Tender, with new chassis, weight, coupler pocket and rear light:
The tender body is secured to the tender chassis with four clips. The body can be removed by carefully bending the sidewalls out where the clips are located.
Rebuilding Märklin 3084, DB 050 082-7, to digital with Märklin conversion set 60901 and new tender chassis
Updated 17.01.2010
This conversion method has also been used on Märklin 3100-2, 3310, 3315 and
3319. This means the older variants of the Br 03, 012 and 50.
As only the motor and the small parts from the conversion set are used, all the
different sets for dcm motor may be used. That is 6090, 60901, 60921 and
60760.
Märklin 3084, DB 050 082-7
Tender, with new chassis, weight, coupler pocket and rear light:
The tender body is secured to the tender chassis with four clips. The body
can be removed by carefully bending the sidewalls out where the clips are
located.
I rebuilt the tender in my 3084, with parts from the newer version 37840. That means new chassis, weight and coupler pocket. I kept the body, bogies and the pulling rod from the 3084. I also installed a 37840 type decoder, to fit in the new tender weight. The old tender body fits the new tender chassis without any modifications.
Decoder:
The decoder is installed in the tender, where the original electro-mechanical
reversing unit used to be.
As I am using the new tender chassis and weight, and the 37840 decoder, the
decoder installation is very simple. Just screw it into position with two
small screws. The noise suppressors for the motor are soldered directly to
the soldering pads on the decoder, and the blue and green wires are soldered to
the suppressors.
Decoder functions:
f0 = light with directional change
f1 = smoke unit
f2 = interior light in the tender cabin, 28 Volt T1 bulb with a 330 Ohm resistor
f4 = acceleration and braking delay off
With the
original type tender:
It is of course possible to rebuild the locomotive by keeping the old tender.
The below photo shows my Märklin 3100, DRG Br 03, rebuilt with the 60921 mfx
conversion set.
Rear light:
The new decoder has a bulb socket for the rear lamp, so I had to install a light
guide in the tender, as 3084 originally has no rear light. The light guide
from 37840 fits perfect. Very carefully drill holes in the rear lamps on
the tender body. Very careful, as the drill has a tendency to slip
sideways in the soft plastic, damaging the lamps.
The final result looks like this:
Motor:
Installation of the motor itself is very simple. Remove the old motor
and make sure that all the rotating and moving parts are clean and work
perfectly. Install the new motor form the conversion set. Carefully
add one small drop of oil to each end of the rotor. To much oil will harm
the operation of the motor. Before inserting the brushes, check once more
that everything rotates and moves normally. Finally, insert the brushes.
Locomotive wiring:
The orange wire from the decoder leads the front lamp, so does the grey
wire. The brown/red wire for function 1 (f1) also goes to
the front lamp holder, which also holds the contact tongue for the smoke unit.
The original bulb holder in the 3084 has a common contact tongue both for the lamp and for the smoke unit. The bulb is installed directly in the locomotive chassis. I wanted to separate the two functions, and to insulate the bulb from the chassis.
The part from e.g. 3319 fits perfect. Bulb holder 280180, which has a separate connector for the smoke unit, and holds a 610080 bulb. One modification to the locomotive body: The original bulb holder has a too small diameter for the new lamp holder to fit. It must be drilled a little bit bigger.
New front coupler pocket:
I wanted to install the new type coupler pockets on my 3084, so a 70163 type
close coupler may be used. First I screwed on a pocket on the original
coupler holder, but I thought the coupler was too long.
The next solution was to install a coupler pocket from a newer locomotive, with
an original close coupler pocket.
The font coupler pocket is as on Br52, 3415 and 3715. The coupler pocket with snow plough
is Märklin part 447410 and the required axle holder is 393280. I had to
make some device for the coupler's centring springs.
The support for the centring springs are quite simply two small bent pieces of wire. At first I soldered one of them to the rivet holding the cylinder, but the rivet rotated, so the support came out of position. A small drop of glue solved the problem. The next support is only glued into position.
And with the leading truck in position, with the old axel from 3084:
On the track:
I think I will paint the coupler pocket itself black and the spring supports red.
New drive rods:
The first thing I did with my 3084, many years ago, was to replace the driving rods for the wheels.
3084 has been produced with three different rod types, with different radius
bars, but they all had the same part numbers. See table below.
Version 1, 1974 - 1981: as in the above photo, with a wire type radius bar and a simple cross head
Version 2, 1982 - 1983: as in the above photo, but with a more detailed cross head,
as in below photo
Version 3, 1983 - 1996: as in the below photo, with a detailed cross head (blue arrow) and a rod type radius
bar (green arrow). The photo is from 3308, DRG Br 85.
The additional parts I have used to upgrade my Märklin 3084:
| Märklin no. | Pcs. | As in | Description | |
|---|---|---|---|---|
| 60901 | 1 | - | Digital high performance conversion set for dcm motor (not
the decoder) 6090, 60921 or 60760 conversion sets may also be used | |
| 602758 | 1 | 37840 tender |
c91 decoder | |
| 567190 | 1 | Tender chassis | ||
| 761710 | 2 | Buffers for tender | ||
| 463300 | 1 | Tender weight | ||
| 750230 | 2 | Screws for tender bogies | ||
| 786750 | 2 | Screws for decoder | ||
| 463330 | 1 | Rear coupler pocket | ||
| 285240 | 1 | Cable holder | ||
| 210132 | 1 | Light guide in tender | ||
| 447410 | 1 | 3415 | Front coupler pocket with snow ploughs | |
| 393280 | 1 | Front leading truck | ||
| 280180 | 1 | 3319 | Front bulb holder with smoke unit contact tongue | |
| 234630 | 1 |
3084 ver. 3 |
Driving rods, right hand side |
Note: same part nos. for all 3084 versions These parts are used on many locomotives |
| 234660 | 1 | Driving rods, left hand side | ||
| 70163 | 2 | - | Close couplers | |
| 610080 | 2 | - | Front and rear light bulbs | |
| - | 1 | - | 28 Volt T1 bulb for interior light in the tender | |