PackEye FHT 681 Replacement

Press and hold the power button for approximately 10 seconds until indicator lights are off.

Shoulder straps should be facing down.

Slowly slide foam assembly out of backpack to access FHT 681 amplifier. This process might take two people; one to pull the backpack and the other to pull the foam assembly.

The gamma detector is connected to the FHT 681 amplifier at PMT1. Push toward connection, turn coupling nut counterclockwise, and pull away from connection.

Use small, slotted screwdriver.

The neutron detector connections will be accessible.

There are two (2) neutron detectors. Unscrew collar counterclockwise. Pull connector away from detector.

There are two (2) hook and loop (Velcro) strips attaching the power supply module to the FHT 681 amplifier. If necessary, use a large, slotted screwdriver to pry the FHT 681 amplifier away from the power supply module.

A significant force might be required to rejoin the components. A snap should be heard when they are successfully reconnected.

There are two (2) neutron detectors. Push connector onto detector. Turn collar clockwise. Hand-tighten the collar.

Use small, slotted screwdriver.

The gamma detector is connected at the FHT 681 amplifier at the connection labeled PMT1. Disconnect and reconnect both connections to the 90-degree elbow several times to remove oxidation.

Slide the protective foam assembly into backpack

Record observations, times, and results for the maintenance report.

As specified by management or contractual obligations.