Non-powered MTH Grounding issue

Are you running it on two or three rail track?

Check the coupler thumbtacks. They're low to begin with and sometimes they kiss the center rail. The paint provides some level of resistance so it doesn't create a dead short without some sort of pressure. The isolator is nothing more than a replacement for the motor mount used in a powered unit that holds the truck to the chassis. Check for scarred paint. Also check to make sure that the wire for the lighting isn't scratched through and that the ground wire connection to the truck (if there is one) isn't touching the hot feed.

 

Hope this helps.

This may not be your Electrical Problem......  However when your layout has

physical electrical blocks (isolators on the center rail)....     Using two

Transformers not plugged into the same wall Power Outlet.....

may cause a power phase volt difference that shows up as sparks at the wheels.....

when running a wired car/engine over the blocked joint area....

 

Each truck (front vs rear) is in a phased power area with a different voltage..

 

Our Modular/Portable O  gauge RR Club....  NEVER uses two different wall or

floor plugs now....      A Good extension cord fills that bill via understanding...

what that PAST voltage difference problem solution was....

 

Dennis M from GBay, WI

 

Questions, questions, questions! First paragraph, "Got a new non-powered MTH Dash 8" so it is a stand alone unit and not part of a set. "Lots of sparking" sounds like something shorted inside? Second paragraph, "I removed the power pickups with no change." If the power pickups are gone where is it getting the power for the sparking?? Hence the question "Are you running it on two or three rail track?" Also the reference to the couplers. If the power pickups are removed it has to get power from someplace. Third paragraph, now you mention a powered unit, is there any connection between the powered unit and the non-powered unit? It still sounds like you have a center rail pickup connection that is shorting to the frame somewhere although the comment about the removal of the center rail pickups makes no sense.

 

Al

I've run into this lately with MTH non-powered engines.

 

Check the light board where it is bolted to the aluminum heat sink.  There should be a nylon insulating washer.  It is missing on some.

 

Dave

So to answer some of the questions:

-This is on a three rail layout.
- It will spark just being by itself on the layout (not connected to a powered locomotive or other cars). But also acts-up when connected to both.

I'll take a look for any other parts hanging too low and making contact.

Some other clarifying points: the sparking is noted above the trucks (between the trucks and the body). I did only remove the power pickups from the rear truck. The fronts are still attached, but I do get sparking above both sets.
Obviously, I should try removing the front set and see what that does.
That's next on the list of fault isolation.

I have seen some scortched paint on the cylindrical bearing that fits into the truck that fits between the truck and the frame.

I will have to see if there's anything to the above suspicions about this being symptomatic of occurring near  track blocks.
When I've checked it out, it checkout does take place near (not neccessarily over, though) a blocked area of track. But I'll see what happens farther down the track.
However, I haven't noticed block issues with the powered unit crossing this area. I actually just spent some time the past few nights sorting out any phasing issues between transformers and confirmed they're all in phase. All are plugged into the same power strip.

Thanks so far for the feedback.

-Joe

OK good, we are back to the internal short. Check out the light board as per Dave's post above.

 

Al

Check the wires coming up from the trucks through the metal frame.  I've seen numerous MTH engines in the last few years with the wires frayed because MTH uses too small/cheap of wire and doesn't put a grommet to protect the wires.

 

I've had about 7 MTH Railking SD70s in the last 4 months with this exact same issue. 

 

Jim

Yes, it's definitely something internal.
Next I have time for a major tear-down to inspect it, I'll check it out.

In the meantime, I've pulled all 4 pick-up rollers from the loco to prevent any current from going through. This has temporarily solved the issue for the time being.
It's an un-powered unit to begin with, so for the time being, I can live with the internal lights not being illuminated. It resides in the middle of a MU anyway so not a huge deal.

Thanks everyone for the responses!

 

-Joe