Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Lighting Problems w/ Aircraft Bubble Sextants
    From: Robert Swartz
    Date: 2015 Dec 28, 22:09 -0800

    All WWII U.S. bubble sextants that have an external battery case and cable plug w/ center pin work as follows:

    Bendix and B&L sextants: Center pin carries +3V potential. Outer ring carries -3V potential from 2 D cells. Instrument frame is  negative (chassis) ground.

    If you have voltage out of your battery case (verified w/ a meter) but no lights--oftentimes you have poor or no ground conductivity

    due to corrosion in the instrument or screws holding parts together. Clean corrosion and voila--lights (of course check bulbs and switch).

    A-10A sextants use a battery case w/4.5V potential from 3 D cells which drive the solenoid of the mechanical averager and have a resistor for 3V lighting.

    A-10 sextants use 2 D cell 3V lighting--Both are frame (chassis) grounded.

    The post WWII Kolllsman series of sextants use 28V aircraft power for lighting and are not supplied w/ battery cases. They are supplied w/power cables that plug and securely screw

    into recepticles on the sextant and aircraft.

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site