MTH Crossing Flasher

Most likely the internal 555 circuit went bad. You could disassemble and fix it. Hooking directly to the insulted rail,although it works is not the best method. The intermittent contact of the wheels completing the circuit to the flasher can generate voltage spikes harmful to PC chips. Better to use relay activation with a capacitor across the coil to eliminate chatter. A TVS on the power line to the flasher is also a good idea.

Dale H

Dale,

   I have the same hookup and will change to a relay. Could you give us a spec for the capacitor? Thanks.

        John

John

Described here. Capacitor depends on relay used but 220 uf or more 35 volt usually prevents chatter. A bigger capacitor actually will produce a delay off operation,about 1 second per 1000uf,depending on relay.

www.jcstudiosinc.com/BlogShowT...=410&categoryId=

If you have accessories on the same power circuit as the flashers that could generate spikes,especially PW type, I would also install a TVS on that circuit.

Dale H

I have the same problem with one of my flashers.  I have mine hooked up to an ITAD, though.  How do you fix the 555 circuit?  I can't screw it up any worse than it already is, can I?

Tom

Thank you Dale.  I take your point about the insulated rail but I've done it this way for years with other signals (including MTH flashers) and never had an issue.  I bought this set used and I suspect that this had something to do with it.  My reaction, based on the information you provided, is that these are not worth fixing unless you want to do so for the sake of it.  York is coming up, so I can certainly find a replacement there.  Thank you again for the help.