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PRE-OWNED Zimo MX646L Micro Sound NMRA DCC Decoder NEM651 6-pin Angled Integral Plug

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MSRP: $111.60
Price: $79.99
You Save: $31.61
PRE-OWNED [ 1 ] pcs In Stock
Backorders Accepted
Item Number: PRE-OWNED MX646L
Manufacturer: SBS4DCC Consignment & Pre-Owned
Manufacturer Part No: MX646L

Optional Configurations

* denotes required field

ZIMO Warranty*
Optional Updates (Standard w/ Sound File Load)
ZIMO Sound File Options
Sound File ZSP Number (or Name)
Coded Sound Project Author (Requires Load Code Fee)

No idea why this is in the clearance box, but it is...  Speaker wires are fresh so I don't this it has been connected to a speaker.  Probably new but sold as pre-owned because that's where i found it.

ZIMOs sound decoders with all the functions of the non-sound decoders: silent drive selectable between 20 or 40 kHz, adjustable BEMF, special settings for coreless motors, optional kph or mph speed control, constant stopping distance, HLU, ABC, advanced uncoupling functions, smart stopping (prevents stops on dirty track sections), firmware updatable, recordable and RailCom.

The Zimo sound decoder offers an innovative concept for sound adjustment and optimization, which makes these procedures particularly simple for the user. The user can produce usable sound even without a computer or detailed configuration variable settings.

For sound generation, the Zimo Sound Decoder is equipped with 4 independent sound channels, 1.1W sinus audio output at 11 kHz or 22 kHz ! depending on sound sample, 32 Mbit memory.

Zimo MX646 DCC Decoders offer the following features:
The miniature sound decoder for various N and TT models suitable as an alternative for 00/H0, driving and full sound functionality like the MX644 or MX645, despite small dimensions, 6 function outputs.
Decoder Versions:
MX646, 11 highly flexible wires 120 mm in length
MX646N, small (6-pin) interface connector

8-pin interface connector on 70mm wire
6-pin interface connector on 70mm wire
MX646L, 6-pin angled interface connector on 70mm wire
Dimensions: 1.10 x .42 x .16 inch (28 x 10.5 x 4 mm)


  • 1.0A continuous, 1.5A peak power
  • 14, 28, 128 speed steps
  • 3-way adjustable back-EMF
  • selectable frequency, low 50 to 150Hz / high 20kHZ to 40 kHz for noiseless operation!
  • for all DC motors inclusive core less
  • NMRA bidirectional communication (RailCom)
  • SUSI
  • 3-point or individual speed table
  • short circuit protected
  • thermal protection
  • reliable overload protection
  • 5 digit addressing
  • 4 function outputs
  • 2 servo outputs
  • 2 logic-level outputs
  • all lighting effects with programmable timing and dimming
  • firmware can be updated by the user via Internet!
Manufacturers Website: Zimo USA
Common features and characteristics
  • Address range from 1 ... 10239, consist range 1 ... 127, functions controlled by main or consist address.
  • 14, 28 or 128 external speed steps, 256 internal speed steps or 1024 steps for acceleration or deceleration process.
  • Over voltage protection for motor and function outputs
    Thermal protection (100 - 120 C), shuts decoder down and notifies user with flashing headlights.
  • 3-point adjustable speed curve (CVs #2, 5, 6) or free programmable 28-step speed table (CV #67 - 94)
    Top speed (CV #5) can be used even when the speed table is used (CV #67 - 94), which means that all entered table values will be reduced automatically (i.e. to 80% if CV #5 holds a value of 200 instead of 252) - and that with a 1024 step accuracy!
  • Shunting button function - selectively switches to low gear and/or reduces or even removes programmed momentum.
  • Programming and readout of decoder CVs on the programming track (Service mode).
    Programming decoder CVs on the main track (Operations mode).
    Hard reset with CV #8 = 8 (as per NMRA) or by (pseudo) programming the address to 0 (only possible with ZIMO cabs); hard reset to another CV set or sound project with CV #8 = 0.
  • Function output dimming, adjustable flasher and function dependent low/high beam.

Zimo features and characteristics

  • High frequency silent drive, selectable between 20 or 40 kHz, makes it suitable for:
    • Standard DC motors
    • Coreless motors (Faulhaber, Maxxon...)
    • Difficult cases, such as the round Fleischmann motor
    • Old motors requiring low frequency 30 - 150 Hz
    • C-Sinus and SoftDrive motors as found in Märklin/Trix locos with the 21-pin plug and C-Sinus board
      (MX64D, MX64DM, MX640C only).
  • Self-adjusting motor regulation and many manual fine-tuning possibilities: PID parameter, reduce or cut regulation, reduce or cut regulation above defined speed, modify EMF sampling rate.
    The self-adjusting feature of the decoder reduces the effort normally required to perfectly match the decoder to a loco.
  • Special circuitry to prevent interference from capacitors, choke coils, which are often found on motors. Even though, in some cases removal of these components may still be beneficial (see decoder manual).
  • Mph or km/h speed control. Each speed step (1 - 128) is interpreted as either 0.5 mph, 1 mph or 2 mph (for high speed trains). All locomotives on the layout are adjusted by means of a semi automatic calibration section (i.e. 160 scale-yards = 72.83 on the layout). In operation, the speed is kept as exact as possible by continuously recalculating and readjusting it.
  • Realistic momentum: in addition to the standard momentum (CV #3 and 4), ZIMO offers exponential (nonlinear) momentum for extremely prototypical acceleration and deceleration and adaptive acceleration to prevent startup jolt.
  • Uninterrupted driving (without stop and new startup) during contact interruptions of up to 1 second; further improvements by adding external capacitors (SPEIKOMP, SPEIGOMP).
  • Uninterrupted driving on dead track sections. The decoder software prevents the loco from stopping when track power is lost, even while the loco is coming to a scheduled stop. This ensures that the loco can start up again even after the capacitors dissipated the stored electricity. Required parts: external energy storage module MXSPEIK or MXSPEIG, other similar products or self-made modules connected to the decoder.
  • Automatic stop in front of a red signal with ZIMOs signal controlled speed influence, but also supports the brake generator method as well as the DC stopping method.
    Automatic stop in front of a red signal with with asymmetrical DCC signal (according to Umelec or Lenz ABC), which requires only 4 diodes on the track.
  • Signal controlled speed influence - the ZIMO method for stop and limited speed sections for single locomotives or consists. 5 different speed limits to choose from as well as stop and even track power OFF (the latter is great for hidden stations), adjustable momentum (separate from the standard CVs #3 and 4); influence can be canceled for each individual loco by simply pressing the MN key on the ZIMO cab. 
  • Distance controlled braking and stopping. The often publicized precise, repeatable stop point that leads to constant stopping distance is not really possible (i.e. interference through poor wheel to rail contacts is unavoidable); by constantly recalculating the already traveled distance a pretty high accuracy is nevertheless possible, especially in combination with brake sections or other measures.
  • Number of function outputs and logic-level outputs; depending on decoder type, between 6 and 14.
    Logic-level outputs can power one LED or any other load by using an external amplifier (i.e. M4000Z).
    Number of servo outputs depending on decoder type; 2 or 4.

