Decoder Instal Question

[tommyr]

I am installing a decoder in a brass loco. I have isolated the motor with 2 sided foam tape & plastic tubing on the motor shaft. I know the pickup wires go 1 to loco frame & 1 to tender frame. My question is -do I have to replace the brass drawbar with an insulated one(plastic)? Thanx for your help.
Tom

[Pennsy58]

You isolated the motor from the frame. Thats because of the potential for power being sent through the frame causing a catastrophic failure to the decoder. This same power surge would be sent into the tender through the brass drawbar. I would strongly recommend replacing it or adding an insulating ring between the drawbar and the frame and using a plastic screw.

[nfmisso]

Tom;

Get out your multimeter, and take some measurements.

[cacole]

If you're sure that the power pickup was originally from both the locomotive chassis and tender wheels, then that drawbar must already be sufficiently insulated and should not need any further modification.

But as fnmisso wrote, get a multimeter and perform a continuity or resistance check between the locomotive chassis and tender chassis to make sure they are not electrically connected.

My guess is that the tender is isolated or you would have had a dead short between the locomotive and tender when running on DC block control.

[tommyr]

Thanx guys. I just checked with my meter ,cacole you are right the tender is is isolated..
Tom.

[tpatrick]

I am doing the same thing with a PFM 2-8-2, except that I plan to wire the black lead to the drawbar pickup inside the engine. All the decoder wires will go to the engine and none will be attached to the tender. The decoder will ride in the tender. My purpose is to make it easier to separate engine and tender or even disassemble them without interrupting the connections to the decoder. On another engine, a PFM Decapod, I tried to fashion a plug connection between engine and tender, but it wasn't really satisfactory. I hope this Mike will be better. Anybody with suggestions or observations, please chime in.