Page 1
CC Technical Documentation
RM-11 Series Transceivers
Troubleshooting - Antennas
Issue 1 02/2004 Confidential ©2004 Nokia Corporation
Page 2
RM-11
Troubleshooting - Antennas CC Technical Documentation
Contents Page
Troubleshooting - Antennas........................................................................................... 3
Failures and Corrective Measures ...............................................................................3
Missing Internal Antenna Cap .....................................................................................4
Missing Antenna Radiator......................................................................................... 4
Missing GPS Antenna, Damaged GPS Feed/Ground Pin, or Damaged Heat Stake. 5
RF Feed Pin/Ground Pin, IHF Speaker Pins in C-cover Missing or Damaged ........ 5
Obstructed RF Feed/Ground Pads, GPS Feed/Ground Pads, IHF Speaker Pads...... 6
CDMA or GPS RF Connector Failure ...................................................................... 7
Display Assembly ..................................................................................................... 8
Missing or Damaged Baseband Shield.................................................................... 10
Page 2 ©2004 Nokia Corporation Confidential Issue 1 02/2004
Page 3
RM-11
CC Technical Documenta t ion Trou bl esh oo ti ng - Ant ennas
Troubleshooting - Antennas
This troubleshooting guide addresses potential failures that can affect the antenna
performance of the RM-11 phone, and discusses methods for correction of these failures.
Failures and Corrective Measures
Figure 1: RM-11 phone, front and back view
Issue 1 02/2004 ©2004 Nokia Corporation Confidential Page 3
Page 4
RM-11
Troubleshooting - Antennas CC Technical Documentation
Missing Internal Antenna Cap
Internal
antenna
Antenna cap
is missing
Figure 2: RM-11 phone with a missing internal antenna cap
Missing Antenna Radiator
Antenna
radiator
Antenna
slot
Antenna
cap
Figure 3: RM-11 phone with a missing antenna radiator
If the antenna cap is missing or if there is a cap without a radiator, install a new antenna
cap with a radiator. If the radiator looks obviously damaged (i.e., dents or corrosion) or
the slot in the radiator has a significantly different shape, then install a new antenna cap
with the correct radiator.
If no antenna or no radiator is installed, the antenna gain will be degraded by more than
25 dB.
Page 4 ©2004 Nokia Corporation Confidential Issue 1 02/2004
Page 5
RM-11
CC Technical Documenta t ion Trou bl esh oo ti ng - Ant ennas
Missing GPS Antenna, Damaged GPS Feed/Ground Pin, or Damaged Heat Stake
GPS ground pin
GPS antenna
Heat stake of
GPS antenna
Figure 4: Back view of RM-11 (3205) C-cover with GPS antenna assembled
The RM-11 GPS antenna is heat-staked to the C-cover. If any of the following events
occurs, replace the entire C-cover assembly:
• GPS antenna is missing
• GPS antenna looks obviously damaged
• Any of the three heat stakes appears damaged; the GPS antenna will be loose
• Any of the three heat stakes are over-heated and the GPS antenna melts into the
C-cover; the antenna will look distorted and bent
• Either the GPS antenna feed or the ground leg is broken or bent so that neither
pin touches the PWB.
RF Feed Pin/Ground Pin, IHF Speaker Pins in C-cover Missing or Damaged
GPS feed pin
GPS antenna
IHF speaker
pogo pins
RF ground
pogo pin
RF feed pogo
pin
Figure 5: Inside view of the C-cover
Issue 1 02/2004 ©2004 Nokia Corporation Confidential Page 5
Page 6
RM-11
Troubleshooting - Antennas CC Technical Documentation
Two pogo pins are inserted in the C-cover. One end of the pogo pin touches the antenna,
the other end touches the pad on the PWB (see Figure 5). If either of the pogo pins is
missing or obviously damaged (i.e., stuck in the C-cover plastic tube, loose the inside
spring force), the antenna will lose the contact to the PWB. In this case, replace the
C-cover assembly with a new one.
If the RF feed does not touch the PWB, then the antenna gain will degrade by more than
25 dB. If the ground pin does not touch the PWB, then the antenna gain may degrade
about 5 to 10 dB.
If either of the IHF speaker pins is damaged or missing, the speaker will not connect to
the PWB and the antenna PCS gain will drop 2 dB. If this happens, replace the C-cover.
