Has anyone used one of the Trix 185 ( TRAXX ) series, e.g. Trix 22636 185 Crossrail, in digital operation ?
They are quite different from the Märklin 185 ( 36XXX Hobby series ), Trix ones have heavy metal frame and plastic body, but some liveries ( e.g. Crossrail ) do not exist in Märklin assortment so I bought one and easily converted to three rails. Unfortunately there is something strange in the pcb, and this seems to be a common problem as it's mentioned in German and Dutch forums.
Inserting a normal ( good, tested ) Lokpilot with MTC21 plug, F0 turns on white lights at both sides, all other functions do nothing. Playing with Lokprogrammer I see that AUX1 and AUX2 do nothing, AUX3 seems to dim the white lights on one side, AUX4 turns on red lights. Combined together I got white light on one side, dimmed white light and red light together on the other.
The statement from Märklin/Trix assistance reported in one forum is (more or less) :" it works with our decoders", so what is the difference between a Märklin decoder and a Lokpilot, regarding the function outputs ? Some suggested that the decoder should have six amplified function outputs.
BTW, onto the pcb there are 6 transistors, 12 diodes and a number of resistors. What are all these components for ?
Thanks for your suggestions.

Best regards


Mario

Hi!
ESU decoders comply with the NEM specification for 21MTC and AUX3 and AUX4 use TTL levels.

Your Trix loco requires a decoder with amplified AUX3 / AUX4 - open collector just like AUX1 and AUX2. This complies with the NMRA specification for 21MTC.

The ESU FAQ describe how you can use an ESU decoder with these locos. Cut off the pins for AUX3 and AUX4 from the 21MTC socket and connect red rear lights to AUX1 and AUX2.

Warning: using the wrong 21MTC decoder can lead to damages of loco and/or decoder. AFAIK nothing bad happens with an ESU decoder in such a TRAXX loco, but don't make experiments with C SIne locos.

BTW: Märklin have sold some TRAXX models with plastic body using the Trix moulds. There were complaints about the printing quality of the Märklin Re 482 compared to the older Trix Re 482 from the same mould.

No, that would be too simple.
You can find both types with factory-installed decoders.

They made the MSD Spezial (NEM compatble) and the MSD (NMRA compatbile).

The new MSD/3 has CVs that allow you to choose between NEM and NMRA.

Do you intend to test the light functions with a different decoder before selling the loco?

The loco manual does not indicate which functions the loco has - a common problem with Trix locos.

Thanks for your suggestions.
I tested again using a Lokpilot FX that has all amplified function outputs and it works. F0 turns on white/red lights, AUX3 and AUX 4 turn off lights on front or rear sides, AUX3 and AUX4 together turn on white lights on both sides. So it works only if AUX3 and AUX are open collectors, or likely if are not connected. Then a Märklin MLD or a Zimo MX632D decoder must be used.
BTW, I reinserted the small board that closes the MTC21 plug for analog operation. It has another two transistors, some diodes, resistors and capacitors on board. I wonder what are all these components for.

Regards

Mario