Ericsson GF 768 Troubleshooting Manual page 9

4/00021-2/FEA 209 544/6 C
• If the resistance is high all the time, replace the corresponding microswitch.
• If the resistance is low all the time, replace the corresponding microswitch. If that doesn't help, check the sol-
derings at D600 pads 1, 123, 124 and 128. If the solderings are correct, replace D600 (class B, fig. 2.3).
• If the switches work, replace the volume buttons and try again.
• If that doesn't help, check the solderings at D600 pads 1, 123, 124 and 128. If the solderings are correct,
replace D600 (class B, fig. 2.3).
2.3 One or more keys non-functional.
Open the phone and check for water damage. Remove the dome foil and check for water damage and mechanical
damage, especially at the non-functional keys.
Clean the key pads thoroughly. Mount a new dome foil and check the keyboard for damages. Assemble the phone
and check the kayboard function as described in 2.1.
If that doesn't help, open the phone, give it power and start it up (using the On/Off key or by setting DCIO high).
Functional schematics are shown in fig. 2.4.
Fig. 2.2
Fig. 2.3
Troubleshooting guide
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