Section III. MAINTENANCE PROCEDURES
2-8. REMOVING AND REPLACING MODULES
DEATH ON CONTACT may result from contact with high voltage in modem modules. Scope
module A2 contains 1,100 volts dc; loop battery in module A5 contains 127 volts dc. Set ON/OFF
switch on the front panel to OFF before attempting any removal procedures.
Be careful during removal and replacement. You can prevent accidental damage to other parts,
and can prevent potential short circuits caused by dropped hardware. When removing and
replacing a part, check carefully for loose hardware or insecure electrical connections. Do not
operate the equipment until you make these checks.
The procedures below are for modules A1, A2, A3, A4 and A5. The procedure for scope module
A2 is listed separately in this paragraph.
REMOVING MODEM CHASSIS FROM CASE
Loosen six captive screws around outside edge of front panel.
Grasp ribbed frame around outside edge of front panel.
Carefully pull modem chassis out of the case.
RECEIVE AUDIO, TRANSMITTER, RECEIVER, LOOP BATTERY MODULES
Remove modem chassis from case.
Loosen the four captive screws holding module to chassis.
Pull up on bail handles to unplug module from chassis connector.
Lift out module.
To remove module dust cover, turn bail handles approximately 900 counterclockwise until they release.
Lift off cover.
Replace dust cover: Place cover over module; press down bail handles and turn approximately 900
clockwise until they lock in place.
Plug new module into chassis connector.
Tighten the four captive screws to secure module to the chassis.
Replace modem chassis in case.