3-2
TROUBLESHOOTING TABLES
No Audio
1. Synthesizer out of lock
Verify U201-4 is at 3V dc.
Troubleshoot synthesizer/VCO
circuits.
2. Defective IFIC
Verify audio is present at U51-8.
Check Q70, Y70, U51.
3. RX audio buffer fault
Verify audio is present at U451-2.
Check U510 and associated
parts.
4. ASFIC fault
Verify audio is present at U451-41.
Verify U451-14 is high.
Check squelch setting, PL/DPL
programming. Troubleshoot/
replace U451.
5. Audio PA fault
Verify U490-1 is <0.2V dc.
Verify audio is present at U490-5
and 8.
Check Q490.
Check/replace U490.
6. Defective speaker
Verify audio is present at speaker
terminals.
If not, check continuity of J471-2
and 3. Check J491. If yes,
replace speaker.
No Receive
(squelch noise
present)
1. No first injection
Check that RF level at T42-6 is
6 dBm.
Check that RF level at U251-8 is at
least -8 dBm.
Check injection filter C40-44,
L40-41.
If yes, check Q280 and associ-
ated parts. If no, check U251
and components on pins 5 and
6.
2. No 5R source.
Verify U401-49 is high in RX.
Verify Q311 gate is 0V dc in RX
Verify Q311 drain is 5V dc in RX.
Check/replace U401
Check/replace Q313.
Check for shorts, check/replace
Q311.
3. Harmonic filter or
antenna switch fault
Apply on-channel 100 mV RF signal
at antenna port. Verify RF level at jct.
C1/C2 per schematic.
Check TX harmonic filter, D120-
121. Should be 0V dc on D120-
121.
4. Back end fault
Apply on-channel 100 mV RF signal
at antenna port. Measure RF levels
from FL51 through U51.
Check components prior to
loss-of-signal point.
5. No second injection
Measure RF level at U51-3, verify
approx. 280 mV rms.
If dc voltages at U51-3 and 4
are OK, check Y51 and
associated parts. If not replace
U51.
Symptom
Possible Causes
Procedure
Corrective Action
Содержание CP 140
Страница 1: ...Commercial Series CP140 CP160 CP180 Portable Radios Detailed Service Manual 6866550D20 O ...
Страница 2: ...ii ...
Страница 4: ...iv ...
Страница 5: ...Commercial Series CP140 CP160 CP180 Portable Radios Service Maintainability Issue December 2003 ...
Страница 12: ...viii ...
Страница 28: ...iv ...
Страница 40: ...1 12 THEORY OF OPERATION ...
Страница 48: ...2 8 TROUBLESHOOTING TABLES ...
Страница 50: ...3 2 CONTROLLER KEYPAD SCHEMATICS ...
Страница 58: ...3 10 Keypad Board Parts List 8466565A01 O ...
Страница 59: ...Commercial Series CP140 CP160 CP180 Portable Radios VHF 146 174MHz Service Information Issue December 2003 ...
Страница 62: ...iv ...
Страница 66: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Страница 90: ...3 16 TROUBLESHOOTING TABLES ...
Страница 92: ...4 2 VHF PCB SCHEMATICS PARTS LISTS ...
Страница 105: ...Commercial Series CP140 CP160 CP180 Portable Radios UHF1 403 440MHz Service Information Issue December 2003 ...
Страница 108: ...iv ...
Страница 112: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Страница 136: ...3 16 TROUBLESHOOTING TABLES ...
Страница 138: ...4 2 UHF1 PCB SCHEMATICS PARTS LISTS ...
Страница 151: ...Commercial Series CP140 CP160 CP180 Portable Radios UHF2 438 470MHz Service Information Issue December 2003 ...
Страница 154: ...iv ...
Страница 158: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Страница 182: ...3 16 TROUBLESHOOTING TABLES ...
Страница 184: ...4 2 UHF2 PCB SCHEMATICS PARTS LISTS ...
Страница 197: ...Commercial Series CP140 CP160 CP180 Portable Radios UHF3 465 495MHz Service Information Issue December 2003 ...
Страница 200: ...iv ...
Страница 204: ...1 4 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Страница 228: ...3 16 TROUBLESHOOTING TABLES ...
Страница 230: ...4 2 UHF3 PCB SCHEMATICS PARTS LISTS ...