Display/Illumination Problems - Ericsson T28S Troubleshooting Manual

5 Display/illumination problems

5.1 Display
Insert a fully charged battery into the phone and start it up by pressing the On/Off key.
If the phone does not start, go to chapter 3, On/off problems.
If the display is missing one or more segments, go to section 5.1.1.
If nothing shows in the display, go to section 5.1.2.
5.1.1 Segments are missing
Open the phone and check for liquid damage.
Replace the display.
5.1.2 Nothing shows in the display
Open the phone and check for liquid damage.
Replace the display.
If the fault remains, power up the board and start it up.
Measure the voltage at pin 1 of V611 (3.80 ± 0.20 V).
If the voltage is incorrect, measure the resistance of R639 (10 ohms).
If the resistance is incorrect, replace R639.
If the resistance is correct, replace C639.
If the fault remains, send the unit on according to the local company directives.
Measure the voltage at pin 2 of V608 (5.90 - 6.20 V).
If the voltage is incorrect, measure the resistance of C637 (>100 kohms).
If the resistance is too low, replace C637.
If the resistance of C637 is correct, measure the resistance of R610 (0 ohm).
If the resistance of R610 is incorrect, replace R610.
If the resistance of R610 is correct, replace V608 and V611.
If that does not help, replace C635 and C636.
4/00021-2/FEA 209 544/19 E
Trouble Shooting Guide, Standard
17(29)