Nokia RH-57 Series Operating instructions

Nokia Customer Care
2112 (RH-57) Series Transceivers
Issue 1 07/2004 Company Confidential ©2004 Nokia Corporation
Troubleshooting — Antenna

2112 (RH-57)
Troubleshooting — Antenna Nokia Customer Care
Page 2 ©2004 Nokia Corporation Company Confidential Issue 1 07/2004
Contents Page
Introduction ..................................................................................................................................................... 3
Internal Antenna is Missing .....................................................................................................................3
Damaged RF Feed Pin or Ground Pin .....................................................................................................4
Wrong Internal Antenna is Installed ......................................................................................................4
Obstructed RF Feed or Ground Pads for Internal Antenna or IHF Speaker Pads .......................5
Grounding of Display Frame .....................................................................................................................6
RUIM Card Flap Grounding .......................................................................................................................7
RF Connector Failure ..................................................................................................................................7

Nokia Customer Care Troubleshooting — Antenna
2112 (RH-57)
Issue 1 07/2004 ©2004 Nokia Corporation Company Confidential Page 3
Introduction
This troubleshooting guide addresses potential failures that can affect antenna
performance of the 2112 phone, and discusses methods for correction of these failures.
Figure 1: Model 2112 front and back view
Internal Antenna is Missing
Figure 2: Model 2112 chassis assembly
RF feed
IHF speaker
pins
Ground pin
RF shield

2112 (RH-57)
Troubleshooting — Antenna Nokia Customer Care
Page 4 ©2004 Nokia Corporation Company Confidential Issue 1 07/2004
If no internal antenna is installed, the antenna gain is degraded by more than 25 dB.
• If the internal antenna is missing, install a new one.
• If the radiator looks obviously damaged, replace the internal antenna.
Damaged RF Feed Pin or Ground Pin
Figure 3: Top (left) and bottom (right) views of the 2112 (RH-57) internal antenna
If the RF feed does not touch the PWB, then the antenna gain will degrade by more than
25dB. If the ground pin does not touch the PWB, then the antenna gain may degrade
from 5—10 dB.
Replace the internal antenna if any of the following situations apply:
• Either the RF feed pin or ground pin are broken or bent such that either pin will
not touch the PWB
• The springs for the RF or ground pin appear damaged
• The slot in the radiator has a significantly different shape
• Obvious damage to the radiator (e.g., dents, corrosion)
• The pin is stuck or has excessive friction in the plastic tube/guiding feature
resulting in the spring not working properly
• Either of the IHF speaker pins is damaged or if the IHF speaker is nonfunctioning
Wrong Internal Antenna is Installed
Figure 4: Top views of the 3100 (RH-19) (left) and 2112 (RH-57) (right) antennas
The 2112 and 3100 antennas are similar in appearance. The important visual difference in
the antennas is that the slot pattern is very different. Also, the 2112 antenna is thicker
than the 3100 antenna and also has a spacer on its back side.
IHF speaker
pins
RF pin Ground pin
Spacer
IHF speaker
port Ground pin RF pin
Radiator

Nokia Customer Care Troubleshooting — Antenna
2112 (RH-57)
Issue 1 07/2004 ©2004 Nokia Corporation Company Confidential Page 5
If the wrong antenna is installed, install the correct one.
Figure 5: Bottom views of 3100 (left) and 2112 (right) antennas
Obstructed RF Feed or Ground Pads for Internal Antenna or IHF Speaker Pads
Figure 6: PWB layout of RF feed and ground pads and IHF speaker pads
If the RF feed pad is obstructed, removed, or covered, the RF feed pin will not touch the
PWB and the antenna gain will degrade by more than 25 dB. If the ground pad is
obstructed, removed, or covered, the ground pin will not touch the PWB and the antenna
gain may degrade by about 5—10 dB.
• If corrosion is present or the pad is missing, replace the PWB and the phone.
• If either pad is obstructed or covered, clear or clean the pad.
If the Internal Hands Free (IHF) speaker pads are obstructed, removed, or covered, the IHF
speaker will not produce sound.
• If corrosion is present or the pad is missing, replace the the PWB and the phone.
• If either pad is obstructed or covered, clear or clean the pad.
Pad for ground pin Pad for RF pin
IHF speaker pads

2112 (RH-57)
Troubleshooting — Antenna Nokia Customer Care
Page 6 ©2004 Nokia Corporation Company Confidential Issue 1 07/2004
Grounding of Display Frame
Figure 7: Display assembly
Note that the display frame is grounded to the PWB through the two top screws. The
grounding of the display frame impacts the radiation performance of the phone.
• If the screws are loose, then tighten them.
• If the screw bosses are stripped, replace the chassis.
• If the screws are missing, install new ones.
The middle screws should not touch the metal in the LCD frame, the metal shield over
the keypad, the PWB, or the RF shield. When driving in these screws, be sure to drive
them in straight. If the screws are driven in at an angle, it is much more likely that the
screws will touch the PWB or the RF shield. If the screws touch, the antenna
performance could change by about 1 dB.
Ungrounded screw
Ungrounded screw
Grounded screw
Grounded screw
RF connector

Nokia Customer Care Troubleshooting — Antenna
2112 (RH-57)
Issue 1 07/2004 ©2004 Nokia Corporation Company Confidential Page 7
RUIM Card Flap Grounding
Figure 8: Conductive sticker grounding RUIM card flap to RF shield
The RUIM card flap needs to be grounded to the RF shield with a conductive sticker
(see Figure 8). If the sticker is damaged or missing, then the radiated sensitivity could be
reduced by 4—8 dB.
• If the conductive sticker is missing or ripped, replace the sticker.
If the RF shield needs to be disassembled from the chassis, the sticker may be damaged
because the sticker needs to be removed to change the antenna module or the RUIM
card flap.
• If you replace the RUIM card flap or RF shield, replace the type labels and
conductive sticker.
• You may need to replace the RF shield and all the labels because the conductive
sticker is located underneath other labels.
RF Connector Failure
The RF connector could fail by not connecting the RF input to the RF output of the RF
connector. If this happens, the antenna gain will degrade by about 25 dB. Check for this
by testing for DC conductivity between the RF input and RF output of the RF connector.
Note that the DC conductivity test must be done without any cables attached to the RF
connector. Because the RF connector is also a switch, the RF output is disconnected from
the RF input when a cable is inserted into the RF connector. When a cable is inserted, the
RF input is connected to the RF connector.
• RF input — connector to a duplexor
• RF output — connects to the antenna pad through vias
• RF connector — connects to a coaxial cable
If the RF input is not connected properly to the RF output, replace the RF connector.
Conductive sticker
RF shield
RUIM card flap

2112 (RH-57)
Troubleshooting — Antenna Nokia Customer Care
Page 8 ©2004 Nokia Corporation Company Confidential Issue 1 07/2004
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