Display - Ericsson GF 768 Troubleshooting Manual

4/00021-2/FEA 209 544/6 C

3. Display.

3.1 Type of fault.
Insert a fully charged battery into the phone and start it up.
• If it doesn't start, go to chapter 6.
• If the display is missing one or more segments, go to 3.2.
• If the display is totally empty, go to 3.3.
• If the display is completely black (all the segments are "lit" and sometimes you can make out what is dis-
played), go to 3.4.
3.2 Segments are missing.
Open the phone and check for water damage. Replace the display.
3.3 The display is totally empty.
Insert a dummy battery into the phone, start it up and check the current consumption. You can also disassemble
the phone, give the board power, start it up with the display mounted and check the current consumption that way.
• If the phone consumes more than 200mA, make sure the display isn't mechanically damaged. If it isn't,
replace the elastomer and try again. If that doesn't help, replace the display and try again. If the current con-
sumption still is too high, go to chapter 6.
• If the phone consumes less than 200mA, open the phone and check for water damage.
Give the board power and start it up without the display mounted.
The component side of the board is shown in fig. 3.1.
3.3.1 Applies for GF 788/768/788e phones (2/ROA 119 3283/7 and 2/ROA 117 3748/2 boards).
Measure the voltages at the V608 (class A) diode. Compare the result to the values in fig. 3.2.
Fig. 3.1
Troubleshooting guide
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