Well, this topic sure disintegrated quickly... there are a lot more
off-topic responses here than useful ones! Is there anyone else out there
who has a way of dealing with Mars Lights in Proto 2000 E units, in DCC? As
suggested by Cheery Littlebottom, I will probably replace the bulb, but no
one has detailed what it would take to get the original bulb to work with a
Decoder installed. It's obviously not wired to the DCC socket, since F0 is
supposed to control both the headlight and backup light, and all F0 does is
turn on the bottom headlight. And none of the other functions turn on even
one of the filaments in the bulb...
The Proto E7 control board is not well designed to operate with DCC. In spite of
their efforts to build a dual purpose board they have failed. This is very
unfortunate since it makes the DCC solution far more complicated than it should
have
been. You are not going to get the as-built dual filament light to work with DCC
without making some serious modifications to the control board. Since neither
I, nor
anyone I know elected to do this, I cannot tell you precisely what to do and
where to
do it......but.......IF you can find the source input for the circuit that
operates
the as-built bulb you can break the trace and substitute the appropriate wire
from
the decoder. This is a multi-layered problem.
First: you have to moderately reverse-engineer the board in order to map out all
the
circuitry associated with the Mars function and to make sure that you have found
all
of it.
Second: you have to figure out how you can isolate it from the rest of the
board.
Third: Then you have to test it to make sure that you do, in fact, have it, and
that
it will work.
Fourth: Because the as-built Mars is directionally sensitive you have to
determine
which decoder wire to use. If the direction control is inside the light circuit
you
will need to determine whether to source it or sink it. The white wire is the
common
for DCC lighting. It is designed to be a common source, so the white is the
"always
hot" wire. The functions are activated by sinking them to ground such that the
blue
wire is the ground for forward and the yellow wire is the ground for reverse.
You will need to determine which way to connect the wires to the light circuit
once
you have it isolated.
Fifth: Because the as-built mars is a low voltage bulb, you will have to add an
additional series resistor so that you won't destroy it with the decoder
voltage.
some decoders have low voltage outputs, You need to determine which you have.
Do you see why I simply replaced the bulb and wired it directly to the decoder?
Not only that, but if you manage to make the as-built bulb operate, you will have
done a great deal of work to acheive an inferior solution to the problem. The Fx
functions will not work properly in the as-built dual filament bulb, so you will
be
forever stuck with a flashing light instead of one that really looks like a Mars.
Replacing the as-built bulb with a single filament one and wiring it directly to
the
decoder gives a much better result.
In fact, I removed the entire control board from the machine and made a
completely
new one from scratch. To this I simply attached all the correct wires to match
the
decoder to its outputs.
I wish I could be more specific and tell you step by step exactly what to do, but
this is the best I can do.
........F>
common source, so the white is the "always hot" wire. The functions are
activated by sinking them to ground such that the blue wire is the ground
for forward and the yellow wire is the ground for reverse.<
Actually Froggy I believe you are wrong here. The blue wire is +
voltage and the other wires (including white and yellow) for functions are
the sink, which are turned on and off.
So after you do what Froggy says about finding the dual filament circuit
you could remap and use the yellow wire (normally the rear light) as the
sink (off and on) for the Mars light. Much, much easier to use the built in
effects of the decoder.
Actually Jon, I think I'm wrong here.. The >blue< wire is the supply and the
other
wires are the sinks which are turned on and off. Thanks for catching that. I
hope
everyone reads beyond my first post. :-)
........F>
On Sun, 09 Jan 2005 01:51:25 GMT, Froggy@The Pond .com wrote:
Fourth: -------snippity-snip----------see below for correction
Let's try this again and this time see if I can get it right it right.
Fourth: Because the as-built Mars is directionally sensitive you have to
determine
which decoder wire to use. If the direction control is inside the light circuit
you
will need to determine whether to source it or sink it. The blue wire is the
common
for DCC lighting. It is designed to be a common source, so the blue is the
"always
hot" wire. The functions are activated by sinking them to ground such that the
white
wire is the ground for forward and the yellow wire is the ground for reverse.
You will need to determine which way to connect the wires to the light circuit
once
you have it isolated.
........F>
I decided to give my approach a shot, and instead of using the PCB, I did
what you suggested-wired directly to the decoder. If you'd like to read more
about it, and download a short video of the final results, please visit my
website (see URL below).
Try the F1 button on your command station. I have an E8 from a recent run
that has a TCS TH150DP installed, and F1 controls the Mars light while F0
controls the headlight. This didn't require any CV programming because I
just reset the decoder to factory defaults prior to pulling the light board
and decoder. I much prefer the Digitrax Mars light effect and am installing
DH123s and 14v bulbs in my LifeLike E units. I expect to pop the TH150 into
a LifeLike 2-8-8-2.
Peter
The simple solution, then, is to follow the wires tfrom the lamp to
the board, cut 'em loose and wire one filament directly to the blue
and violet (or green) wires at the decoder.
Sorry, I forgot they had sockets now - I don't have one like that, so
I don't know which wires are connected where. After my first
experience trying to retain a factory light board, I figured it was
easier to rip out the whole wretched mess and wire the decoder in
directly.
On Sun, 09 Jan 2005 20:10:46 -0500, Cheery Littlebottom
The only HO scale locomotive I ever plugged a decoder into without having to
modify
the circuit board was a Stewart F3. All it had was a single front LED headlight.
It
operated properly on F0. On Life-Like engines it is easier and quicker to just
remove the board and hardwire everything.
........F>
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