decoder instalation

[robman]

Help.. Just doing a decoder install on a Mantua 2-6-6-2 and I find that the motor is not completely isolated from the frame. Has anyone done  one of these locos and did you have to do anything to the loco? Cheers Rob.

[SteamGene]

If it's not isolated, it must be.
Gene

[robman]

Thanks Gene. I do realize that the motor must be isolated and I presume that means the outer case of the motor as well. It was the outer case that showed up on the test meter to have a circuit to one set of drivers.  Cheers Rob.

[Hunt]

Rob, you must have an old model of a Mantua 2-6-6-2.The current model I have seen is DCC ready with a 9-pin JST connector on a wiring harness in the Tender to accept a decoder after the removal of the jumper plug.



For DCC decoder to work, power must only reach the motor brushes thru the decoder. Easiest way to isolate the motor brushes is to isolate the motor.

[robman]

HI Guys. Thanks for all your help on this, I just hope I'm not being a pain in the $&%@*^!!. The loco is brand new,ex the USA one week ago and it has got the DCC plug on board but I suppose I was being a bit paranoid because although the brushes are probably isolated I still got a reading from the motor can to one side of the drivers. Ah what the heck' I'll bang it on the track and find out. I'll let you know the outcome.  Cheers from over here.  Rob. 

[Hunt]

....
I suppose I was being a bit paranoid because although the brushes are probably isolated I still got a reading from the motor can to one side of the drivers. Ah what the heck' I'll bang it on the track and find out. I'll let you know the outcome.  Cheers from over here.  Rob. 

DON’T put it on a DCC powered mainline track. You may ruin the decoder. Use the lower powered DCC programming track.

Before you try to use DCC, best to do a continuity test with multimeter from both rails to both motor brushes to be sure the brushes are isolated from all electrical pickups.

[RAM]

ob, I would check that one set one of drivers to see if something is wrong there.  If not, than try putting some tape under the motor.

[Tim]

Rob

The Mantua articulated loco's use the older method of power pickup.

One side of the pickup is through the frame, thus the connection to
case of the motor.

The wheels on this loco are all metal, one side picks up through the axle
and frame.  The other side is rim insulated at the tire, and has wheel
wipers to pick up that side.  Or through the tender.

The motor brushes are isolated from the case of the motor.

Go ahead and plug in your decoder, it will be ok.

Tim Anders
Souderton, PA

[Hunt]

Thanks Tim. Saved me some time and gasoline.

I was going to try to make the time today to check the wiring and test the isolation of the motor brushes.

[ta152h0]

wonder if i have a different Mantua 2-6-6-2 articulated. Mine has a tender and it has a 9 pin flat connector ( on the board ).

[RAM]

They make a 2-6-6-2 and a 2-6-6-2T.

[robman]

  To one and all. Thanks for all your input and with nervous hands on the throttle it all worked out fine. It does appear that the brushes are isolated even though the can is not. Once again thanks and what a neat forum. Cheers from here to there, Rob.