This declassified, color, U.S. Navy training film from 1974 is about how to maintain the Fire Control System Mark 86, also known as the MK 86 Gun Fire Control System (GFCS). This system was created to provide ships of destroyer size and larger with an economical, versatile, lightweight, gun and missile fire control system effective against surface and air targets. The film shows basic steps in troubleshooting various bugs (called “casualties” or “faults” by the narrator) with electronic systems of the MK 86, most of which were apparently transistor based and utilized programs stored on magnetic tape. The process of identifying bugs, and replacing defective parts, was clearly difficult. This film was made by H.G. Peters & Co. with a script by Esko Townell. A related film about the MK 86 can be seen here: https://www.youtube.com/watch?v=4WsFbklrT_w

Navy fire control technicians / fire controlmen sit at Mk 86 consoles, which have analog radar displays. Manuals and binders on a desk. Controlman focuses on his radar screen. Analog push buttons on the control panel. A red indicator of the OPC alarm common illuminates (:39-2:25). Technician looks for a fuse indicator that has gone out. Two controlmen review an electronic circuit diagram or schematic. Controlman moves a knob to pre-standby so that a power supply can be removed and replaced. Two technicians remove a power supply.. Another controlman uses an electrical meter to test the resistance of component transistors. A controlman screws in the part. The machine door is closed. Buttons are pushed on the console. A working MK 86 surface radar screen (2:26-4:32). Controlman pushes buttons on his console as part of daily testing of the system. He stares at his machine, his must isolate his problem. He goes and opens a machine, looks at the data list on the inside door. A light is lit on a board. Two men radio one another to try and figure out a problem as they look at screens and lights. Two men look at a manual (4:33-6:24). A console is opened under the machine, revealing rows of circuit boards / logic cards. One is removed using a special tool (7:00). A “scope” — probably an oscilloscope or electric meter — helps to ensure proper operation. Input monitor. Controlman work at their stations. An operator uses the system in the air defense mode and the “comb filter” display is normal, but then one segment — Range Gate B — drops out. This casualty must be fixed. The technicians look at a manual and open the computer to isolate the problem and fix it. Voltages and fuses are checked in a fault isolation process A decal inside the machine shows normal operating conditions. A finger is against a decal (6:25-9:10). A machine is turned on. Two men check a receiver and have a manual at the ready. A new piece slides into a machine. The radar display is again normal. Controlmen work at their stations. A radar operator notices the tracking scan is erratic, he checks documentation and runs a test (9:11-11:12). A manual listing system maintenance tables is examined. The technician opens a signal data converter and examines the operational tape, which is stored in a metal container. A finger turns a switch on. The controlman studies the U.S. Navy manual as he stands before the faulty computer. Seated, another man looks at a manual and turns and pushes switches and buttons. (11:13-13:04). A radar display that isn’t correct is shown. Schematics are examined in depth. Controlman is handed a new part and he places it in the machine. Operational program placed into a computer’s memory and then it is restarted. The problem is solved, and the fire controlmen are able to return to normal operations (14:35-15:59). End credits (16:00-16:13).

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This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. For more information visit http://www.PeriscopeFilm.com