you missed a decimel point it should be 1000 not 100
15 divided by .015=1000
15 divided by .15=100
I personally use 820 ohms for Athearn locos
cacole to get 250 ohms I measured the voltage put out by the Rear headlight and it as 15 volts at 15 (0.015A) mA so Ohms law is R = V/I which gives 100 Ohms and i used 250 just to be safe.
Where or how did you determine that you need a 250 Ohm resistor? By Ohms law calculation you possibly need 700 to 1000 Ohms, depending on the mA draw of the Athearn 1.5 Volt bulbs. With 250 Ohms, the bulb is likely to just be a short, bright flash and burn out.
I don't see anything in the Digitrax DH165A0 documentation about light function output voltage ratings or built-in voltage regulators on the light functions, only that the functions are rated for 250mA max..
How do you want this controlled? On when the headlight is on, on when headlight is on but only when stopped, on when headlight is on but off if goign in reverse, or completely independent of the headlight and controlled by another function key, like F1? It's different in each case.
Let's say you want independent control on F1:
CV50 to 34 (MARS light, non-directional)
CV34 to 0 (F0 button does not control yellow wire) (ok solder pad for a 165A0)
CV35 to 2 (F1 button controls yellow wire)
Now whichever light you connect to the rear light connections will simulate a MARS light when F1 is on, and be off when F1 is off.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hello All,
I have a Athearn Genesis F3 that I am putting a DH165A0 decoder in, and would like to make one of the headlights a Mars light. I already know that I need a 250 ohm resistor on the 1.5 volt lamp, the wiring is not what confuses me. The problem is the CV's that I need to change. I plan on hooking the Mars light up to the rear head light terminals. Could Someone possibally give me a list of CV's that need to be change to make it work?
Thanks,
Andy