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    Re: Electrical Wire
    From: Doug Royer
    Date: 2004 Mar 25, 11:16 -0800

    All,
    I've converted a few Davis sextants and older Astra IIIB sextants(bulb
    illumination)to led illumination.
    Here is what I use:
    Hewlett Packard HLMP 2300-2500 series light bars.High intensity red light
    only.You'll be useing the illumination at night so the red light will not
    disrupt night vision as will white or clear light.
    These are double led bars.Connect in series at 20 ma.Both diodes acts as a
    drop resistor while on.No drop resistor used.Connected to existing switch
    and the batteries(2 AA in series)internal to the handle.Replaced existing
    wire with stranded Thermax 24 awg.
    This gives a lot of light to read the measurement of the sextant.
    On the Astra 2 2300 light bars in parrallel were used.Remove the existing
    light guard remove the bulbs and wire,place one bar in each cut-out in the
    guard.
    On the Davis remove existing light and place as above.
    More than enough light to read the instrument with.Robust in the real
    world.Never had one burn out.Battery life extended compared to bulb systems.
    
    
    
    
    Geoff, with conventional LED's and conventional battery voltages tehre are
    many options and they are fairly simple. In fact there are a number of
    places on the web that supply "LED replacements" for regular flashlight
    bulbs, in the same form factor and case so they can just be dropped in as
    replacements. Probably not in the tiny size found in sextants, yet.
    
    
     Good eyes and fine fingers may be needed though. If you have a
    burned out Plath bulb, I could probably try converting it to a direct LED
    replacement for you. The burned out bulb makes a very useful contact/mount
    for the LED.
    
    
    

       
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