Tony, You are forgetting something important.
TonyWalsham said:
…Likewise the regular DC user is going to have to make “modifications” to the socket to get a normal sound system to work at all. Never mind completely revising the chuff design to get it to work at low speed. …
DCC equipped locos run on DCC AND Analog DC track. Many of us have DCC in out garden railroads, but, we often run our trains on analog DC layouts. The point you failed to mention is that any special provisions needed to make the chuff work on DC will probably have to be made on DCC installs too. Just because there is a DCC decoder installed, that does not mean there is always power for the optical chuff. All of my locos have DCC, Nearly all of them have sound, I’m adding sound to the last few locos now. All of my locos run on DCC or DC. Many DCC users rely on the ability of DCC locos to run on DC. While My Garden railroad and indoor railroad at my home in Tallahassee both run DCC, my switching yard and small railroad in Alabama are DC. The other two railroads I regularly run on are also analog DC. Now, let’s look at the Kay. When I put in a DCC decoder, with sound, the sound does not work at low speeds on DC, only DCC. Not a big issue, you would think. Sound systems have a battery so they keep working on DC when the loco stops. It would seem like one could just hook the battery too the plus and minus pins on J1 to keep the loco supplied with enough voltage to run the optical chuff for hours. ( A diode and resistor must be added to limit charge rates), But no, the smoke unit, regulators and other circuits will kill the battery in short order. A bigger battery is no help, the current needed to charge it up during running creates problems on DCC. One has to select a battery voltage high enough to keep the optics working, but low enough to have the battery re-charge when running. This would have been easy if the regulated 12 volts had been provided on pins in the interface, but it isn’t. One might think that you could connect the battery to the regulated 12 volts on the tender, but you can’t. That voltage only supplies the backup light circuit and a fan plug in the tender. There is a separate regulator in the loco for the optical chuff. You are dead on with your other observations.
TonyWalsham said:
… Just ask for the opinion of some of the DCC modellers who had been hoping for a proper DCC PnP socket that would designed to take advantage of the features being built into the latest DCC decoders. That is something that has yet to really see the light of day. …
The Kay socket seems to have been MADE for battery/RC. Not DCC. It has a switch for battery, It has screw terminals for battery, It has all sorts of electronics to “FLICKER?” the firebox lights and switch on or off the headlights. These all seem aimed at allowing simple “MOTOR CONTROL ONLY” RCsystems. What is is we DCC users always hear? “Why am I forced to buy DCC stuff I can’t use and don’t need” Imagine how a DCC user feels. There are NINE circuit boards packed with electronics that I, as a DCC user, can’t use, and don’t need. The component count alone tells me I am paying three times as much for those useless electronics than what I pay for a DCC decoder that would replace all of them. What is DCC all about anyway? Many battery/RC and Analog DC users are only aware of DCC’s ability to control multiple locos and activate some functions like turning on a light or blowing a whistle. THAT IS OLD HAT For longer than I have been using DCC outdoors (11 years) DCC has advance way beyond the basic control advantages. DCC decoders are about realism. They coordinate the lights, sounds and movements to make the loco behave in a realistic manner. Imagine, what would be the first thing you would do if Bachmann sent all the Kay’s out painted silver and red, lettered and decorated like the Santa Fe Chief? That is how I feel about the red and yellow strobe lights flashing in the firebox. Absolutely mortifying. Someone holding a Rock Concert in the belly of the Kay? The flashing red and yellow strobe lights have to go just as quickly as the Super Chief War Bonnet paint scheme. All DCC deodar manufactures have to provide basic control. So why do you suppose 90% of them haven’t gone under? Why is it that the lowest cost decoder is not the only one still in business? Realism. Decoder manufactures compete fiercely to produce the most realistic features. (Some compete by offering no features at a low price.) The red and yellow lights in fireboxes on many DCC locos don’t just flash at two different rates. They vary their brightness just like a real coal fire. In