Manual 7-9415-1.4 Page 21
TX RX Systems Inc. 08/31/06
61-65-50 UserMan page 21 of 24
down firmly into place. Each type of module is
keyed uniquely to fit in only one slot within the
card cage. Once the card is seated into place
properly tighten the thumb screws.
The SB II low level and mid level amplifier stages
are field replaceable by simply removing the mod-
ule and plugging in a replacement. These modules
are HOT switchable meaning they can be swapped
without powering down the system. RF cables
attached to the modules must be removed (5/16”
wrench) prior to swapping the modules and must
be re-attached after the new module is in place.
when replacing the RF cables do not overtighten
the SMA connectors. They should be tightened just
slightly more than hand tight or to the specification
of 7 in/lbs.
Modules can be swapped between the uplink and
downlink branches for troubleshooting purposes. If
a problem exists in one branch and the problem
moves to the other branch when modules are
swapped around this indicates a defective module.
Note:
After an amplifier module is
replaced use the Calibrate Currents
software function to properly set the
amplifiers alarm trip point, see page
15. Due to slight differences in compo-
nent tolerances the trip point must be reset for any
new amplifier assemblies introduced into the sys-
tem.
Display/User Interface Assembly Replacement
The SB II Display/User Interface assembly is field
replaceable. Follow the steps listed below in
sequential order. No tools are required.
Note:
Power to the SB II cabinet must
be turned OFF during the display/user
interface replacement process.
1) Loosen the two thumb-nuts which hold the dis-
play/user interface assembly to the card cage.
2) Gently tilt only the top of the assembly up from
the card cage. Keep the bottom of the assembly
in place. The bottom mounting plate (part of the
card cage) has an overhang on it to support the
display/user interface board. If the assembly is
lifted straight out the overhang could possibly
damage the interface circuit board.
3) With the display/user interface board standing
up straight gently move it upwards while lifting it
out about an inch or two. This should allow the
overhang to clear the interface circuit board
without damage.
4) Remove the ribbon cable that connects the dis-
play/user interface assembly to the card cage,
see
Figure 13
.
5) To replace the display/user interface assembly
repeat steps 1 through 4 in reverse order.
Power Supply Replacement
The SB II power supply assembly is field replace-
able. Follow the steps listed below in sequential
order. The required tools are a #1 Phillips screw-
driver.
1) Turn off AC power at the junction box.
2) Disconnect the 3 conductor cable that brings
AC power to the supply from the junction box.
3) Disconnect the red and black leads from the
power supply that connect to the card cage.
4) Remove the Phillips screws that hold the power
supply mount bracket to the back plate and
remove the assembly from the cabinet.
5) Reverse steps 4 through 2 to install the replace-
ment power supply.
Duplexer / Filter Replacement
The component assemblies of the duplexer are
field replaceable. Follow the steps listed below in
sequential order. The required tools are a #1 Phil-
lips screwdriver with an extended shaft to reach
down far enough into the unit to loosen mounting
screws.
Note:
Power to the SB II cabinet must
be turned OFF during the assembly
replacement process.
1) All RF cables attached to the assembly must be
removed.
2) Remove the Phillips screws that hold the
assembly mount brackets to the back plate and
remove the assembly from the cabinet.
NOTE
NOTE
NOTE
