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Page Title:
Table 3-2 Checkout/Troubleshoot the Receiver-Transmitter RT-1277/URC-92-Continued |
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|  TM 11-5820-873-34
Table 3-2 Checkout/Troubleshoot the Receiver-Transmitter RT-1277/URC-92-Continued
STEP
ACTION
INDICATION
NEXT STEP
110 Set signal generator to 0 dB. Connect oscilloscope
Oscilloscope displays waveform similar to Fig
Yes: step 111
probe to 1A3XA2J2-5, ground lead to ground.
3-2D.
No: step 115
111 Connect oscilloscope probe to 1A3XA4.14-11,
Oscilloscope displays waveform similar to Fig
Yes: step 112
ground lead to ground.
3-2D.
No: step 116
112 Connect multimeter between 1A3XA4J4-9 and
Multimeter indicates +12 VDC 0.8 VDC
Yes: step 113
ground.
No: step 132
113 Connect multimeter between 1A3XA4J4-13 and
Multimeter indicates between +2.0 VDC and
Yes: step 114
ground.
+ 8.0 VDC.
No: step 132
114 Connect VTVM (AC) to 1A3XA4J4-6, ground
VTV indicates 0.1 minimum.
Yes: step 133
lead to ground.
No: step 132
115 Connect frequency counter to 1A3XA1J1-15,
Frequency counter indicates 29.9994 MHz.
Yes: step 117
ground lead to ground.
No: step 132
116 Connect frequency counter to oscilloscope ver-
Oscilloscope displays waveform similar to Fig
Yes: step 132
tlcal output jack Connect oscilloscope probe to
3-2M.
No: step 119
1A3XA2J2-11, ground lead to ground.
117 Connect multimeter between 1A3XA1J1-3 and
Multimeter indicates + 12 VDC 0.8 VDC.
Yes: step 118
ground.
No: step 132
118 Connect multimeter between 1A3XA1J1-P and
Multimeter indicates between +2.0 VDC and
Yes: step 137
ground.
+8.0VDC.
No: step 132
119 Connect multimeter between 1A3XA2J2-9 and
Multimeter indicates + 12 VDC 0.8 VDC
Yes: step 120
ground.
No: step 132
120 Connect multimeter between 1A3XA2J2-P and
Multimeter indicates + 2.0 VDC and 8.0 VDC
Yes: step 121
ground.
No: step 132
121 Connect multimeter between 1A3XA2J2-3 and
Multimeter indicates + 12 VDC 0.8 VDC
Yes step 136
ground.
No: step 132
122 Connect multimeter between 1A3A5-E5 and
Multimeter indicates + 12 VDC 0.8 VDC
Yes: step 123
ground.
No: step 132
123 Set signal generator to 0 dB and 100% modula-
Oscilloscope displays waveform similar to Fig
Yes: step 124
tion. Connect oscilloscope probe to 1A4XA1-13,
3-21.
No: step 126
ground lead to ground.
124 Connect multimeter between 1A4A6-E16 and
Multimeter indicates + 12 VDC 0.8 VDC
Yes: step 125
ground.
No: step 132
125 Connect multimeter between 1A4XA1J1-L and
Multimeter indicates +12 VDC 0.8 VDC
Yes: step 138
ground.
No: step 132
126 Connect oscilloscope probe to 1A3XA2J2-11,
Oscilloscope displays waveform similar to Fig.
Yes: step127
ground lead to ground.
3-2M.
No: step 128
127 Connect multimeter between 1A3XA4J4-7 and
Multimeter indicates + 12 VDC 0.8 VDC.
Yes: step 133
ground.
No: step 132
128 Connect multimeter between 1A3XA2J2-7 and
Multimeter indicates + 12 VDC 0.8 VDC.
Yes: step 136
ground.
No: step 132
129 Check DC fuse 1A6F3 and fuse cartridge.
DC fuse and fuse cartridge check good.
Yes: step 132
No: replace fuse
1A8F3
130 Connect multimeter across contacts of COUP-
Multimeter indicates + 12 VDC 0.8 VDC.
Yes: replace 1A2DS2
LER STATUS FAULT lamp 1A2DS2.
and go to step
13
No: step 143
131 Set mode switch to OFF. Disconnect antenna
Multimeter indicates less than 300 ohms.
Yes: step 143
coupler control cable Connect multimeter across
No: replace faulty
contacts of indicator that did not illuminate
indicator
132 Unit not authorized for repair at this mainte-
---
nance level Route entire RT-12771URC-92 to
next higher maintenance lev level for repair
133 Replace Audio CCA 1A3A4 Route original Audio
---
CCA to next higher maintenance level for repair
134 Replace Sideband Generator CCA 1A3A3 Route
---
original Sideband Generator CCA to next higher
maintenance level for repair
135 Replace RF Power Amplifier Assy 1A7A1 Route
---
original RF Power amplifier Assy to next higher
maintenance level for repair
136 Replace IF Filter CCA 1A3A2 Perform 2nd IF
---
adjustment Route original IF Filter CCA to next
higher main tenance level for repair
3-11
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