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ESD and DCC???

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  • Member since
    April 2014
  • 4 posts
Posted by Schinpop on Thursday, April 24, 2014 9:10 PM

Had to send the unit in to MRC.  The "link" light was not blinking when Doug (MRC guy) said it should.

So, whatever I did, I blew up something.  Will definitely be more careful in the future.

On the plus side, I suspect my 3 decoders might still work!

  • Member since
    May 2012
  • 602 posts
Posted by NP01 on Thursday, April 24, 2014 7:42 AM

So interestingly I never thought about ESD when touching the rails. I do practice safe handling when building circuit boards etc in the train room. I realized that I unconsciously touch metal grounds prior to working on things when this thread came up. 

So far so good! OP, are you back in business?

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Saturday, April 19, 2014 7:24 PM

Schinpop
There's 15Vac on the track. I put a scope on it's a square wave with two distinct pulse widths. I have ground all over the table, just forgot to touch it before touching the track... :-(
 

 
Okay, so your DCC system is functioning properly.  The next step would be to reset the decoder in one of your engines and see if it comes back to life.  If so, then the others probably need to also be reset.
 
  • Member since
    July 2006
  • From: Central Vermont
  • 4,565 posts
Posted by cowman on Monday, April 14, 2014 6:54 PM

Welcome to the forums.

Spounds like a snappy topic!  (bad pun), but I have seen it mentioned as a problem several times.  Not to  hijack the thread, but what do most folks  have for ESD protection?  I know when I take off my sweater, I can get a good pop off from the support post by the train room door.  Do you  have a place to touch to ground yourself?  If so,  is it on the controll pannel, by the door or on the edge of the layout, don't do anything?

Thank  you,

Richard

  • Member since
    April 2014
  • 4 posts
Posted by Schinpop on Monday, April 14, 2014 4:44 PM
There's 15Vac on the track. I put a scope on it's a square wave with two distinct pulse widths. I have ground all over the table, just forgot to touch it before touching the track... :-(
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Monday, April 14, 2014 12:06 PM

 Steel plate, wired to earth ground via a 1 megaohm resistor. Always touch theplate before touching the track or components to discharge yourself.

 A static strap, maybe, which is a writsband with a conductive surface and a wire with a 1 meg resistor in it, but that ties you down to where the wire reaches.

 There's nothing you can put in the track circuit that wouldn't affect the DCC signal. I wouldn;t try connecting the rails to earth ground, and even if you did, you'd want a lot bigger resistor, like 1 megaohm. You need the large resistor to protect yourself in case of a wiring fault, like an outlet with the hot and neutral reversed. On the rails, this would allow mostof any large ESD to go intot he decoder and command station and not really protect anything.

                 --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January 2005
  • From: Winnipeg Canada
  • 1,637 posts
Posted by Blind Bruce on Monday, April 14, 2014 11:45 AM
First step, is there a fuse in the command station? Second, check the track voltage with a digital voltmeter. Should be 12 - 16 VAC.

73

Bruce in the Peg

  • Member since
    April 2014
  • 4 posts
ESD and DCC???
Posted by Schinpop on Saturday, April 12, 2014 7:53 PM

I'm new to DCC.  Running (or was running) an MRC Prodigy Advance with Digitrax DN135 decoders.

The other night I had 3 engines on the main line when I got a healthy ESD hit on the track.  After that, nothing worked.  I couldn't even program or read on the program track.  I initally thought I blew out all 3 decoders, but I just got a new decoder and I still get no response on the program track.

I'm putting a call into MRC on Monday, but my general question is regarding ESD protection and/or safeguards that we should take when operating DCC equipment.  The documentation that comes with both the supply and the decoders doesn't talk about ESD at all.  Can we just drop locos on a hot track???  This is always a bad idea when working on your computer, but I don't see any warnings against it for DCC.

I live in the desert.  It's dry and we get big time ESD buildup.  I've grounded my table, but the track is just floating.  I thought about 100k from the track to earth, but that still won't protect the decoders and track driver from a hit.

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