3.  Weather Radar Trouble Shooting Procedure
________________________________________
 A.  When the TEST mode is selected on the weather radar control panel, the entire system is energized. The receiver-transmitter circuits are tested (system transmits) for 4 seconds and then are muted. The antenna scans, and a test pattern appears on the indicator.
 B.  The R/T front panel contains seven annunciator lights, which in conjunction with the test pattern and fault messages on the indicator, assist in isolating faulty LRUs.
 WARNING: DO NOT OPERATE WEATHER RADAR WHILE THE AIRPLANE IS BEING
_______ REFUELED OR DEFUELED AND DO NOT OPERATE IN ANY RADIATION MODE WHILE A FUELING OPERATION IS BEING CONDUCTED WITHIN 300 FEET OF A RADIATING ANTENNA OR INJURY TO PERSONNEL MAY OCCUR.
 PERSONNEL MUST NOT ENTER AN AREA CLOSER THAN 50 FEET OF A RADIATING ANTENNA OR INJURY TO PERSONNEL MAY OCCUR.
 C.  AF 121, 122; On weather radar control panel set the mode selector switch to TEST. The test pattern should appear similar to test pattern shown in Fig. 101. In event of a fault in a line replaceable unit (LRU), a fault warning message will be displayed in yellow in the center of the display. Replace the displayed LRU.
 EFFECTIVITY
 AF 121, 122; SN 351-399  CONFIG 3  03 B Page 102  Sep 25/9434-43-00
FIELD C FIELD E FIELD A 4  TEST RNG COOL  10  MRK 5 0.0 CAL MIN  FIELD B FIELD D FIELD F FIELD H  RED 
YELLOW 
GREEN 
3  1 
FIELD C FIELD A FIELD E  TEST RNG 10 COOL  MRK 5 0.0 CAL MIN  FIELD B FIELD D FIELD F FIELD H  MAGENTA RED 
YELLOW 
GREEN 
3  2 
3 FIELD G  ANT FAULT ATT FAULT IND FAULT CON FAULT R/T FAULT COOL FAULT  YELLOW 
4 3 2 1  AF 121,122; RNG IS 15 Figure 101 Weather Radar Test Patterns and Message Field Display FOR ILLUSTRATION PURPOSES AREAS ARE DARK (NO COLOR) SHOWN REVERSED SN 352-399 SN 351; AF 121,122 

EFFECTIVITYAF 121,122; CONFIG 3 SN 351-399799B Page 103
34-43-00
 Sep 25/94
INDICATOR LEGEND FIELD  MESSAGE - NORMAL DISPLAY  MESSAGE - MALFUNCTION DISPLAY  REPLACE 
A 1  '10','20','40','80','160','320' Selected range - than selected range Blank display, or a flashing number other  Indicator 
A 2  '15','30','60','120','240' Selected range - than selected range flashing number other Blank display, or a  Indicator 
B 1 '5','5','10','20','40','80' Corresponding range mark inter-val for selected range - No numbers displayed, or a number not correspond-ing to selected range  Indicator 
B 2  '5','10','20','40','80' Corresponding range mark inter-val for selected range - No numbers displayed, or a number not correspond-ing to selected range  Indicator 
C 3  Selected mode -'TEST','WX' or 'MAP'  Blank display  Indicator 
C 4  'TEST','WX', 'TURB' or 'MAP' Selected mode - Blank display  Indicator 
D  Antenna tilt setting -'15.0 thru 15.0 '  'STAB' displayed in yellow  (AMM 34-41-00/ Troubleshoot gation system inertial navi-Receiver/Trans-mitter or 101) 
E  Blank Display  'COOL'  R/T Cooling fan Mount Receiver/Trans-mitter or 
F  (GAIN control not set to AUTO) 'CAL' displayed in blue  Control panel 
'CAL' displayed in yellow  mitter Receiver/Trans-
SN 351-399 AF 121,122 AF 121,122; SN 351 SN 352-399

Weather Radar Indicator Failure Messages and Faulty LRU Figure 102 (Sheet 1)
EFFECTIVITY

 CONFIG 3
AF 121,122; SN 351-399
799B Page 104
34-43-00
 Sep 25/94
INDICATOR LEGEND FIELD  MESSAGE - NORMAL DISPLAY  MESSAGE - MALFUNCTION DISPLAY  REPLACE 
G  Blank Display  'R/T FAULT'  mitter Receiver/Trans-
'ANT FAULT'  Antenna 
'CON FAULT'  switch or waveguide Control panel 
'IND FAULT' - When mode position selector is in TEST  Indicator 
'ATT FAULT' - When mode position selector is in TEST  (AMM 34-41-00/ Troubleshoot gation system inertial navi-101) 
'COOL FAULT' - When mode selector is in TEST position  Refer to Field E 
H 3 Blue MAX 9 thru 1, MIN Out of AUTO (In MAP mode only)  No message or incorrect message  Control panel 
H 4  Blue MAX 9 thru 1, MIN Out of AUTO (In all modes)  No message or incorrect message  Control panel 

Weather Radar Indicator Failure Messages and Faulty LRU
Figure 102 (Sheet 2)

EFFECTIVITY

CONFIG 3 AF 121,122; SN 351-399 799B Page 105

34-43-00
 Sep 25/94
 D.  SN 351-399; With the mode selector switch in TEST the test pattern should appear similar to test pattern shown in Fig. 101. In event of a fault in a line replaceable unit (LRU), a fault warning message will be displayed in yellow in the center of the display. Replace the displayed LRU.
　
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