With turnout decoders here I differentiate between so-called "four-turnout
decoders" and "single turnout decoders". The four-tournout ones are the boxed or
bare circuit decoders mounted underneath the layout, where up to four
double-solenoid turnouts are connected to. The single turnout ones are bare
circuit decoders to be mounted directly into the turnout. This makes a turnout
with built-in decoder so that no more wiring is necessary, which is most
convenient for temporary layouts.
four-turnout Decoders
type | number | no of turnouts | processor | programming | comment |
---|---|---|---|---|---|
märklin k83 | 6083 | 4 | 145027 | DIP, inside box | the märklin reference. schematic. |
Viessmann | 5211, kit 5291 |
4 | 145027 | DIP, accessible | short circuit protection, separate power supply possible, 2 A per output |
LDT QS-DEC-II | QS-DEC-II, kit QS-DEC-II-B |
4 | Z80 microcontroller | program button | ULN2003 driver ICs (NPN), inverted output voltages, 1 A per outputs 1,2,3; 0.5 A per output 4 |
LDT S-DEC-4-MM | S-DEC-4-MM-G, S-DEC-4-MM-F, kit S-DEC-4-MM-B |
4 | Z80 microcontroller | program button | ULN2803 driver ICs(NPN), inverted output voltages, separate power supply possible, digital input and power input separated via optocoupler, short circuit protection, 1 A per output |
tams elektronik | WD-1 | 4 | 145027 | 4 jumpers | discrete NPN drivers, inverted output voltages, 1.5 A per output |
Carsten Meyer WD4 | do-it-yourself WD4 | 4 | 145027 | DIP | separate power supply possible, limited output protection |
inverted voltage - usually, the internal operating voltage is taken from the negative supply pulses (because in the digital signal the voltage is longer negative than positive). The yellow output is the internal negative voltage, the blue outputs get the internal positive voltage switched by PNP transistors. The internal positive voltage level is equal to the brown (typically called ground) input connection. Decoders with inverted voltage, however, have opposite voltage levels at their output. Whatever version it is, it should always be possible to wire push buttons (like signal box 7072, between blue turnout wire and brown supply wire) for manual operation in parallel to the decoder.
The Viessmann decoder offers best compatibility with the original k83, as well as the WD4. the Littfinski S-DEC-4-MM is unique as it has electrically insulated separate power supply. The QS-DEC-II and WD-1 are low price alternatives.
The Viessmann decoder and early versions of Märklin's k83 have individual
common power transistors for each output, which are easy to replace if damaged.
New k83 have special SMD transistors making their damage difficult to repair.
single turnout Decoders
type | number | no of turnouts | processor | programming | comment |
---|---|---|---|---|---|
märklin k73 | 6073 | 1 | 145027 | solder bridge | tailored to M-track turnouts. Out of production. |
märklin ??? | ??? | 1 | 145027 | solder bridge | a decoder like the k73. Was factory built-in into "digital" M-track turnouts. Only very restricted number of addresses configurable! |
märklin 74460 | 74460 | 1 | 145027 | DIP | tailored to C-track turnouts. |
Viessmann | 5231 | 1 | microcontroller | 6021 programmable | tailored to C-track turnouts. Märklin Motorola and DCC multi-protocol. separate power supply possible. |
Dr. König | do-it-yourself | 1 | 145027 | solder bridge | Dr. König's DIY decoders, equivalent to märklin's decoders. He offers versions for M- and C-turnouts. A variant is also available for three-way turnouts. König's speciality is the possibility to remotely switch the lantern light. |
A user has reported that from time to time his Viessmann's multiprotocol
decoders may unwantedly reprogram themselves. I cannot prove or confirm this.
last update: 2004-02-21;
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