Decoder installation and red lights separation

Choosing the decoder

I chose a Lenz Silver+ decoder with an eight pin plug. It has two additional wires, purple and brown, corresponding respectively to the outputs D and E.

New red light wiring

The output C of the decoder is by construction assigned to the fan motor; so I will connect the red lights to the outputs D and E. Rather than butchering the PCB (once bitten, twice shy!), I prefered to simply disconnect the red LEDs from this circuit, and connect them to the purple and brown wires of the decoder via external not CMS resistors, and of a slightly higher value than the original (1.5 kΩ instead of 1.0 kΩ). Simply, to facilitate the decoder disconnection, this connection will be done through HE14 type connectors.

PCB with decoder


  1. Connection between front LED and resistor
  2. Male pins
  3. Decoder wires (brown and purple)
  4. Connection between rear LED and resistor
  5. 1,5 kΩ resistor
  6. Female pins
  7. 1,5 kΩ resistor

Here is a detailed view of the (black) wires to unsolder. Left, from no. 7; Right, between no. 3 and 4. This picture is of course viewed in the same direction as the previous one.

PCB - detail

The connector may be of a different type, provided it is not too large. It is held by a small piece of double-sided adhesive, as well as the resistor wires, the latter protected by a heat-shrink sleeve.

Small concern: the lights, thus separated from the original circuit, are no longer connected to the capacitors supposed to avoid blinking in case of bad contact. The tests showed that this is not a problem. Moreover, without knowing the capacity of these capacitors, which, given their size, should not exceed 47 nF, I am convinced of their practical uselessness.

Setting the decoder

It goes without saying that the following settings are personal and may be adjusted at will.

CV Value Key Output Effect
35 8 F1 fwd D Rear red lights on D output by F1 key
47 16 F1 rev E Front red lights on E output by F1 key 1
36 3 F2 A + B Front and rear white lights by F2 key 2
37 24 F3 D + E Front and rear red lights by F3 key 3
38 4 F4 C Fan by F4 key
64 Dimming of light intensity of front and rear white lights 4
116 32 Dimming of fan speed
58 16 F5 Shunting mode by F5 5
59 32 F6 Inertia suppression mode by F6 5

Notes :

  1. Reminder: on the Lenz Silver+ decoder, the F1 key is directional, thanks to the CV 47. The red lights will therefore automatically reverse if the direction of travel is changed.
  2. I like to turn on all white lights ( when shunting)
  3. Same for red lights (parking)
  4. Here there are two small problems:
    • This setting introduces a slight crackling of unknown origin, reported on the Loco Revue forum.
    • A very visible blinking appears on the videos, which I noticed with all my Lenz decoders, but not with the ESUs for example. I think this is due to an integer ratio between the decoder PWM frequency and that of the video itself. One solution would be to replace the LED resistors by 4.7 kΩ ones, which would make it possible to increase the duty cycle value (CV 55 and 56).
  5. Some will have noticed that I used the F3 and F4 keys, which are by default assigned to the shunting and no inertia modes. I assign these modes to the F5 and F6 keys.