Motorola Xtl5000 Detailled 6881096c74 B Manual

6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-21
5.6.7 Low or No RX Injection Signal (136–174 MHz)
Figure 5-11.  Low or No RX Injection Signal (136–174 MHz)

	





 



	



    
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May 25, 20056881096C74-B
5-22Troubleshooting Charts: Flowcharts
5.6.8 Low or No TX Injection Signal (136–174 MHz)
Figure 5-12.  Low or No TX Injection Signal (136–174 MHz)

		


 
 
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6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-23
5.6.9 TX or RX VCO Unlock (Fail 001) (136–174 MHz)—Part 1 of 2
Figure 5-13.  TX or RX VCO Unlock (Fail 001) (136–174 MHz)—Part 1 of 2

	



  
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May 25, 20056881096C74-B
5-24Troubleshooting Charts: Flowcharts
5.6.10 TX or RX VCO Unlock (Fail 001) (136–174 MHz)—Part 2 of 2
Figure 5-14.  TX or RX VCO Unlock (Fail 001) (136–174 MHz)—Part 2 of 2

	


  
  

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6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-25
5.6.11 No Output Power at TX Mode (136–174 MHz)
Figure 5-15.  No Output Power at TX Mode (136–174 MHz)


    
	


  

	


 
  
 

    


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May 25, 20056881096C74-B
5-26Troubleshooting Charts: Flowcharts
5.6.12 No Output Power and IDC < 2A at TX Mode (136–174 MHz)
Figure 5-16.  No Output Power and IDC < 2A at TX Mode (136–174 MHz)


 

	
 




  
 
   
     

  
 	


 
 
 	
  

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6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-27
5.6.13 No 16.8 MHz Reference Oscillator Frequency (380–470 MHz and 450–520 MHz)
Figure 5-17.  No 16.8 MHz Reference Oscillator Frequency (380–470 MHz and 450–520 MHz)
U5751DC Voltages
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5No connection
1.5
Ground
1.5
3
>800mVpp
16.8MHz? Probe pin 3
of Y5750 for
16.8MHzSTART
No 16.8MHz
Reference
No
Ye s
>800mVpp
at pin 23
U5752?No
Ye sCheck
C5761Replace
Y5750 3.0VDC
at pin 4 of
Y5750?No
Ye sCheck 3.0V
regulator path...

May 25, 20056881096C74-B
5-28Troubleshooting Charts: Flowcharts
5.6.14 Poor RX Sensitivity or No RX Audio (380–470 MHz and 450–520 MHz)—Part 1 
of 2
Figure 5-18.  Poor RX Sensitivity or No RX Audio (380–470 MHz and 450–520 MHz)—Part 1 of 2
 Poor Rx
Sensitivity or no
Rx audio
Measure Transceiver
12dB Sinad by injecting
signal at antenna portYe s
Ye s3kHz FM Deviation
1kHz Audio  tone
12 dB Sinad
Sensitivity
< - 117.5 dBm Std.

6881096C74-BMay 25, 2005
Troubleshooting Charts: Flowcharts5-29
5.6.15 Poor RX Sensitivity or No RX Audio (380–470 MHz and 450–520 MHz)—Part 2 
of 2
Figure 5-19.  Poor RX Sensitivity or No RX Audio (380–470 MHz and 450–520 MHz)—Part 2 of 2
1
Inject a standard FM test
signal into the antenna port.
Use a spectrum analyzer and
high-impedance RF probe to
measure the signal at TP5301

May 25, 20056881096C74-B
5-30Troubleshooting Charts: Flowcharts
5.6.16 RX IF—Poor SINAD or No Audio (380–470 MHz and 450–520 MHz)—Part 1 of 2
Figure 5-20.  RX IF—Poor SINAD or No Audio (380–470 MHz and 450–520 MHz)—Part 1 of 2
Level
is -3dB
referenced to 
R5412?No
No No Ye s
Measure the IF
signal level
(109.65MHz)
at C5403 Measure the IF
signal level
(109.65MHz)
at C5406
Check Y5400
Level
is +20dB
relative to the RF
input level
at C5406?No
Ye s
Voltage
level of 9.0V 
at R5404? 
Ye s
Voltage
level of
0.7V...