GTX 327 MAINTENANCE MANUAL
Page 3-7
190-00187-05
Rev. B
Table 3-3. Test Failures and Recommended Actions
TEST FAILURE
TEST
PARAGRAPH
RECOMMENDED ACTION
Visual Inspection
3.3
Replace damaged cables, diplexer, chassis
components and board assemblies as required
Power On Check
3.5, 5.9.4
If voltage is not measured at fuse F301, replace
fuse on main board
Switched Power Output
5.10
Replace Main Board (see paragraphs 4.3.7,
4.4.2)
Panel Lighting Test
5.9.1, 5.9.2, 5.9.3
Replace Front Display Assembly (see
paragraphs 4.3.4, 4.4.5)
MAIN BOARD TESTS
Interrogation pulses at receiver TP2
and main board I204 pin 64 but not
at main board I204 pins 58, 59, 60
3.6
Replace Main Board (see paragraphs 4.3.7,
4.4.2)
With receiver, transmitter
disconnected, main board power
supply voltages are incorrect
3.6
Replace Main Board (see paragraphs 4.3.7,
4.4.2)
No LCD pulses at I204 pins 67-70
3.6
Replace Main Board (see paragraphs 4.3.7,
4.4.2)
Valid altitude inputs at J3271 but no
altitude pulses transmitted
3.6, 5.12.1
Replace Main Board (see paragraphs 4.3.7,
4.4.2)
FRONT DISPLAY TESTS
Error found in matrix test, Table 3-2
or steps listed in paragraph 3.7
3.7
Replace Front Display Assembly (see
paragraphs 4.3.4, 4.4.5)
Keyboard test locates a fault not
related to main board assembly
3.7
Replace Front Display Assembly (see
paragraphs 4.3.4, 4.4.5)
RECEIVER, TRANSMITTER
Front panel display indicates reply
but unit is not transmitting
3.8, 5.12
Troubleshoot diplexer cable and transmitter
Assembly per paragraph 3.8
Unit does not operate over dynamic
range from –74 dBm to –20 dBm
3.8, 5.12.1
Replace Receiver Assembly (see paragraphs
4.3.5, 4.4.2)
Receiver voltages are incorrect
3.8
Replace Receiver Assembly (see paragraphs
4.3.5, 4.4.2)
No pulses at receiver TP-2
3.8, 5.12.1
Replace Receiver Assembly (see paragraphs
4.3.5, 4.4.2)
Side Lobe Suppression not
functioning over dynamic range
3.8, 5.12.1
Replace Receiver Assembly (see paragraphs
4.3.5, 4.4.2)
The document reference is online, please check the correspondence between the online documentation and the printed version.
