2017_05_11 A good discovery?

2017_05_11   Working for loco maintenance and signals branch this Al's Day

I wrote an email to a mate and thought it was probably a good blog entry for today.

My friend Al and I worked the whole day on one DCC territory that had somehow developed a short.

We started by removing every dropper from the DCC bus and then connecting just one black return to bus and found any red wire added caused a short to return.

As every point was fitted droppers but wired with insulated  two middle rails (electro frogs live with own dropper via a juicer) I decided to insulate all four rails on the frog end? Of course a fools errand and as expected that did not work.

Al had me putting sound in his G Class, and he sat on a stool, with the short lighting up a car tail lamp, and started at the other end and reconnected every dropper for me. I told him that as the short persisted, with every thing disconnected, and no path was left for the rails to be the problem, to take particular notice of where the red and black wires were soldered. Perhaps I had bundled two incompatible reds together, or had a red dropper from a black rail?? I have done this before.

We worked from 10.00 am to 5.00pm and  Al called me over to show me one complicated section. The Apex Junction, which had given me so much grief a few months back. He went on and completed the rest of the wiring. I found about 5 bundles of red wires. two wire bundles soldered together were easily traced to the same rail or a pair of rails in the same section. No short possible.

But one bundle had 5 red wires. I cut the spade joiner off and re bundled them in pairs and connected them to the same rail district. Al tells me that the taillight had gone out and we had power back on the section all 13.7 volts of it!

I touched the final wire to the bus and indeed the short appeared.

So I traced it back and found it was actually a SG wire feed which should have been short free. However I had allowed the SG main line to come past the end of the district about 3 feet, and in fact I was crossing into the next district! Damn!! I moved the insulators in track ending that line at the edge of district and added the 3 feet back into the (shorting district) connected the wire and the short was indeed gone. Thank God I decided to use connectors to link wires to the bus. :D

I have 10 NCE circuit breakers on layout, creating districts. As well I have 4 Command stations (3 wired as slaves) giving me 14 districts.

This is the first time I have made this error though. The Digitrax stations are finally silent. I can turn them on and off without  hundreds of warning chimes and the tick tick tick sound has finally been put to silence (I knew this was a warning that two command stations were incorrectly wired together) So the wonderful sound of silence!

Cheers
Rod