Atlas 544099, 447299 User Manual

Atlas #544099 and #447399 DCC Decoders

The Atlas #544099 and #447399 DCC Decoders are factory-installed in
Atlas N scale DCC-equipped SD-24 and SD-26 locomotives. The
#544099 decoder is used in locomotives with high hoods; while the
#447399 decoder is used in locomotives with low hoods.

The principle features of these decoders are:

∗ Extended (4-digit) addressing
∗ Advanced consist control (lashing up locomotives that have

different DCC addresses)

∗ Will operate on conventional DC layouts; this feature may be

disabled by setting a CV.

∗ Supports the forms of DCC programming described in

NMRA RP-9.2.3.

∗ Both short form instructions and long form instructions

supported in Operations Mode programming (programming
on the mainline)

∗ Settable for operation with 14/27 speed-steps, 28/55 speed-

steps, or 128 speed-steps with direct drive

∗ Directional headlights

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Atlas Low Profile #544099
and #447299 DCC Decoders
for N Scale Locomotives

Item Nos. 544099 and
447399
Revised 03/08/2005

Atlas #544099 and #447399 DCC decoders are in conformance with

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Atlas #544099 and #447399 DCC Decoders 2

NMRA DCC Standards and Recommended Practices. They have been
augmented to work well with all major DCC systems on the market.

The Atlas #544099 and #447399 DCC decoders provide the following
features

• Extended (4-digit) addressing

• Advanced consist control (lashing up locomotives that have

different short or long DCC addresses)

• Settable for operation with 14/27 speed-steps, 28/55 speed-steps,
or 128 speed-steps with direct drive

• The forms of programming described in NMRA RP-9.2.3 supported

• Both short form instructions and long form instructions in

Operations Mode programming (programming on the mainline)
supported

• Operates on conventional DC layouts; this feature may be disabled
by setting a CV.

• Directional headlights

The characteristics of these decoders can be programmed to customize
the decoder to the locomotive in which it is installed. For details on the
configuration variables supported by these Atlas N scale decoders,
please read the Configuration Variables and their Definitions section of
this manual. The #544099 and #447399 DCC decoders support all
NMRA-specified programming modes.

Preparing to Install an Atlas #544099 or
#447299 DCC Decoder

Before installing an Atlas #544099 or #447299 DCC decoder in your N
scale locomotive, it is necessary to test (and adjust, if necessary) the
locomotive for proper operation on conventional DC power. Replace
any worn out parts, such as brushes. Also clean any dirt or oxidation
from the wheels and pickups to in order to insure that electrical contact
is good. Now is also a good time to lubricate your locomotive. A
locomotive that runs well under conventional DC will also run
exceptionally well under DCC.

The Atlas #544099 and #447299 DCC decoders are quite small and will
fit into Atlas N scale SD-24 or SD-26 locomotives in place of the existing
printed wiring board that controls the headlights in the conventional DC
(analog) version of the locomotive. Use the #544099 decoder in
locomotives with high hoods and the #447299 decoder in locomotives
with low hoods.

Precautions to Take When Installing the Decoder:

Although the Atlas #544099 and #447299 DCC decoders have many

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Atlas #544099 and #447399 DCC Decoders

internal safeguards to prevent damage, you must not allow any metal
part of the locomotive to touch surface components of the decoder other
than the pickup pads on the decoder that connect to the wheel-sets, the
headlights, and the motor brushes. Any contact to other parts of the

decoder can cause a direct internal short circuit and destroy the
DCC decoder.

The Atlas #544099 and #447299 DCC decoders are not completely
protected against static electricity and have sensitive electronic parts.
When installing one of these decoders in your N scale locomotive, it is
recommended that you wear a grounded anti-static wrist strap. Also be
careful in handling the decoder, especially in the area around the top
rear part of the decoder (the area where the microprocessor is located).

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All Atlas #544099 and #447299 DCC decoders come with
two LED headlights already installed. The light outputs of
these decoders are designed only to drive these LED
headlights. The Atlas warranty is void if the LEDs are
removed from the decoder PC board.

Step by Step Installation

In the following steps, please refer to the instructions provided with your
Atlas locomotive.

1) Remove the locomotive's body shell. Use care so as not to
damage any of the fragile parts.

2) Loosen the two screws that hold the frame together; these screws
are located at the front and rear of the frame.

3) Carefully remove the lighting control circuit board, which is located
at the top of the frame.

4) Place the decoder between the two halves of the frame so that the
decoder label is at the top of the board and the two motor pads are
at the bottom of the decoder. These motor pads will connect with
the two copper motor contacts when the decoder installation has
been completed.

5) Carefully press the two frame halves together, with the sides of the
decoder inserted into the notches in the two halves of the frame.
Some pressure is needed to press the two frame halves together.
This pressure fit insures good electrical contact between the frame
and the decoder.

6) Tighten the two screws that hold the locomotive frame together.

7) Carefully check to make sure that the motor contacts are not
touching either half of the frame. It is necessary to look down from
the top through the frame cutouts in order to check for such

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Atlas #544099 and #447399 DCC Decoders 4

unwanted shorts,

There must be NO electrical contact between the motor
contacts and any part of the frame

Place the locomotive (without its plastic body) on your DCC
programming track and read back the locomotive's address from the
decoder. If the decoder is properly installed, you will be able to read
back the factory pre-set address 03. If your system does not support
reading decoder properties, observe carefully the decoder's behavior
while on the low current programming track. Each time you try to
program the decoder you can see the acknowledgement that is sent by
the decoder in the form of a brief and minor jerk of the locomotive. A
successful acknowledgement means that you have installed the decoder
correctly.

Remove the locomotive from the track and, if necessary, correct any
installation errors. Once you have successfully programmed the
decoder, reinstall the plastic body and retest the locomotive on the
programming track. If this test is successful, the locomotive is ready to
use.

Programming Atlas #544099 and #447299
DCC Decoders

Atlas #544099 and #447299 DCC decoders support service mode and
also operations mode programming. Using these programming
methods, many features (such as the locomotive's address,
acceleration, and configuration) can be customized to the individual
locomotive in which the decoder is installed. The properties will be
saved in non-volatile memory locations on the locomotive decoder so
that they will retain their values even after the power has been removed.
The values are set electronically, which means that the locomotive does
not need to be opened again after the decoder has been installed in
order to read or modify the values of these so-called Configuration
Variables (CVs). DCC decoders have a total of 128 CVs. Not all of these
CVs are used at this time since many have been reserved for future
use.

All NMRA-compliant DCC Command Stations can be used to program
Atlas #544099 and #447299 DCC decoders. With several entry-level
systems, only CV #1 (the locomotive address) can be set unless you
use a separate DCC programmer. More advanced DCC systems
support the ability to set many more CVs.

This decoder is most readily programmed in either Direct Mode on
the programming track or in Operations Mode on the main track.

The specific details for reading and writing Configuration Variables with

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