Rebuilding Märklin 3417, NSB 63 2770, to digital with Märklin conversion set 60901 and mfx sound module 60931

Updated 15.06.2009

Märklin 3417, NSB 63 2770
During the second world war the Germans brought several of their BR 52 to Norway.  When the war ended, the locomotives remained in Norway and was used by NSB.  This was a very valuable addition to the excisting locomotive park, and gave NSB more time to supply new Diesel locomotives.

Decoder and speaker:
I stripped the decoder for it's rubber cover and glued it with a green detachable stuff to a decoder holder, Märklin part number 258820.  This holder fits in the tender tub.  I glued the two noise suppressors for the motor in the bottom of the tub, under the decoder holder.  The orange wire from the decoder is soldered to a distribution pcb (Printed Circuit Board) glued to the RH inside of the tender tub.  The orange wire is distributed to the rear lamp, the front lamp and to the connector for the interior light in the locomotive.  Also the brown ground wire has a distribution point on the pcb.

The speaker is installed where the cylinder shaped weights used to be.  By cutting off most of the center divider and filing off a little bit of the speaker plastic house, it was possible to press fit the speaker house into the coal box.

The decoder functions:
f0 = front light, changing with direction
f1 = smoke generator
f2 = interior light, driver's cabin
f3 = engine driving sounds
f4 = shunting speed
f5 - f15 = other locomotive sounds
See also the downloadable excel file at the bottom of this page.

Motor:
The motor parts from the Märklin conversion sets 6090, 60901, 60921 and 60760 may be used.  Basically, only the decoders are different in these sets.  In this case it doesn't matter, as an mfx sound decoder, Märklin 60931, is used.  Installation of the motor itself is very simple. After removing the old motor, make sure that the mechanical parts are clean and work perfect.  Axels, rods and gears must rotate smoothly.  If necessary, oil the moving parts very carefully.  After installing the new motor, without the brushes, check again that it all rotates perfectly.  Then install the two brushes.  The below photo also shows the orange and brown/green wire to the interior light connector.

Front light and steam generator:
The grey wire from the decoder goes all the way forwards to the front lamp, with an orange wire.  These wires are soldered to the lamp holder.  Also the brown/red wire for function f1 goes all the way forwards, soldered to the contact tongue for the steam generator.

Tender weights:
To keep the good running performance, I had to put the removed weights back in the tender.  I fixed them together with insulating tape and just put it on top of the rear lamp.  It is held into position by the rear wall and the lateral divider.

Interior light in driver's cabin:
A small 28 volt T1 bulb is glued to the rear end of the driver's cabin ceiling, indicated by the gray arrow. The wires go through a slot in the RH side of the driver's cabin.  The connector is glued to the locomotive body. A 330 Ohm resistor is soldered to the connector, to reduce the voltage to the bulb, to reduce the light intensity.

My setting of the decoder:
Decoder settings, 3417 Default Mine
Analog settings:
    Enable analog mode check <
  Starting voltage 7,300 <
  Maximum voltage 23,000 <
Control settings :
  Swap directions uncheck <
  Max. speed 255 80
  Min. speed 4,000 <
  Acc. time 7,000 20,000
  Dec. time 3,750 20,000
  Forward trim 1,000 <
  Reverse trim 1,000 <
Motor settings:
  Motor PWM-frequency:
  Low frequency uncheck <
  High frequency check <
  Load Control
  Reference parameter 11,300 <
  Control parameter K 60 <
  Control parameter I 120 <
  Control influence 255 <
Special options:
  Preserve direction check <
  Persistent acceleration uncheck <
  Persistent speed check <
  Persistent functions check <
Sound settings:
  Volume 255 155
  Driving Sound Rate:
  At min. speed 1,000 <
  At max. speed 1,512 <
  Random Sound:
  Min. gap 30 15
  Max. gap 50 <
  Braking Sound Threshold: 14 18

My Märklin 3417 NSB 63 2770 functions:
mfx
60931
Light Smoke
unit
Light
driver
Drive
sounds
Shunt
speed
Flute
short
Flute
long
Bell
1
Bell
2
Bell
3
Air
pump
Acc/
dec
Brake
sound
Steam
release
Coal
shuffle
Rocking
grate
Injector
sound
front rear
f0 f. on                                  
r.   on
f1 f.     on                              
r. on
f2 f.       on                            
r. on
f3 f.         on                          
r. on
f4 f.           on                        
r. on
f5 f.             on                      
r. on
f6 f.               on                    
r. on
f7 f.                 on                  
r. on
f8 f.                   on                
r. on
f9 f.                     on              
r. on
f10 f.                       on            
r. on
f11 f.                         off off        
r. off off
f12 f.                             on      
r. on
f13 f.                               on    
r. on
f14 f.                                 on  
r. on
f15 f.                                   on
r. on
Stop f.                                    
r.       on                            
Drive f.                                    
r.             on                      

3417 functions xls-file