My N-scale layout runs on a Digitrax system. My command station is a DCS 240+. I also have a DB 220 booster. The layout has four power districts, two of which are powered by the DCS 240+, and two of which are powered by the DB 220. There is only one place on the layout where a district powered by the DCS 240+ meets a district powered by the DB 220. The districts are separated by insulated joiners at that connection point. The track on either side of the connection point is not part of a reversing section or any polarity switching device.
When locomotives or passenger cars with metal wheels go over the bridge between the two districts, a high-pitched buzz is emitted by the locomotive or car until all of its wheels are in one district or the other. There is no effect on the performance of the locomotives, just the buzz, and the circuit breaker is not triggered on either of the power supplies. I do not have this issue at any other place where two power districts meet.
Is there anything i can do to eliminate the buzz? I also want to make sure this is not going to harm the decoders in my locomotives
I donât know if this has anything to do with your issue, but NCE says that when a booster is used with a separate command station the two units should be grounded to each other.
In addition to proper grounding, also make sure your wiring is properly phased - that is, make sure Rail A and Rail B are the same physical rails everywhere. I have 3 zones - two run with a Digitrax DCS 52 for each zone and one with a Digitrax DB210 booster. Also make sure your power supplies are only connected with circuit breakers as you cannot connect two DCC supplies to the same power district. I assume your DCC supplies have roughly the same voltage output. I do not get any high pitch buzz when any locomotive crosses from one power district to another.
Thanks, Maxman and Chris, for the recommendations on grounding the CS and booster. I installed the ground connections, but that did not eliminate the buzz. I appreciate your advice and feel like my equipment and locomotives are better protected now.
Thanks for the advice, User1234. I will double check all my connections. Absent finding an issue there, I will check with Digitrax Technical Support to see if they have any ideas. Many thanks for taking the time to provide suggestions.
Evans Designs make LEDs that are pre-wired with resistors and diodes so they can use any power up to I think 18V AC or DC. I attached the leads of one of them to a pair of small alligator clips and use that to check my track at where itâs gapped. If you attach one clip to one rail on one side of the gap, and the other clip to the same rail on the other side of the gap and it lights up - you have a problem.
BTW doesnât hurt to test that out with one section of track having itâs power turned off. If the bulb lights when one clip is connected to the dead track, it usually means one track connection is connected to the wrong feeder, so is connected up to the âotherâ power. If so, the layout may still work, but might cause the problem you indicate.
A canonical âcheap alternativeâ for this test, I think, is Mel Perryâs old use of an 1157 automotive bulb in a holder salvaged from an automobile scrapyard with some of the wire pigtails still attached. Even if the bulb does not glow very bright, you can tell current is there that âshouldnât beâ ⌠and the bulb does not care about polarity of I^2R current flow.
The context here is specifically gaps. The buzz will not be a loss of continuity (as that would promptly stop the train if absent, and have no effect if correctly lined).
What you want to measure first is any difference in voltage across each gap.
Thank you, Woke and Wjstix, for flagging the cross-gap voltage issue. I had checked for continuity across the gap (there is none), but not for a voltage differential. Your suggestions for how to test are helpful.
Iâm concerned that your statement that your equipment is better protected now may dissuade you from investigating further. While Iâm pretty sure that isnât the case, the fact that the buzzing is still occurring is not a âgood thingâ. My limited experience suggests that a buzzing indicates either a short or other electrical unhappiness.
Once you get this solved, please get back to us with the solution.
Oh, in case you donât have one, get yourself an inexpensive volt/ohmmeter. Places like Harbor Freight generally sell these for around $10 or so.
Thanks, Maxman. I intend to stay after a fix for this problem. I will post the cause and the fix once I get there. Many thanks for your help and advice.
You know, when I was a kid, Iâd sometimes sit in my little room in the dead of winter working on a plastic model kit with an open tube of Testors for hoursâŚwhich sometimes also caused a âmystery buzzâ.
