PS2 light circuit issue.

Check the bulbs themselves.  I just had a repair where the boiler mux board went bad due to a bad smoke motor, and it blew all the bulbs.  I had to replace the mux board and obviously all the bulbs.  It also melted the smoke motor wire in the tether, so it got a new tether as well.

You must have grounded out the Positive voltage either via a wire pinch or short at the smoke element.  Most likely you blew the PV trace that feeds the lights.   G

• Thanks guys, the smoke unit is working, the bulbs, show continuity. Where and or what is the "PV" trace  & how do I diagnose it?

I'd guess that George is thinking of the mux board in the locomotive, the PV goes through that, and that's the most "fuse like" place in the line.

Is this a steam or diesel engine?

Take a look at this thread and specifically the picture in this post:

https://ogrforum.com/t...74#38737270033470374

Since you apparently have a meter, measure the availability of PV or "Positive Voltage" using the DC voltage mode as described.  All the lamps share this PV wire so if ALL lights are out, it stands to reason that the PV voltage has been disrupted at the connector or in the wiring from the connector to the lights.  There is more complicated wiring in a steamer with PV having to work its way up to the engine from the tender via the tether.  But if there's no PV voltage at the 12-pin connector to begin with, I'd say you have a problem on the board itself.

To your point, yes, there are individual transistors that provide independent control of the separate lamp circuits.  I suppose each transistor could have failed.  But given the circumstances of what you did and what you're seeing it does sound like there's a problem on the common or PV side of the circuits.

I was not thinking mux necessarily because as Stan states we do not know what engine type this is.  If all light have issues at one time though, it can be the PS-2 3V trace.  Of course if this is PS-3, all bets off.   G 

Thanks for your input, BTW,  it's a diesel. I will check the wiring and get back with my results. Last evening after further scrutiny, I discovered two pinched wires on the ditch lights. Apparently this initiated the problem.

I'm working through the thread mentioned, thanks again.

After reading the link from Stan2004, BTW Thanks, I realize that PV circuit is shot. No lights, or couplers.

So I need to get a RA from MTH. I Greatly appreciate everyone's thoughts & information. Thanks again.

If you want to send me the circuit boards I can fix it.  E-mail in profile.   G