Ok. First time since may that I fired up tiu.  Plugged power to var. 1. Thought my track locking was bad. Nope.  Wires all tight.    Now, there is power. At aux. Input. I see a red light on tiu.  I plugged power to fixed 1 and I saw a red light.  Nothing in fixed 2 or var. 1 or 2. 

I get no output power to track. Lock on won't light up. What the heck could it be?  I never had any issues before. Now all the sudden I do! 

I have the older tiu. Not a rev. L version.

Thanks for any help
Chris
Original Post

 

take the cover off and check the internal fuses if it has them some of the older ones did not have them.

Alan

 

which version is the tiu the rev is on the bottom of the case!please show us a picture of the bottom of the case! also do you use it with a remote or only use as variable control? 

o gauge  trains ,music ,computer repair windows 7 and 10!

ASC Tech MTH school completed! 2019 !

Just to make sure we're on the same page...

 

You MUST have power on the input to a specific channel in order to have any output voltage.  Just making sure we're not expecting otherwise.

 

When you apply power to the TIU, do you see the light blink once to indicate the TIU address?  If you power the fixed #1 input, can you run DCS locomotives using the fixed #1 output?

 

I run my TIU with the variable channels configured in fixed mode.  That allows command operation normally, and they'll revert to variable if I select a track and vary the voltage.

 

What are you using for power into each of the 4 channel inputs?

 

Are your variable channels set to fixed or are you scrolling up power to them using the TRK screen on there remote?

 

Did you check all the fuses (in the TIU or external) and circuit breakers?

Barry

 

DCS Ambassador & author of The DCS Companion series of books

Train-Ca-Teers - All For O and O For All!

 

I put the z1000 on first, the variable 1. I had no red indicator on tiu. And no lock on light. Tried to apply power to variable 2.  Nothing.  I got a red light on fixed 1. Only.  Fixed 2 nothing.  I also got a red indicator when I plugged in the z1000 into the tiu input.  So something is working. But I'm not getting any output voltage. 

Reset tiu?  I don't have any fuses in mine that I see.  Soldered connections though on terminals.

you always get a red blinking light n the tiu on power up , should blink 1 time when first turned on.!

Alan

You always have to have power either fixed input one to power up the tiu control circuits or the aux power input! either input will power the tiu. if your using variable one or two you need power at one of those inputs.

But remember if you power fixed variable voltage 1 in you must have power also to either fixed voltage in or aux to power the tiu electronics!

Alan

you should buy barry's  book it explains everything you need to do to run DCS or variable control form your remote and has all the requirements and what to check in detail when you have a problem such as you do ,will save you a lot of time troubleshooting by using the  DCS COMPANION!

Alan

o gauge  trains ,music ,computer repair windows 7 and 10!

ASC Tech MTH school completed! 2019 !

Kind of sounds like you're not  powering up the tiu . The TIU need a power supply to  turn on, operate  /function.

 

2 ways to turn it on.... power to fixed 1 or an aux power supply

 

. Nothing works unless   the tiu is powered up...Fixed 2 is a straight through connection so even though power flows through it the tiu is still  dead and there's no dcs signal. The Var channels are also dead.

Bottom line make sure the tiu is turned on by checking out the led on the top of the tiu.

I think I found my issue.  Mth. Pigtail was loose on the inputs. Wire pulled out from the plug end.  I'll find another and hope it all is fine. I'll make sure I first use the fixed 1. And see if that will light my track up. Then I hope all goes well after with startup.  I thought I changed my var. To fixed last year. But maybe I changed it to run a bump and go trolley.  Memory failing!  Lol

Chris,

 

You MUST power the TIU from either the aux power input or Fixed #1.  You will never get any output from the variable channels unless one of those two power sources is connected and active. 

Chris,

 

From page 95 of The DCS Companion 3rd Edition:

 

Providing Power to the TIU

Like any other electronic component, the TIU requires a power source. MTH designed the TIU so that it can be powered in two different ways.

 

One way is to use the track power that is present at the inputs to TIU Fixed Channel #1. This power source is

available whenever the O gauge operator is running trains on tracks connected to Fixed Channel #1.

 

Another way to power the TIU is to use a separate power supply that is plugged into the TIU's Aux. Power port. In this case, the TIU would have power all the time. Any power supply that provides between 12 and 22 volts AC or DC at 1.5 amps or greater, equipped with a compatible barrel plug, may be used.

 

If the TIU is a Rev. L (or later) that has a USB port, the TIU may alternately be powered via the USB port. However, this should only be done when using the TIU solely to update TIU or DCS Remote software. In order to perform DCS engine sound file transfers, DCS Remote backup or recovery, DCS engine operation, or activation of switch tracks or accessories connected to a TIU's AIUs, power must come from either the Aux.

Power port or Fixed Channel #1 Input.

 

When the TIU is powered through Fixed Channel #1 Input, every time the power to the tracks controlled by Fixed Channel #1 is interrupted for any reason, the TIU turns itself off. However, when the TIU is powered through the Aux. Power port, the TIU remains turned on regardless of the state of power applied to the tracks controlled by Fixed Channel #1.

 

This and a whole lot more is all in MTH’s “The DCS Companion 3rd Edition", available for purchase from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at MTH's web store!

Barry

 

DCS Ambassador & author of The DCS Companion series of books

Train-Ca-Teers - All For O and O For All!

