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lunedµ 20 dicembre 1999
A
Have you same issue also
using DCS RX WAY ? set
RF generator at 1842,8
MHz and digit 450700#
test command.
YES
Is IF 400 MHz
frequency present on
U432 pin 3 & 4 ?
YES
Is RF RX signal present on:
U432 pin 18 AT 947,8 MHz
frequency (GSM way digit
450062#)
U432 pin 12 at 1842,8 MHz
( DCS way digit 450700#)?
YES
Check on U432 pin 7 for RX VCO presence
at 1347,4 MHz for GSM or at 1442,8 MHz
for DCS ,if ok check U432 for
correctbias,else check U253 for faulty.
Note:
RX_VCO250 see on Q172
RX_DCS*GSM see on Q160
V_tuning,on pin 1, see R221,U200.
SEE U432 DIAGRAM ON PAG.18
Is RF signal (digit
450062# ) at
NO
947,4 MHz
present on FL 472
Check C472 , C473 ,
L471 for missing or
dry joint ,else check
C484 , C486 , L485 ,
L482 , R481. If all is
ok replace U432
YES
Is RF signal ( as
before) present on
NO
FL472 in using GSM
way or on FL 480 IN
using DCS way way ?
Is there RF signal
on C470 for GSM
&DCS way?
Check for faulty:
J300,U100,Q110.
TX_EN comes from
U800,RX_EN comes from
U800 , -5Vcc comes from
U903
- MOTOROLA CONFIDENTIAL PROPRIETARY -
Dual band Taishan level 3 debug rev 1.0
YES
pin 2?
NO
Is IF 400 MHz
YES
frequency present
on FL 490 pin 5?
NO
REPLACE
FL490
NO
YES
NO
REPLACE
FL470
NO RX
GSM/DCS
Check RF at GSM freq.
presence on FL 472 IN, if
it is ok replace FL 472 ,
else problem is FL 470 (
true only if you are sure
that on DCS way
everything is ok ).
Check Q490 for correct bias
: base = 0,8 V ; collector =
1,6 v ; emitter = GND .
SW_VCC comes from
U200 , else check any
components surround it for
faulty or missing
REPLACE FL
472 (GSM )
FL 480 (DCS)
NO
Is there same signal
on FL 472 ( GSM
YES
WAY )
FL 480 ( DCS WAY )
YES
Check for GSM
C472,C473,L471.
for DCS C482 ,
C483 , L481
Page 6
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