Display Fault - Ericsson I 888 Trouble-Shooting Instruction

5 Display fault

5.1 Type of fault.
Start the phone with a fully charged battery using the On/Off-button.
• If the phone doesn´t start, proceed to chapter 3 ("Doesn´t start"-fault).
• If the display missis one or more segments, proceed to section 5.2.
• If the display shows nothing at all, proceed to section 5.3.
5.2 One or more segments are missing.
Open the phone and check for liquid damages. If there are no, change the display
and try again.
5.3 The display shows nothing at all.
Start the phone with a dummy battery and check the current consumption (should be
lower than 200 mA). Open the phone and check for liquid damages or if the display
is mecanically damaged. If there are no damages, replace the elastomer and try
again. If that didn´t make it , change the display and try again. If the current con-
sumption is larger than 200 mA, then proceed to chapter 3 ("Doesn´t start"-fault).
Give the board power and start it up without the display. Measure the voltages on
the display pads H623, Fig 5.1.
7. Not connected
6. I2CDAT
5. VLCD
4. VDLCD
3. GND
2. I2CCLK
1. RESETO
If one or more of the voltages are incorrect, proceed to the corresponding section
below. To see the components placing go to Fig 5.2.
RESETO: If the value is incorrect, measure the resistance between the pad and
D600:77, check also the soldering at the same pin. It should be 0 ohm, if it is con-
siderable larger is there a foil damage and the phone has to be discarded. If the
resistance is correct, replace D600 (class B).
I2CCLK: If the value is incorrect, measure the resistance between the pad and
D600:4. It should be 10 kOhm, if it is larger measure the resistance of R615 (10
kOmh). If R615 is faulty, replace it (class A). If R615 is correct is there a foil dam-
3.2V
-2.7V
3.2V
0V
3.2V
3.2V
Fig 5.1
4-00021-2/FEA 209 544/5.C
I888, Standard Electrical Repairs
H623
7
1
21
(42)