Nokia Customer Care 6255/6255i/6256/6256i (RM-19) Mobile Terminal Antenna Description and Troubleshooting Issue 2 05/2005 Company Confidential ©2005 Nokia Corporation
6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care Contents Page Introduction ..................................................................................................................................................... 3 Whip Antenna .............................................................................................................................................. 3 Failures and Corrective Measures ................................................
6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care Introduction This troubleshooting guide addresses potential failures that affect antenna performance of the 6255/6255i/6256/6256i, and discusses methods for correction of these failures. Whip Antenna Check the following minimum visual quality standards of the whip assembly: • No physical cracks or mechanical defects. • No excess oil, dirt, or particles appear on the parts.
6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care In addition, the connector area includes the NMP code, date code, and supplier information. Figure 2: NMP code, date code, and supplier information area The whip antenna is shipped fully retracted with the telescopic section fully collapsed. The feed contact must appear at a 45-degree angle and must be free from damage, deformation, or unusual bending. The straw must be approximately 5.
6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care Failures and Corrective Measures Figure 3: Whip retracted and whip extended Note in Figure 3 that when the whip is properly installed, the cap clicks into the antenna tower when the whip is fully retracted. When fully extended, the length from the end of antenna tower to the top of the cap must be around 109mm. Damaged Whips Figure 4 shows what the whip must look like when it is retracted and extended.
255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care Antenna Position into D-cover The internal antenna and whip are assembled into the D-cover as shown in Figure 5. If no internal antenna is installed, the antenna gain will be degraded by more than 25 dB. Whip antenna Figure 5: D-cover assembly • If the whip antenna is missing, install one. • If any part of the whip/stub antenna looks obviously damaged, then replace the whip/stub antenna.
Nokia Customer Care 6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Matching circuit RF feed pad Figure 7: PWB layout of the RF feed pad and the matching circuit The matching circuit is right next to the RF feed pad. The matching circuit consists of a shunt inductor of 27nH, a series cap of 1.2pF, and a series inductor of 5.6nH.
6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care Bottom clip Bottom matching circuit Figure 8: Bottom antenna clip and matching circuit • If the antenna clip is installed backwards, is damaged, or is missing, install a new bottom antenna clip in the correct position.
6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care GPS Antenna The GPS antenna is a ceramic chip soldered on the PWB. It has a matching circuit of series 0R and a shunt inductor of 2.7nH. GPS antenna Matching circuit Figure 10: Position of the GPS antenna on the PWB • If the GPS antenna looks obviously damaged, replace it. • If the GPS antenna is not present, install one.
6255/6255i/6256/6256i (RM-19) Antenna Description and Troubleshooting Nokia Customer Care Bluetooth Antenna The bluetooth (BT) antenna is an inverted F antenna (IFA) printed on PWB. Figure 12: BT antenna on the PWB Perform a visual inspection of the BT antenna to ensure that the edge plating is not corroded, faulty, or peeling.
