MTH TIU Issue

Power down everything including aux port power supply and restart.

CurtisH posted:

Power down everything including aux port power supply and restart.

 

Tried. No luck. 

I don’t power my track with the aux power...only tried it as a test after the failure. I use fixed 1 for my single track. 

did you open up and check all your fuses and what rev is your tiu L G H I etc?

does the tiu work if you power fixed one and aux power input? does it report to your remote and tiu talk to each other?

Applying power to Fixed 2 or either variable would not power the TIU and therefore the light would not come on.  Only FIXED 1 and the AUX can power the TIU. 

Sounds like you did not have transient voltage protection on the circuit.  The short blew the diode D300 on Fixed 1.  This can be checked and replaced, preferably by a qualified technician.   Do yourself a favor, since you have had derailments in the past, install a TVS system with 10amp fast blow fuses.

bruce

Alan Mancus posted:

does the tiu work if you power fixed one and aux power input? does it report to your remote and tiu talk to each other?

TIU is Version l (not sure if this is I or L--it looks like a lowercase L).

Haven't tried power to aux & fixed 1. I'll try later.

bruce benzie posted:

Sounds like you did not have transient voltage protection on the circuit.  The short blew the diode D300 on Fixed 1.  This can be checked and replaced, preferably by a qualified technician.   Do yourself a favor, since you have had derailments in the past, install a TVS system with 10amp fast blow fuses.

bruce

Thanks, Bruce. I'll reach out to a local certified repair shop for MTH. And yes, I'm thinking that will help tremendously...a few questions, though, assuming the blown diode on fixed 1:

• Is the Diode replacement cheap?
• What is a TVS system?
• I cannot operate/power the TIU on Fixed 2 as I would normally with via Fixed 1? Fixed 2 requires Aux power as well?
• Would a Z4000 suffice as a workaround for the TVS? I believe, from what I can remember, a friend has his Z4000 hooked up to Fixed 1 and 2, and the Z4000 serves as a fuse/breaker.
• Do you recommend getting a newer TIU? Mine has the serial port.

TVS...Transient Voltage Suppressor It's a chip that looks like a diode. It conducts when there is a voltage spike greater than whatever voltage rating you buy.

https://www.digikey.com/produc...E36CALFCT-ND/1530580

A short on the fixed channel is very likely to be what Chuck is saying, I've replaced a few of those TVS parts on TIU's.

gunrunnerjohn posted:

A short on the fixed channel is very likely to be what Chuck is saying, I've replaced a few of those TVS parts on TIU's.

I believe so. I tested the TIU with AUX power and power to Fixed 2 and it works. Bruce suggested it's the diode on fixed 1.

check the input of fixed 1output with a vom on ohms you'll probably see a dead short as was suggested!

if the input of fixed one was shorted you would trip the breaker on your transformer or if using the z4000 the red overload light would light!