Atlas SD60 LokSound 73100 Install – Capless in Seattle

[conrad]

Here it is: my 19 year old Atlas SD60 with ESU 73100 decoder and 73431 sound file (EMD 16cyl 710G3A Turbo).



This is my third LokSound install.  Practice makes perfect, a smooth installation.  Minimum filing just in the decoder area.  I followed Steve Ruger’s technique but moved the decoder slightly forward (6.2mm) for more speaker room.  With a little frame filing, the slightly wider decoder at the speaker pads just fits at the rear motor cage area.  The  downside is the blockage of the power pickup screw terminals in the front.  Just another set of wires to unsolder to remove the decoder.

For now I have an 8x12 sugar cube with a simple enclosure.  Future plan is to construct a longer, stepped box like the ones in my SD60M and GP40-2.  I may even go for a 9x16 speaker used in those locos although the 8x12 is plenty loud.  You will notice the magic blue wire.  As with the SD60 it comes from the +UB pad at the rear of the decoder.  Well caps are coming – “polyester” tantalums (go Bee Gees).

As an aside, here’s a 11/8/20 NY Times crossword clue for all you chemistry types: “Brick made of acrylonitrile butadiene styrene”.

Conrad

[CR4100]

As an aside, here’s a 11/8/20 NY Times crossword clue for all you chemistry types: “Brick made of acrylonitrile butadiene styrene”.

Conrad

Lego.

[tehachapifan]

Nice install! I see you didn't use any of the pre-existing slots on the frame for power pickup?

[Steveruger45]

Looks good Conrad.  You will have room for a 9x16 speaker as I got one in mine with the decoder further back.  I see you haven’t removed as much metal with this variation so a shallower but longer speaker enclosure will be needed and me thinks will take up all the space available commencing about 5mm forward of the frame end to allow for the rear light lens and get the desired 750 to 800 mm3 enclosure volume.
Not sure enough space forward for caps due the forward light lens though. At least without modification.  Still, with most six axle locos that I have, caps aren’t really needed as long as the loco trucks/wheels/pickup and track are good.  But It’s good you have it pre-wired in case you want or need.

[conrad]

Lego.

Correct

Conrad

[conrad]

Nice install! I see you didn't use any of the pre-existing slots on the frame for power pickup?

No, using frame slots for power pickup does not work. 

First, the 73100 is too thick thus slots would have to be opened up and that is tricky because the slots are not just "slots".  The lower part has a nub then a dip and the upper part has a nub slightly offset back from the lower slot.  With the thinner lightboards this makes a slight flex to get a good grip.  Not something the ESU board can do.

Second, using the front slots makes the rear of the board interfere with the rear motor cage frame holes.

Third, using the rear slots makes the front of the board interfere with the front motor cage frame holes.

I used Steve Ruger's method of drilled and tapped holes to connect the power.  See his SD60 install of 2/12/20.

Conrad

[conrad]

Looks good Conrad.  You will have room for a 9x16 speaker as I got one in mine with the decoder further back.  I see you haven’t removed as much metal with this variation so a shallower but longer speaker enclosure will be needed and me thinks will take up all the space available commencing about 5mm forward of the frame end to allow for the rear light lens and get the desired 750 to 800 mm3 enclosure volume.
Not sure enough space forward for caps due the forward light lens though. At least without modification.  Still, with most six axle locos that I have, caps aren’t really needed as long as the loco trucks/wheels/pickup and track are good.  But It’s good you have it pre-wired in case you want or need.

My plan is to build a upside down stepped enclosure like I used for the SD60M but with the speaker on top.  I must say that compared to the 60M with the 9x16 speaker, the 8x12 is not too shabby.  In both cases I have reduced the max volume so as not to hurt my ears.  The main difference I detect is less bass in the smaller speaker.

For caps, I have put the LED right up against the decoder thus plenty of room.  Check my photo, the LED doesn't extend into the shield.  I measure 7.5mm long x 7.9mm wide x 5.3mm high in the light shield.  I'm looking through DigiKey data sheets for caps that fit.  AND, you are correct, 6 axle locos with (ahem) clean wheels do not drop out.  Don't ask me how I know.

Conrad