The SFCM is recognized by one carbon brush and one copper brush, connected to a
In a locomotive it looks like this:
This is from the Märklin 2870 train set, same layout as in Märklin 3170.
The conversion sets:
There have been three different conversion sets for locomotives with the SFCM motor.
|c91||No longer produced by Märklin|
|60943||none||A decoder must be bought separately|
The decoder in 60903:
This photo shows the c91 decoder without it's plastic cover. The lamp on the top does not belong to the decoder.
In the 60903 it was (not produced anymore) a so called c91 decoder, with a row of eight switches (so called Mouse Piano) to set the decoder address and two potentiometers to adjust the maximum locomotive speed and the acceleration and deceleration time. The decoder receives data from the digital train controller, one way communication only. With a Märklin control device you may select between 80 locomotive addresses. The decoder dimensions are 36 x 21x 9 mm. If required, it fits into a holder 258820.
The decoder in 60923:
In the 60923 conversion set we find a mfx decoder. It means, among others, that the decoder
is adjusted from outside, from the train controller. You can set a lot of
things, like the address (if you use a Delta controller or the 6021 Control Unit),
the maximum speed, which can be set rather accurate, the acceleration and
deceleration time can be set individually and you have some control of the
different functions of the decoder.
If using The Märklin Systems, either with the Mobile Station or the Central Station, the decoder is reporting itself to the control system, two way communication. It is not necessary to set an address. The decoder dimensions are 22,3 x 15,5 x 5,5 mm. If required, it fits into a holder 456200. This decoder is wrapped into a sort of rubber tube in the conversion sets.
The Märklin conversion sets 60903 and 60923 are no longer available from Märklin, and are replaced by a separate motor set and a choice of separate decoders.
The new motor conversion set, 60943:
The conversion set 60943 is the motor and small parts only. I think these parts are identical to the motor parts from 60903 and 60923, but I have not seen them yet. The decoder of your choice must be bought separately. There are four different decoders types to choose from:
The new decoders:
60942, mLD, multi protocol decoder (mfx, MM1, MM2 and DCC) with an amplifier board, six function outputs
60962, mLD, multi protocol decoder (mfx, MM1, MM2 and DCC) with wires and an 8-pole NEM connector, four function outputs
6094?, mSD, multi protocol sound decoder (mfx, MM1, MM2 and DCC) with an amplifier board, six function outputs and speaker
6096?, mSD; multi protocol sound decoder (mfx, MM1, MM2 and DCC) with wires and an 8-pole NEM connector, four function outputs and speaker
The sound decoder's number last digit: 5 is for steam engines, 6 is for diesel and 7 is for electric locomotives.
The mSD decoders 60948 and 60949 has special amplifier boards suited for the 36-series Hobby locomotives with bogies. 60948 for diesel engines and 60949 for electric engines.
The mSD decoder 60940 has a 21 pole mtc connector, to fit into locomotives with a factory fitted mtc21 amplifier board.
See this Märklin web site for detailed information.
Märklin 60903, 60923 and 60943 consists of a number of parts:
|Part name||Pcs.||Part number|
|Decoder, c91 with DIP-switches||1||603617|
|Bulb 22 Volt||2||2||2||610080|
|Tool to adjust the decoder||1||610080||Parts from a 60923 set with a 60760 decoder. The 60923 mfx|
decoder looks identical, but has more wires. A 276770 bulb
socket is already installed in the 3000's original bulb holder.
The decoder functions:
|Function||Direction||60903||60923||Remarks for 60923|
|f0||forward||on, changing with direction||on, changing with direction||On the mfx decoder in 60923 these selections|
can be done with the Central Station 60212. In
addition to the acceleration and braking delay,
this decoder also have a shunting speed
setting, normally also controlled with f4. This
may be set to e.g. f3 with the Central Station.