some cases the manufacturers record the light from a fire through two different filters, red and yellow, to reproduce the exact same variations in the red and yellow bulbs. The light outputs are not turned on or off, but pulsed to vary the light output anywhere from dim to bright to match the behavior of a real fire. When the sound card decides it’s time to shovel coal, the lights play a brighter pattern to simulate the firebox doors opening. When the sound card decides to turn on the blower, the flickering speeds up to simulate the forced air blowing over the coals. This isn’t just about the flickering firebox lights. Remember, it is about coordinating the sounds, lights and movements. Place a modern DCC equipped steam loco on the rails. It does a startup sequence. Headlights and marker lights are off. The firebox flicker gradually increases, you can hear the flames growing stronger. You can hear the water starting to boil and steam starting to leak. Select the loco’s address. Now the loco prepares to run, You hear the Johnson rod move. Valves open, the steam driven electric generator starts to whine, and as the pitch raises, THE LIGHTS GRADUALLY BRIGHTEN in time with the sound of the generator. Notice that all of the above has nothing to do with pressing a button to turn on anything. It has everything to do with coordinating lights and sounds to create the effects of realism. To those of us who are used to seeing the lights and sound coordinated with the movement, it is like comparing the molded on details of a New-Bright Christmas sets to those on “super detailed” Accucraft brass locos. So, I should be able, if I want to spend an extra 100 dollars for DCC, plug all these “super detailed effects” right into the Kay, I can’t. The Kay thwarts me at every move. Bachmann totally missed the concept of plug and play. To understand plug and play, look at the HO and N scale decoders and the NMRA literature. There are three types of decoders. 1 Wired decoders. 2 PLUG AND PLAY with a standard NMRA plug. 3 PLUG AND PLAY decoders designed for specific locos. For the plug and play decoders the concept is simple. All of the lights, motors and wheel pickups and such are brought out to a set of pins. As shipped from the factory these pins are connected by a circuit board or jumper to make the loco function on Analog DC. For the NMRA standard plug, these pins are defined as to their shape, size and position. For custom PLUG AND PLAY decoders, these pins are defined by the loco maker. For a decoder made for a particular loco, the DC CONTROL CIRCUITS are on what is commonly called a “Lighting board” For a decoder made for a NMRA plug, the DC CONTROL CIRCUITS are on what is commonly called a dummy plug. In either case, you remove the dummy plug or lighting board to install your control system. this removes all of the control circuits needed to run the loco on DC. What gets removed may be as simple as some lands that feed track power to the motor and lights. Here is an example:
(http://www.lscdata.com/users/bobgrosh/_forumfiles/basic01.jpg)
In the drawing above, you remove the dummy plug (DARK GRAY BOX) then plug in the new control system. Or, it may include diodes to make the lights directional. Like this:
(http://www.lscdata.com/users/bobgrosh/_forumfiles/basic02.jpg)
Again, remove the dark gray “Lighting board” to install some other control system. Or it may include diodes to make the motor start at a higher voltage so the lights can be on when the loco is stopped. It may even include circuits to flash the ditch lights when slowing down, or make the firebox light flicker. All sorts of fancy features may be added by the manufacturer to attract the DC user. Then it looks like this:
(http://www.lscdata.com/users/bobgrosh/_forumfiles/basic03.jpg)
The important thing to remember is that ALL of the DC CONTROL circuitry for the motor, lights and smoke have to be removed. The DC control circuits will interfere with the new control systems ability to operate the loco. Everything, from the simplest jumper to the most complicated electronics has to come out or be disconnected. All that should remain is the motor, lights, smoke units, and track pickups. They should be exposed to the new control system via either a set of defined NMRA pins, or manufacturer pins and connections identified by the manufacturer. All of the above diagrams follow the standard practices used in the smaller scales. In each case you remove the gray box to expose the loco components and install a new gray box with the control system of your choice. This next diagram shows what happens when this simple concept is ignored.
