Low voltage out on Var 1, even after factory reset TIU and controller

Marty, I have no idea what's wrong but proto-2 engines start up in neutral in conventional mode unless purposely locked into a certain direction

 

In command mode the engine should remain dark and silent until instructed to do something.

 

Are you sure the dcs signal is turned "ON" and Are you running the PE( TMCC? with the dcs remote in command mode?

 

You may be familiar with this......Menu/System/DCS set up/ a lot of options here.

Try setting the Variable channel to FIXED and see if it works. The channel should work like your other fixed channels.

Menu

System

DCS setup

Variable 1

S5 softkey sets it to FIXED

 

 

Marty,

 

Please test as follows:

• Connect a power source to either Fixed In #1 or the Aux. Power port
• Connect a power source to Variable In #1, preferably 22  volts or 18 volts
• Make sure that Variable #1 is in variable mode
• Disconnect everything else from the TIU
• Using the remote, set Variable #1 output to 18 volts
• Measure the voltage at both the Variable #1 Input and the Variable #1 Output.

If the voltage at the output is close to 18/22 of the voltage at the input, the TIU channel is operating correctly.

"In command mode the engine should remain dark and silent until instructed to do something."

 

The key word is should.  It does happen occasionally that a dark & silent loco will start moving. 

Gregg, Joe,Barry 

Thank you, all good suggestions. Thank you for taking the time.

 

Gregg - I agree. It should do as you say. It didn't, but it does behave on the good channels, so that issue is moot. It is the new RC Polar Express. The LionChief remote controls it on the DCS 18V

 

Joe - Been there, see below

 

Barry

I did as you suggested.

Radio Shack 18V to Aux Port - it has been a constant (2nd yr)

Z1000 to Var 1

DCS Setup Var 1 Variable

Everything else already disconnected

Vin 19.9 V

Vout 10V

It doesn't matter what Variable Voltage I choose, 22V, 18V 10V including TZV which does read 0.0 on the handheld. Vout = 10V

Change Variable 1 to FXD. Vout = 10V

Disconnect at Vout Vout 1.7V, 

 

Side note/ complication. Now that I am troubleshooting, I keep blowing the 20A fuse on Fixed 1. If it was a track short it would blow the Z1000 fuse. I’ve done it enough.

 

What blows the internal fuse as soon as you power up the TIU? My power supplied are Phased and my Variable 1 loop isolated from the other loops.

Marty,

 

It appears that Variable #1, at least, has a problem.

 

If Fixed #1 keeps blowing its fuse without anything connected to Fixed #1 Out, then Fixed #1 has a problem, as well.

Thanks
It hasn't blown with nothing attached, but I haven't left it in that state for long. It does periodically blow under load.

To my question of where to get it fixed? My 2 LHS would just send it in. Does anyone actually fix them in thier shops? 3 Christmas layouts, 3 years of failed channels. for the sake of argument I could have blown a channel through inexperience, but this isn't me. If it were that fragile, the product line woulf be dead.
Most love DCS, so do I. I may contact them, but I'd rather not.

There are a number of talented  repair forum members right here on the forum.... GGG is one of them, saved me a bundle

Marty, Depending on the exact problem, it can be a time consuming repair problem as several FETs have to be remove/reinstalled to determine which one failed.  I can do it, but I can't promise this one in a timely manner.   G

Marty,

 

You first stated that everything was disconnected, then that Fixed #1 kept blowing the fuse. If this is not the case and Fixed #1 fuse only blows under load, then the issue is most likely on the tracks connected to Fixed #1, and the channel itself is OK.

 

You can verify this by swapping the tracks on Fixed #1 with the tracks on another channel. If the problem stays with Fixed #1, the channel is the issue. However, if the problem moves to another channel, the problem lies with the tracks.

Barry, 

Agreed as Fixed 1 is running well now. I had a derailment on fixed 2 tonight, and the z breaker tripped. What kinds of things take out the 20A fuse? What kinds of things take out a channel permanently?

Marty,

What kinds of things take out the 20A fuse?

That's hard to say. I use Z4000's and, in 10+ years using the current layout, I've never blown a fuse in a TIU.

