ESD and DCC???

[Schinpop]

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.

Comments???

[Blind Bruce]

First step, is there a fuse in the command station? Second, check the track voltage with a digital voltmeter. Should be 12 - 16 VAC.

[rrinker]

 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

[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... :-(

[cowman]

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

[cacole]

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.

 

[NP01]

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?

[Schinpop]

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!