TIU CHANNEL DEAD

The TIU should be repairable for considerably less than the cost of anew TIU.

I suggest using a 10 amp, fast-blow fuse or a circuit breaker that would open at 10 amps.

This and a whole lot more is all in "The DCS O Gauge Companion 2nd Edition", now available for purchase as an eBook or a printed book from MTH's web store site! Click on the link below to go to MTH's web page for the book!

The original fuses were 20amp.  Which does seem over sized.  If you open the TIU you can inspect the fuse to see if it is blown.  Just 4 screws on the bottom.  G

My reference to 10 amp fuses was to place them outside of the TIU, between the transformer's Hot terminal and the TIU channel's red input terminal, one fuse per transfrmer Hot used.

Are you sure that your "dead" channel isn't just a blown internal fuse?

My TIU is old enough to not have fuses.

You "may" have a problem getting it fixed.  Our club has an original first version of the TIU, and I was trying to get a dead channel fixed, but tech support told me they couldn't fix it because there was a burn mark on the bottom of the PCB.  That supposedly signaled some failure that they can't address, not sure what exactly the failure is.

I'd call MTH tech support and see what they say, when they discovered it was the original version, they had me remove the board and check the bottom for the burned trace.  Obviously a known failure mode.

I'm no MTH technician, but last year we popped a Rev L on the primary channel. An ohm meter indicated a dead short as did the Z-4000 on the channel.

This blew because the Aux Power In was out of phase with the track power supplied by the Z-4000. It was a simple matter of desoldering the "Bi-Directional Diode" on the output and replacing it. The hard part was finding the diode itself. They are in parallel with the output load terminals.

If the channel's at a dead short (Zero to 50 ohms), it's probably that.

Link to article for info purposes:

http://en.wikipedia.org/wiki/T...ge-suppression_diode