What kinds of things take out a channel permanently?

That could be due to a weak or defective component in the TIU, or a failure of the TVS circuit in the TIU. It's really hard to say. However, if you have adequate external circuit protection (fuses or circuit breaker) it really should be a rare occurrence.

If a 20 amp fuse keeps blowing, this indicates to me the circuit has inadequate protection.  Somewhere there should be a 10 amp or so fuse or breaker which would blow first.  If more than one transformer feeds the TIU, are you sure they are properly phased?

Is the TVS after the fuse?  If so, that going bad would explain the fuse going.  Since I've replaced a couple of those already, they do go bad.  Fortunately, they're easy components to replace.  Mine would trip the 180W brick CB, but if you had a slow circuit breaker on the transformer, it could take that fuse instead.

 

 

Marty, Responded to your e-mail.  It is interesting, since the transformers are much lower amperage that the 20 amp fuse is blowing.  Unless there is some sort of phasing issue with your layout.  Maybe different loops not phased right at some connection point?

 

G

Actually, you can blow a larger fuse with a lower capacity transformer, it's all in how fast the circuit breaker reacts.  The fast blowing fuses don't give much time for a current surge before they go.  If that wasn't the case, it would be almost impossible to blow the 20 amp fuses in the TIU, since you rarely power the TIU with a transformer that has that kind of output capability.

Easy way to know if your loops are phased.... Use  a light bulb with a couple of wire leads or  a volt meter Place  one lead on the center rail of one loop and the other lead on the center rail of the other loop.     The voltage should be very low.. (2 or 3 volts at best and the bulb should be really dim. If the voltage is high or bulb bright, the loops are out of phase.... Yep! measure center rail to center rail not center to outside rail.

 

We should really do this at the beginning of wiring   the layout.

I understand that John.  And the 20 amp fuse is not a quick blow either.  I have not had to deal with fuse, though I am sure others have.

 

He states his Z1000 was popping the breaker.  Isn't that just 7amps.  So unless it really is bad I am having trouble pointing to the issue unless a second transformer is sourcing current too.  G

I'll agree that this is an issue that it would help "to be there", sometimes diagnosing in ASCII is difficult.  FWIW, I saw nothing about the 20A fuse in the TIU to suggest it was a time delay or slo-blow fuse.

Wow, 

Took a while to read all that. Thanks.

The Channel that blew (10V out under load) was protected by an Atlas 80W transformer. That transformer never had a fuse trip. Not sure how it handles shorts.

The Channel that was blowing the 20A fuse was powered by a Z1000. The loop is a large (50' ish loop), with a siding. RC Polar Express, 8 cars and a Premier Berk, pulling a few cars that use track voltage.

 

After Variable 1 blew, I took my other Z1000 and have it powering Fixed and Var 2,  by jumpering on the input. All loops are separate, except that they all come back to the TIU. There is no track connection, between the 3 Channels. I blew 5 or 6 fuses on Fixed 1 yesterday, but have been fine last night, for a few hours and this morning before work, for 2 hours. I'm going to run tonight. I checked my transformer phasing by putting my meter leads into the positives and read 20V, not 40. I thought this meant they were in Phase. I will post the Track plan, but it isn't on this computer and don't think it will shed any clues. The upside is it got me to consider putting my electronics elsewhere next year.

 

As to troubleshooting, I don't think any of you are in Central Jersey, but I always like to show off the Christmas layout, LOL. I will send the unit to GGG after the season and we ill take it from there.

 

I'm thinking a higher end transformer might be my next wish list purchase, but want to investigate other vendors as the Z4000, seems outdated, as the bells and whistles are aimed at PS1, where the Lionel transformers give Amperage readings.... We will see.

The fuse keeps blowing on Fixed 1 because there is a problem inside the TIU I believe. What version TIU do you have? It's on the bottom and will be something like I3A, I-3, etc. Since I believe you stated VAR 1 had already gone out also, I'd think of a new TIU as it sounds like some of the Chinese electronic components have reached the end of their life. We have to realize that the electronics we all love, are not going to hold up like the post war stuff.

