The locomotive has a Drum Collector Motor (DCM) and a mechanical reversing unit. I am rebuilding it to digital, with an mfx decoder.
Updated 06.06.2013
The conversion set 60760 is produced by Märklin. It is a set with a
powerful 5-pole Märklin motor and a simple decoder, remotely programmable.
Another
option is to use a
motor kit, no. 60941 (same motor as in set 60760), 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.
This conversion is as if I used the Märklin mfx conversion set 60921, which is no longer produced by Märklin.
Märklin 3106 locomotive, DB 78 355:
The locomotive has a Drum Collector Motor (DCM) and a mechanical reversing
unit.
I am rebuilding it to digital, with an mfx decoder.
The locomotive inside before disassembling:
The locomotive inside after the conversion:
Disassembling
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 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 removed 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 decoder, due to it's reasonable price, programmability and
mfx protocol. This was before the Märklin mLD decoder
was available.
The decoder is installed in a decoder holder, Märklin part no. 456200, where the
reversing unit used to be.
In this case, the wires are a mix of Märklin
colour codes and ESU colour codes, which I normally don't do.
Ground point:
I used the screw for the valve gears with a small soldering lug, as a ground
point.
The noise suppressor circuit board
I made a
small circuit board, to distribute the power to the motor (via the inductors)
and the common "plus" to the functions.
The decoder functions:
| function | 3106, DB 78 3557 | |
|---|---|---|
| f0 | f. | Light front end |
| r. | Light rear end | |
| f1 | f. | Light, driver's cabin |
| r. | ||
| f2 | f. | Not connected |
| r. | ||
| f3 | f. | Shunting speed |
| r. | ||
| f4 | f. | Acceleration and deceleration delay off |
| r. | ||
Front and rear lights:
The
original bulbs were 600150, installed directly in the locomotive chassis.
From earlier conversions, I had some bulb sockets in my spare part box.
The fitted perfect in the original bulb holes.
Front light:
I used the original bulb contact as a wire distribution point for the short gray
wire from the bulb socket.
Rear light:
For the rear light I installed a small board, as a distribution point for the
common "plus" and for the gray wire from the bulb socket.
Cabin light:
A 28 Volt T1 bulb is used for the cabin light.
A two-pole bulb holder is glued to the top of the motor, next to the
magnet.
Part list for the conversion:
| Part number | Pcs. | Description |
|---|---|---|
| 60760 | 1 | Digital high propulsion conversion set, motor and small parts only |
| 276770 | 2 | Bulb socket with wires, from an earlier conversion set 609?3 or 609?4 |
| 456200 | 1 | Holder for decoder |
| 756100 | 1 | Screw for decoder holder |
| ESU 61600 | 1 | Loksound V3,0 M4 decoder with wires |
| - | 3 | 28 Volt T1 light bulbs |
| - | 1 | 2-pole bulb holder, cut from a SIL connector |
| - | 1 | Home made experimental circuit board, 3 rows, 3 holes |
| - | 1 | Home made experimental circuit board, 2 rows, 3 holes |
My setting of the decoder:
| Decoder settings, 3309 | Default | Mine | |
|---|---|---|---|
| Analog settings: | |||
| Enable analog mode | check | < | |
| Starting voltage | 15,500 | < | |
| Maximum voltage | 25,500 | < | |
| Control settings: | |||
| Swap directions | uncheck | < | |
| Max. speed | 255 | 95 | |
| Min. speed | 3,000 | 1 | |
| Acc. time | 7,000 | 8,500 | |
| Dec. time | 5,250 | 8,500 | |
| Forward trim | 1,000 | < | |
| Reverse trim | 1,000 | < | |
| Motor settings: | |||
| Motor PWM-frequency: | |||
| Low frequency | uncheck | < | |
| High frequency | check | < | |
| Load Control, 5* Märklin motor: | |||
| Reference parameter | 12,500 | 11,300 | |
| Control parameter K | 32 | 60 | |
| Control parameter I | 24 | 128 | |
| Control influence | 255 | < | |
| Special options: | |||
| Preserve direction | check | < | |
| Persistent acceleration | uncheck | < | |
| Persistent speed | check | < | |
| Persistent functions | check | < | |
The 3106 function table:
| 3106 DB 75 355 | |||||||
|---|---|---|---|---|---|---|---|
| mfx | Light | Light driver |
Not used |
Shunt speed |
Acc/ dec | ||
| funct. | dir. | front | rear | ||||
| f0 | forward | 3 | |||||
| reverse | 3 | ||||||
| f1 | both | on | |||||
| f2 | none | ||||||
| f3 | both | on | |||||
| f4 | both | delay off | |||||
The wiring diagram:
C1 = noise suppressor circuit board, C2 = rear lamp circuit board, C3 = front lamp contact
tongue
Central Station 1 screen shot:
Future improvements:
I will install close couplers with coupler holders Märklin part no. 286900 and
repair the broken hand rails on the front end.