Several months ago I converted a small (34" x 87" shelf layout), common-wired DC layout with 7 blocks, including a reversing loop, into a DCC and DC operation in which, when I run in DCC (Bachmann E-Z Command), I engage a cutoff switch which denies DC power to all blocks and the common. I kept the DC operation option because I have a number of 30-year old brass locos that I want to keep operating that way, but I also have some newer DCC On Board locos and want to get into sound. I realize the danger here, but long as I am the only one operating the layout, I'll take the risk of burning out either a loco or a transformer/control if I accidently power both systems at once. And everything has been running just fine until the last few days.
My single main line has two blocks. Recently, after a few minutes of OK operation, when a loco operating in DCC hits block #2, it stops dead. I tested the track on block #2 with my multi-tester and, when this happens and the loco is sitting at the beginning of block #2, there is no power to the track. Sometimes when I run a loco into the other end of block #2, it runs a few feet in to the block and then shuts down - same thing, no power to track showing on the meter. I pull the engine, shut down the entire system for a few minutes - say 5- and sometines, but not always, when I power it up again, block #2 runs for awhile, then shuts down when an engine hits it or has run part way in to it. No engine burn out, no apparent damage to the E-Z Command control, no smoking contacts, all other blocks, including the reversing loop operate fine in DCC. The same phenomemon happens when I run a DC engine on the one analog loco operating circuit on the E-Z Command.
Something is causing the block #2 circuit to open somewhere when an engine bridges the gap, but the usual short circuit flashing and clicking on the E-Z Command control does not occur.
Has anyone got an idea about what is wrong and how I can fix it? Advice wil be gratefully appreciated.
Regards,
edwardjIII
I'm guessing that the wiring to that block has a loose connection. That would explain the intermittent nature of the problem, and the fact that nothing has burned out.
If you've got a meter, check the voltage on both the working and non-working blocks. Then, see if one rail or the other is the problem, by checking the voltage betweeen rail A on the working block and rail B on the non-working block, and then the other way around. If you don't have a meter, use a 16-volt light bulb.
How does the reverse loop figure into this? Is it wired with a DCC auto-reverser? Do the trains crossing into your problem block still have their caboose in a reverse loop, by any chance?
First, make absolutely sure the DC system if OFF. Unplug it, and if you can, disconnect it completely.
It takes an iron man to play with a toy iron horse.
Ed,
Like Mr B has suggested either a reverse polarity between the two blocks is happening or a bad contact/ wiring. How were the blocks controlled in DC? Is there a DPDT switch that changed polarity while in DC that could be set wrong? Does the block in question pass a quarter test? Does this block have the reverse loop?
Pete
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