036

Higher numbers mean the higher the voltage it will pass. Again, factory, your TIU had 33, the recommendation for external was 39, and internally the TIU for the variable channels used 51. I think the recommendation is for putting a 39 in but wanted to give you all the links and options and you decide what is best for you. Remember higher passes higher voltage before blocking the spike. Lower number like 33 in theory lowers the threshold.

The Z4K should be tested with nothing attached. If it powers up and acts correctly, then the issue is not the Z4K, but rather something downstream , such as the TIU. As noted, fried on board TVSs can cause the symptoms described.

If the Z4K acts correctly, then I suggest changing the title of this thread to more accurately reflect the problem.

Chris

LVHR

@lehighline posted:

The Z4K should be tested with nothing attached. If it powers up and acts correctly, then the issue is not the Z4K, but rather something downstream , such as the TIU. As noted, fried on board TVSs can cause the symptoms described.

If the Z4K acts correctly, then I suggest changing the title of this thread to more accurately reflect the problem.

Chris

LVHR

I agree with that because that is how i tested mine that had the same issue as his transformer is doing. Nothing was attached.

This is simple. Unplug the wires on output of Z-4000 that is shorting.  Power up Z and raise handle.  No short, plug back wires in.  Now follow that wire to the channel it goes to into the TIU.  Lets assume Fix 1.  Remove output of Fix1.  Power up.  If it shorts, fixed 1 TIU channel is bad.  Probably the TVS.  If it does not short TIU is fine.  So you have to start isolating the layout.

The TIU can be repaired, but it could be more than just TVS.  You might find you know have a DCS signal issue too.

But the obvious first issue is where the short is.  I repair TIU if no one around you does.  G

Vernon, The picture you sent is exactly what I needed.  My son works for USAF instrument repair so he might be able to repair it.  I have 2 types TVS diodes.  I have 1.5 KE36CA it is black and about 5/16 X 3/16.  I also have 1.5 KE36CALFCT-ND  30.8vm 49.9vc about 3/16 X 1/16 gray stripe and black body.  Will any of these work?

We checked the fuses and they looked good.  Checked the Fixed ports 1&2 seemed fine.  Put it back together and no more Overload. Started an engine and it ran fine.  Then I shut the right side of the transformer it stilled showed 18vs.  I found by disconnecting & switching lines even from the track nothing changed.  I found if Fixed ports 1&2 were plug together that was causing the problem.  So it is a short in the TIU.  Fixed 1 works fine so its Fixed 2 has the problem.  Would that be a TVS problem or something  else.  I tried 2 engines with the remote and signal worked fine with the Fixed 1.

If the above TVS diodes will not work I will order the TVS's suggested.  This is very important because the Proctor Historical Museum layout will also need to add the TVS diodes.

I very much appreciate everyone's help.

GGG, St Paul MN is the closest 160 miles.  If I have mail it I will send it to you.  Can you give me an estimate.

Gerry

gerryanddiana@aol.com

Again, check, but yes, highly likely the fixed 2 TVS diode is shorted. Like I said, with a meter set to ohms or diode test, this is very easy to check. Physically the device may not show damage, however, electrically to a meter and to normal track power it should be open circuit as if not even there. The whole idea is when it sees a high voltage, it then clamps (AKA shorts) the high voltage until it falls under the threshold and then acts normal open circuit. However, enough abuse and they fail shorted all the time.

Test first, then cut once.

Either of those 2 TVS diodes would work. 36 has been a suggested value in various forums for a while, and though slightly higher than the original 33, again, well within a reasonable range.

And, rather simply, you could just cut one leg of the offending shorted failed TVS diode in the TIU. Then test the circuit with a meter. If it now passes with a meter (the TIU output is not shorted anymore) then place your external TVS 36 diode across the output terminals and attempt powering. If that works, then technically you have fixed the fault- a failed TVS, and added an external TVS diode, then that channel could be used again normally.

@Missabe posted:

This is very important because the Proctor Historical Museum layout will also need to add the TVS diodes.

Just to talk further about this protection side of the system.

