Tom Grossman’s Andromeda page 3

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As I learned the hard way, you can fry LEDs with battery current. I was advised by my friend and fellow modeler Scott Longberry that I could use a formula to calculate the resistance needed to limit the current. For LEDs in series: resistor in ohms = (voltage of power supply – sum of voltage drops across LEDs) desired current in amps For testing with 2 AA batteries at 20 mA (.02 A): (3v – 1.75v)/0.02 = 62.5ohms. For the 18 V main power off the stand at 20mA: (18v – 16.35v)/0.02 = 82.5ohms. Confused? So was I.

But it worked. After replacing one or two of the LEDs, I managed to get the whole thing wired up and everything tested

In the original design, the gun turret posts come through the upper half of the hull and are held in place with caps underneath. Before gluing the hull halves together, I had to make some sockets for the caps so that I could add the turrets after painting and they would still turn

I used styrene stock available at most hobby shops. These were glued in place

Before gluing the hull, I tested everything one more time.

Once the hull was glued together, the lights stopped working. Not knowing where the problem was, I decided to open the hull around the socket for the stand.

I tested everything inside again through my new panel. I did discover a wire that was close to breaking so I soldered it. I reset the panel by adding more styrene stock to each side of the opening.

This gave the panel some support. After I have done more assembly, I noticed that my patch job was cracking on one side due to the stress applied when taking the ship on and off the stand. I cut the crack open wide enough to put another piece of stock in. (PHOTO andr020b)

This was glued in place, trimmed and primered over. Now, at last, it was just another model.

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