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Ya, thanks for putting that up.The N scale sound market must be a lot worse than I think it is, because it seems like advancements have stalled for years...I havent added any more sound units after installing multiples of Digitrax sound drop ins... and most of them required some mods (and with only fair sound files).Im burned out on all the hardwire decoder installs that have taken place, and would jump on more user friendly designs from Tsunami or Loksound. Maybe when the economy starts rolling a bit more?Jeffhttp://espeeoregondivision.blogspot.com/
Just curious, between which pads on the decoder do you attach the capacitor to? And do you need a resistor on one of the sides to limit the charging current?
Nice summary John.I also want to add my warning about voltage ratings for tantalum caps. I prefer to err on the side of caution, and use 20V or 25V rated caps. For me 16V is too close for comfort in N scale DCC applications. As John mentioned (and experienced), tantalum caps have spectacularly violent failure mode. Unlike LEDs or other semiconductor devices which simply let the smoke out when they fail, tantalum caps are more like fireworks! Back in the day when I used to troubleshoot and repair comuter circuit boards, I had a tantalum cap actually fly off the board like rocket, missing my head by few inches. It happened rather quickly. I saw a brief bright glow on the board I was repairing and next thing I knew was that the red-hot cap body took off the board and flew past my head. I suspect that this cap was installed backwards (it was so burned that it was impossible to confirm that). But that incident made me treat tantalum caps with respect. Electrolytic caps can also fail, but they usually go with a small pop as the safety vent simply relieves the built up pressure.Of course the tradeoff is that caps rated at higher voltages are physically larger than equivalent value caps rated at a lower voltage. In N scale space is at a premium, so this makes a difference. But still, I prefer caps rated at 20V.As far as advancement goes, for me the next big step will be when (if ever) QSI will release a N scale version of their Titan sound decoder. I just love QSI sound decoders (for steam locos).
We do have several models with factory-installed sound decoders.BLI E7sWalthers Y2 MalletsAthearn Big Boys and ChallengersThe latest is Bachmann DDA40XI might have missed few. But at least it is a start.
I don't use a resistor. For caps of this (relatively) small size, the charging load isn't that high, and they don't induce a "fake short" mode in my command station. The positive side of the cap is wired to the blue function common wire. The negative side of the cap is wired to the pad that is directly opposite the blue function wire pad on the "back" side of the decoder. If you look at this side of the decoder, you will see a bare gold pad, and then next to it at the very edge of the board, a pad with some solder on it. The negative side of the cap gets wired to this pad (the one with the solder on it). You'll have to cut away a bit of the plastic wrap to get to this pad.John C.
Just a word of caution to the novice sound decoder installers out there about hooking up the stay-alive cap. Every decoder is different. If John is talking about a specific brand and model of a decoder, then his description works. But different brand decoders (or even different models from the same manufacturers) might have different hookup pads for the cap. Best way to find out how to properly hook up that cap is to read the decoder's manual. If the manual does not mention adding the cap then the decoder is not designed for a stay-alive cap. In that case, someone who is electronically inclined could trace the circuit traces to find a suitable hookup point for the negative side of the cap.
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Topic: Best Of LokSound Installation Threads and Techniques List (Updated 10/24/2024) (Read 60797 times)
