Motorola XTS 2500 Service Manual page 284

6.5-22
6.5.23900MHz Transmitter RF Troubleshooting Chart
No/Low TX Power
Is
Yes
TX current
>300mA?
No
No
Is B+
at C128?
Yes
Is B+ at
No
U101 pins 6,7,
and 14?
Yes
*
Is Vdc
No
at TP101
>2V?
Yes
*
Is Vdc
No
at U101 pin 1
>2V?
Yes
*
Is Vdc
No
at C142
>1V?
Yes
*
Is
No
RF at U101
pin 16 >2
dBm?
Yes
*
Is
No
RF at U101
pin 6 >20
dBm?
Yes
Check C128,
C127, C219,
and C142
February 14, 2012
900 MHz Troubleshooting Charts: 900MHz Transmitter RF Troubleshooting Chart
*
Is RF
Yes
input drive at
continuity across
U101 pin 16
>2dBm?
No
Go to Frequency
Change U106
Generation Unit
Chart
Check E101,
E102 and L103
Check L107
and L108
For Analysis, shields SH103 and SH104 need to be removed.
Check ALC IC
Check R114,
R115, and R119
Replace Q101
Go to Frequency
Generation Unit
Chart
Check L110,
C101, C114,
Replace U101
C116, C161,
C162 and C164
Is
Is there
Yes voltage drop
across CR101
U106?
>0.5V?
No
Check U102
and the ALC IC
= Transmitter enable Low.
*
MAEPF-27349-O
* *
Is
Yes
there RF
at connector
J101?
No
No
Check L114, L115,
C127, C129, C131,
C132 and C133
Remove SH102
Check CR102,
and R103
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