Prodigy advance 2 test track

Model Railroader Electronics and DCC
1

what size of a resister should be used for a test track?

thanks

2

Why a test track? All you have to do is read back the 2 digit address on the programming track to see if a decoder is installed correctly.

David B

3

My test track was taken from an MR article. It has a few pieces of track, a single turnout controlled by a ground throw, a rerailer. I use a center-off DPDT toggle to switch between programming and run on a Zephyr. I have never had a need for a resistor.

But Digitrax does say a 1K resistor could be required between PROG A and PROG B in some cases, Bachmann is an example. Not my case.

http://www.digitrax.com/kb/index.php?a=801

4

The idea for a resistor is to keep full power from decoders when first testing, see a recent post of leting the smoke out. I had one on my first prodigy, but dont remember the value.

5

The advance already has a separate program track output that has built in current limiting .no need for a separate resistor.

6

Great

thanks

7

All the units with seperate programming track limit the current applied in programming to the bare minimum for acknowledgement. It’s an NMRA requirement.

The resistor is like wearing a belt with your suspenders.

8

To actually answer the question, a 20 ohm 2 watt resistor should be fine for a test track. I don’t believe the PA programing track has a limiting resistor. I think it only puts out the carrier signal.

I don’t have my “test track” hooked up anymore, I use the programming track.

Tilden

9

I forgot I had read about this and looked it up. 120 Ohm 2 watt is the recommended resistor, if you must.

http://www.digitrax.com/ftp/lt1inst.pdf

We get so confident that we drop this and just test it on the program track. If it reads back, no reason to test it on a test track. The engine MUST allways acknowledge the command station via pulse to motor on the programming track. If it shorts out or anything, you will know.

I found my resistor from my LT1 tester. I had shrink-wrapped the resitor but forgot to identify it. Now I remember.

Thanks.

10

You Digitrax link is for a DB150 and you are either using a DCS100 or DCS50 (because of the CV readback feature). The DB150 doesnt have seperate programming leads, hence the need for the resistor.

David B

11

As this, the LT1 tester and document are included with all Digitrax command stations and used mainly (as per instructions) for testing purposes, I think they suggest it is applicable to all Digitrax command stations as a voltage limiting test track off rail A and rail B. No were is it stated as limited to the DB150

As per Digitrax :

How do I test a mobile decoder?

The LT1 is a simple decoder tester.

LT1 Instructions (.pdf)

The LT1 is included with all Digitrax Starter Sets. It consists of a harness with 6 conductor Telco type wire and a male plug, a tester with a female 6 conductor jack and a protection resistor.

Features:

  • Use as a diagnostic test light

  • Test decoders prior to installation

  • Test track power

  • Test LocoNet cables

    Parts List:

    1 LT1 1 LocoNet Cable 6"
    1 120 Ohm/2 Watt Resistor 1 Instruction Sheet

    Click here for LT1 Instructions

12

With DCC that’s all there is! It may or may not be current limited, but there is only one signal on the track in any case.