Welcome to the NavList Message Boards.

NavList:

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

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: Lighting Problems w/ Aircraft Bubble Sextants
    From: Gary LaPook
    Date: 2015 Dec 29, 07:14 +0000
    And with the Kollsman sextants, both periscopic and hand held, you can replace the 28 volt bulbs with 6 or 12 v bulbs after you make up a small battery power supply. If you want to keep the 28 volt system then wire three nine volt batteries in series. If you have one with the electronic averager then you need to supply the averager with 28 volts but it eats batteries so better to use a 28 volt lawn sprinkler transformer or a solid state 28 volt supply powered off of your cigarette lighter socket (oops, politically incorrect, no one smokes anymore in California, must be a "12 volt socket") about 25 bucks in components. I have posted information about all of this in the past, just use the search box. 

    gl



    From: Robert Swartz <NoReply_Swartz@fer3.com>
    To: garylapook---.net
    Sent: Monday, December 28, 2015 10:39 PM
    Subject: [NavList] Lighting Problems w/ Aircraft Bubble Sextants

    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.


       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    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:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    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