In August of 2006 I became aware that by David Bodnar was making a MARS light that was unique-the light is a seven LED light aray. It prompted me to contact David for more information. After the conversation I purchased a MARS light fully assembled-not in kit form-as I am modeling challenged as well as electronically challenged. The intended unit for installation was a USA Trains AT&SF PA. David suggested that I purchase the unit with 5mm LEDs as the light characteristics were better, but that he was unsure of the installation constraints of the USA PA. The article above had pictures of the unit installed in an Aristo-Craft FA1 . David offered to exchange the unit for another with 3 mm LEDs if I found that the smaller unit would work better.
As I was about to retire and move the MARS unit sat in my tool chest until January 2008. As luck would have it the 5 mm LEDS were too large for the upper light receptacle in the PA. True to his work, nearly 15 months later, David replaced the unit right away at no cost.
Imagine my extreme pleasure when the 3mm-light MARs unit fit perfectly into the PA's upper light receptacle.
David advised me to purchase a small bridge rectifier from someone like Radio Shack. As Radio Shack does not normally carry the item in the store, you can order the bridge rectifier from Radio Shack on-line for delivery to your nearest local store with no delivery charge.
Installation was relatively simple once I received help from a club member, Ralph Merrill, who is skilled in electronic installations. We tapped into the track power source NOT to the light contact points on the circuit board under the nose of the PA. It seems that the voltage on the nose circuit board is regulated to ~3.8 volts. The MARS light requires a higher voltage input. By doing this we have the MARS light working regardless of the direction of travel of the A unit in which it is installed.
The light works to perfection!!!! I could not be more pleased.
As the lower light was still a stock bulb, it appeared to be yellow by comparison, and dimmer. I replaced lower light with a 3 mm LED light, put a 1,500 ohm resister in series with it and tapped into the power lines between the bridge rectifier and the MARS light. The lights now match in color and intensity.
The real pleasure/satisfaction came at a train show in Sacramento a couple of weeks ago when I was observing our modular layout at a time when my AT&SF Super Chief was running. Every once in a while I would look up and see some person looking at my MARS light, talking to a fiend/child/spouse, pointing with one hand at the train and making figure eight motions with their other hand.
Check out David Bodnar's web site at http://www.trainelectronics.com/.
Thanks David! And, thanks Ralph.
Rod Hopkinson, Sacramento Valley Garden Railway Society
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