Decoder shorting out, no idea why.

[lisican]

I've got a Kato NW2 with a DZ123K3 drop in decoder. I got it two weeks ago, and am on my third or fourth decoder. I'll install a new one, and everything will be fine, I'm able to program it, run it, control the lighting, everything works fine. Then I'll turn everything off and start it up later and then it shorts out, starts making that beep sound and a few times smoke has shown up. This most recent time, Nothing had changed with the engine, the wiring, the track or the controller. I used it for a while, unplugged the Zephyr, a while later plugged it back in, and it shorted. There was nothing shorting out the track either. I'm not too fond of paying $30 everytime I want to run this engine. Does anyone have any ideas as to why this keeps happening? Thanks.

[jeffrey-wimberly]

Check all the wiring in your loco to include the pickups and any and all electrical connections. Somewhere you have something touching where it shouldn't.

[lisican]

I checked, and saw nothing. Plus, I figured that if something was touching, it would short out immediately, not after using it for a while. Thanks though. I'll keep trying to figure it out.

[lisican]

So the motion of the motor over time moves the lead into an area where it touches the frame?

[lisican]

My guess is that the motor clips are moved through the motion of the motor, which causes them to touch the nearby frame. Does that sound like a possibility? Thanks.

[lisican]

Also, this is n scale and the decoder is a replacement circuit board. And I've got another question - Once the initial short circuit had happened, I removed the motor clips and the clicking/beeping still happened. So, does that mean that the short is caused by something else? Or does the decoded itself begin to short out after the initial short circuit? I'm still trying to understand that ins and outs of decoders. Thanks.

[60YOKID]

It is not likely you would get more than one defective decoder.  That means you need to look at these other issues.  Make sure you have the correct power supply for the Zephyr.

When you turn on your Zephyr, does it run for a short time? Or did it go up in smoke as soon as the power came on?  Also, do other DCC locos work OK?  Does the NW2 run OK on DC?

You can measure the current consumption of the NW2 motor by hooking it up to a standard DC train transformer (without the decoder installed) and use a DC ameter in one lead while holding it in a stalled condition at full power.  The rating of the decoder must be at least that much.  If the motor is faulty, it may be drawing too much current, thereby causing the decoder to fail.

 

 

[lisican]

The engine was running fine for a while, then it would short out. It runs fine on DC. Other locomotives run fine on DCC. The power supply came with the unit, new from the store. I'll check the ameter. Thanks.