Installation of Loksound decoder in Athearn SD70M - Ulrich Models

Loksound Installation – Precision Craft Big BoyKit Revised 02-4-2009IntroductionThis kit installs LokSound 3.5 into the Precision Craft Models Big Boy. The kit upgrades thenon-sound Big Boy to be identical to the released factory sound model.|The PCM Big Boy sound file loaded into the decoder has been edited to improve the bell andchange the whistle to the low base whistle of the large articulated Big Boy.Figure 1 – PCM Big BoyThe Upgrade KitFigure 2 – The Upgrade KitThe upgrade kit consists of:• One LokSound MTC-21 pin decoder• Two 100 Ohm speakers• 2 Pin JST connector for speakers (Plugs into the PCM circuit board in the tender)http://www.UlrichModels.bizPage 1 of 3

InstallationFigure 3 - Installed Kit1. Remove the tender shell by removing the 4 screws located at the four corners of thetender floor. Remove the rear coupler and lift the tender shell off the frame.2. Uninstall the smoke unit jumper located on the circuit board. Removing the jumperwill disable the manual DC smoke switch and enable decoder control of the smokeunit. The jumper can be left attached to one pin or totally removed.3. Remove the circuit board from the mount by unscrewing the mounting screw locatedat lower left corner of the board. It also holds the smoke switch panel. Move theboard aside, it will still be connected to the harness and backup light.4. Remove the speaker retaining frame, located under the circuit board, by unscrewingthe two screws located in the center of the frame.5. Place the two speakers from the kit in their mounts as shown in Figure 4. Run thewires connecting the two speakers as shown to avoid pinching them between thespeaker and the frame.Figure 4 – Speaker Placement6. Reinstall the frame. Run the speaker wire with the connector up through the slot inthe middle of the speaker retaining frame.http://www.UlrichModels.bizPage 2 of 3

Figure 5 – Speaker and Retaining Frame Installation7. Reinstall the circuit board and connect the JST 2 pin connector to the open headeron the board. See figure 3.8. Install the 21 pin MTC Loksound decoder. When you install the decoder, you mayneed to reposition the large capacitor and flatten the leads. Be sure any barecapacitor leads do not touch each or the decoder. Install the decoder with the blackconnector up. It is keyed to prevent improper installation. Figure 3 shows thecorrect installation9. Reinstall the tender shell and test the locomotive.http://www.UlrichModels.bizPage 3 of 3