Nokia 1508 User manual

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Nokia Customer Care
1508 (RM-338)
Mobile Terminal
RF Description and Troubleshooting

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Contents
1508 RF troubleshooting

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Contents Page
Component Layout................................................................................................4
TxTroubleshooting................................................................................................ 6
Tx System Block Diagram....................................................................................6
Tx Introduction......................................................................................................6
Main Tx Component.............................................................................................6
AMS Setup for Tx Troubleshooting......................................................................6
Tx DC Test Points................................................................................................7
Tx RF Test Points................................................................................................8
Tx DC Test Points................................................................................................9
Tx Path Troubleshooting....................................................................................10
RxTroubleshooting..............................................................................................11
Rx System Block Diagram..................................................................................11
Rx Introduction....................................................................................................11
AMS Setup for Rx Troubleshooting.....................................................................11
Cell Receiver Check from RF to IQ.....................................................................12
Receiver DC Test Points....................................................................................14
Receiver RF Test Points.....................................................................................14
Rx Path Troubleshooting....................................................................................16

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Component Layout
Figure 1 and Figure 2 show the main components of the 1508 mobile terminal.
Figure 1: Component layout (Top)

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Figure 2: Component layout (Bottom)

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Tx Troubleshooting
Tx System Block Diagram
Figure 3: Tx system block diagram
Tx Introduction
The GRF6401 (Figure 3) provides the Zero-IF transmit signal path for Cellular-CDMA
transmission. For this chipset, Cellular-CDMA refers to band classes 0 and 3 as defined by
the cdma2000 standard, with mobile station transmitters operating between 824 and 849
MHz. The transmit signal path includes baseband amplifiers, quadrature upconversion, gain
control RF amplifier. The gain control RF amplifier output is routed to the final stages of the
transmit chain –Tx saw filter, power amplifier, direction coupler, duplexer, and antenna.
Main Tx Component
Figure 4: Tx main components
AMS Setup for Tx Troubleshooting
Put PWB on the module jig. Use the following steps to configure AMS for RF
troubleshooting.
1. Connect RF connector to a CMU200 or 8960.
2. Connect the PWB to a PC via the Module Jig, and connect a power supply.
3. Open AMS Tools software and select RF Tool.

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
4. Choose CP Enable, Enable“off”, then send.
5. Choose DSPM AFC Config. Set Pdm Val “0x0200”, then send
6. Choose CP PLL Channel Config. Set Band “Cell”, Channel “384”, then send..
7. Choose CP TX CDMA Test send
8. Choose DSPM TX AGC Config. Set Hyst State “medium gain”, Power (dBm) “24dBm”
then send
9. Choose CP AUX ADC Get. Set TX PCG Sync “off” then send to get Power detector ADC
value.
Figure 5: FTM dialog box

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Tx DC Test Points
Figure 6: Tx DC test point
Table 1 shows the Tx DC test points shown in Figure 6
Test Point Description Value
1 PA_ON 3.08V for PA turning on, 0V for turning off
2 PA_R1 2.16V for high gain mode,1.6V for low gain mode
3 LOCK_DET 3.08V for Lock, 0 V for unlock
4 TX_AGC 1.92V for 5dB, 2.16V for 15dB, 2.4V for 25dB.
5 Tx IQ in 0.8 V With oscilloscope: 500 mV p-p
6 Tx_on 2.8 V
Table 1: Tx DC Test Points

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Tx RF Test Points
Figure 7: Tx RF Test Points
Table 2 shows the test points shown in Figure 7.
Test Point Description Value
1 Tx saw output about 4dBm
2 PA input about 2dBm
3 PA output about 28dBm
4 TCXO_RF about 0dBm
5 RF connector about 24dBm
6 Coupler output about 26dBm
Table 2: Tx RF Test Points

1508(RM-388)
RF Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Tx Path Troubleshooting
No No No
yes
No
yes
No
yes
No
yes
No No
yes
No No
yes
No
yes
No
yes
Tx path faults
Measure DC test points
at table 1,is it OK?
Measure Tx RF test point
1 at table 2, is it OK?
Measure Tx RF test point
2 at table 2, is it OK?
Measure Tx RF test point
3 at table 2, is it OK?
Measure Tx RF test point
6 at table 2, is it OK?
If RF antenna feed point pad
obstructed, clean the pad,
connect system simulator to the
MS antenna, is it OK?
Tx troubleshootin
g
finished
Check ACT5805,
CBP5.6 Reheat solder joints of ACT5805
Measure Tx RF test point
4 at table 2, is it OK?
Chan
g
e U202
Reheat the solder joints of R113
Reheat the solder joints of U101 Change U101
Reheat the solder
j
oints of L113
Measure Tx RF test point
5 at table 2, is it OK? Reheat the solder
j
oints of C119, U108,U107
Reheat the solder joints of L112, L123
Check antenna module
Change U403
Chan
g
e U104