I purchased a Digitrax DH165A0 with the intention of adding Yeloglo LED's for the headlight and Mars light on an Athearn blue box F7. The paperwork that comes with the decoder states:
"The DH165A0 is configured to control the forward-headlight F0F/white lead
and reverse-headlight F0R/yellow lead for directional lighting. These two headlight
function leads are current regulated for LEDs or lamps, with factory setting
of approx 15mA, with no resistors required."
Great news!...but then I went to the Miniatronics site and their website indicates: "You must use a 560 ohm resistor that is included in the package. "
So what gives...would I be safe in assuming that the Yeloglo's would function correctly and not cause any harm to the decoder if I were to install them without the supplied resistor, or might I need an altogether different resistor since the decoder has some sort of built in resistance, but perhaps not the correct resistance...(I'm electrically challenged, so please excuse my befuddlement). I emailed Minitronics and Digitrax with the same question a week ago and have yet to receive a response. Does anybody here have the answer?
Thanks
Richard
Richard,
The L0 series decoders from Digitrax are built specifically for Proto locomotives. The board has a current regulator built onboard the decoder that drops the voltage down to 1.5V so that you can use either an LED or 1.5V incandescent bulbs for your headlights. The Miniatronics warning is generic, since not all decoders comes with a built-in current regulator. You should be fine.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
tstage wrote: Richard, The Miniatronics warning is generic, since not all decoders comes with a built-in current regulator. You should be fine. Tom
The Miniatronics warning is generic, since not all decoders comes with a built-in current regulator. You should be fine.
...ahhh, so the decoder is smarter than the operator in this case!
Thanks for the insight.
tstage wrote: The board has a current regulator built onboard the decoder that drops the voltage down to 1.5V so that you can use either an LED or 1.5V incandescent bulbs for your headlights.
The board has a current regulator built onboard the decoder that drops the voltage down to 1.5V so that you can use either an LED or 1.5V incandescent bulbs for your headlights.
I'm glad to see this information. I was considering one of these for an Atheran RTR, but sometimes I have a hard time digging out proper info on the Digitrax site.
Has anyone tried the Soundbug that plugs into this board? To be honest, I haven't seen many positive comments about the Soundbug. I'm tempted to try one, but woould really like some input on it. I have some Soundtraxx stuff now and am well pleased with it, even the LC ones.
The one thing that sort of "gets" me about the Digitrax Soundbug though, is if you don't want the generic sounds that are pre-programmed, you HAVE TO spend more money and buy the programmer. Not sure why they can't program a few choices.
Ok, so I finally got around to installing the headlight (3mm Yeloglo LED) and Mars Light (GOW bulb). Everything went fairly smooth until I was packing up for the day. That was when i noticed the label on the Yeloglo LEDs...it suggested a 3V power supply...does anyone know what voltage is supplied to the current regulated headlight functions on the DH165A0? I have a feeling 1.5V? I have posed the question at the Digitrax site, but haven't yet heard.
(I would drop it on my track and test it, but the track is at my father's house 45 mins. away)
As always, any and all input is greatly appreciated.
From the looks of the documentation, the decoder will control the current to 15ma or 30ma if you cut some traces on the board. Do the LED's you have specify a current? I would suspect 15ma would be safe for them, but they may actually need less. Lacking a specification, you could connect one LED in series with the recommended 560 Ohm resistor and a 14 volt DC power supply and measure the current flow with an ammeter. There is a writeup on the Digitrax site about installing a resistor in parallel with the LED to take some of the current, which reduces the current to the LED. To calculate the resistor value you need the forward voltage when the LED is on.
Jim
The LEDs will work fine, assuming the polarity is correct, I installed the same decoder and LEDs in a loco recently too.
Don