DCS Problems signals from10 to 3 and more

@mike g. posted:

I sure hope someone has some suggestions as everything was running find last week when I ran them. I did have a little short, but it did not trip any breakers before I was able to kill the power!

So there was a short circuit, but the breakers didn't trip? Sounds like that short damaged the TIU channel. If you try a different channel and everything goes back to normal then the TIU channel you are currently running has an issue, probably caused by the short that didn't trip the breaker. What kind of power source and circuit breaker do you have?

Hi Lou, I am running power with a Z4000 with 5 amp breakers between the TIU. The thing is it is on both fixed out puts. I have one section of track that reads 10's and the engine runs fine. I am asking here as i am tired of banging my head against the wall! LOL

The one track that reads 10's is on #1 fixed output with all my other track on my lower level. But it's not reading the engine on #2 fixed output for my upper level.

does the TIU have power when you're testing fixed out # 2?

try swapping out the channels and see if the other loop of track then works.

I didnt check at the TIU, the red light is on!

Let me run out and check on the power and I will get back to you!

Hi Joe, I checked power to both outputs and it matches the Z4000, I also found out if I move each engine to the outer loop the TIU finds them and adds them.

Did you try swapping channels as Engineer Joe suggested?

Not yet, the CEO said it was dinner time. I will check it later or in the morning.

Let's just recap a few known things about TIUs.

#1 they need power to operate the internal electronics. There are 2 basic methods to get this power- channel1 fixed input the tiu logic can borrow power, or AUX power in, the little round coaxial power jack on the end of the TIU. So as such, you did not mention an AUX in power supply when describing your system so we assume that then means you must always power channel 1, whenever you want to use channel 2.

Ok, so let's say you knew that or already were doing that -always ensuring fixed channel 1 had power in- or you actually do have an aux power wall adapter plugged in. In other words, we know beyond any shadow of doubt the TIU has constant power and the red power light is on inside the TIU.

#2 Then, even a minor short, derailment, accident, can cause damage to the DCS signal generator portion of the TIU on a given channel. So it's entirely possible you damaged one of your channels- example fixed2, and so whatever track is connected to that channel might then have low signal- not be able to find engines and so on.

That leads to...

#3 You can swap tracks between TIU outputs. Giant Caveat here again is that the TIU must have logic power to operate. So again, based on what you have said to this point, TIU channel 1 input power must be on for your TIU to be powered and then what you would be doing is plugging in your outer loop to the TIU channel fixed1 output. Now if suddenly those same engines work fine on your outer track while it is connected to fixed1 output of the TIU- we begin to suspect you damaged TIU channel fixed2.

Again, as long as you follow the rules and the TIU logic internally has power, you could then connect and repurpose say one of the variable channels to then power your outer loop.

You can ignore TMCC/Legacy portion if you do not have it.

Hi Vernon, I am powering the TIU from an Aux power source. I use Chanel 1 for my lower level and #2 for the upper level.

The track on the outte lop on the lower level works fine. But the inner tracks have poor signal.

By chance are there any Lionel TMCC/Legacy engines on the inner tracks or powered sidings?  If so, remove them and retest.  

I have no Lionel engines, just MTH.

Great, hopefully you can perform the channel swap and then if that proves channel 2 fixed is damaged.

That then means you should be able to use one of the variable channels or fix the tiu or have it fixed.

Ok, great. Can you tell us a bit more about the track configuration, approx # of feet of track, wiring and number of drops/connections to the TIU?  

I thought he said that the lower level which includes inner and outer loops is powered by the same channel and the outer loop is working good?

My room is 12 x 24 I have about 13 switches, power drop about every 6-8'.

The outer loop and all the other track on the lower level is on fixed 2 and the upper loop is on Fixed 1

As Vernon suggested, I would swap between fixed 1 & 2 to determine if the problem stays with the track or with the TIU channel.  Let us know how it goes.

Will do that first thing in the morning!