TIU FIXED 1-no output

Afterthought

Anyone have a schematic for this device?

My fixed one stopped working and it was due to a loose nut connecting the terminal to the banana plug.  Make sure yours are tight.  I’m not saying that’s what you have but it’s worth checking out. Good luck!

@Strap Hanger posted:

My fixed one stopped working and it was due to a loose nut connecting the terminal to the banana plug.  Make sure yours are tight.  I’m not saying that’s what you have but it’s worth checking out. Good luck!

That was the first item on my agenda

This TIU has been through it…it has melted the case and the banana plug sockets-because they were loose..the guy at MTH attempted to claim it was my fault-until I told him, I only use make Banana plugs to connect my feeders to the device.
Then the WIU wouldn’t work-turns out the center of the USB plug on the TIU broke off…that was replaced no charge at MTH.

I have a second TIU, which I’m using now.

I don’t see a screw holding the board to the case..

I believe I’ll take to my LHS MTH repair wizard-see what his test jig says.

Probably blown internal TVS

@1drummer posted:

That was the first item on my agenda

This TIU has been through it…it has melted the case and the banana plug sockets-because they were loose..the guy at MTH attempted to claim it was my fault-until I told him, I only use make Banana plugs to connect my feeders to the device.
Then the WIU wouldn’t work-turns out the center of the USB plug on the TIU broke off…that was replaced no charge at MTH.

I have a second TIU, which I’m using now.

I don’t see a screw holding the board to the case..

I believe I’ll take to my LHS MTH repair wizard-see what his test jig says.

Who is that?  In St. Louis area?

@MR_P posted:

Probably blown internal TVS

I agree. Repaired mine about a month ago for same issue. Although my symptom was a high amperage reading when I applied voltage to that channel because TVS was shorted

When mine occurred, I just snipped a leg off of the internal one off and added a new TVS between the external output posts. The new TVS leeds were just long enough.

What version hardware?  If it's the original version G, that's a bad sign.  There is an internal trace that was undersized and burns out with an overload.  You mention fuses, does this unit have internal fuses?

Mike H -it’s in Overland

Mr P-or anyone-what is this TVS, where is it ?

@1drummer posted:

Mike H -it’s in Overland

Mr P-or anyone-what is this TVS, where is it ?

Check for continuity across it. It should read OL. Any reading besides that would indicate a bad TVS diode. Let us know what you find. The parts are readily available from Digikey and very inexpensive if this is the issue.

@gunrunnerjohn posted:

What version hardware?  If it's the original version G, that's a bad sign.  There is an internal trace that was undersized and burns out with an overload.  You mention fuses, does this unit have internal fuses?

Rev l

yrs it has fuses

and I just found the problem

seems there was no connectivity on the red wire from the banana plug to the board

when I first plugged in power, it was not on..

so I didn’t notice the red power light was off

then, I tested all the other inputs/outputs

with out turning the power off-on my Z ,controller.
mans when I reconnected to Fixed 1 input the power light came in for a second

So as I checked power on the board at the fixed 1 input side, and I moved the red wire-and the power light came on

Further inspection shows nothing

I pulled the banana assembly to check for loose connections

the solder joint at the board feels tight

the lock washer/nut/ terminal are secure

I’ve repositioned the red wire,

reassembled everything

Then moved to wire with power applied

and a meter on the output

no issues.

Ghost in the machine

Gremlins

Karma

I have not removed the circuit board from the case bottom to inspect

I see no screws-must be adhesive

But, I'm going to let this dog go back to sleep😁

@Sparky74 posted:

Check for continuity across it. It should read OL. Any reading besides that would indicate a bad TVS diode. Let us know what you find. The parts are readily available from Digikey and very inexpensive if this is the issue.

I thought it might be those “idiot fuses”

and had searched the Web

I was about to test-so working from the KISS agenda-started checking all the inputs/outputs-

and I found the issue when I attempted to retest voltage on the board on the fixed 1 input-

No idea what was blocking the coulombs

but when I moved the red wire-my red power light came on.

I tested output with power on, wiggling the red wire-no loss of power

it’s working now

going to leave it alone

my other TIU is reverse l Also

Now I have to find where my power blocks are crossing-seems I have both throttles powering the same block of isolated track…

I did find an MTH isolation section where the rails are touching..will take the dremel cut-off wheel to it tomorrow after the wife wakes up..

she’s definitely one I don’t want to awaken😁  

Thanks for everyones help.