Updated 20.08.2012

Märklin 3143
This big Diesel engine is one of my favorites.  It's prototype was made by NoHAB in Trollhättan, Sweden, in the 50's and the 60's, based on a GM locomotive from USA.
The NSB Di3a 3.605 was delivered to NSB (the Norwegian State Railway) in 1957, with the factory number 2341. In 2001 it was sold to TÅGAB in Sweden to be used as spare parts.
This is another NoHAB link.

Conversion of my Märklin 3143, NSB Di3, to digital with Märklin 60901, later added mfx sound decoder


Basics:
This locomotive used to have an electro-mechanical reversing unit and one light bulb in each end.  My first conversion of this particular model, bought in 1983, was to an electronic reversing unit, to avoid the jumping and light flash when reversing.  Later on a 6080 was installed.  6080 was Märklin's first commercial digital decoder.  The new functions of the 6090 decoder, with it's acceleration and braking delay was very interesting, so I wanted to convert to 6090.  But, this was only available for the motors with a drum collector armature, not for the large flat one in 3143.

Motor:
Later on Märklin launched a new motor bogies for the NoHAB models.  I saw this first time in the 28461 Danish train set, with a Danish edition of the NoHAB.  I just had to buy a new motor bogie, Märklin part number 437500.  In addition, the holder 437530 is required to install the new bogie in the locomotive chassis.  At that time, the digital conversion set 60901 was available, so this was a natural choice, with it's two additional function outputs (f1 and f2) and acceleration and braking delay cancel (f4).
Some time later the conversion set 60904 was launched from Märklin, suitable for the Large Flat Collector Motor (LFCM) in the 3143.  That was of course the best choice for the remaining two Di3s.  See the conversion of Märklin 3068, NSB Di3b 3.641.  Another Di3 was already converted with a new motor bogie and 60901.

The motor from the 60901 conversion set (and the 6090, 60921, 60941 or 60760 sets), for Drum Collector Motors:

This motor type is installed in 3143 A and 3143 D.

The motor from the 60904 conversion set (and the 60924 or 60944 sets), for large Flat Collector Motors:

This motor type is used in 3143 B and 3143 C.

Decoder:
When the 60932 sound decoder became available, I of course had to install this in one of my favourite locomotives.  The decoder is glued to the bracket used for the electro-mechanical reversing unit.  The speaker is "glued" with a detachable green sticky stuff from 3M.  I later replaced the speaker with a 28 mm from ESU to get a fuller sound.
But, as the sound in 60932 is from a Diesel-hydraulic locomotive, I was not very happy with the sound.  ESU has an mfx sound decoder with sound from the NoHAB Diesel.  I just had to replace the Märklin decoder with ESU Loksound 62438.  The 60932 was later on used in the transparent Märklin 3772 DB 212 225-7 Diesel hydraulic locomotive.  My philosophy is to only use Märklin parts for my conversions, but sometimes you just have to use some other parts.  Maybe I will use the decoder from Märklin 37692, the NSB Di 3.618, next time.

New Märklin conversion sets:
The 60901 and 60904 conversion sets with c91 decoder are no longer produced by Märklin.  Neither are the newer 60921 and 60924 conversion sets with mfx decoder.  Today I would used the 60941 (for DCM) and 60944 (for LFCM) motor conversion sets and a separate decoder.
See this Märklin web site for detailed information.

The photos show the 60932 mfx sound decoder with the original 20mm loudspeaker.


With the 28mm loadspeaker

This photo shows a mfx decoder:

The c91 decoder from the sets 60901 and 60904 would have the same position.

Light installation:
Light detail, in this case I soldered the lamps directly to a home made PCB.  The upper headlight is Märklin no. 610080, the bulb for the two lower are 28 Volt T1 bulbs.  This makes a stronger light for the upper "high beam".   The lamp in the top of the picture is for the driver's cabin light.  The green connector to the right is supposed to be used for power supply to another Di3 in double traction.  Then both locomotives get their power supply from one pick-up shoe. Notice the "shade" under the upper lamp.  This is to avoid light from the lower lamp in the upper light guide.  It is made of a thick black paper.  Both lamps are on in forward direction, the lower is on in reverse.

Front end, in reverse with interior light


Snow ploughs:
Further on, I wanted to install snow ploughs.  As I have the Märklin NSB El 18, Märklin 34635, I checked the ploughs from this, as they where identical to the ones on the NoHAB in the 28461 Danish train set, except for the colour.  The most tricky part is to cut off the front skirt on the locomotive body, in height with the bottom of the original coupler opening.  Paint the bare metal with a suitable colour.  The plough itself is very easy, just remove the original coupler, file off the plastic part (between the arrows in the below photo) somewhat and install the plough with the original screw.  If you don't file off a little bit, the coupler becomes a little bit too high.  Don't cut it, as I have done in the photo. 
If I should do this again, I would only install a plough in end 1, as the prototype very often was seen like this.  The driver's cabin in end 1 had better noise insulation than in end 2.  If possible, the locomotive was turned around at the end stations, so end 1 always was in the front.  This happened for instance in Storlien, on the Trondheim (Norway) - Storlien (Sweden) route.  Storlien station has a built-in turntable.



