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    Re: A-10 Sextant Maintenance Manual
    From: John D
    Date: 2007 Dec 14, 16:03 -0800

    Thank you for the very complete information, I am working on the
    bubble problem with a Navy machinist friend who has worked on small
    instruments.We should be able to handle it succesfully. Well probably
    get together in a couple of weeks. Both of us are socents on the
    Battleship New Jersey now housed in Camden, NJ
    
    Thanks again, and excuse the delay in getting bacvk to you. I'll let
    you know how it goes.
    
    
    
    
    
    On Dec 11, 2:33�pm, jean-philippe planas
     wrote:
    > As I am not sure this answer went through the net and reached Arthur, I repost it.
    > If it did go through the net, please disregard it.
    >
    > The bubble assembly has to be refilled with xylene which is some kind of a paint solvent.
    > You have to separate the bubble assembly from the main sextant body.
    > 1- Unscrew the 2 small screws that maintain the lighting arrangement below the assembly.
    > 2-Unscrew the 4 main long screws to separate the bubble assembly from the optical system.
    > 3-Unscrew the bottom lens of the bubble assembly
    > 3-1 with a wristwatch caseback wrench, �unscrew the lens retainer ring.
    > 3-2 carefully remove with a blade the metal and paper compression gaskets
    > 3-3 unstick the lens with a thin blade or a suction cup
    > 4 Remove the thin lead inner gasket and be prepared to replace it by 
    neoprene O ring that fits in the lead gasket channel. The O ring is about 
    1.5mm thick by 20mm diameter.
    > 5 Take out all remaining fluid by operating the �enlarger �knob back and forth
    > 6 Clean the lens and inner of the bubble assembly with fresh xylene and �Q-tips
    > made of natural �cotton
    > 7 Pour fresh xylene into the cavity (top it up) and work the enlarger knob 
    back and forth to eliminate air from the reservoir. Repeat the operation 
    until no more bubbles appear from the reservoir.
    > 8 Top up again the cavity with xylene
    > 9 Place neoprene O ring in place and lens
    > 10 Replace paper and metal compression gaskets above the lens
    > 11 Replace the bottom lens retainer ring and screw it by hand only
    > 12 With your fingers of one hand applying controlled pressure on the top and 
    bottom lenses, with the other hand carefully work the enlarge-reduce knob 
    until a small bubble appear
    > 13 Tighten the bottom retainer ring with the watch caseback wrench
    >
    > Check the bubble after one or two days. If it grows you will have to repeat 
    the process. Sometimes it is necessary to repeat the process numerous times 
    until you get a stable bubble of the right size (about 1.5 or 2mm diameter)
    >
    > The enarge reduce pump system will most �likely not be working anymore as 
    these bubble assemblies used to be filled under a vacum to correctly operate 
    as specified.
    >
    > Hope this helps
    >
    > JPP
    >
    > glap...---.net wrote:
    > Gary writes:
    >
    > I will look at my A-10 manual tonight to see if it has this
    > information.
    >
    > gl
    >
    > On Dec 6, 11:56 am, Camelot �wrote:
    >
    > > I need assistance in loading or refilling the bubble on an A-10 WW II
    > > Air Force Sextant. If you can help, or direct me to help, please
    > > replThank you.
    >
    > > Arthur Hill
    >
    > ---------------------------------
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