Category Archives: Electronics

Puzzle solved

This afternoon I solved the puzzle of why my 40 year old PCRy engine motor turned counter-clockwise while all the other Athearn motors turned clockwise, with the same polarity DC power applied to the motors. Somewhere back in forgotten time, I took the motor apart and then reassembled it with the center magnet reversed. So, today I again took it apart, turned the tubular magnet, reassembled it and it now turns clockwise like it is suppose to do.

When dissembling the engine you will need to twist the weights to pry them off the ends of the motor shaft. Other than that be very careful when you take the brass straps off the top and bottom or you will loose the small spring and brushes under each one.

Motor Anomalies

After wiring up a “new to me” GN engine, with another NCE decoder, I found that the engine ran in reverse when it should have gone forward like my older PCRy engine, (the lower engine in the picture). So I tried the motors in two other Athearn blue box engines, which I acquired two years ago, and they all  turn in the same direction as the newer GN engine motor. Now I have to decide if I want to modify the PCRy engine or all the other three engines. It only takes switching the + and – wires on the motors. I use brass clips on all the decoder wires so switching them is relatively easy.

Converting an Athearn PC board

I recently set out to convert an Athearn/Digitrax digital PC board from using light bulbs to powering LEDs. The process involves removing the eight limiting diodes and increasing the two series resistors from 150 to 1K ohms. Since I could find no schematic of the PC board I drew a circuit representation on my CAD program to aid in identifying what circuits to modify. The project has proven to be a great success.