I have 2 questions. This is a Soundtrax DSD-AT100LC EMD 2nd Generation.
The engine runs backwards. The lights work forwards. Is there a CV that changes the direction of travel? I matched the engine polarity on the stock board. Should I reverse it?
The speaker comes with a bi-polar capacitor.
It is this correct?
Board (-) …(long)BPC(short)… (-)Speaker
Board (+)…(+) Speaker
Actually I can think of 8 possible combinations and I haven’t a clue.
Thanks
If you’re using a long address and 28/128 speed step, CV29 has a value of 34, so add 1 to make it 35.
For a short address and 28/128 speed step, CV29 has a value of 2, so make it 3.
The SoundTraxx decoder should have come with an Installation Instructions sheet that has a wiring diagram on page 2. You will probably find it helpful, too, to download the SoundTraxx Technical Reference Manual, which comes in 2 parts, so you can see what CVs need to be tweaked for better sound.
Thanks.
There is a diagram showing the wiring, but it is not a schematic rather a drawing. Nowhere is polarity shown. If I were to follow the drawing, they show the BPC on the negative output of the board. Is there a significant difference?
There are long and short leads on the capicitor. Does it make a difference which direction it is attatched?
There are short and long
No, a bipolar capacitor means that it has no polarity so it doesn’t matter which way it is connected.
Unless SoundTraxx has changed their documentation recently, the drawing should indicate that the capacitor is connected to pin 2 of the decoder; that pin 2 is the second from the bottom on the pinout view; and that pin 2 is the Speaker (+) connection.
Sounds like we have different decoders. This one is made for the Atlas Geep and replaces the Lenz that came with it. Wires are attatched with retainer clips. Pins are used as follows:
1-4 are on the front end of the board
5-6 are in the center of the board
7-10 are at the rear of the board.
The speaker connectors are holes at the rear of the board just inside the connectors for the rear. I am to solder wires to these holes. They are marked simply by a plus and a minus. The BPC (according to the drawing) is attatched to the one marked (-).
Every SoundTraxx decoder I have installed, whether HO or G scale, calls for the capacitor to be connected between the positive (+) side on the decoder and speaker.
The documentation I was looking at is for a DSX decoder, not one of the plug-n-play versions like you have. I guess you need to contact SoundTraxx and ask them for clarification on which terminal should get the capacitor, though I can’t see why it would make any difference because the capacitor is going to have the same effect on the speaker whether connected to the plus or minus side.
The online documentation shows the BPC on the (+) side. Maybe I can fini***his sucker.
The only purpose of the capacitor is to keep DC current out of the speaker, so it should not matter to which terminal you connect it. A capacitor will pass AC (the sound) but block DC. A DC current could cause a hum in the speaker and weaken the sound output. The decoder should not be outputting DC on the speaker teminals, so the capacitor really just insures that the speaker is protected against decoder failure.
Another Question.
The best place to put the speaker and housing is right on top of the decoder. The only other place is the rear vent and I would have to take off half the rear weight, remove the optics and move the light.
The question is, if I put the speaker on top of the decoder, the speaker magnet will be about 3/32 from the largest chip, of course covered by the plastic housing. Is this asking for trouble or is it something that is done all the time?
I uess I’m bumping this because I need help.
As long as the speaker’s bottom is electrically insulated from the decoder there should be no problem other than adequate air circulation to that microchip. If the decoder has shrink wrap around it, you’re safe.
Thanks