MTH Signal Bridge - Product Number 30-11009

I had another type of bridge in mind.

 

I am afraid that yours might require a replacement in full.

 

However all cannot be lost. See if you can take down the old heads and wire in some new ones on the existing structure.

Dave is absolutely correct.  I have the same signal bridge you are referring to.  Occasionally, one or more of the lights appears to be burned out.  I just wiggle the signal head, and presto, the lights come back to life.

Mth makes add on signal heads for these, item # 30-11009A.

Heres a link http://www.mthtrains.com/content/30-11009a

Thanks to everyone for the great info: We only meet once a week to fix things & keep the Wilmington RR Museum O Gauge Layout in order. At next week's gathering I'll be armed with 1000% more info than before !!

 Wolf -- if you take the signal bridges off the layout, hook them up to a transformer and something to trip the LEDs like an infrared detector, do the LEDs work correctly IF you position the bridges on one or more of their sides or even hold it upside down?  That would at least confirm it's a wiring problem inside the signal bridge's wiring path.

I ran into a situation with one of the MTH "double-head" traffic lights where the left head's red LED would not illuminate when the signal was in the proper vertical position.  (Keep in mind this traffic light had the problem right out of the blister pack!)   If I removed the traffic light from the layout and laid it flat on my work bench or leaned it on an angle against something, like a parts cup, the problem red LED worked fine.  After several attempts to resolve this problem including a worthless phone call with MTH, I just threw the traffic light aside once I realized it was probably some wire inside shorting out when the traffic light was in the proper vertical position.

I took one of the heads apart to fix the position -- they're set up green on the bottom. The head is held together with a single, very small screw. I don't recall anything in them other than wires from the leds to the electrical plug (there's enough slack so you can turn the LED cluster around). Many modern digital multimeters have a continuity/diode check. You can check the diodes with one of those. As Dave said above, it's more likely there's a connection problem with the base than with the LEDs.