TIUs have these built in TVS diodes. If they fail and you cut a leg as I have shown to take the diode out of the circuit. My comment is just that it is prudent to ensure you effectively replace the TVS protection on that channel where you removed a failed TVS. The logic is, something created spikes that blew that protection device, they likely will happen again and with no protection this could cause further expensive damage. That said, it could be either installed via desoldering the old failed TVS and new one put in it's place, or externally, just as long as there is a good connection to the output terminals. We could have some kind of debate about which is better and so on, I'm just trying to be practical.

OK, so this other layout "the Proctor Historical Museum layout" if it has a TIU, then it currently has the built in TVS protection of the TIU channels. Now, another debate and discussion was that you can add external TVS diodes and even at track connections, even inside engines. The cautionary tale of that was that the more TVS you add the circuit- this can degrade the DCS track signal. So some sort of balance has to be met. Somewhere between 0 added TVS for maximum signal strength VS too many for ultimate protect but then signal strength suffers.

Last, based on your responses and specifically the current (amperage readings), which is why I personally really like using Z4000s, indicates that you do not have any extra external fuses or circuit breakers between your transformer and the TIU.  Some would argue no, the TIU has fuses (20A and inside the tiu under the cover), or the Z4000 has breakers and short sensing. The fact remains, your own observations are that the Z4000 can and will output 12A (and let's be honest- that's just what the display shows) for a few seconds on a short. Given the high cost of replacement TIUs, not to mention possibly expensive engines and cars running on a display track, coupled with the fact that derailment shorts happen, TVS diodes can and do short, your trains probably do not require 10A of real power at 18V to run, we could put a fast acting fuse or circuit breaker at a lesser amperage rating for safety between the Z4000 and TIU inputs to protect the TIU and anything downstream from short circuit high currents.

All I'm saying is, we need to understand both current and voltage and they are separate, but just as important things to protect against. Fuses and circuit breakers protect against current. Current is what burns up wires, melts things.

TVS diodes protect against voltage spikes. Voltage spikes are what damages electronics causing them to fail. However, when they fail, then they become a short and that's when current kicks in and then burns them extra crispy.

According to the multimeter Fixed 2 tvs shows no short/ failure.

So what happens when you apply power to it? Should be no or minimal amperage.

We checked the fuses and they looked good.  I expected them to look good, if they were blown, there could be no short.

Checked the Fixed ports 1&2 seemed fine.  How and what did you check here? For short circuit with a meter?

Put it back together and no more Overload. Did you somehow swap fixed input1 and fixed input2 wiring to the track and or transformer?  We need a much clearer description of what is connected to what and how you are testing.

Started an engine and it ran fine.  So channel1 of the TIU and then one handle or side of the Z4000 works together.

Then I shut the right side of the transformer it stilled showed 18vs.  OK, right here is where we are screwing up badly. Is this the handle was raised to 18V, or the handle is down and it's reading 18V? What is the amperage at this time?

I found by disconnecting & switching lines even from the track nothing changed. We didn't think the track was shorted

I found if Fixed ports 1&2 were plug together that was causing the problem.  You are going to have to explain how this is wired. Again, how are channel 1 and 2 connected and to what? One side of the Z4000 or both sides?

So it is a short in the TIU. But earlier you said there is no short in the TIU. "Checked the Fixed ports 1&2 seemed fine." and then just now "According to the multimeter Fixed 2 tvs shows no short/ failure."

Would that be a TVS problem or something  else. It could be something else, but if actually shorted, then we also should be able to find that with the meter. So far, it sounds like twice you did not find it shorted or are not using the meter correctly is the only guess I can make.

I tried 2 engines with the remote and signal worked fine with the Fixed 1.- Asuming connected to the left handle of the Z4000?

Recap:

Test #1 is the Z4000 with nothing attached to any terminals. Both the left and right handles can be raised and lowered and there should be variable voltage that goes from 0V rising slowly as you raise the handle to 18V, and then lowering the handles brings it back down to 0V. Also, there should be no real amperage being drawn because again nothing is attached to the Z4000. Does the Z4000 pass this test both handles?