 

Ok. Got it going fine. Dcs responded fine. Remote worked.    Fixed voltage 1.  Powered one of the engines. Went fine. Then stop...... breaker popped on my z1000.  So nothing derailed.  Pulled the engine off.  Just to see if the tiu was ok.  Plug back in.  Breaker popped.  What the? ?????????   Put power to aux.  And no breaker pop.   So I put back on fixed 1.  And breaker popped.  So now what's up???  Can run power to fixed 1.  A short?  It immediately popped when I plugged in z1000.  Ugghhh!

Can you determine whether it's a faulty tiu Fixed 1 channel or a wiring issue  with fixed 1's track.... Disconnect fixed 1 out and see if anything blows.... 

 

How many power supplies are you using and  what channels do they power including the aux power. What are they??

Gregg, I have the tiu. Nothing hooked up to it. Apply the brick to fixed 1 and immediate blows.  So that channel has a short inside.  I can power the tiu through aux input.  Red light on the tiu.  I found a 14watt. Walwart. Output is 12vdc.  Plugged that into aux input. That powers the tiu. Is that safe to use? To power tiu?  I guess fixed 1 is blown.  I can try fixed 2 if I can use the walwart.  Correct?

Can i use this safely on the aux input to power up tiu. ? Low watts.   I wondered because there is no switching breaker on this power supply I can see.  I can power up fixed 2 then with z1000.  And then convert var 1 and var 2 to fixed. So at least I can have 3usable channels.  

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Not enough juice, you should have at least an amp or more.

 

The channel 1 issue may be the TVS protection diode, they're a common failure point and easy to replace.

 

You can power Aux power with that for testing.  I would power via AUX, then use the Z-1000 brick to power Fix2 and see if that works, if so, than test VAR1 an 2.  If they all work, the TVS probably shorted on FIX1 and that can be repaired.

 

Let me add that the only way a TIU gets power is via Aux input or Fixed 1  Since several people mentioned....G

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 G, thanks for the advice on that. TVS shorted. is that something I can do easy or someone like you could fix? I really don't want to be messing on a board if I can mess the whole thing up. Why would that short out? 
 
 Originally Posted by GGG:

You can power Aux power with that for testing.  I would power via AUX, then use the Z-1000 brick to power Fix2 and see if that works, if so, than test VAR1 an 2.  If they all work, the TVS probably shorted on FIX1 and that can be repaired.

 

Let me add that the only way a TIU gets power is via Aux input or Fixed 1  Since several people mentioned....G

 

If you are comfortable soldering on a PCB, the TVS diode is a fairly large thru-hole device.

 

The large cylindrical component next to the red wire is the TVS.

 

 

Here are the locations of the TVS diodes in the early Rev. G TIU, I don't have a picture of the later version, and I don't feel like taking one apart.

 

 

TVS Locations

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I bought a used one that looks like the above picture.  No power is coming through the Variable 2 port.  I tried changing it to fixed and still no power.  Are there fuses and if so, where or will it be a diode gone bad as mentioned earlier in the post.  Also I have another question.  I have a trolley I'd like to run at a slow speed.  Is it possible to hook up a transformer at a lower output to a fixed channel so it will just run at a constant speed.  I already have 2 other line that truly will need the variable output channels.

Thanks,

Eddie

Not all who wander are lost.

Eddie,

I bought a used one that looks like the above picture. 

If it's exactly the same as the above Rev. G, then it's a Rev. G.

No power is coming through the Variable 2 port.  I tried changing it to fixed and still no power.  Are there fuses and if so, where

If it's a Rev. G, there aren't any fuses. Every successor to the Rev. G has had fuses, however, the Rev. G did not.

or will it be a diode gone bad as mentioned earlier in the post.

It could be any one of several failed components.

I have a trolley I'd like to run at a slow speed.  Is it possible to hook up a transformer at a lower output to a fixed channel so it will just run at a constant speed. 

Yes, you could connect a lower-voltage source to a Fixed channel. However, the trolly won't necessarily maintains constant speed unless it has speed control, or the track is both straight, with no curves or grades, and the voltage is constant across the entire length of the trolly's route.

Barry

 

DCS Ambassador & author of The DCS Companion series of books

Train-Ca-Teers - All For O and O For All!

 

Ran some tests and TVS diode was bad but that did not fix the problem, still no power out on variable 2. (FYI, swapped TVS Diodes from one output to the other for test).  So now the question is it worth repairing and who would be able to repair it.  The remote works, have there been internal changes to it since Rev G?  It would help save some fund if that didn't need to be  replaced as well.

Thanks,

Eddie

Not all who wander are lost.

EddieZ posted:

Ran some tests and TVS diode was bad but that did not fix the problem, still no power out on variable 2. (FYI, swapped TVS Diodes from one output to the other for test).  So now the question is it worth repairing and who would be able to repair it.  The remote works, have there been internal changes to it since Rev G?  It would help save some fund if that didn't need to be  replaced as well.

Thanks,

Eddie

I think  it's worth fixing providing the other 3 channels are working.  I'm still using an original "G". I believe RJR  does as well.   No you don't need a new remote. They're pretty much  all the same.

 There are a number of repair techs  here on the dcs forum ... They'll all good.

Look on the back side of the PCB on that TIU.  One issue with the original TIU was power traces were too small, and they would show up as a burned trace inside the board.  No documented fix for that, MTH just says "buy a new TIU".

I suspect the likely cause would probably be the drivers, they will die if they're overloaded.  For VAR #2, that would be the circled group.  That would be the first components I checked.

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