Older Decoder questions

Model Railroader Electronics and DCC
1

Got 2 free Digitrax DH 121’s and a NCE DA102. I looked on Digitrax site and saw the 121 was replaced by the DH 123. Does anyone know the power rating of the DH 121? I hope to use them in a A B set of F9’s by Stewart Hobbies.

What can you tell me about the NCE DA102? Will it run LED’s with no resistor? Does it have EMF? (I hope that is the right term)

Thanks for the coming answers.

Ken

2

Ken

Here are the instruction sheets for the decoders you acquired:

http://www.digitrax.com/v1/ftp/dh121.pdf

http://www.ncedcc.com/pdf/da102eu.pdf

Note that these decoders have older technology than current models.

The Digitrax DH121 decoders have a lower frequency PWM motor control circuit that may generate audible noise through the motor.

Neither decoder utilizes Back-EMF.

You must use a current limiting resistor with LED’s and lamps under 14 volts.

I hope this helps.

3

In addition to above re DH121

  • does support only the older programming modes (page and register) “older technology” indeed
  • behaves differently in 28 speed step mode then with 128 (126) speed step modes, some CV (speed table for sure, maybe also CV2,5,6) are not used in 128 (126) mode
4

Ken,

To decipher a Digitrax decoder version number, keep the following in mind: For the DH121, it means –

D = Digital (or DCC)

H = HO scale

1 = 1 Amp continuous power rating

2 = Number of Functions

1 = Software version number programmed into the decoder

5

Since the issues are by now at least 10 years old and gone, I forgot about this early series DH 121 problem and yet another
You want to check before you use the decoder, unless you know it is a working one.
Good news is: It’s 9pin connector makes replacement with any other 9 pin decoder(*) easy [;)]

(*) DigiTrax DH123 series or better, TCS T1 series or better, etc. incl. Lenz and NCE and who else is there