The mfx conversion set 60901 s no longer produced by Märklin. It is replaced by a
motor kit, no. 60941, and a separate mLD decoder 60942 (including a circuit board with
six function outputs) or mLD decoder 60962, with wire ends and four function outputs.
mLD means märklin Locomotive Decoder. See the
Märklin web site for detailed information.
The mSD (märklin Sound Decoder) 60947 (with the circuit board) or 60967 (with wires) may of course also be used, if there is space for the loudspeaker.
Märklin 3309 locomotive, DB 85 007:
The locomotive has a Drum Collector Motor (DCM) and an electronically controlled mechanical reversing unit, which also controls the Telex couplers, and constant light intensity regardless of the driving speed.
I am rebuilding it to digital, with an mfx sound decoder. This fantastic locomotive deserves the best.
Unfortunately I have no photos of the locomotive inside before disassembling.
The locomotive inside after the conversion:
This is before the final interior light installation.
Very simple to explain: remove everything. After removing the pick-up shoe, carefully remove the plastic part under the locomotive, including the brake shoes. Unsolder the wires to the pick-up shoe contact and to the ground point. Unscrew the two screws on the motor cover, the screw holding the electronic unit and the plastic screw holding the reversing unit. Then it should be possible to "lift out" the reversing unit, the electronic part and the motor in "one piece". I carefully pack these parts in a small plastic bag and store them.
I also remove the front and rear leading axels and couplers, to be sure of no accidents during the work.
Cleaning the locomotive's rotating parts
The next step was to clean the locomotive thoroughly, to remove all dust and old oil. I use dish washing detergent, an old toothbrush and as hot water as I can handle. After cleaning and brushing, I rinse very well in hot water. I remove the friction tyres before cleaning the wheels. Then carefully oil the rotating parts..
Installing the motor:
No problem at all. Install the new magnet and enter the rotor. Be careful to hit the inner bearing. Install the motor cover and secure it with the two 2x12mm screws. Add a tiny drop of oil on each rotor end.
Installing the decoder:
I decided to use a ESU V3,0 M4 sound decoder, due to it's programmability and it's mfx protocol, and that ESU has a sound project for a three-cylinder steam locomotive. It can be installed on an amplifier board, with six function outputs. See below table.
I have replaced the wires on the amplifier board, as I wanted to use Märklin colour codes.
Before selecting this decoder I installed a Märklin 60931 mfx sound decoder with four function outputs; f0-f and f0-r for the lights, f1 and f2 for other functions. I connected f1 to the smoke unit and f2 to both Telex couplers. If both f1 and f2 was on, the decoder was overloaded. I saw that I needed more outputs.
The decoder functions:
|f0||forward||Light front end|
|rervers||Light rear end|
|f2||both||Light, driver's cabin|
|both||Sounds, shunt speed|
acc/dec delay off
For space reasons I have chosen to use a 20mm speaker with a square chamber, which came from a Märklin mfx sound decoder set, no. 60933 (used in my 37292). This speaker has 100 ohm impedance, the same as the speakers suitable for the ESU V3,0 M4 sound decoders.
If not using the speaker that comes with a conversion set, check the impedance of the conversion set's speaker before connecting the new speaker. The speaker impedance may be different from one decoder to the next, Some have 100 Ohm, others may have 4 or 8 ohm speakers. The different impedances are not interchangeable and may damage the decoder if it's wrong.
The impedance is normally printed on the speaker. If not, use only the speaker that comes with the decoder.
To be able to install the speaker where I wanted, I had to do some modification
the the speaker chamber.
This was to be able to install it far enough forwards not to interfere with a wall inside the locomotive body.
The wall fits between the speaker and the motor.
I also had to cut a groove in the chamber, visible just below the white wires, to assure free movement of the articulated locomotive chassis.
The speaker is glued into position, and the decoder is installed.
The wires going backwards in the locomotive is secured with black tape.
I also had to grind off a bit of the top of the speaker chamber, not to hit the inside of the locomotive body. At the time of the installation I did not have a good file for this purpose, so I used my soldering iron (not the tip) to melt away some of the plastic. It doesn't look good, but it does the job.
The amplifier board for the decoder is glued to the bracket for the old reversing unit, as far down as possible.
I had to cut off a bit of the board, not to hit the inside of the locomotive body.
The noise supressors for the motor is glued to the chassis, one on each side of the decoder.
Front and rear lights:
I use the original bulb sockets as they were already insulated from the chassis. The original bulbs, 600190, is for 1,9Volts only, controlled by the electronic unit for the reversing unit, so I use bulb 600100, including a 100 Ohm resistor to reduce the light intensity.
The electronic unit used to be fastened with the screw in the photo.
I have made a small circuit board, which serves these purposes:
1. distribution of the red wire from the pick-up shoe, so I don't have to remove the big plastic part under the locomotive if I wish to make some changes.
2. distribution of the brown ground wire. The ground wire is connected to the motor, to the front part of the chassis and to the decoder.
3. distribution of the orange + wire to the front Telex, to the rear of the locomotive and the resistor to the front light.
The orange wire is connected to the bulb socket via a 100 Ohm resistor. The input to the resistor serves as a distribution point to the rear Telex and to the interior light.
The rubber hose is to prevent light spill, especially downwards.
A 28 Volt T1 bulb is used for the cabin light.
A two-pole bulb holder is glued to the rear wall of the motor, next to the magnet. A bulb with isolated wires are installed on top of the motor.
I am not sure that this will be the final solution.
Part list for the conversion:
|60901||1||Digital high propulsion conversion set, motor and small parts only|
|600100||2||Light bulbs for screw socket|
|207648||1||Speaker chamber, square||From a Märklin|
60933 mfx sound
|207649||1||Holder for speaker|
|??||1||Speaker, 100 Ohm 0,5 W, 20 mm|
|ESU 62489||1||Loksound V3,0 M4 sound decoder, 21 MTC, programmed with|
ESU sound project file 62402, three-cylinder steam locomotive
|ESU 51968||1||21 MTC Amplifier board with f3 and f4 outputs|
|-||1||28 Volt T1 light bulbs|
|-||1||2-pole bulb holder, cut from a SIL connector|
|-||2||100 Ohm resistor for front and rear lights|
|-||1||Home made experimental circuit board, 3 rows, 4 holes|
My setting of the decoder:
|Decoder settings, 3309||Default||Mine|
|Enable analog mode||check||<|
|Load Control, 5* Märklin motor:|
|Control parameter K||32||<|
|Control parameter I||24||<|
|Driving Sound Rate:|
|At min. speed||1,000||<|
|At max. speed||1,240||<|
|With speed sensor||uncheck||<|
|Without speed sensor||check||<|
|Steam chuff at speed 1||50||<|
|Steam chuff at speed 2||35||<|
The 3309 DB Br85 function table:
|3309 DB 85 007|
Screenshot from the Central Station 1:
The left part is my Märklin 3308, DR 85 006, which is converted to digital with a Märklin 60901 conversion set. One day it will get a Märklin 60962 multi protocol decoder.
The right part is my Märklin 3309, DB 85 007.
The 3309 wiring diagram:
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