I would advise reading more of the posts here and on other forums. There are extensive threads on the K27 electronics.

1. The stock boards do NOT snap in or out.
2. There are locations on the stock board in the tender where you COULD solder in screw terminal strips.
3. #2 above may not be sufficient for the conversion you want.
4. Nothing snaps back in, but there are some decoder boards that do plug in.
5. Yes, (some) DCC sound decoders will plug into the tender board, and at least two will work.

To answer your question on the subject line:

1. You could leave the factory board in the tender, solder in screw terminals, and use an AirWire receiver, and it will "work".
2. You could plug in a QSI decoder to the socket, add the Gwwire receiver, and then an AirWire transmitter will control the locomotive, thus "airwire will work with the factory board".

Hope this helps,

Greg

Just checking: are you using the Bachmann steel track (you can check with a magnet).

Indoors or outdoors?

Regards, Greg

I will make the following assumptions:

1. Bachmann K27
2. Phoenix 2k2 sound board.
3. No control system specified, i.e. no assumptions on battery, track, dcc, mts, dcs or other control system.

Yes, people have made this work.
You may need to do the "transistor" trick, although it works for a reason different than many people believe (but I could be wrong)
No, it does not plug in, no sound only board plugs into the K socket.
So far the QSI and the RCS boards seem to plug in just fine. Read elsewhere what these are, try the MLS forum, or the QSI and the Remote Control Systems web sites.

Reading between the lines, I'm not sure exactly what you want to put into the loco, the control system used will most likely have an interaction with the sound system you choose, if only mechanical.

Regards, Greg

p.s. was doing my reply when you updated and added the post about K27...

Almost every electronic device that handles current will dissipate heat.

Yes, have heard they can make heat.

I would not worry about melting the tender, but to make your task easier, and since you were going to put the batteries in the stock car, which would be wonderfully ventilated, I would consider putting everything in the trainling car.

This would mean you would have to run the motor and lamp leads from the loco to the tender to the trail car. I believe all of those wires are already in the tender.

I'd be interested in TOC's opinion, this is more his arena.

Regards, Greg

Why not put everything in the trailing car, since you have the sound system and the batteries there already?

Just a starting suggestion.

Regards, Greg

Phil, sorry if we were not helping in the right direction.

I will look to see if someone has measured the current through the resistor so you could make a regulator to set it....

The fan should be 12v, but, again, I will try to find out for you.

The Aristo site has a lot of threads on this smoke unit, so you might want to ask there...

Regards, Greg

I would go ahead without fear. Get one that has the DCC ready on the box, and the instruction book shows the wiring layout and how to fit a Digitrax decoder.

With the screw terminals and the Bachmann-supplied wiring diagram it should be a snap.

Regards, Greg

CA is not solvent welding... did you mean you will use the CA instead of a solvent welding type glue, or understood Dr. Mike's is solvent welding?

I have to admit gluing stuff is a black art to me, some plastics love CA and some shrug it off.

Regards, Greg

No, I do know the later ones have the screw terminals that make it a lot easier, and are advertised as "DCC ready" or something similar.

Have you bought the loco yet?

Regards, Greg

Not yet, but will do my Annie that way, have an NCE in it. Really pretty easy, get the "magnum" adapter of course. Use the auto-chuff, it works great, so no magnets... I would put the decoder in the boiler if possible, and then run back to the speaker in the tender.

Regards, Greg

Dealing with China is a cultural thing, and also different business practices.

The company I work for gets a lot of material from China, made to our specification. We get samples, then order. We often get something different from the sample. Unfortunately, the sample is not made on the production line (sound familiar), so this happens.

One huge problem is that everything is paid for before it even gets to the docks in China. So, what is our alternative? Ship it back? We are often "stuck".

There is no easy solution for "short run" production items.

By the way, Kader makes Bachmann, Sanda Kan makes Aristo and USAT.

Regards, Greg

A friend and I will be doing one soon. I did my annie with a NCE decoder a while back, more effort to open it up. I did disconnect all wires from the boards, rather than try to figure out if there were any sneak paths.

What decoder are you going to use?

Regards, Greg

I understand the humming is the PWM frequency, not related to the voltage applied. I do not think you can adjust this. I have heard this complaint from several people. CV2 is the starting voltage, which, again, will not adjust the PWM frequency of the decoder.

You may have to use a different AirWire receiver.

Regards, Greg

Your problem is probably one of several things... First, the capacitor is an attempt to reduce "noise" in the circuitry.

I think that is bogus.

The transistor used is also a red herring, it is not needed to "invert" the signal.

The fundamental problem is that the ground reference for the chuff circuitry is from the K, and the ground reference from your sound board is from your sound board.

Connecting the grounds together is not the answer, you can burn up diodes.

The best solution in my opinion is to power the chuff circuitry from the power from your sound decoder. That does mean cutting into the K circuitry.

I realize that you may not like these answers/options, but they are the information that can be proved, not guesses.

You might just give up and use magnets.

Regards, Greg

The sd-45 type has an on-board regulator, so it can be fed higher input voltages. The regulator is actually a microprocessor, so it often resets if the input voltage goes too low.

The method of how/why the units shut off has not been determined (since it's code in a micro), but I surmise it tries to watch the current draw on the resistor that heats the wick and vaporizes the fluid.

It's thought that the aging of the resistor, changes in capillary action in the wick as it ages, and maybe some other things are the variables that cause a once nicely-functioning unit to not run well.

Replacing the wick/resistor assembly does not always solve the problem.

So Aristo customers just keep sending them back until they get ones that run well.

I have a friend that has 9 of them, and is slowly getting a few to work, and continually sending the non-functioning ones back.

Regards, Greg