I have several old brass engine from the '60 and '70 with the old open fram pittman motors. Can DCC decoder be installed in these engins. They were expensive years ago and super expensive today. I know I can replace the motors, but then they would not be orignal equiptment ( then putting a DCC decoder will changes things as well ).
You should be able to put DCC in, as long as you can insulate both brushes. A 2 or more amp decoder would probably be best (those old Pittmans and their clones draw a lot of current).
Two factors that determine the feasibility of putting decoders into these locomotives are the current draw of the Pittman motors and whether or not they can have both brushes isolated from the frame.
In order to determine the current draw of the motors, you’re going to need a VOM (Volt-Ohm-Milliammeter), a piece of track, and a DC power pack. After determine the current draw of the motor, you can then select an appropriate decoder.
Isolating the brushes from the frame can get complicated if the motor frame is screwed directly to the chassis, which is probably the way these engines are built. Removing the motor, placing electrical tape between the motor and frame, and using a nylon screw instead of metal to reattach the motor, is the simplest way to isolate it, but you will need to check with a VOM to insure that both motor brushes are totally isolated; otherwise the decoder will become an instant smoke generator for a very short period of time.
THANKS, TIME FOR ME TO GET TO WORK. GOT MY METER IN HAND.
There’s another possible approach to isolating Pittman style motors. Frequently, one of the brushes was grounded to the motor frame by a tab of sheet metal. One could disable this connection and then deliver power to that brush in the manner that was used to feed the insulated one. This is often a wire soldered to the top of the piece. You would then have a wire from each brush. You wouldn’t have to worry about isolating the entire motor. I would think there might be a variant approach for Tenshodo motors, but I don’t have one handy to check.
Ed