Testing Decoders

[Guest Closed Account 1]

I recently had a difficult hard wire install and at some point may have damaged the stationary decoder. It work then wouldn't. The train is 100% functional.

 

Decoder was replaced under warranty luckily.

 

What value resistor is needed to test a decoder?

 

Per TCS:

In order to test Function decoders you need to fool the

command system to think there is a motor to read/ recognize

then test.  What the NMRA and TCS say to do is put

a temporary resistor across blue and green for the fakeout motor.

Then you can read and test.

[KenS]

I haven't ever done that, as I test with a motor.  I use an ESU Decoder Tester, which works pretty well, and has easy to use spring clips and LEDs for checking the function outputs.  Well worth the money.  ESU isn't the only company that makes decoder testers, but they make a good one.

 

My only concern is that the motor looks like an HO motor, and might be too heavy for a low-amperage decoder. That said, extensive fooling about with a DZ125 at high throttle didn't seem to harm the decoder.

 

Googling about a bit I found someone recommending a 100 ohm resistor, coupled with setting the speed tables to all zero, so there would never be any normal throttle power put into the resistor (otherwise you might need a fairly large one to handle the power since 18 volts DCC and 1 Amp is about 18 Watts and would toast a typical 1/4W resistor in a flash, literally).

[The_Ghan]

I had this discussion with Digitrax a year ago.  They recommended a 1k Ohm, 1/4W resistor resistor.  It will be pulling about 0.182W and 0.0135A of current, based on a maximum voltage of 13.5v.  This can be permanently connected between the motor terminals if the decoder is only being used for directional lighting.

 

Cheers

 

The_Ghan