So a couple of weeks back the RMCQ went up to Bundaberg to run trains at the Bundaberg Model Train Show and what a great time we had, as usual.
I had decided that this year I wouldn't run freight trains, but would run some of my passenger sets. One of course being the Atchison, Topeka and Santa Fe Railway's "Super Chief". I ran the 8 car set and then added the 4 extra sleeper cars to it. Motive power was of course the AT&SF liveried EMD F7A and F7B combo of 4 power units. They ran well for the weekend, but the sound in them was very weak. Here is half of the motive power set - the lead A and B units.
Of the 4 motive power units, 2 have sound decoders and 2 have plain decoders - so the train has some real horse power and never has a hauling issue. I've had sound in them for yonks and it is first generation MRC sound - MRC 1658 decoders in fact. I have thought about it and decided the other day to see what I could do for the sound. In the shot below you can see the sound decoder in the A unit has a small coil speaker stuck on the circuit board and the B unit has no sound and I have also removed the front LED from the B unit as it doesn't need a headlight. The decoder in the B is a Digitrax DN163K0b.
So the first step was to do some measurements and yep, there was room for a small Sugar Cube Speaker up the front of the B unit - NOT in the A unit. Hmmmm. OK, let's swap the decoders around and put the sound in the B unit and the non-sound decoder in the A unit.
Let's start with the speaker. So I had a left over ESU 11 x 15mm sugar cube speaker and some baffle bits. I cut the base plate at the bottom left of the shot in two. Then glued a strip of styrene along the edge to give 4 sides - the red arrow points to the styrene strip.
Normally you will not see the motor contacts soldered down, but I have found , and read, that it is good practice to make sure conductivity is 100%. Now in the A unit, I found it wasn't needed, so it still had the plastic wedge clip in place. Again a red arrow to mark it in the below shot.
A quick test with the Decoder Pro software of JMRI and the shell was back on again. The A and B units of one of the EMD F7 sets was now ready to rock & roll.