Close couplers without plough:
If you don't want the snow ploughs but still want close couplers, it may be done like this, as I have done on all my other NoHABs:
Unscrew the normal coupler and and store it somewhere.  All the other parts, like the locomotive body, bogie frame, centring spring and the screw remains as they are, without any modifications.

Take two Märklin 363950 coupler pockets and cut off approx. 3 mm of the upper part of them, as shown in the photo.



Install them upside-down (related to their normal usage), using the original centring spring and screw.  The pocket in one end can only be installed with the locomotive body is fitted.  Otherwise it is impossible to fit the body over the pocket ends.  Finally insert the close coupler 70163.  This is done on 3143 B, C and D



My settings of the mfx sound decoder:

Decoder settings, NSB Di3		Default	Mine
Analog settings:
	Enable analog mode	check	<
	Starting voltage	7,300	<
	Maximum voltage	23,000	<
Control settings:
	Swap directions	uncheck	<
	Max. speed	255	60
	Min. speed	4,000	<
	Acc. time	7,000	15,000
	Dec. time	3,750	15,000
	Forward trim	1,000	<
	Reverse trim	1,000	<
Motor settings:
	Motor PWM-frequency:
	Low frequency	uncheck	<
	High frequency	check	<
	Load Control, 5* Märklin motor:
	Reference parameter	11,300	15,000
	Control parameter K	60	11
	Control parameter I	120	150
	Control influence	255	<
Special options:
	Preserve direction	check	<
	Persistent acceleration	uncheck	<
	Persistent speed	check	<
	Persistent functions	check	<
Sound settings:
	Volume	255	50
	Driving Sound Rate:
	At min. speed	1,000	<
	At max. speed	1,512	1,576
	Random Sound:
	Min. gap	30	10
	Max. gap	50	<
	Braking Sound Threshold:	14	10

The Central Station image, 3.605 A with mfx sound decoder, 3.605 B with 60904 conversion set:


My NSB Di3 locomotives are like this:

		Motor	Decoder	functions	Intended usage
3143	A	60901	ESU 62438 mfx	f0 = front light, change with direction 3+2 f1 = light in driver's cabin end 1 f2 = light in driver's cabin end 2 f3 = locomotive driving sounds f4 = shunting speed on f5 to f15 other locomotive sounds	Free to use in passenger and freight trains
	B	60904	60904 c91	f0 = 3 directional front lamps, LEDs f1 = low beam end 1, LEDs f2 = low beam end 2, LEDs f4 = acceleration/braking delay off	Free to use in passenger and freight trains
	C	60904	60904 c91	f0 = front light, change with direction 3+2 f1 = light in driver's cabin end 1 f2 = light in driver's cabin end 2 f4 = acceleration/braking delay off	Free to use in passenger and freight trains
	D	60901	c91 from 37665	f0 = front light, change with direction f1 = interior light (home made) f2 = horn 1 f3 = horn 2 f4 = acc/brake delay cancel	Intended for a fixed passenger train, 3 x Märklin 4243 NSB B1 19 926 1 x Märklin 4242 NSB F1 21 402 The 4242 with interior light control for all four cars, decoder 60960

Wiring diagram, 3143 A, with mfx sound decoder:

The diagram is with Märklin wire colours.  ESU (and others) use different wire colours.

The additional parts I have installed (I hope the part numbers are correct):

Märklin part no.	3143				Description
	A	B	C	D
437500	1			1	Motor bogie for drum collector motor
473530	1			1	Motor bogie holder
60901	1			1	Digital conversion set for drum collector motors, motor and small parts only
60904		1	1		Digital conversion set for large flat collector motors
ESU 62438	1				Digital mfx sound decoder for NoHAB locomotives
ESU 50443	1				Ø 28 mm 100 Ohm loudspeaker in sound chamber
606471				1	Digital decoder from 37665 NoHAB GM
602749				1	Sound unit from 37665 NoHAB GM
508600				1	Speaker from 37665 NoHAB GM
207648				1	Speaker chamber from 37665 NoHAB GM
207649				1	Speaker holder from 37665 NoHAB GM
258820		1	1	1	Holder for decoder
786790		1	1	1	Screw for decoder holder
571460	2				Snow ploughs with coupler pocket, from Märklin 34635
363950		2	2	2	Long close coupler pocket
70163	2	2	2	2	Close coupler (available in 50 pcs. set 7203)
610080	2		2	2	Light bulb
-	4		2		28 Volt T1 bulb
-		2			LED light units, home made

Märklin 3143 B, C and D, NSB Di3a 3.605, look almost the same:






Links to a lot of NoHAB Di3 prototype information:
http://www.jernbane.net/norge/di/di3/di3.htm
http://www.lolkebijlsma.com/di3/di3.shtml
http://www.bahnbilder.de/name/galerie/kategorie/Norwegen~Dieselloks~Di3.html
http://en.wikipedia.org/wiki/NSB_Di3

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