Test #2 With nothing attached to the TIU using a multimeter set to diode or beep test (Ohms) first touch the meter leads too each other to test the meter. Then once the meter is confirmed working and can detect a short or low resistance, you test the fixed channel 2 output terminals for a short. IF shorted, then with the cover off, check the resistance across the TVS diode. If it shows shorted, then cut one leg and re-check the channel output terminals- now the short should be gone.

Problem fixed.  Disregard previous post.

Thank for the all the help.

Vernon,  My son rechecked everything and found it ok.  I'am too embarrassed to say. But all of you deserve an answer.  Because my transformer sits almost touching a leg and it's dark I failed to see a circuit breaker popped.  I thought the 1st thing I did was check them.   Sorry for all the time and  effort you's put into this problem.

Just a note:  Even through the wires are all marked mistakes can be made.  Part of my problem was with the Lionel Cab 1 hooked to the TIU.  When the TIU was dissembled and put back together I assumed I would remember the simple reconnect.  after doing this 3 times how could I make a mistake.  On the 2nd or 3rd time I connected the hot side.  So the problem was recurring.  Finally after going back to the DCS hand book to the chapter on DCS & Lionel Cab 1&2 did I realize it was wrong and it should have been connected to the common side on the TIU.

The older I get, the wiser I should be.  Evidently I'm not.

A while back from one of the many discussions about TIUs, wiring, fuses or circuit breakers, TVS diodes, I edited one of the drawings for my personal "what I suggest" drawings. I stupidly did not pay more attention to who made the original drawing to give them credit so for that I am sorry.

Vernon, I will be making copies of your attachment and of who ever made it.  It's the most simplistic drawing to understand.  It should be added to the DCS Companion book in the future.

Since there is no Radio Shack.  I assume Digikey  would have them.  Suggestion on type to buy.

Any O gauger who doesn't support this forum wealth of information & help.  Needs to rethink the future help the might need.  Again thank you O gauge Forum.

Gerry

Vernon Barry,

  I think you want to give credit to CAPPilot, See his reply to PSX1-AC on 2-16-2021.  I have also copied his work, his drawings are very clear. I wish I had a better way to make my own electrical drawings.  k

@Missabe posted:

Vernon, I will be making copies of your attachment and of who ever made it.  It's the most simplistic drawing to understand.  It should be added to the DCS Companion book in the future.

Since there is no Radio Shack.  I assume Digikey  would have them.  Suggestion on type to buy.

Any O gauger who doesn't support this forum wealth of information & help.  Needs to rethink the future help the might need.  Again thank you O gauge Forum.

Gerry

As a bare minimum a fuse or a reasonably fast acting thermal breaker such as the "Multicomp AN-501 Self Resetting 5 Amp Breaker"

Again, thermal  breakers are slower to trip than some other fas acting forms of breakers like magnetic based versions. This is because it takes a certain amount of time before a thermal breaker is heated during the overload to then actuate. That said, their lower cost is attractive. I've been using them on my personal layout since roughly 2019. I am planning on putting in PSX-AC version of electronic breakers Sunday, I've just been trying to integrate an MP3 player announcer module that says what track is shorted based on which PSX-AC tripped.

Again, there are faster acting protection methods that provide even more "safety" in that they trip the instant a current threshold is tripped.

Previous discussion https://ogrforum.com/...c/155152949957522430

PSX-AC discussion with credit to @CAPPilot for his excellent diagrams. https://ogrforum.com/...25#70693070953394325

@Missabe posted:

Vernon,  My son rechecked everything and found it ok.  I'am too embarrassed to say. But all of you deserve an answer.  Because my transformer sits almost touching a leg and it's dark I failed to see a circuit breaker popped.  I thought the 1st thing I did was check them.   Sorry for all the time and  effort you's put into this problem.

in my opinion, No apology required

you gave everyone an opportunity to stretch their brain muscle  

in Electronics we have a term..it’s

KISS Keep it simple stupid

i reverse the last two-keep it stupid simple…which means check all the basics first…

is it’s plugged in? Is the outlet hot?

is it on? Is it connected properly?

etc  

on the bright side, you have gained insight you might never have gained  

and we gained some too😁