Paul,

it's a Rev L that I bought at myLHS 2 years ago. This is the beginning of it'e 3rd season. Channels have blown every year. This is the first ear Var 1 has blown. Previously, it's been the fixed channels

 

And I take back my comment about looking beyond the Z4000 for my next Power supply. I like the lighted readouts. I'll need them for where the unit will sit

I think the TIU should have a useful life of more than two-three years!   I think the TVS protection diode may have shorted, which will take out the fuse.  Another reason might be excessive voltage on the input just reaches the firing threshold for the TVS protection diode.

 

I cannot comprehend a properly functioning 80-watt transformer not having its breaker open on a current that blows a 20-amp fuse in the TIU.  4-5 amps should be close to an overload.  Therefore, below in this post I am assuming the transfomrer is not.  For now, I must disagree with GRJohn.

 

Do I understand correctly that all three of your loops are entirely separate--that a train cannot go from one to another?  If a train can do so, your loops are connected together electrically, like it or not.

 

The fuses in a TIU are on the black side, if I recall correctly.  Somehow, ground from your layout is passing through the TIU black wire, but not going to the 80-watt transformer.  You have a wire going from the transformer to the black TIU input, and another going from the transformer to the red input.  Are any other wires connected to the black input wire or on the terminals of the transformer or TIU to whicih the black wire is connected?

 

If the answer is yes, you have a wiring issue, which could be transformer phasing, or it could be that somewhere on the layout a ground wire is disconnected.  To phase 2 transformers:  disconnect both transformers completely from the track; connect the corresponding ground terminals together (usuallyU), set both transformers to 15 volts.  With your AC voltmeter, check the corresponding hot terminals, you should get 0 or pretty close to it. If you get around 30, you're out-of-phase.

What can I say, you're free to disagree.  I have seen this on several occasions.  The fuse is much quicker acting than the breaker.  I can take the MTH Z1000 with a properly functioning 6A breaker and connect it to a 20A automotive fuse of the type found in the TIU, and it'll blow the fuse and not open the breaker.  Try it, you might be surprised.

 

GRJ, iIf an 80-watt transformer is putting out over 20 amps, the breaker should mblow pretty quickly.  A 20-amp fuse will take slightly more than 20 amps for a considerable period of time before it blows.  On my layout, I have 5 or 7.5 amp breakers in series with 10 amp fuses for redundancy & have never blown a fuse.

 

I think there is a phasing issue on this layout, or a defective ground wire.  That's why I want to know if there are any other paths betwixt transformer ground and TIU ground.

I'll go further than that, 2-3 yrs useful life is an oxymoron!

The 3 loops are COMPLETELY separate. 1 raised oval. 1 figure 8. No turnouts on these. 1 larger loop with a siding (2 Wye turnouts)

On the channel that is now dead, 1 red wire 1 black wire to the corresponding inputs.

On the channel that blew fuses, same

 

On the Channels that have been flawless (this year)1 red, 1 black to fixed 2 in. fixed 2 is jumpered to var 2, so I can use both channels.

 

I'm going to rewire everything next Christmas. This year from the TIU directly to the oval and figure 8, I have original MTH banana plugs, going to realtrax lockons.

 

For the larger loop, I had MTH bananas to MTH terminal strip. From the terminal strip to 4 lockons, I used copper wire you would use to rewire a lamp. On the terminal strip end, I put a spade connector. On the lockout end, I went through the hole, in the post, and crimped down. 

 

After the fuse blowing, I replaced the banana plugs, to the terminal strip, with lamp wire. This may have had an effect, but I wanted to get through a day of playing (I mean modeling ), before I said anything.

 

Next year, it will be all new lamp wire. I will draw out and confirm where I should tie my grounds together, but I think that since my loops are separate, I'm good.

 

I will mention the TVS Diode to GGG, when I send it in. Chances are, he knows that, but, why collect this knowledge and sit on it.

 

 

I would try removing all the inputs to Fix2 and VAR 1 and 2.  Just power Fixed 1 with the transformer of your choice and run the one loop to see if the fuse still blows when only one channel in use and no other transformers attached.  G

No blown fuses since Sunday. Keeping fingers crossed and not touching anything, unless something blows, or the Volt meter car dips way below 18