Ericsson I 888 Trouble-Shooting Instruction
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Ericsson I 888 Trouble-Shooting Instruction

Ericsson I 888 Trouble-Shooting Instruction

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I888, Standard Electrical Repairs
Approved according to 1776-2/FEA 209 544
Trouble-shooting
instruction
I 888
Standard electrical repairs
4-00021-2/FEA 209 544/5.C

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  • Page 1 I888, Standard Electrical Repairs Approved according to 1776-2/FEA 209 544 Trouble-shooting instruction I 888 Standard electrical repairs 4-00021-2/FEA 209 544/5.C...

  • Page 2: Table Of Contents

    I888, Standard Electrical Repairs Table of contents Conditions ..................3 No serv or can´t place call..............6 Doesn´t start..................10 Audio ....................15 Display fault ..................21 Charging fault ................. 24 SIM fault (Insert card) ..............27 Keyboard ..................29 Illumination and buzzer.

  • Page 3: Conditions

    I888, Standard Electrical Repairs 1 Conditions 1.1 Component classifications. After each component, which fault can be verified by the troubel-shooting guides in this folder, is the components classification written. The components are divided in four classes, A,B,C and D. The classes are seperated depending on how much of the phone´s prestanda that is affected by changing the component.
  • Page 4 I888, Standard Electrical Repairs 1.2 Abbreviations used in the trouble-shooting instructions. B: Crystal C: Capacitor D: Digital circuit F: Overload protection H: Buzzer, ligth diodes, pads to the display J: Connection L: Coil N: Analouge circuit R: Resistor U: BALUN. Component that converts a balanced signal to a nonbalanced or the opposit direction.
  • Page 5 I888, Standard Electrical Repairs VBATT: Voltage of the battery. VDIG: Voltage to processor and memories (3.2V). VDSP: Voltage to DSP (Digital Signal Processor) (3.2V). VDSPC: Voltage to DSP (Digital Signal Processor) (2.5V). VLCD: Negative voltage to the display that controlls the contrast (-2.7V). VDLCD: Feed voltage to the display.

  • Page 6: No Serv Or Can´t Place Call

    I888, Standard Electrical Repairs 2 No serv or can´t place call. Find out if the fault is related to Rx(reciever) or Tx(transmitter). Connect the phone (with signaling program) to a GSM test instrument and try to get serv at -68.5 dBm on the input signal. If the phone gets serv proceed to section 2.2. If the phone doesn´t get serv, there is probably a fault in the LO part or too big losses in the signal path.
  • Page 7 I888, Standard Electrical Repairs D105 L403 1 28 N570 L560 D600 B510 N401 N560 VRAD Z201 Z250 VVCO Z500 D103 Z202 Fig 2.2 Measure the voltage on pin 4 and 6 on N303 (Fig 2.1). The voltage on pin 4 (the control voltage) should always vary between 0.8-2.8 V (usually it starts at 1.7 V).
  • Page 8 I888, Standard Electrical Repairs 2.2 Connect a call. To test GSM900,connect a call at power level 5 against the instrument with the input signal at -68.5 dBm. To test GSM1900 use power level 0 and an input signal at -68.5 dBm.
  • Page 9 I888, Standard Electrical Repairs 900) and Z202 (GSM1900)(all at Fig 2.2) plus Z205 (Fig 2.3). If the fault still remains, send the phone to the next repair level. If the Rx level value is above 45 steps at input signal -68,5 dBm you need to cali- brate the phone, therefore send the phone to the next repair level.

  • Page 10: Doesn´t Start

    I888, Standard Electrical Repairs 3 Doesn´t start. Find out if the phone will start by using the On/Off-button. Attach a fully charged battery and press the On/Off-button. If the phone doesn´t start, proceed to section 3.2. If the phone starts as normal when it is complete, but shuts down in the trouble-shooting fixture, measure the current consumption.
  • Page 11 I888, Standard Electrical Repairs 3.2 Visual check. Make an outer visual check. Make sure the battery screws are fine and fully attached, the isolation plate by the battery screw is mounted, the volume buttons are mounted and the system connector isn´t dirty or liquid damaged. Proceed to section 3.3.
  • Page 12 I888, Standard Electrical Repairs replace the corresponding regulator (fig 3.1, all are class A). If the resistance is too low, send the phone to the next repair level. C720 VBATT N706 R719 V702 R720 C720:+ V711 Fig. 3.2 Check the amplitude on the “clock” B510:1 (~1v t-t, class C, fig 3.1). Measure the amplitude using an oscilloscope, spectrum analyzer, frequenzy counter, diode prob...
  • Page 13 I888, Standard Electrical Repairs 3.4.3 Uses more than 200 mA. Open te phone and check for liquid damages. Make sure the system connector pads are not damaged or burned. Attach the board to the fixture. Keep it powered up with DCIO high.
  • Page 14 I888, Standard Electrical Repairs On/Off-button ONSRQ VBATT Fig. 3.3 Give the board power. Make sure VBATT exists one the marked side of the On/Off- button (fig 3.3), if it doesn´t, is there a foil damage and the phone has to be dis- carded.