    On some decoders, the same function outputs can be used as either logic-level, servos or SUSI outputs.

    SUSI interface for the connection of other external modules, most often sound modules.
    On some decoders, the same function outputs can be used as either logic-level, servos or SUSI outputs.
    Sound decoders, in addition to the above, also have inputs for sound synchronization.
  • Number of function outputs has been extended to 20, will be further extended to 28.
    NMRA function mapping.
    Additional ZIMO function mapping (CV #61=...) for special cases such as direction dependent taillights and cab light in SWISS engines.
    ZIMO special function mapping procedure (CV #61=98) enables mapping of any output to any function key, directional or non-directional, which is not possible with NMRA function mapping.
  • Special programming mode for Lokmouse-2 and other systems with only 2-digit display (up to 99)
  • Numerous special effects: Soft start for function outputs, stop light logic, output time-out function, speed and load dependent smoke generation and fan control...
    All US lighting effects (Mars, strobe, double strobe, gyra, ditch light I and II) with variable cycle times and minimum dim values.
  • Virtual cam sensor for sound synchronization of steam engines lacking a real cam sensor. A function output is programmed to send 2 or 4 signals per wheel revolution, which causes the sound module to playback a chuff sound with every signal received. This output is connected to the same input on the sound module that normally connects to a real cam sensor.
  • Special CVs for automatic uncoupling: After pressing the function key defined for this action, the loco backs up a few millimeters to unload the couplers then actuates the uncoupler and movers forward away from the train. The distance the loco backs-up and moves forward as well as the loco speed step is definable with CVs.
  • ZIMO loco number identification and location - the decoder acknowledges commands with brief high power pulses, which will be interpreted by detectors in the MX9 track section modules.
  • RailCom - bidirectional communication - hardware is found in all ZIMO decoders. Basic functions are activated at delivery, which includes CV read-out on the main, actual loco speed and address feedback to local detectors. RailCom will be expanded further with new functions and implemented with future decoder software updates.
    RailCom is a trademark of Lenz GmbH.
  • User Updatable - Install the latest firmware yourself, in minutes, at no charge and without opening the locomotive. All ZIMO decoders come with this feature (including function and accessory decoders).
    The first user updatable decoders were delivered in 2004 and the update module MXDECUP, required for user-updates, since 2005. Since 2006 the update can be performed via a USB stick using the MX31ZL cab released in that year and from 2010 on the new MX10 command station will have the same capability.
    The new firmware is always available at no charge from the ZIMO web site (on the UPDATE page) along with the required computer software ZIMO Rail Center (ZIRC) or ZIMO Sound Programmer (ZSP).
  • Automatically recognizes and switches between the MOTOROLA and DCC format.
  • Operates with standard DC analog power packs, PWM power packs (i.e. ROCO analog mouse...) and DC power supply. Motor regulation and momentum are also available in analog operation.
    Designed to startup at extremely low threshold voltage.
  • Automatically compensates for gear backlash when loco changes direction; eliminates startup jolt after direction has changed.
  • AC analog operation with Märklin transformers; decoder also recognizes the power surge that initiates a direction change (due to the required voltage surge protection, only available in the MX630 at this time).

Zimo features and characteristics (Future Updates)

They will be released with new software versions (free download from,/ UPDATE page), which can be downloaded by the user and installed in the decoder with the help of a decoder update module such as the MXDECUP.

  •  Expansion of the ZIMO signal controlled speed influence (a.k.a. HLU method) by making it directional (i.e. dont stop if signal is approached from opposite direction), adding location dependent function control (as already available in the ZIMO function decoder) and the feedback of other position-related data.
  • CV sets, predefined or self-defined: by storing more than one CV set, a locomotive can quickly and easily be changed for various duties that require different CV settings (i.e. single traction or consist, layout at home or club etc.)
  • Automatic operating sequences (i.e. shuttle train operations) executed by the decoder. Logic-level outputs will be used as inputs (the MX69/MX690 already has such inputs), which can influence driving and functions with preprogrammed commands and make use of the signal controlled speed influence as well as asymmetrical DCC. This release of this software is planned for 2009.


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