Boonton 1121A, Инструкция по эксплуатации

Страница: 66 / 181

Section 5 Maintenance
5-4
NOTE
There are two positions available for optional filters.
These positions are located on the right and left-center
part of the circuit board. The right position corresponds to
optional filter No. 2 which is activated by the right-most
optional filter key on the front panel and the left-center
position corresponds to optional filter No. 1 which is
activated by the left-most optional filter key. Either
position will accommodate any of the available optional
filters.
c. Install the optional filter in the desired position and
replace the circuit board.
There are voltages at various points in the instrument
which can, if contacted, cause personal injury. Observe
all safety precautions. Service and adjustments should be
performed by trained service personnel only.
d. Set the option switch A4S1-7 to the open position
and connect power to the instrument.
e. Set the LINE ON/OFF switch to ON and depress
the LCL/INIT key.
f. After the initialization sequence is complete, de-
press the SPCL key and enter the special option number
listed in Table 5-2 that defines the filter type and position
for each filter installed.
g. Set the option switch A4S1-7 to the closed position
and set the LINE ON/OFF switch to OFF.
h. Disconnect all power to the instrument and replace
the instrument top cover. After the optional filters are
installed, they should be calibrated as described in
paragraph 5-20.
5-14. Firmware Integrated Circuit.
Remove the
EPROM as follows:
a. Remove the instrument top cover as described in
paragraph 5-10.
b. Remove the CPU board (green extractors). Refer
to paragraph 5-12. Place the board on a flat,
non-conductive working surface with the components up.
When removing and replace an integrated circuit (IC)
note the mark or notch used for pin number identification.
c. Locate EPROM A5U14. Remove the IC with a
straight pull away from the board.
d. EPROM is a replaceable part and does not require
reprogramming. Install the replacement IC and replace
the circuit board.
There are voltages at various points in the instrument
which can, if contacted, cause personal injury. Observe
all safety precautions. Service and adjustments should be
performed by trained service personnel only.
e. Connect power to the instrument and set the LINE
ON/OFF switch to ON.
f. Depress the LCL/INIT key to initialize the in
strument. The new firmware number will appear in the
SOURCE display for a few seconds before the instrument
resumes normal operation.
g. Enter special function 25 to initialize the program
memory.
h. Set the LINE ON/OFF switch to OFF, disconnect
all power to the instrument and replace the instrument top
cover.
5-15. Electronic Component Repair or Replacement.
Most components are readily accessible for inspection
and replacement when the instrument covers are
removed. Solid-state circuit components, mounted on
plug-in circuit boards, are used throughout the instru-
ment. Refer to NAVAIR 01-1A-505 and/or T.O. 00-25-
234/TM 43-0158 for repair or replacement procedures of
electronic components. EPROM is replaceable and
does not require reprogramming.
NOTE
References:
NAVAIR 01-1A-505 (Installation Practices, Air
craft electric and Electronic Wiring)
T.O. 00-25-234/TM 43-0158 (General Shop Practice
Requirements for the Repair, Maintenance, and Test of
Electrical Equipment)
5-16. INSPECTION.
5-17.
If an equipment malfunction occurs, perform a
visual inspection of the instrument. Inspect for signs of
damage caused by excessive shock, vibration, or over-
heating, such as broken wires, loose hardware and parts,
loose electrical connections, or accumulations of dirt and
other foreign matter. Correct any problems discovered,
then perform the performance tests to verify that the
instrument is operational. If a malfunction persists or the
instrument fails any of the performance tests, refer to the