  • Page 15: Audio

    I888, Standard Electrical Repairs 4 Audio 4.1 Type of fault. Make a call to another phone and check the microphone and the earphone. Connect a handsfree to the phone, make a call and check external microphone and speaker. • If only the earphone on the phone is silence or if the sound comes and goes, pro- ceed to section 4.2.
  • Page 16 I888, Standard Electrical Repairs Check the solderings on N800:24 and 26 (Fig 4.2). If they are good, measure the resistance between the connection J810 and ground and also between the two pegs on the connection. If the resistance to ground is lower than 25 kOhm, then replace C840 and C841(both class A, Fig 4.1).
  • Page 17 I888, Standard Electrical Repairs If the fault remains, check the solderings on N800:13-18(Fig 4.2). If they are good, measure the resistance of C850 (>100 kOhm, class A, Fig 4.2), C851 (>1 kOhm, class A, Fig 4.2), C829 and C830 (>100 kOhm, Both are class A, Fig 4.2) and over C818 and C819 (>100 kOhm, both are class A, Fig 4.2).
  • Page 18 I888, Standard Electrical Repairs 4.4) and R805 (15 kOhm, class A, Fig 4.4). Measure the resistance of C835 (>1 kOhm, class A, Fig 4.4) och C817 (>100 kOhm, class A, Fig 4.4), C810 (>10 kOhm, class A, Fig 4.4) and C812 (>100 kOhm, class A, Fig 4.4). If the fault remains, send the phone to next repair level.
  • Page 19 I888, Standard Electrical Repairs VDSPC is too low, then measure the resistance to ground. If the value is lower than 10 kOhm, then replace, one by one and check the resistance between, C903 (Fig 4.6), C904 (Fig 4.6), C905 (Fig 4.6), R727 (Fig 4.1) and D900 (Fig 4.6), all of them are class A.
  • Page 20 I888, Standard Electrical Repairs voltages are correct then check the solderings on D600 (Fig 4.4), D900 (Fig 4.6) and N800 (Fig 4.2). Measure the resistance of R703 (0 ohm, class A, Fig 4.6) and C850 (>100 kOhm, class A, Fig 4.2), C851 (>1 kOhm, class A, Fig 4.2). If the fault remains, send the phone to next repair leve.

  • Page 21: Display Fault

    I888, Standard Electrical Repairs 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. •...
  • Page 22 I888, Standard Electrical Repairs age and the phone has to be discarded. Check VDIG on R620 (2,2 kOhm, class A), if it is lower than 3,2 volt proceed to chapter 3 (“Doesn´t start”-fault). If the things above are correct replace D600 (class B). Is ground and should be 0 volt.(Measure the resistance to another ground point.) VDLCD: If the value is incorrect, measure the resistance between the pad and D600:45, it should be 0 Ohm.
  • Page 23 I888, Standard Electrical Repairs N702:5 R619 R620 D600 R808 C824 R807 C633 V608 C632 R639 C636 C634 R616 V611 R615 C631 C615 R614 C674 Fig 5.2 (42) 4-00021-2/FEA 209 544/5.C...

  • Page 24: Charging Fault

    I888, Standard Electrical Repairs 6 Charging fault 6.1 Type of charging fault. Do a visual check of the battery screws and the system connector. Change if neces- sary. Start the phone with the On/Off-button and a fully charged battery. • If it doesn´t start, proceed to chapter 3 (“doesn´t start”-fault). •...
  • Page 25 I888, Standard Electrical Repairs DCIO V704 VBATT N450 Fig 6.1 Check the feed voltages VDIG (3.2 V) on the side that is marked of C600 (Fig 6.2) and VRAD (3.8 V) on N450:13 (Fig 6.1) and measure the resistance of R703 (class A, 0 Ohm, Fig 6.2).
  • Page 26 I888, Standard Electrical Repairs After every repair of the charging function, you have to verify the function using the method mentioned in section 6.1.1. If the fault still remains, send the phone to the next repair level. 6.4 The phone starts, but doesn´t charge, even though it shows charging.

  • Page 27: Sim Fault (Insert Card)

    I888, Standard Electrical Repairs 7 SIM fault (Insert card) 7.1 What is a SIM fault? Attach a fully charged battery and a SIM card to the phone. • If the phone shows “Wrong card” or “Insert correct card” when started, then the phone is SIM locked and can´t be repaired at this repair level.
  • Page 28 I888, Standard Electrical Repairs D600 R684 R680 R686 D602 8 14 C626 R618 C625 C627 C630 C628 R600 C629 R627 R617 R628 C638 Fig. 7.2 Measure the resistance of R600 - 33 Ohm, R617 - 15 kOhm, R627 - 33 Ohm, R628 - 33 Ohm, R680 - 15 kOhm and R684 - 33 Ohm.

