Nokia 1508 User manual

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

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

1508(RM-388)
Antenna Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Introduction
The mobile terminal includes an internal antenna. This antenna arrangement is used for
Cellular frequency bands. The internal antenna assembly adopts Monopole Antenna
structure used for the cellular engine.
Visual Quality Requirements
Below are the minimum acceptable visual quality requirements of the internal antenna
assembly:
zWear gloves to assemble the antenna. Don’t touch the antenna radiator with bare
hands.
zNo visual cracks or mechanical defects.
zNo oil, dirt, or particles are present on the parts.
zRadiator must be aligned with the plastic housing.
zRadiator must be flat with no warping.
zThe length of all pins must be identical and the pins align.
Failures and Corrective Measures
The internal antenna is assembled into the Back Cover Assembly as shown in Figure 1.
If no internal antenna is installed, the antenna gain is degraded by more than 20 dB.
zIf the internal antenna is missing, install antenna-asm Module.
zIf the radiator looks damaged, replace it with a new antenna –asm Module.
Figure 1: B Cover Assembly

1508(RM-388)
Antenna Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Monopole Antenna
The internal antenna has a monopole antenna radiator attached to the plastic support.
Figure 2: The top view of internal antenna
Damaged RF feed point Pin
The pin (spring clip) of the antenna must be properly connected to the PWB.
zIf the main antenna’s RF feed point pin does not touch the PWB, the antenna gain
degrades by more than 17 dB.
zIf the RF feed pin is broken or bent so that the pin does not touch the PWB, replace
the antenna-asm Module.
zIf the RF feed pin spring appears damaged, replace the antenna-asm Module.
Figure 3: back view of internal antenna

1508(RM-388)
Antenna Description and Troubleshooting
Nokia Customer Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
Obstructed RF feed point pad
If RF feed point pad is obstructed, removed, or covered, the antenna pin does not touch
the PWB and the cellular antenna performance degrades.
zIf corrosion is present or the pad is missing, replace the PWB.
zIf a pad is obstructed or covered by something, clear and/or clean the pad.
zIf any component of antenna match circuit is missing ,replace the PWB
Figure 4: PWB layout of RF feed point and antenna match circuit

1508(RM-388)
AntennaDescriptionandTroubleshooting
Nokia Customer
Care
Issue 1
Copyright © 2008 Nokia, All rights reserved
RF Connector Failure
The RF connector fails when it does not properly connect the RF input terminal to the
RF output terminal during the SMT. If this happens the antenna gain degrades by 25
dB. Check this by testing the resistance value between the RF input and RF output of
the RF connector and see if the value is close to zero. If the RF input is not
connected properly to the RF output, replace the RF connector.
Note: Perform the resistance value test without a RF cable attached to the RF
connector. Because the RF connector is also a switch, the RF output is
disconnected from the RF input when the RF cable is inserted into the RF
connector.
zRF input terminal – connect to duplexer.
zRF output terminal – connect to the antenna pad through antenna match
circuit.
zRF connector terminal – connect to RF coaxial cable.
Figure 5: RF input / output terminal
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