@Rod Stewart posted:...
Yesterday I hooked up a 3 aspect track block signal to the setup. So now the NC contacts activate green and the NO contacts activate red when triggered. Seems to be working as expected, except occasionally the green stays lit even while the red and yellow are lit. Balky relay I suspect? Time will tell. Its a vintage ROWI 4040 signal that is just seeing its first use since new.
That would be a new one for me! Just to confirm, you are using just one 153IR? In other words, this is NOT where two or more 153IRs are driving the 4040 signal with the NO and NC outputs tied together?
I found the following wiring instructions apparently from the back of a carded 4040 signal. So this has a signal common and 2 inputs, one to NO, one to NC.
So this sounds more like a problem with the signal itself. I assume this is has the timed-yellow function before returning to green? In other words, NO turns the signal red. NC turns the signal yellow first (for several seconds) then green; this is automatic. In other words, there should be no way to have Yellow and Green on at the same time.
While I'm sure someone can concoct a scenario where a double-throw electro-mechanical relay fails in a way that both NO and NC are active...I'd place my bet on a fault in the 4040 circuit.
