Profile view of the car

DU65 No. 5M 154 reference REE MB-072, here equipped with modified Herpa and other characters.

Electrical findings

The current pickup is done on the inside of the wheels. The strips are very flexible. Attention in case of disassembly: you have to check the position of these strips with respect to the wheels. Chance of short circuit!

The cab is lighted by default.


Before running-in, at 12 V DC, the car consumes 32 mA at slipping and 150 mA motor blocked.

Assembly and test of the decoder

Before installing the decoder, it is necessary to remove the analogue plug, and it is rather delicate. The connector has a large retention force, and the entire circuit board tends to come with the plug. Very thin LED wires could be broken.

I chose (if we can say, because the type of decoder is practically imposed) the Zimo MX630P16 decoder, Plux16 interface, no sound. Testing and programming will be done on a test track with the ESU LokProgrammer. The original operation before any intervention on the decoder is as follows:

It is impossible to switch off the cab lighting (tried with F3 to F19!)

In white lighting, I see as another person on the Loco-Revue forum that the headlights are more or less weak depending on the angle of vision. Explanation: the two-colour LEDs are slightly offset, arranged horizontally, and set back from the surface of the optics. As the light-emitting junctions are not in the axis, and especially the white ones, the white junction is half masked by the strapping of the headlight in oblique view. Personally, on the BB 63500 Roco I equipped, I arranged the LEDs vertically, just to prevent the headlights from “squinting”.

Desired operation


For lighting, I wish if possible to control the red lights with the only F1 key, with reversal depending on the direction of travel, and the cabin by F2. This in order to keep substantially the same controls as on most of my models.

I also wish to be able to switch off all the lights on the coupled side, regardless of the direction of travel. I find this function very useful. It avoids, in case of change of direction, the following gymnastics:

  1. turn off the white lights;
  2. reverse the direction;
  3. turn on the red lights.

When this function is activated, these three operations are done in only one: reverse the travel direction.

Setting the decoder

Maximum speed

The real machine is limited to 70 km/h. CV5 = 210 gives 84 km/h in forward direction and 77 km/h in reverse (still without running in). The motor is noisy in the forward direction.

Cab lighting by F2

With some testing, I found that the cab lighting is wired on the FO5 output in Zimo terminology (it would be AUX3 at ESU).

The decoder manual tells us that the FO5 and FO6 outputs are assigned by default to the SUSI interface (§ 3.25, page 33, English edition). To assign them to the logic outputs, we must set the CV124’s bit7. So, add the value 128 (27) to the previous value of CV124 which was 3:

CV124 = 128 + 3 = 131.

Now the cab lighting doesn’t work anymore! This is normal: you have to assign a function key. I want to control it by F2, whose CV is CV36:

CV36 = 64

Explanation: the value 64 is found in the Zimo table for FO5 output. In fact, this table value is the number of the bit to set, which is far from being obvious when reading the document (§ 3.14, p. 24)! We find 6, which gives 26 = 64.

Output selection table

Note that the outputs are sometimes called FAn, sometimes FOn… Probably a hesitation between the ‘A’ of German Ausgang and the ‘O’ of English Output!

Turn on all red lights with the same key

Currently, the front red lights (FO1 output) are lit by F1 and the rear ones (FO2 output) by F2. I want to free F2 for cab lighting (see above).

I therefore assign both outputs to the same F1 key whose CV is CV35.

CV35 = 4 (for FO1) + 8 (for FO2) = 12.

Now all the red lights come on at the same time!

Here’s how to make this operation direction dependent. CV127 must contain the number of the output that will be activated in forward; CV128 must contain the number of the output that will be activated in reverse:

CV127 = 2 for FO2 output (rear red lights).

CV128 = 1 for FO1 output (front red lights).

The F1 key is now directional.

Turn off all lights on the same side

As already mentioned, I want to turn off all the front lights by F3 or all the rear lights by F4. CV107 and CV108 are responsible for this function.

The F3 and F4 keys must first be reset, since they must not control any output:

CV37 = 0

CV38 = 0

Note: using CV107 and CV108 (so by setting a value other than 0), we systematically switch off the white lights on the side concerned. The setting is to specify what other outputs should be switched off in addition.

To turn off the front lights, the CV concerned is CV107.

We have to multiply the number of the output concerned (namely FO1, front red lights) by 32 and add the number of the key to be assigned, namely F3.

CV107 = 1 × 32 + 3 = 35.

Explanation: “1” is the number of the FO1 output; “3” is the number of the key to assign, namely F3.

To turn off the rear lights, the CV concerned is CV108. Same principle, therefore:

CV108 = 2 × 32 + 4 = 68.

Explanation: “2” is the number of the FO2 output (red rear lights); “4” is the number of the key to assign, namely F4.

Here we are. Now, you turn on the white lights by F0, the red ones by F1. They all reverse depending on the direction of travel. If you couple a wagon to the back, press F4. The corresponding lights turn off. In the forward direction, only the front white lights will be on; in reverse, only the front red will be on.

Dimming certain lights without influencing others

The dimming is done by CV60, which affects all the outputs. It is possible to specify the outputs not to be dimmed in CV114. For example, to avoid dimming the cab lighting wired on the FO5 output, write:

CV114 = 2664, according to this correspondence table:

Output FF FR FO1 FO2 FO3 FO4 FO5 FO6
Bit 0 1 2 3 4 5 6 7
Value to add in CV114 1 2 4 8 16 32 64 128

Just add the values ​​of all the outputs to be excluded from the dimming.

For example, for the “early morning” photo below, I had to use a long exposure, and as a result the white lights were “burnt”. I applied a high attenuation (10 for a maximum of 255). But then the cab was not lighted enough to see the characters. So I excluded the latter from dimming as explained above.

Nocturnal view of the car