Aug 1, 2008
The Proto 2000 GP9 and SD9 locos are virtually identical inside. So, if you are working with an SD9, check out the GP9 of the same vintage.
This installation was done in 2008 using the QSI Revolution decoder. An "Atlas light board" decoder from any manufacturer will work in this version of the decoder installation.
The locomotive was disassembled. An end-milling machine was used to cut the weight down to level right at the highest point on the motor. Absent a mill, a belt sander can be used carefully to remove the metal.
The black plastic covers were removed from behind the two rear most fan grilles. The rear light pipe was removed and cut down to clear the speaker. A drop of Faller Expert styrene cement on the machined end of the light pipe gets rid of the scratches quicker than all the polishing you can imagine!
The speaker was installed in the shell and connected to the two-pin connector MALE side.The speaker was sealed to the shell with bathtub caulk.
The decoder was installed with the LEDs wired with the anode to one rail and returned to the function pad with a 750 ohm series resistor. If the decoder you selected has an eternal capacitor, it can be secured above the front truck with double sided tape.
For those of you who have attended Bruce's clinics on "How do I get the sound out?" will recognize the technique: The positive pressure goes out the grilles and the negative pressure gets routed mostly to the front truck. Here is a detailed photo of the speaker mount.
An alternative speaker mount is shown below, with a speaker and enclosure combination replacing the cab details. While this is a more conventional mount, the sound quality is SIGNIFICANTLY POORER than with the grille mount shown above.