Decoder Tester

Test your DCC-Decoders befor installing. Use this simple to build adapter for testing.

  1. Schematic
  2. Use
  3. Description
  4. Parts
  5. Building


SCHEMATIC: DECTESTS.GIF [ dectests.gif ] Remarks:


Connect the Decoder Tester to your booster or programmer and plug the decoder into J1.

If the decoder is not equiped with an NMRA-Plug simply use two times four pins of a single-inline-ic-connector an solder the wires of the decoder to this plug. It is an good idear to plug these contacts into J1 for soldering. The color codes can be found in the NMRA RP-9.1.1 (look for Medium Interface).


D1 simulates the motor. D2 and D3 simulates the headlights.


count ref description Conrad part# Preis/DM
1 D1 Duo-Led (green/red) ?? ?? ??-?? 00.00
2 D2, D3 Led (5mm / green) ?? ?? ??-?? 00.00
1 R1 Resistor 120 Ohm, 2W ?? ?? ??-?? 00.00
2 R2, R3 Resistor 2.2 k Ohm, 1/4W ?? ?? ??-?? 00.00
1 R4 Resistor 1 k Ohm, 1/4W ?? ?? ??-?? 00.00
1 J1 Plug ?? ?? ??-?? 00.00
Sum 00.00

(this will be filled, if Conrad sells me a new Cataloug)


I have build this circuite on a piece of vero-board (the type with stripes). Cut the traces where the red X-marks are shown:

BOARD DRAWING [ dectestb.gif / print with 150dpi ]

This is best done before soldering the parts on the board. BUT: keep in mind that this drawing is "TOP VIEW". The cuts below J1 could be done with a sharp knife. The others could be done with the usual drill.

The black lines are some wire, soldered from the top side. The other parts are also soldered from the top side.

I have soldered two flexible wires to the positions marked "trk1" and "trk2" (in the schematic named "track1" and "track2", sorry). These can be plugged into the track outputs from the booster.


© 1998 by Martin Pischky (
[ | Datenschutzerklärung | creation 971120 | version 980423 ]