MÄRKLIN 3021 CONVERSION TO DIGITAL WITH SOUND
Chassie with old 3-pole motor and relay for analog use.







Motortruck removed from chassie with old motor.







Motortruck with new 5-pole motor, Märklin kit 60944.






Truck reinstalled on chassie, old relay removed together with the old handlebar
for shifting driving direction.



Decoder ESU V4.0 No 56499, Cabin light LED-strip (Small PC-board) ESU No 50704 and speaker with sound chamber installed.
Choke coils soldered onto the motor.






On the testbed. Everything connected with new cable harness. Light bulbs minus insulated with shrink tubing. (See enlarged photo)
Uses different minus potential (not chassie). Blue connection from decoder used. (Important)
Decoder programmed with 21 functions. See specification in folder Models/DB/Locos.










Cover milled (slot beside screw hole) to make space enough for new cable harness, to avoid problems with truck movements.