Page 2 H0 Sound Decoder MX640
1.
Overview
Sound decoders of the MX640 family are for H0, 00, 0m, 0 or similar scales (possibly also for H0e,
H0m and TT). They are compatible for engines with standard DC motors as well as for coreless mo-
tors (Faulhaber, Maxxon, Escap etc.); special settings are available for the latter.
The MX640 operates primarily in the standardized
NMRA DCC data
format as used by ZIMO DCC
systems as well as DCC system of other manufacturers, but can also operate in the MOTOROLA
protocol.
.
MX640
”Hardwire” Version
(11 highly flexible wires, color coded according to NMRA
DCC standard)
for rails, motor, 4 function outputs and speaker.
MX640R
MX640 with 8-pin plug (medium interface per NMRA RP 9.1.1.) on 70 mm
wires. Separate speaker wires.
MX640F
MX640 with 6-pin plug (small interface per NMRA RP 9.1.1.) on 70 mm wires.
Separate speaker wires.
MX640D
Version with 21-pin socket on decoder
(as per NMRA RP 9.1.1.).
MX640C
Version with 21-pin socket on decoder for
Märklin and Trix locomotives
with
C-Sinus
or
Softdrive-Sinus motor
and 21-pin interface (via C-Sinus board).
2. Technical Information
Allowable Track voltage **) .................................................................................................. 12 - 24 V
Maximum continuous motor output .......................................................................................... 1.2 A
Peak motor current ..................................................................................................................... 2 A
Maximum continuous power of 6 function outputs *) .. .............................................................. 0.8 A
Maximum continuous power of 5 LED outputs ................................................................ each 0.1 A
Maximum continuous total current ............................................................................................ 1.2 A
Storage capacity for sound samples ...................................................................................... 32 Mbit
Sample rate, adapting to sound sample characteristic ............................................ 11 or 22 kHz
Number of independent playable sound channels ........................................................................... 4
Amplified output ............................................................................................................. Sinus 1.1 W
Impedance of speakers ........................................................................................................... 8 Ohm
Operating temperature ............................................................................................... - 20 to 100
o
C
Dimensions (L x W x H) .. MX640, MX640R, MX640F (with shrink tube).............. . 32 x 16 x 6 mm
MX640D, MX640C ............................................ 31.5 x 15.5 x 6 mm
*) The short circuit protection is carried out for the total current of all outputs. In the unlikely event
that the outputs are turned off due to cold-start problems of light bulbs (power surge at turn-on lead-
ing to a short), the “soft-start” option should be utilized (see CV #125 = 52 etc.)!
**)
When used with the DiMAX command station (Massoth): The DiMAX 1200Z, according to its in-
struction manual, should deliver 24V to the track (which would only by marginally higher than speci-
fied by the DCC standard). In reality though, the unit (especially older versions) powers the track
with a varying voltage heavily dependent on load, starting with 30V at idle (depending on line volt-
age!) all the way down to 20V under heavy load. The ZIMO large-scale decoders (usually….) just
tolerate the 30V (in contrast to many other brand decoders); it is better though to lower the track
voltage with a constant load (@ 0.5A) to an allowable level.
OVERLOAD PROTECTION:
The motor and function outputs of ZIMO decoders are designed with lots of reserve capacities and
are additionally protected against excessive current draw and short circuits. The affected output is
turned off once an overload situation exists and subsequent load tests are performed by the de-
coder, which is often recognized as flashing headlights.
Even though the decoder is well protected, do not assume it is indestructible. Please pay attention to the
following:
Faulty decoder hook-up, connecting the motor leads to track power for instance or an overlooked connection be-
tween the motor brushes and rail pick-ups is not always recognized by the overload protection circuit and could
lead to damage of the motor end stage or even a total destruction of the decoder.
Unfit or defective motors (e.g. shorted windings or commentators) are not always recognized by their high cur-
rent consumption, because these are often just short current spikes. Nevertheless, they can lead to decoder dam-
age including damage to end stages due to long-term exposure.
The end stages of loco decoders (motor as well as function outputs) are not only at risk of high current but also
voltage spikes, which are generated by motors and other inductive consumers. Depending on track voltage,
such spikes can reach several hundred volts and are absorbed by special protection circuits inside the decoder.
