Loco-Decoder 75 420
Digital Decoder for DC-Motors
for the Märklin-Motorola Format
Suitable for dc-locos by Bemo, Brawa (Life-Like), Fleischmann, Gützold, Liliput, Lima, Piko,
Märklin-Hamo, Rivarossi (Atlas), Roco, Trix.
Not suited for coreless instrument motors!
Properties
Locos with dc motors can be operated digitally by using the 75 400 decoder. This decoder
operates on both the old and the new extended Motorola data formats. It features two direction-
dependent lamp outputs that are controlled by the function/off keys and an alternate address.
Uhlenbrock decoders can be programmed by Intellibox or Märklin Control 80f. Decoder address,
acceleration/braking rates, as well as starting and maximal motor voltage can be set and altered
at every time.
Digital Operation
When running in digital mode, the loco works according to the parameters set by the user. These,
as well as speed and direction settings, are permanently stored. This means that a loco will retain
its settings and will continue to operate as before after the track power has been reestablished.
Therefore, a loco can be run in standard automatic block systems.
When crossing over into an analog powered section, it will retain its speed and direction settings
provided the track voltage is high enough. Changing of direction or speed is not possible though.
Analog Operation
In analog mode the decoder acts like a standard reverser. Loco will stop when entering a digital
section.
Setting the Operation Mode
Switching over from digital to analog mode is done as described in the programming instructions.
A value of 01, analog code, is assigned to programming modes function 08 . Factory set code
value is 02 for digital operation.
Important: The state of the lamps set in digital mode will be retained in analog mode, i. e. when
lamps should light in analog mode, they must have been switched on in digital mode.
A decoder can be set back to digital when in analog mode, by holding the transformers control
knob in overvoltage position for at least 16secs.
Momentum Control
Use f4 to switch momentum on or off.
Important: Dip switch #2 on back of Märklin Control Unit 6021 must be set to ON in order to transmit
the new Motorola format.
Compatibility
The decoder is compatible to Märklins accelerating/decelerating circuit for their C90 decoder.
This circuit was published in Märklin-Magazin 4/93 and 5/93.
Technical Data
Max. motor current:
0.7 amp, 1.0 amp with heatsink
Motor surge current:
2.0 amps
Ancillary outputs:
2 x 0.9 amp
Total load:
max. 1.0 amp
Size:
19 x 16 x 5 mm (3/4" x 5/8" x 3/16")
Address range:
1-255, accessible by Intellibox
1-80, when employing another central unit
The decoder is factory preset to address 01 and digital operation.