Obstructed RF Feed/Ground Pads, GPS Feed/Ground Pads, IHF Speaker Pads
GPS feed pad
GPS RF
connector
GPS ground pad
IHF speaker
pads
Internal
ground pad
Internal feed
pad
CDMA RF connector
Figure 6: Obstructed RF feed and ground pads, GPS feed/ground pads, and IHF speaker pads
If the RF feed pad is obstructed, removed, or covered, then the internal antenna feed
pogo 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, then the ground pogo pin will not
touch the PWB and the antenna gain will degrade by more than 5 dB. If corrosion is
present or the pad is missing, replace the PWB and phone. If either pad is obstructed or
covered, then clear or clean the pad.
If the GPS feed pad is obstructed, removed, or covered, then the GPS antenna feed leg
will not touch the PWB. If the ground pad is obstructed, removed, or covered, then the
ground spring clip will not touch the PWB.
Page 6 ©2004 Nokia Corporation Confidential Issue 1 02/2004
Page 7
RM-11
CC Technical Documenta t ion Trou bl esh oo ti ng - Ant ennas
If the Internal Hands Free (IHF) speaker pads are obstructed, removed, or covered, then
the IHF speaker will not produce sound. The antenna PCS gain will be degraded by about
2 dB. If corrosion is present or the pad is missing, replace the PWB and phone. If either
pad is obstructed or covered, clear or clean the pad.
CDMA or GPS RF Connector Failure
CDMA and GPS use the same type of RF connector. The RF connector could fail by not
connecting the RF input to the RF output of the RF connector. If this happens to the
CDMA RF connector, then the antenna gain will degrade by about 25 dB. If this happens
to the GPS RF connector, the GPS antenna gain will degrade by about 20 dB. Test for DC
conductivity between the RF input and RF output of the RF connector.
Perform the DC conductivity test without any cable attached to the RF connector.
Because the RF connector is also a switch, the RF output will be disconnected from the
RF input when a cable is inserted into the RF connector. When a cable is not inserted, the
RF input is connected to the RF connector. The locations of both RF connectors are
shown in Figure 6.
• CDMA RF input — Connects to the duplexer
• CDMA RF output — Connects to the antenna pad through vias
• GPS RF input — Connects to the GPS ceramic filter output
• GPS RF output — Connects to the GPS antenna matching circuits
• RF connector — Connects to the coaxial cable
If the RF input is not connected properly to the RF output, replace the RF connector.
Issue 1 02/2004 ©2004 Nokia Corporation Confidential Page 7
Page 8
RM-11
Troubleshooting - Antennas CC Technical Documentation
Display Assembly
Grounded position
Display frame
plated area
Display frame
Display shield
Figure 7: RM-11 display assembly (top) and side view (bottom)
First, the display shield is connected to the display frame plated area (screw boss area),
and then to the PWB through the two top screws. The grounding of the display shield
and frame impact the radiation performance of the phone. If the screws are loose,
tighten them. If the screw bosses are stripped, replace the chassis. If the screws are
missing, install new ones.
If the plated area of the display frame is cracked or the metal plating is peeled off, then
the grounding of the display shield and frame will not be guaranteed. If this is the case,
replace the frame.
Page 8 ©2004 Nokia Corporation Confidential Issue 1 02/2004
Page 9
RM-11
CC Technical Documenta t ion Trou bl esh oo ti ng - Ant ennas
Wrong Display Assembly Installed
RM-11 display shield
RH-34 display shield
Figure 8: Side view of RH-34 and RM-11 display assembly
No plating
RM-11 display
frame plating
RH-34 display
frame plating
Figure 9: Back view of RH-34 and RM-11 display assembly
The RH-34 (6585) and RM-11 (3205) display assemblies are very similar. However, the
side of the RM-11 display shield is different than the side of the RH-34 display shield
(see Figure 8). In addition, the metal plating at the top area of the RM-11 frame is
different from the top of the RH-34 frame (see Figure 9). For the RH-34 frame, the screw
boss area is plated but isolated from the rest of the frame, and also there is no plating in
the top area. For the RM-11 frame, the whole top area is fully plated.
If the wrong display shield or frame is installed, replace it with a correct one.
Issue 1 02/2004 ©2004 Nokia Corporation Confidential Page 9
Page 10
RM-11
Troubleshooting - Antennas CC Technical Documentation
Missing or Damaged Baseband Shield
RM-11
baseband
shield
RM-11
without
baseband
shield
Figure 10: Baseband shield for the RM-11
The baseband shield is part of the display assembly. If the baseband shield is missing or is
obviously damaged, the radiated phone performance will be impacted. Check the spring
fingers on the baseband shield to ensure that they are raised up so that they make
contact with the PWB when installed. If damaged, install a new baseband shield.
Page 10 ©2004 Nokia Corporation Confidential Issue 1 02/2004
Loading...