LGB Decoders & Sound Boards


This page is not intended to be complete, but intended to be information that is harder to find, so look for detail pages.

Much of this information provided by Dan Pierce.


For older train sets, the loco address was set to short address 2, except sets with 2 locos, and then the addresses 2 and 4 were used

CV 106 is decoder load, this is a read only CV and determines the reset values of voltages (need more detail)

Early boxed set had a Schoema diesel with Lenz 55020, and train mouse. Serial functions only,

Later sets has Massoth 55020 (there is no logo on the decoder)

FRR engines (Chloe, Johnny), had a special small mts decoder which only had motor and one light output (2 pins).  Also note these engines had reversed track power and motor leads to this small decoder.  Usually LGB motor blocks like USA trains had outer pins for motor and inner pins for track. 

Porter engines had a small decoder which could do motor, front light, cabin light, and smoke.

Older DCC locos with digital sound had SUSI to sound board, usually dual motor decoders


The new MFX decoders are basically really a pain if you run traditional DCC. The first thing you should do is change CV50 to either 0 (DCC only) or 2 (DCC &  analog). Without changing this up front, many people have experienced erratic operation, and erratic CV operations.


Came in several versions, earliest were made by Lenz, see below:


There was a single function available. Don't know where on the decoder it is. C

CV51 - sets to F1 to F8 for this.

Some more information from Dan Pierce:

- V1 (labeled "LGBE1_V1," rare, only few made): Don`t connect smoke generator directly to the function pins, but use relay as shown in instructions. (I never found the 'LENZ' instructions)
- V2 (labeled "LGBE1_V2"): Connect smoke generator directly to function pins (no matter what the instructions say).
- V3 (labeled "LGBE1_V3"): Same as V2, but using different electronic components.
- ME1-1 (no "V" number, sticker with a serial number): Same as V3, but advanced functions can be programmed.


Later 55020 were made by Massoth as below (or was this the 3rd gen?)

LGB 55020



older LGB decoders (55021 and 55027) do have standard features and have manuals.
The onboard decoder does have standard connections but cv's are preprogrammed differently.

LGB 55021


CV 106 is the number for the factory load on these decoders.


CV49 = 1 turns pulse strings (serial functions) into F1-F8, also makes A1 ignore these commands except normal F commands, like F2 is lights on still.

CV49=9 is fast pulse on..

CV51=1 - f1 output as in 55020, i.e. F1-F8 actually simulate pressing F1 n times (1 through 8)


what is CV 54?

 73 - small single motor porters are
129 - Unitah mallet, and Coke Mogul, and most American steamers with the 2 motor board
146 - American trolley and F7, and most American 2 motor diesels
148 - Track cleaner loco

LGB 55021
CV 51
= 9 F1 Key serial
10 F2
11 F3
12 F4
13 F5
14 F6
15 F7
= 16 F8 Key serial

Setting CV51 to 9..16 causes the F1 output to be driven normally by one of F1 to F8


LGB switch decoder

See this page for details on programming contributed by Mark, of GScaleCentral

click for programming details LGB 55025 page



Dual decoder, by massoth, early versions 14 or 28 speed steps, later ones 128.

LGB 55027

 LGB 55027a


- 2 function relay board, could be added to 55020/21



LGB sound board.


model 20252

part number 8.837010.1









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