Strange Short Between Power Districts

Model Railroader Electronics and DCC
1

My layout is divided into two power districts, one controlled by a Digitrax DCS100, and one by a DB150 wired as a slave, each with its own power supply.

Each district is divided into two sub districts through a PM42. When passing from one power district to another (not the sub-districts), all trains powered by diesels cross the gaps without a hitch. Neither of my brass steamers will cross the gaps without causing a short. Three of my passenger cars also cause a short:-all three are brass six-axle coaches. There are other brass coaches
in the same consist, but they are four-axle, and don’t cause a short (don’t know why this would make a difference).

If I place a coin across the gaps, one rail shorts out. If I reverse the rail outputs from the booster, both rails short out using the coin. I measured the voltage across the gaps, and the meter indicates 1.2 volts in both the DC and AC settings. The reading isn’t surprising, as the two power supplies have different voltage outputs, one at 13.5 Volts, and the other at 15 Volts. I have double checked everything I can think of. The only other thing that is abnormal, is when the system is shut down, the DB150 emits 5 beeps, indicating a short, but there are no beeps on startup. What am I missing?

2

Some DB150’s including the one I own have their A B track outputs reversed compared to the norm. In my case I had a dead short running from my Zephyr powered district to the DB150 powered district. Reversing the track leads from the AB on the DB solved it.

3

Ditto here too… I had the same issue…

4

Also make sure you have a wire between the ground terminal of the DCS and the DB150. Don’t hook them to ground, just to each other. Also make sure the wire is at least 16 gauge, 14 gauge if a long distance.

5

ANd if the Loconet cable between the command station and booster is a telephone wire, that will also ‘flip’ the outputs of the DB150, so even if it isn’t oen fo the factory flipped ones, the wrong cable will flip it.

Definitely add the ground - should go to the PM42 as well. I don’t have a ground wire between my Zephyr command station and DB150 booster, but the Zephy’s track outputs do not power any of my track., only the DB150 goes to the track, via a PM42.

–Randy

6

Thanks for the input, guys. Swapping the rail A&B outputs from the DB doesn’t help. Ground wire is in place between the DCS and the DB. Loconet cable between units is correct orientation-pin 1 to pin 1. Situation still persists.