HO GP35 & SD40
Circuit Board Conversion

Please note: The following procedure is intended for information purposes only. The replacement of the circuit board should be done only by qualified individuals. KATO USA is not responsible for any damage that may occur to the model that may result from attempting this procedure. Caution is advised.

Modelers who have an earlier production EMD GP35 (1992 & 1995 productions) or EMD SD40 (1991 & 1993 productions) locomotive model with Light Bulbs can upgrade their model with a new LED Circuit Board. Benefits include our White LED Headlight and a DCC-Friendly™ plug for easy conversion to DCC operation.

Because the circuit board will be replaced, and its dimensions are different, it will be necessary to replace the truck wires so they are long enough to reach the new circuit board. To complete this procedure, the following parts are required. They can be ordered via our Online Parts Catalog.

After carefully removing the bodyshell and trucks, follow this procedure to install the new White LED Circuit Board.

Step 1: Replace the truck wires.

Picture 1Picture 2

Disassemble the trucks by removing the bottom gear case cover - this releases the sideframes. With the sideframes removed, disconnect the original, short wires and install the new, longer wires (stock #O37-1298). Reassemble the trucks and reinstall them on the model.

Step 2: Remove original circuit board and weight.

Picture 3Picture 4Picture 5

The early GP35 and SD40 had a gray plastic "circuit board" with a weight on top. Remove the weight and circuit board, saving the screws that attach the circuit board to the motor mounts.

Step 3: Install new circuit board.

Picture 6Picture 7
Picture 8Picture 9

Install the #958036 White LED circuit board using the original screws from the model with the NMRA DCC Plug toward the Rear of the model. Put motor leads UP through holes in circuit board and bend to outside edge. Attach the truck wires to the #966010 Circuit Board Clips, used to secure motor leads to the circuit board. Note: DO NOT attempt to reinstall the weight on top of the circuit board!

Step 4: Weight mounting options.
It is not possible to reinstall the original weight in the same location on these models. The weight mounting was modified on future releases so that the weight mounted on the inside roof of the bodyshell. It may be possible to mount the weight to the inside roof with double sided foam tape. Another option is to discard the weight and purchase stick on weights from a local hobby shop. Regardless of the option chosen, be certain to check for clearance inside the shell so the weight does not created a short on the circuit board.


This site designed and maintained by the Kato USA team.
100 Remington Road • Schaumburg, IL 60173