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LGB 55040 Additional function board:


If the DCC system is only able to transmit Parallel commands, will only be able to activate Relay 1, and the remainder of this Blog posting is only of academic interest.

As the PIKO/Massoth DCC systems are capable of Serial commands both Relay 1 and Relay 2 can be activated.

Board setup and tested as per factory default, one press of Function key 1 activates Relay 1, second press of Function key 1 deactivates Relay 1.

One press of Function key 2, transmits two Serial Pulses to operate the Function F1 output which activates Relay 2, second press of Function key 2 deactivates Relay 2.

Setup PIKO/Massoth Navigator to send Serial Commands. 

With the help of this relay function board, two special function of the locomotive may be operated, bell, whistle, smoke, lights etc. can be operated from the Navigator Handset.

Up to four additional function boards, which enable up to eight special functions to be operated, can be fitted into one locomotive.

The additional functions can be activated via the Navigator handset. For each function select between four types of function available.

ON/OFF switch (for smoke unit, internal lighting etc.)

Momentary contacts with adjustable times (for bell, whistle etc.)

Flashing ON/OFF identical (flashing lights)

Flashing ON/OFF intermittent (blinking lights)

Connection of the three leads from LGB 55040 board to the LGB 55021 decoder,

White to Decoder Positive,

Red to F1 Function Output,

Black to Decoder Negative.


Further 55040 boards can be fitted to the pins that are adjacent to the leads. This operation can be repeated with up to four 55040 boards so that a maximum of eight functions can be activated.

Allocating the function number, the mode of operation and the timer period, via the block of eight DIP switches. The position for these switches is illustrated in the following picture.