  • Page 29: Keyboard

    I888, Standard Electrical Repairs 8 Keyboard 8.1 Type of keyboard fault. Put in a Sim card and a fully charged battery. Start the phone with the On/Off but- ton. If it doesn´t start, proceed to chapter 3 (“Doesn´t start”-fault). Press all buttons (remember the volume buttons) and verify which doesn´t work.
  • Page 30 I888, Standard Electrical Repairs 8.3 Flip fault. Make sure that the little plastic “spike” that pushes the little button just below 0 and # isn´t broken. If it is broken, change the flip and try again. If the fault remains, open the fault and check for liquid damages, especially around the little button men- tioned above (Fig 8.4).
  • Page 31 I888, Standard Electrical Repairs Row 1 D600:125 Row 2 D600:124 Flip X820 Row 3 D600:123 Row 4 D600:122 Row 5 D600:120 > < VBATT column 1 D600:126 column 2 D600:127 column 3 D600:1 ONSRQ column 4 D600:128 Fig 8.3 Make sure there is a voltage (3.2 V) on the faulty keyboard pads according to Fig 8.4 below.
  • Page 32 I888, Standard Electrical Repairs If the voltage is missing on a part of a row, e.g on button 2 and 3 but not on button 1, is there a foil damage and the board has to be discarded. Verify by measuring the resistance between a working pad and a faulty pad.

  • Page 33: Illumination And Buzzer

    I888, Standard Electrical Repairs 9 Illumination and buzzer. 9.1 Type of fault. Attach a dummy battery and a sim-card to the phone, press the On/Off-button and wait until the phone has got serv. (Against an instrument or a real network). •...
  • Page 34 I888, Standard Electrical Repairs R606 V606 V606:1 C620 H600:3 VBATT H600 C619 Fig. 9.1 If the resistance is incorrect, then replace R651 (class A, Fig 9.2). Didn´t that make it there is a foil damage and the phone has to be discarded. Measure the resistance from V606:1 to ground, if the resistance is lower than 2 MOhm then replace C653 (class A, Fig 9.2).
  • Page 35 I888, Standard Electrical Repairs Give the phone power and start it up. If only a few, but not all, LEDs in a group, H651-H654 (display light) or H655-H660 (keyboard illumination), are not lit replace them. If H655 and H656 are not lit, measure the resistance of R659 (33 Ohm, class A, Fig 9.3).
  • Page 36 I888, Standard Electrical Repairs 9.4 Green top indicator doesn´t work. Open the phone and check for liquid damages. Make sure the double LED H650 (class A, Fig 9.4) is correctly soldered. C655 C654 H650:3 R646 H650:1 C621 H650 H650:2 Fig. 9.4 If the soldering is fine, give the phone power and start it up.
  • Page 37 I888, Standard Electrical Repairs damage (the value is larger than 0 Ohm) the phone has to be discarded. Otherwise replace D600 (class B). If the fault still remains, send the phone to the next repair level. 9.5 Red top indicator doesn´t work. Open the phone and check for liquid damages.

  • Page 38: Rtc (Real Time Clock)

    I888, Standard Electrical Repairs 10 RTC (Real Time Clock) 10.1 Find out what kind of fault it is. Start the phone with a Sim card and a fully charged battery. Set the clock for correct time. Remove the battery and connect it again after one minute. •...
  • Page 39 I888, Standard Electrical Repairs C690 B600 C691 D600 Fig. 10.2 (42) 4-00021-2/FEA 209 544/5.C...

  • Page 40: Irda Fault

    I888, Standard Electrical Repairs 11 IRDA fault. 11.1 Type of fault. • If it is short range of the IRDA transmission, proceed to section 11.2. • If the IRDA communication doesn´t work, proceed to section 11.3. 11.2 Short range. Open the phone and check for liquid damages. Make sure the window in the front cover is clean.
  • Page 41 I888, Standard Electrical Repairs R653 R670 J604 D600 L601/R690 C623 Fig. 11.3 Check the solderings on J604 (class A, Fig 11.3) and the connection pins for dam- ages. If the solderings and the pins are fine, replace H661 (class A, Fig 11.1). If that didn´t make it, replace C683 (class A, Fig 11.1).

  • Page 42: Component List

    I888, Standard Electrical Repairs 12 Component list Component list in document 131 22-2/fea 209 544/5 (42) 4-00021-2/FEA 209 544/5.C...

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