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Can a lamp short out a decoder? ...A new question...

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  • Member since
    May 2008
  • From: Hollywood
  • 101 posts
Can a lamp short out a decoder? ...A new question...
Posted by lisican on Monday, July 21, 2008 12:11 AM

I just wired up a Bachmann N Doodlebug with a DZ125, for the first test, it worked fine, then I tried with the body on, and nothing happened. I removed the body and saw that the cabin light (which I hadn't wired in yet) had its two wires near the rest of the electronics. When I tested the engine, the light didn't flash, could it still have shorted everything out? I'm guessing that the leads from the light touched some metal and shorted everything out.

Is it possible to short out everything through the lamp lead (12v lamp that came with it)? I know open wires will short things, I figured that the bulb would have acted as some sort of resistor.

 If you could tell me your thoughts, I'd appreciate it.

Thanks

http://www.1223artistry.com http://www.ohnoamonster.com
  • Member since
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  • From: Hollywood
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Posted by lisican on Monday, July 21, 2008 12:23 AM
Nevermind. When I first tested it, the plastic piece that connects the engine to the powered truck snapped, so I removed a screw to have a look. Didn't put that screw back, turns out that screw is the link to get power from the track to the decoder. Soooo didn't destroy the decoder. All's well on my end.
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  • Member since
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  • From: Bedford, MA, USA
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Posted by MisterBeasley on Monday, July 21, 2008 6:33 AM

Glad to hear that all is well.

For future reference, any piece of loose metal, be it a wire, handrail, screw or whatever, could short out the electronics and fry the decoder.  So, always be careful of such things when putting the shell back on an engine.

I've fried a couple of individual "function" outputs on decoders.  If you short out the leads to a light, and then turn that light on, you may burn out that particular output.  (If the decoder contains a "current limiting" resistor for that function, such as you would use for connecting a LED, then the resistor will probably protect your decoder.)

You can sometimes see physical evidence of burnouts on your decoder.  Take a look at the decoder's plastic wrapping.  If there is a small blackened dot, similar to an insect bite, then you may actually be looking at the spot where the electronics literally burned out.

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  • From: Orig: Tyler Texas. Lived in seven countries, now live in Sundown, Louisiana
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Posted by jeffrey-wimberly on Monday, July 21, 2008 9:55 AM
Can a shorted light fry a decoder? In a word, ABSOLUTELY! I had it happen to me one time. I had just finished a hardwire installation, all connections were neatly soldered and wrapped in electrical tape, all except for one little place where a wire from the headlight joined to the decoders circuit board. I didn't even give it a second thought. I programmed the loco with a new address on the programming track, put the shell on it and put it on the mainline for it's maiden run. Everything was fine until I hit F1 (on Bachmann EZ-Command) to turn the light on and POOF! The decoder went up in smoke. It didn't take long to find the cause. Now I wrap ANY suspect connections or insulate them with a dab of hot glue if they can't be wrapped for some reason.

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Dub
  • Member since
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  • From: Seacoast, New Hampshire
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Posted by Dub on Monday, July 21, 2008 10:52 AM

Integrated chips operate in the 5 to 1.5 volt range and your track has full power.

Insulate and don't be sorry.

Bob
  • Member since
    May 2008
  • From: Hollywood
  • 101 posts
Posted by lisican on Monday, July 21, 2008 8:32 PM

Now I've got another problem with the same decoder. I tried changing the engine's address, and the values of the cv to keep the rear lamp on all the time, and now all I've got is an engine that sits there with it's rear light on. I tried resetting the decoder according to the manual's directions, and when I "cvrd" the loco's #, I get '003', so I try to control engine number '03' and nothing happens, short of the rear lamp that I have no control over. Any ideas?

Thanks again.

http://www.1223artistry.com http://www.ohnoamonster.com

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