Also the output type and intensity can be
selected, like light, flashing light, smoke unit etc.
|reverse||on, changing with direction||on, changing with direction|
one direction only and/or
on/off with start or stop
may be selected.
braking delay cancelled
|Shunt speed and|
delay may be separated
A Central Station screenshot:
The left half shows an mfx decoder, identical to the one in the 60923 set, the right half shows a c91 decoder, like the one in 60903. The different functions are indicated far left and far right in the picture. From the top we have f0, front head lamps, f1, for instance interior light front end, f2, for instance Telex rear end, f3, shunting speed (not on the c91) and f4, cancelling the acceleration and the deceleration delay. The function order and position (which key to press) may be altered with the mfx decoder, but are fixed with c91 decoder.
Installation in a locomotive
A number of locomotives may be converted without any problems, but some require additional work. If you have some mechanical and soldering skills, it is normally no problem to install the conversion set into a locomotive. The locomotive must of course be in a good mechanical condition prior to the conversion. If you don't have the skills yourself it is recommended to leave the work to professionals, like your Märklin dealer or the Märklin Repair Service in Göppingen, Germany.
This list shows some of the locomotives that are
reported to be difficult or impossible to convert, with information
regarding some of the conversions I have done:
|Märklin model||Problem with conversion||My solution|
|This locomotive may have different problems, according to the production series. In my case, with a locomotive produced between 1974 and 1995, was that the lower screw for the motor cover was too long and blocked the lower gear from behind.||The simplest solution was to use a shorter screw. M2x11 would be perfect but as I did not have any I used a M2x10. It is a little bit short. I used the motor from a 60903 set and a 6090 (c90) decoder.|
|On Märklin item 3003, Br 24, and other models based on this locomotive the head of the lower screw for the motor cover interferes with the rear driving wheel flange.||I grinded off the screw head a little bit, to make sufficient clearance between the screw head and the wheel flange. I used the motor and small parts from 60903 and the decoder from Märklin conversion set 60760. The 60903 decoder also fits perfectly.|
|Some reports says that the motor cover needs some additional work. My 3016 was made in 1988.||I did not need to do any additional work. A plain conversion. I used the conversion set 60903.|
|This locomotive, Br 38 or P8, and other models based on this locomotive, is reported to be impossible to convert. The explanation is that the original motor cover is a special one and that the one from 60903 or 60923 does not fit.||The locomotive body hits the motor cover, so it will not fit properly. The solution is to grind or cut off approx. 1 mm from the cover, horizontally above the rotor shaft. Maybe the decoder from 60903 is a little bit too big. The mfx decoder from 60923 fits perfectly, as it is smaller.|
|On Märklin item 3095, Br 74, and other models based on this locomotive the head of the lower screw for the motor cover interferes with the rear driving wheel flange.||I grinded off the screw head a little bit, to make sufficient clearance between the screw head and the wheel flange. I used the motor and small parts from 60903 and a smaller c91 decoder, Märklin no. 603462. The decoder from 60903 also fits without any problems.|
|Märklin item 3064, Br 260, and other models based on this locomotive, is reported to need some modifications to the motor cover. My 3148 was made in 1989.||I did not need to do any additional work. A plain conversion. I used the conversion set 60903 and installed Telex.|
|On Märklin model 3171, D 109, and other models based on the same locomotive chassis, the motor cover is reported to be too thick, interfering with the inside of rear left driving wheel.||I did not need to do any additional work. A plain conversion. I used the conversion set 60903. If the problem occurs, grind off 0,6 mm from the motor cover, in the area inside the wheel.|
Some photos from the installations:
Märklin 3000 DB 89 motor, using the 60903 conversion set:
The yellow arrow indicates the shorter screw, M2x10. The long one, M2x12, sticks to the magnet for illustration.
Märklin 3103 KPEV T12, using the motor parts from a 60903 set and a
mini c91 decoder:
Notice the modified screw head just above the driving wheel flange. The decoder is in this case a smaller version of the c91 decoder, without the f1 and f2 functions.
Märklin 00380 DB 38, using the motor parts from a 60923 conversion set:
Notice the flat area above the rotor shaft. This is cut away to give sufficient space for the locomotive body. The photo is from the Märklin locomotive set 00380, Br 38 1967.
This locomotive has the dame basic construction as other Br38 based on the chassis from 1967.
There are many internet sites regarding this kind of conversions and how to solve the difficulties. Just search for Märklin 60903, 60923 or 60943 conversion.