Greetings all, I am new here, but not to model rr. I have and n scale layout with 5 districtswhich has run fine for years. Had andopp session on Tuesday and it ran perfectly. Everybody left and the layout was still ok, shut it down for the night. Next day I turn it on and had a short on themiddle deck section. I did everything I knowto find the short…. Removed locos off track, ran a magnet across the entiretrack, vacuumed them, used a magnifying glass to check each turnout, check anddouble checked all the wiring and no luck. I have spent hours trying to find the short and I am at my witsend. I was wondering if anyone has tipor trick I have thought of yet. Ithought of disconnecting the section from the system and unwire all thereversers and put 120 volts to the track….poof, ah yes there it is. I am concerned that will do more damage andgood. HELP!! Paul F
Sometimes destructive testing is the last resort but works. Long ago in one of my jobs, I was checking computer PC boards from the assembly area to see if they worked and correct any defects. Sometimes a faulty component or solder bridge would not show up under visual inspection. We would just hook it up to a high amperage power supply and throw the switch (while hiding under the workbench to avoid any shrapnel). There was usually a pop and a puff of smoke. Then we would go in and repair the obvious area. (sometimes having to replace the copper traces in an area with new wire, but it sure ended up saving a lot of time)
DC or DCC is the key question. There was an article a while back in Model Railroad Hobbyist by a friend of mine, Dick Bronson. If it's DCC, place a resistor in the main power lead for that section of the layout so it won't blow the breaker. Now you need a clamp on AC ammeter. With the power on, clamp it on the buss about halfway through that section of the layout. If the current reads ZERO, go back to the 1/4 point. If it's not zero, go to the 3/4 point. You will quickly find the point and the feeder where the short is.
It would help if we knew what DCC system you have and what auxiliary circuit breakers (if any) you are using. Putting an automotive tail lamp in series with the offending power district will prevent the breaker from tripping and aid in troubleshooting.
I was going to suggest hooking up 120V across the rails to see what flames up, but I didn't expect to find it in seriousness! I guess we all have the urge to simply destroy those little things that stand in our way. Could it be a failed wheelset on a car, like a resistor?
