I would aim for 15mA - if that turns out to be too dull, you can reduce the resistor.
Most LEDs are very bright at 20mA and at HO scale 15 seems better. In this case it is also safer.

I used 1 Kohm resistors for all the leds when I converted my EL18 2241 with the MSD3 and E172883 (1 at each pads for white lights). The LEDS are a little too bright but can be dimmed in the decoder settings. See the picture to compare with the EL18 2255 that is originally fitted with that LED board.

Be aware that the light conductor for the top light needs to be shortened to line up correctly behind the LED board.

Thanks for the information, and picture to illustrate.



Thanks for the tip.

The 172883 gives you many possibilities to comply with signal combinations actually used by the operator of the locomotive.

When you look at the side with the soldering pads with the cutout down as it will be when placed in the bracket the connection points is:
1- left white marker light
2- U+
3- Long distance light

4- right white marker light
5- Both red marker lights

The led in the middle of this side is the long distance light. Delta locomotives have a light conductor pointing toward one of the light bulbs. Locomotives delivered with 172883 have a different light conductor pointing toward the led in the middle. That is why it is necessary to shorten the light conductor or buy the 231483 set that includes the new one.

You may connect four outputs to each board, but the MSD3 only have 6. If you do not need the signal combinations used in Switzerland, you could use the same output to both white marker lights.

To achive more output possibilites you can take advantage of the possibility to set aux3 and aux 4 to logical output. Then you can connect transistors to these outputs. I prefer IRF7103 Mosfets soldered to a SOIC8 to DIP8 adapter board. When using these you can turn aux 3 and/or aux4 on and off and they will give power depending on light forward and light backward.

Trykk 401 (https://jernbane.net/norge/Trykk401/Contents.html - sorry, only in Norwegian) §311 spesifies how to use signals on trains in Norway.

Line operation:
2 white marker lights and upper light are lit forward when
-The locomotive are in front of the train.
-The locomotive is alone

2 red marker lights are lit backward when
-The locomotive is alone
-On a locomotive that is pushing the wagons.

Shunting operation:
2 white marker lights both forward and backward all the time.


Even thoug this is how signals are supposed to be operated it is not uncommon to see locomotives pulling a train with white marker lights lit both forward and backward and the upper light forward. I cannot remember having seen an EL 18 showing signal backward into the first wagon.

NMJ www.nmj.eu sells locomotives and wagons related to Scandinavia. They have both B3 and B7 wagons that suits the EL 18. Since the majority of model railroaders in Norway are running on DC, they are delivered with DC wheels. NMJ sells AC wheels, interior lighting kit and rear marker lights (B3) for the wagons. Viessmann power conducting couplings and Roco short slider fits both wagons. Both the B3 and B7 wagons are derailing with DC wheels on Märklin tracks. The AC wheels fits the B3 wagons perfectly, but the B7s boggie is a little too tight for AC wheels. You can solve that by making small cuts in the boggies so the wheels can spin freely. The B7 wagons are very long so they have some problems with R1 radius. B3 wagons are working very good on Märklin tracks when the wheels are swapped.

I have had no problems running the B7 wagons with DC wheels on C-track with R1 curves. One wagon has been constantly derailing on a (R2) turnout with pushing lok, but I believe that is caused by the buffers on that particular wagon.

The B3 wagons I have not run that much.

Regards

Tor