I have had a significant number of failures (3) of my TIUs. It seems more than I should expect listening to others users including my son who uses DCS extensively. Currently, I have a TIU L unit that failed (lost variable #2’s ability to deliver variable voltage) in the morning and when I substituted it with variable 1, it loss its variability function also. I like using the variable channels because I still have numerous passenger cars and cabooses where the heat from the incandescent bulbs without constant voltage functions can melt the plastic when using noncontrolled channels of 18-22 volts. We have had a several cabooses destroyed from the heat.
I have repaired one TIU by replacing the mosfets that had failed - indicated by the melted outside case. I replaced them and it is still working today. However, my recent failure of a variable channel failure diagnosis was not so obvious this time. My layout track is powered by Lionel 180 watt bricks of various ages. I believe they all are phased correctly. The Z 4000 (used for signaling and switches) does use a common ground with the other brick transformers. The 4 120v circuits are all off the same leg at the breaker box. I use 2 WIU’s for the WIFI control. I am using iPads and a iPhone X as controllers along with both Cab1 & MTH remotes. Software 6.0 is on the TIU’s and MTH remotes. I am running trains using nearly 10 amps constant draw.
Examples:
Q. Can TIUs be worn out by excessive amp drawing?
A. MTH suggested there is a danger when drawing constant heavy Amps (over 10), that a sudden direct short may spike the amps without enough time to blow the fuses but can harm Mosfets. Note to MTH if this is incorrect or stated poorly please correct me. They suggested using a fast blow fuse of 12-15 amps being placed after the TIU on each channel. The Fuse needs to be between Track and TIU Channel. I was in fact running 3 trains on one brick, 2 were lighted passenger trains and one car had a recurring dead short, when my failures occurred?’s
Q. My question is, are there lists of issues that actually identify or site events or conditions that break, fry, or confuse these TIU units?
Q. Can a TIU be burned up by transformers that are out of phase or not synchronized?
Q. If there are faulty breakers in a brick, will the TIU fuses prevent damage?
Q. Do repeated direct shorts cause TIUs to fail?
Q. Are there any other situations that are known to damage TIU’s?
Thanks for any information on known issues, conditions, or procedures you know that are harmful to TIUs. If you know of ways to test the TIUs for damage, that would also be extremely helpful too.
Thanks for any replies
Tplee
