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Page Title:
Table 5-3. Troubleshooting Guide |
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|  TM 11-5820-917-13
Troubleshooting Guide
Indication
Location/cause
1.
System main power pushbutton
Main line input disconnected; Fuse F 1
(on 4028 unit) does not illuminate.
blown Transformer T1, diode bridge CR1,
lamp malfunction, or overvoltage crow-
bar U9.
2.
No CRT raster
Cabling to 6025 disconnected; CRT drive
or tube malfunction (check fuse F101 on
assembly 1A7). 4028 power supply or 6025
voltage regulator malfunction.
3.
Transmitter out of sync; current PATH
CRT raster, but no video
display.
PROGRAMMER switch off; antenna cable
Perform self-test (see fault indications,
step 9).
4.
AGC display, but no Chirp-
Receiver baseband section faulty; spectrum
sounder record display.
analyzer or receiver control circuit mal-
function. Check presence or absence
of audible tone and of cursor lines in
lower part of display.
5.
Chirpsounder record display,
Input attenuator set too high; fault in
but no AGC.
receiver. AGC detector or output
amplifier.
6. Audio tone absent, or incorrect
Fault with receiver oscillator Y1 or assoc-
frequency or volume.
iated divider, etc. (receiver output
section assembly 2A2). Use test push-
button to check effect of calibrator
oscillator; also check speaker, audio
amplifier and gain control.
Excessive drift of Chirp sounder
7.
When use of the slip rate switch to
record display on CRT.
correct vertical path display drift is
insufficient or too frequently required
for all received paths the cause is prob-
ably frequency standard precession in
receiver. Refer to paragraph 5-21 for
adjustment.
8.
Numeric display stopped or
For Frequency; Fault in frequency counter
incorrect.
1A4A2, sweep synthesizer 2A1, display
elements 1A9, or +5V supply. Check per-
forming LAMP TEST (for display ele-
ments) and receiver TEST (for power
supply).
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