(http://www.lscdata.com/users/bobgrosh/_forumfiles/basic04.jpg)
In the drawing above, we see a complicated Analog DC control system, A very small part of it is on the lighting board. Transistors were added so that a new control system could operate the DC control system. In effect, when you remove the lighting board you now have TWO control system. If you plug in a DCC decoder, it controls the Analog DC control system, not the lights, smoke and other hardware. At first glance this should work. And it does, marginally. The basic stuff like pushing a button to turn on the cab light works. But, what happens when you want to uses any of the special effects. If the decoder feeds a constantly varying flicker voltage to the base of a transistor, it will sometimes turn on the flashing firebox circuit, but most often it turns it back off before the flasher circuit has a chance to flash even once. Any decoder that tries to brighten or dim the lights smoothly, can’t. Above a 1 volt the transistor turns the lights on, below one volt the transistor turns the light off. The transistors only sink a couple milliamps when you turn them on. At first glance this seems nice, you can turn on the smoke generator with less than 3 milliamps of current at the function lead, even though the smoke generator takes 225 milliamps to make it work. But, where does that current come from? Look at the specs of most decoders and we see that there are two limitations, the maximum current for each function and the maximum combined current for all functions INCLUDING the motor. Exceed the maximum combined total and you burn out the bridge rectifier in the decoder. Replace the Kay’s dummy card with a decoder and the decoder bridge has to supply the three milliamps to the smoke function transistor AND 225 milliamps to the smoke unit AND still more power to the regulators, and circuits that Bachmann added. Isn’t it ironic? The DC board has a bridge rectifier able to provide enough current for all the functions. But, it is the one thing that is removed when you swap the dummy board for a decoder. Now the decoders bridge rectifier has to handle enough current for the motor, all the functions, and all the voltage regulators and circuitry on the eight boards in the Kay. Even more puzzling is that any new control system you install will need a replacement for the bridge rectifier that you just removed when you unplugged the dummy board. Otherwise the light, flasher, Optical Chuff and smoke will not work. Had the bridge rectifier been left in place, even a battery system would work through it, and it would have prevented a catastrophic failure should the battery be accidentally connected backwards. We have seen that all this fancy Analog DC circuitry gets in the way of the special effects of advanced control systems, but, does it work with simple on / off functions? Well, that depends on the decoder. Decoder designers have a huge task trying to make decoders small enough for HO, N and even Z scale. One problem, especially in sound decoders is the size of the resistors. Those tiny surface mount resistors can only dissipate a tiny fraction of a watt. Sometimes, the engineers need to dump more wattage, for example on the charging circuit on a sound card. They have learned that there is a handy place where they can dump some voltage in a place that is not on the board. They use a light output, usually the headlight, or sometimes the flickering firebox lights. Look at the headlight on a loco equipped with a SoundTraxx LC series decoder. Look close. It glows slightly even when off. It is being used as a resistor by some of the internal workings of the decoder chip. Remove the headlight and, eventually, you will notice some strange symptoms. (Note, the fact that the light is on or off does not alter the fact that is is used to offload some of the heat from the board. This little trick has even been carried over into large scale decoders. Most notably, the Digitrax DG583AR. The very decoder that the Aristo and Bachmann interface were based on. Without connecting a good current sinking device like a bulb or LED to the headlight function output, some features of the decoder do not work. The base of the transistor just will not sink enough current. If you use all the advanced features of the decoder, you will have to add yet another external piece of electronic hardware to the pins of the interface. How many other decoders are affected? What sort of problems will they encounter? We can only guess. Remember, function outputs are designed to operate light bulbs and LEDs. Some are specifically designed to directly operates smoke generators, relays, or servos. Some decoders even have a CV setting that alters the output to specifically work with either a incandescent bulb or a LED. The characteristics of each are quite different. The base of the transistor and the circuits it controls in the Bachmann interface have an entirely different characteristic. No decoder manufacturer has ever designed the function outputs to operate another set of electronics that in turn would operate as function outputs. That just wouldn’t make any sense to them. Sorry if I got a little technical. If you had trouble understanding the above, the try this explanation: You decide you like dimmers on the lights in your house. You find some really nice dimmers that even have a little remote control you can keep in your pocket. You replace all the light switches on the walls with these new dimmers. All your ceiling, table and floor lamps can now be dimmed using the remote. You buy a really expensive new floor lamp. Set it by your favorite reading chair. You plug it into an outlet that is controlled by a dimmer on the wall and turn on the little switch on the new lamp. For some reason, the light will not dim. it just dims part way and then goes off. It has the same bulbs as all the other lights, but it still does not work. You take it apart and find out the switch is not wired to the light bulb. instead, the switch turns on a relay and the relay connects the bulb to the incoming wire. The relay will not turn on until the dimmer on the wall is at nearly full brightness. You grab the instructions and find this is a new PLUG and PLAY remote control lamp. You will have to take the dimmer out of the wall, and install it inside the new lamp in place of the switch. They even made the switch so it can be unplugged. Your dimmer does not fit the plug, but the lamp maker provided solder pads. You solder in the dimmer and find that the relay still does not turn on and connect the bulb until the dimmer is turned all the way up. You get ticked off and rip out the relay and bypass it. Now the lights at the top of your new floor lamp dim. You notice that the cute little green glowing night light built into the base of the expensive floor lamp is out. Turns out it was somehow wired into the coil of the relay. To get the night light in the base to work, you are force to re-install the relay and jumper around it. Now the light dims, the remote works and the green night light works, but a few weeks later the dimmer burns out. Turns out it can’t handle the inductive load of the relay coil. That is just about as close as I can come to explaining what happens in the Kay.
