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I have MTH bldg 30-90342 with blinking sign.  It resembles the Miller Engineering signs, but I don't know for sure if MTH used Miller.

The sign stopped working.  I have validated the board is good because I hooked it up to another sign.

I guess it's the wire, the connection or the sign itself.

When I put a meter on the contacts by the sign I get 12v on the outside two wires.  I get a 0.5 reading when I touch the center wire with hot and ground on the outside.

Any thoughts?

Thanks

Ron

IMG_20200508_152405219

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Do you hear the squeal (high-pitched whine) of the board?  You may need to turn off any trains or what have you.

I realize you tested the board, but my question is does the squeal change pitch when you plug the sign vs. not plugged in.  That is, I don't know what the actual voltages are but they are somewhat difficult to accurately measure since it's a high-frequency AC voltage probably 100V or so.  A typical hobby multi-meter cannot accurately measure such a high-frequency signal.  I only suggest this because it should only take a couple seconds and if the squeal changes, it can indicate that some form of electrical connection is being made to the sign itself.

Presumably you carefully inspected the 3 connections where the gray cable mates to the copper colored flex-cable.  Virtually impossible to confirm the 3 connections between the flex-cable and the sign itself.  You might try pressure against the tape and sign to see if a loose connection there...though it would be verify difficult to repair (e.g., conductive paint/glue) without damaging the sign.  The current is very low so you don't need "0 Ohm" joints.

Oh well, the squeal cycling sounds the same with the broken sign; I was "hoping" for a shorted sign which might be found by visible inspection - where you might hear the board "groaning" under the load.  But both videos sound the same with a peaceful un-labored pitch.

For the technorati, I did an audio frequency analysis of the video.  The squeal frequency of the step-up voltage oscillator is about 3400 Hz.

squeal

If you can get a new sign for free that's obviously the closest exit!

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OGR Publishing, Inc., 1310 Eastside Centre Ct, Ste 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

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