Motorola ASTRO Digital Spectra Service Manual

Troubleshooting Charts 5-21
6881076C25-D October 28, 2002
Chart C.27 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 1 of 4
No
Yes
A
B
Yes
No
Inject a 1kHz tone into MIC
with sufficient amplitude to
produce 3kHz of deviation,
PTT radio
Measure waveform at
TP208, should match
Figure 6-13
Waveform
Correct?
Amplitude of
Waveform
may vary
Measure waveform at R208
(left) should match Figure 6-13
Waveform
Correct?
Check 5V supply of U202-8
and GND U202-4
Measure waveform at
TP209, should match
Figure 6-13
Waveform
Correct?
Amplitude of
Waveform
may vary
Amplitude of
Waveform
may vary
OK?
Inspect and Repair
U202
Measure waveform at
should match Figure 6-13
U201-9
Make sure the following components
are placed and soldered correctly:
U202, R207, R208, C216, R209, R226,
C223, C217
OK?
Repair proper
components
Replace U202
No
Yes
No
Yes
No
Yes
No
No
Yes
Waveform
Correct?
No
Yes
Check that 3V is present at
U201-45, 31, 27, 3. Check
GND at U201-30, 28, 4
OK?
Measure waveform at J501-49
should match Figure 6-13
Amplitude of
Waveform
may vary
Waveform
Correct?
Inspect and repair
J501
Yes
Yes
No
No
Measure waveform at J501-48
should match Figure 6-13
Amplitude of
Waveform
may vary
Waveform
Correct?
Inspect and repair
J501
No
Yes
Keyed 9.4V
Check for 5V at
J501-45
Present?
Yes
No
Check for GND
at J501-14
Inspect J501
connections
Present?
No
Yes
OK?
Make sure the following parts
are the correct value: R207,
R208, R209, R226, R202,
R231, C216, C215
Correct?
Replace proper
components
Yes
No
No
Repair J501
Yes
Make sure the following parts
are the correct value: R401,
R408, R405, C405, C403,
R400, R407, C402, R438,
R437, R406, C404
Correct?
Yes
No
No trouble
found
Replace proper
components
Measure waveform at C203
and C204, should match
Figure 6-14 Traces 1 and 2
Waveform
Correct?
Check 5V supply of U202-8
and GND U202-4
Make sure the following components
are placed and soldered correctly:
U202, R202, R231, and C215
Check that 3V is present at
U201-45, 31, 27, 3. Check GND
at U201-30, 28, 4
OK?
Repair U201
Yes
OK?
Yes
No
Inspect and repair
U202
Repair U201
Replace U202
Repair proper
components
OK?
Yes
No
Amplitude of
Waveform
may vary
Continued on
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Motorola ASTRO Digital Spectra Specifications

General

Brand	Motorola
Model	ASTRO Digital Spectra
Category	Radio
Language	English