I blew a fuse in my TIU

You need Fixed 1 operable to power up the TIU. You can also power it up using an auxiliary power supply. The Manual should tell you what you need. Radio Shack had one that was recommended but they are long gone. Try an auxiliary supply and use one of your other channels to run the layout.

Looking down on the TIU from the INPUT side, do you see an LED lit inside in the lower left hand corner?

Yes, it is lit.

OK, that means the TIU is getting power.  Leaving FIXED 1 input powereds, run a jumper from it to FIXED 2 input, and move the track feed from FIXED 1 OUT to FIXED 2 OUT.  This will check if the failure is in the FIXED 1 circuitry.

Thank you.  I will try that tomorrow.  I ordered a new fuse and I really, really, hope that helps.

Snag a fuse from one of the variable channels.  A money saving tip:  If you use external circuit breakers of 10amp rating, you won't be taking the TIU apart every time your have a derailment.

I moved a fuse from a variable channel to the number 1 fixed channel.  It did not help.  All I get is an error message that no WIU or TIU can be found.  I have pushed the button to reset the WIU.  Everything is lit and booted up properly.  I am going to try the suggestion of moving everything the the second fixed channel and also trying a jumper wire.  Meanwhile, any other suggestions are more than welcome.  

I have two separate loops on my layout.  Each loop is powered by a separate Z1000.  Variable #1 powers one loop and #2 powers the second look. Neither one is working. I just get a message that no WIU/TIU can be found.

I am still unable to figure out why the app on my iPad says that no WIU/TIU is found.  I initially thought it was because I blew a fuse on fixed 1.  I moved a fuse from a variable channel to replace the blown fuse, but I still get the error message.  The tracks have power.  The engines power up and light, but nothing else will operate.  This equipment is too expensive for me to even think about replacing the WIU and/or the TIU without even knowing what the problem might be.  Any help is appreciated.  All the proper lights on the units light up a and everything seems fine, but I cannot connect with the app.  I am using the MTH Wi-Fi setting and I am signed in to the proper network I’d for that Wi-Fi.

It looks like I may have two separate problems going on.  If one caused the other or if they are related, I cannot tell.  I have two separate loops of track, not connected in any way.  One loop, on fixed #2, is an elevated track with a trolley.  The second loop is below that on the table top and is powered by fixed #1.  A few days ago I blew a fuse in fixed Chanel #1 of the TIU and I moved a fuse from an unused variable channel to fixed #1.  When I tried to run trains again all I would get is an error message that no WIU/TIU could be found.  The Wi-Fi in the WIU is properly lit and it seems to connect properly to my IPad under the MTH Wi-Fi setting.  Each track loop is powered by its own MTH Z1000 brick.  
Today I replaced the fuse that I had talked from the unused variable slot in the TIU.  I reset the WIU.  I deleted and reinstalled the MTH Wi-Fi app on my iPad.  When I turn on the power the WIU seems to connect to the iPad and the proper lights go on on the WIU. The red LED is on inside the TIU.  The engines (3 of them) power on, light up, and begin cab chatter.  I no longer get a message that no WIU or TIU can be found.  However, that is all that happens.  There are no active engines on the list.  I am unable to add an engine.  Nothing moves or responds in any way.  I feel like I am making small but mostly meaningless progress.  I have no way of knowing if the WIU or TIU might be bad.  I am just about a month out of warranty (figures !!).  It is virtually impossible to find another TIU anywhere at a reasonable price.  A TIU can be had, but they are still expensive.  I am looking for any help I can get.  I have almost no experience in these matters and I have spent hours reading everything I can find.  Thanks for any possible assistance.

You could try removing the WIU from the system and running a train in conventional on each loop rather than command and see what happens.

BTW, are you sure it was a fuse and not a TVS - was the fuse black or broken ?

sounds like your not getting your watch dog signal!

your dcs could be turned off in your tiu! make sure you turn your dcs on in your tiu with remote!

Alan

I do not have a remote.  Just Wi-Fi and the MTH app.  I don’t see anything on the app that will let me do this.  Thanks for the suggestion.

It was blackened.  A yellow two prong automotive fuse wot 20 printed on top.

@RJR posted:

OK, that means the TIU is getting power.  Leaving FIXED 1 input powereds, run a jumper from it to FIXED 2 input, and move the track feed from FIXED 1 OUT to FIXED 2 OUT.  This will check if the failure is in the FIXED 1 circuitry.

I just tried that and nothing has changed.  Power goes to the tracks.  The engine starts up immediately.  The Wi-Fi app does nothing to move or shut down the engine.  It appears that the engine is not getting the signal to stay still until it gets a command.  It seems to be starting like it is a conventional engine, even though I am using DCS.  All 3 of my engines now do that and I cannot add them to my active engine list or make them do anything.  

In your start-up sequence are you turning on the TIU and WIFI first and letting them come up to full on before turning on track power ?

Yes.  I have them switched separately.  I wait for everything to become stable with the TIU and WIU before I turn on track power.  The engine immediately powers up and cab chatter begins.

I had a hard time finding a new TIU, but I found one and things are up and running.

After the 2nd time opening up my TIU I installed an external fuse block. So now if a derailment blows a fuse its a very easy and very fast fix.

If you put a 10-amp or smaller in external block, you'll never blow an internal one.

I just installed external fuses.  I can’t afford anther TIU.  Thank you everyone for helpful suggestions.

You can send me your bad TIU for a repair if you like.  E-mail in profile.  Not sure what was happening, but the fuse blow probably came from a pretty good short/voltage spike.  Normally do a TIU reset to see if that clears things up.  Turn on DCS on all channels.  But that does require the TIU to be communicating with the WIFI or remote which you do not have.  It could be you lost DCS on F1.  G

Thank you sincerely for the offer of repair.  I have no idea what a repair could possibly cost or if it is something I can afford.  I will certainly consider that.  If Covid ever ends I want to be able to show my layout to others and I would love to have a backup TIU.  

I have always found GGG to be very reasonably priced.  You could e-mail him outside of the forum and discuss the issue further.