# Help



## Madman (Aug 22, 2020)

I've toyed with these in the past without any luck. Yesterday, I thought I'd try once more. I hooked up an MTH 153 block signal using an insulated rail, as per the wiring diagram shown. Nothing happens. The green or red light does not come on. Track power is at 18 V. The green or red light does not come on when the insulated rail is bridged either. Nothing, nada, zilch.


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## SF Gal (11 mo ago)

Test for power, check light bulbs work on their own.


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## gregc (Apr 25, 2015)

is there a diagram for how to insulate the *track rail(s)*?


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## Madman (Aug 22, 2020)

SF Gal said:


> Test for power, check light bulbs work on their own.


Yep, bulbs work.


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## Madman (Aug 22, 2020)

gregc said:


> is there a diagram for how to insulate the track rail(s)?


As the diagram shows, the three wires on the left go to the track.


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## gregc (Apr 25, 2015)

Madman said:


> As the diagram shows, the three wires on the left go to the track.


diagram showing where insulators, presumably 2, need to be on the track


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## Lemonhawk (Sep 24, 2013)

Center rail, Outside rail are marked, but is the sense wire a center or outside rail? Its not clear on the wiring diagram. I wonder if you just isolate only one of the outside rails and use that as the sense. That way as the train makes its way over the "sense rail" the wheels will ground sense rail and trigger the relay. If you isolate both outside rails then this unit would have to supply the ground and sense current and there does not seem to be enough components for that. It also seems that you could supply a dc voltage to the relay common with the appropriate jumper (or none to isolate the relay contacts) and use LEDs with resistors as the indicators! You could even use a single multi color LED as the indicator with the relay output going to the color you want (red, green or blue)!


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## gunrunnerjohn (Nov 10, 2010)

If you wired it exactly like that diagram, it's hard to see why it doesn't work. 

I'd consider testing it, maybe there's a problem with it. You must have had these for years, they've been out of production for quite some time. The new ones have a 10A relay.

Connect an ohmmeter across the COM#1 and NO#1 terminals. It should read an open circuit.










Leave the Ohmmeter connected to those terminals and connect track power to the SENSE and HOT terminals.










The ohmmeter should read a short circuit whenever track power is connected as directed, open circuit without track power.

If you're tried to use this before, inspect it closely for cooked traces, I have a few come back where a short circuit fried PCB traces.


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## Madman (Aug 22, 2020)

gregc said:


> diagram showing where insulators, presumably 2, need to be on the track


In place.


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## Madman (Aug 22, 2020)

We have ignition ! I wired one of these up to an MTH block signal, on the bench. Worked perfectly. Then rewired my MTH block signal already on the layout up and it works perfectly !

Thanks to everyone who had input.


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