Rebuilding Primex DB 023 033-4
(or Märklin 3005) to digital with Märklin conversion set 60903Updated 15.06.2009
This conversion method may also be used on Märklin 3005, as the Primex 33005 and the Märklin 3005 are quite identical. The Märklin 3005 was built in six different versions from 1954 to 1972. From 1954 to 1957 it was called DA 800
Primex was made by Märklin from 1969 to 1992. Normally the Primex models were rather simple, and had a more sophisticated Märklin "counterpart". To keep the Primex name alive, Märklin offered two Primex models even after stopping the production. That was item no. 30031, DRG 24 069, produced in 1996 and 1997, and the 33005. More information about Märklin and Primex can be found on this German link. Another link, in English, here.
The Primex 33005 was produced in 2000 and 2001 and had a Delta decoder.
Primex 33005, DB 023 033-4 after the conversion
Decoder:
The decoder is installed where the Delta decoder used to be, in a 258820
decoder holder.
Decoder functions:
f0 = light with directional change, two in both ends
f1 = smoke unit (will probably be installed later, see loose wire end above the
decoder)
f2 = interior light, driver's cabin, 28 Volt T1 bulb
f4 = acceleration and braking delay off
This photo was shot during the test driving. Click on the photo to get a
bigger version, 2,7 Mb.
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.
I do not remember, as the conversion took place some time ago, but I think the
front brush spring stopper have to be adjusted a little bit downwards, not to
hit the locomotive body.
Front lamps
Normally the 33005 has two bulbs, Märklin no. 600000, inserted in the front
bulb holder, connected directly to the locomotive chassis. In digital
operation, this will give a very bright and flickering light. I installed
two 600080, connected in series. This gives a much dimmer light, more
suitable for an old steamer, and the bulbs become insulated from the locomotive
chassis. The connection between the grey and the orange wire gives a
constant and flicker free light.
I removed the front axel and coupler holder, remove the bulb contacts and
the bulb holder itself. By adjusting the bulb holder a little bit, the
600080 bulbs fitted perfectly.
The connections behind the bulbs:
The gray wire from the decoder is connected to the outer pin on the RH bulb. A short piece of violet wire is connected between the inner pins of both bulbs, and the orange wire to the decoder is connected to the outer LH bulb. It gives this light:
Before attaching the locomotive body to the locomotive, I insulated a part of the inside of the body. Some clips are used to install a handrail outside the boiler. These may touch some electrical parts inside the locomotive. I used normal black insulation tape. The simple windows are also visible in the photo.
Rear light in the tender:
I also wanted rear light, so two holes were drilled in the centre of the indicated lamps.
Light guides from the NoHAB diesel (Märklin spare part number 215230) was glued into position.
The bulb holder is cut off a SIL (Single In Line) holder, and secured to the
tender chassis with some green detachable stuff. Also the wires are
secured this way. I had to cut a small groove in one of the inner walls in
the tender, to give space for the wires. See the red arrow. The
green stuff doesn't look nice, but it is flexible and may be adjusted a bit to
fit the tender inside when installing the tender body to the chassis.
When assembled, the rear end of the tender bottom looks like this. Notice the two wire and the green stuff visible next to the screw.
The connection from the locomotive to the tender is made with two cut pieces from the SIL holder. One is glued to the locomotive, the other one is soldered to the wires from the rear lamp.
The rear light from the outside:
Rear close coupler
I have rebuild the rear coupler to a Märklin close coupler, using a coupler from
the set 7205, containing 40 coupler for cars and 10 for locomotives. I have
used one for a locomotive.
I cut the original coupler and bent it in an S-shape. Then I glued a locomotive coupler from 7205 in place, and secured it by bending the two "ears" meant for the moving part of the original coupler. From below it looks like this:
Interior light
As it may be seen on the photo of the motor, I have installed a small T1 bulb on top
of the motor. This bulb is also installed in a piece of a SIL holder, just like the rear light.
A have also made some simple windows, cut from clear plastic.
A photo of the locomotive during a test run:
