Dr. König´s Märklin-Digital-Page

Digital- and Delta decoder controls DC-motor
with keepig of auxiliary function


Probably because of Märklin´s model, price, and quality policies, ever more people are buying locos from other manufacturers. Since these come with DC-motors there arises the problem of converting decoders constructed for use with the Märklin-"Reihenschlußmotor". The

The available solution has the grave disadvantage not to function with the digital decoder and to prevent the upgrading of the Delta decoder to include the auxiliary functions. So it was time to invent a better solution.


Time limits prevent me from displaying and explain the circuit here. However, it is very small and fits into any loco.
The photo on the left illustrates the wiring and saves many words. For clarification: The leads from the motor can be soldered onto either side.

Those interested in the circuit may send me an e-mail. The little pcb seen above can also be bought, as usual, from Mario Binder. He can also provide the resistors 4k7 and 22k, as well as the diodes IN4004. For the transistors the FZT705 of ZETEX, known from the c81 and 6090 decoders, are actually recommended. Unfortunatly, these are difficult if not impossible to obtain, but Farnell has them.
However, MJD6036 or similar from Conrad can also be used. Since they are somewhat too large the two little legs have to be bend by 90 degrees and cut even with the housing. The right, or lower, MJD6036 needs to be connected via its collector pin (present only as a small stub) to the anode 1N4004 which is directly in front, through a small wire bridge, or as shown in the above picture, via a blob of solder. Also, because of this transistor´s large collector area, one must insert an isolation between pcb (copper) and the housing. A small piece of insulating tape, etc., is sufficient for this. The red circle in the top photo shows a protruding corner of this insulation.


This translation was made by Dr. Hans W. Mueller from Gießen/Germany. Many thanks to him for this grateful work. Some mistakes you probably find are my work as result of trying to correct some misunderstandings.

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© 1999 by Dr. M. Michael König | Antoniter-Weg 11 | 65843 Sulzbach/Ts. | Contact | Stand: 29.10.2001
© 2001 by Dr. Hans W. Mueller | Gießen (Germany) | muhawyc@yahoo.com

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