I have an inquiry about installing Stay Alive Devices: Many manufacturers provide their models with decoders; but, do not provide a plug for a Stay Alive device; or, in some instances are not the manufacture of the decoder, so have no idea how to install them. I would like to have all my steam locomotives to have stay alives. Is there a way to do this. Please understand I am not an electronics guy! However, my soldering skills are good enough to make connections if I know where to go. So telling me that one lead needs to connect to the "Boot Jack Frepicator" and the other lead to the "Number 3 Flit-Flat, will not be helpful enough! However, any information you can give me will be helpful! Thanks in advance!
Yes, the positive side of a the circuit goes to the blue wire. The trick is where to put the negative. This should go to the decoder's "ground", but finding it may or may not be easy. Many newer sound decoders do provide this as a solder pad, but in other cases, one needs to find the bridge rectifier of the decoder and solder to the negative output there. Unfortunately, there is no single solution, and the best bet is to ask for specifics of the individual decoder.
A keep alive can be added to nearly any decoder as long as one knows what to look for. As Rick points out, the difficulty is usually where to attach the negative wire. But it's usually not THAT hard to figure out - on the vast majority of decoders, the "bridge rectifier" Rick mentions isn't the normal single-case component that is in nearly all electronics. Instead, the decoder typically has four separate diodes that connect to form the rectifier (A single-case bridge rectifier is nothing more than four diodes in a single case). These diodes are nearly always marked with a positive and negative end: the positive end has some sort of stripe on the case while the negative end doesn't. So you find the two rectifier diodes that have their positive ends attached to incoming track power, and the negative end of either of those is where you solder your keep alive wire. The real problem is that these components are often tiny surface-mount components. You can't solder wires to them with most conventional soldering equipment. You need a soldering iron with a very small tip (1/32, 1/64") that can be temperature-controlled (or is extremely small wattage) so that you don't damage the component you are soldering the wire to. Some battery-operated soldering irons fit this bill, as do high-end soldering stations used by professionals for PC board repair. Here is a link to a web page that shows how to add the negative side of a keep alive to a decoder's rectifier diodes and how to find a decoder ground when it is not obvious: http://www.members.optusnet.com.au/mainnorth/alive.htm Just don't try doing this without the proper soldering equipment. John C.
Thank you very much to the three of you who responded to my question. Your right, the positive side of the Stay Alive is easy enough to do, it's determining where the negative lead goes which I have struggled with. I have Bachmann Mogul locomotive with sound that I have had problems with determining where to attach the Negative lead to. Bachmann is uncertain who is providing the decoder for them in this model.
it really doesn't mattter who made the decoder ... the negative hook up in one area [the negative on the diode block] and this can be determined fairly easily .. however, once you take the shrink wrap off, and take a soldering iron to the decoder, you will -probably- have cancelled any warranties that may be left on the decoder .. if you are relatively comfortable doing that on a a $100 sound decoder, keep going ..
I am comfortable with the process. I've built locomotives from kits, back when they where available that way and have installed all kinds of decoders in my models. A comment I would have for the manufacturers would be: Why haven't they all provided lands to solder Stay Alives to, making this process easier! However, it is, what it is! Again, thanks for the help!
some manufacturers have put the 'stay alive' connections outside the shrink wrap ... as an example these Lais [non sound] decoders have that ... however i was unsure of the pad to wire connections, and removed the shrink wrap and redid them
Putting the soldering Lands outside the decoder Shrink Wrap is thinking ahead on Lais manufactured decoders. However, I had never heard of Lais Decoders until now.
the Lais decoders actually did not have pads or lands outside the shrink wrap .. i removed the shrink wrap in the above photo .. all of it ...
