Ericsson GF786, GF788, GF788E free download

File name ERICSSON GF786, GF788, GF788E.PDF

4/00021-2/FEA 209 544/6 C Troubleshooting guide Troubleshooting guide. GF 788/768/788e Standard. Contents page Component Classes 2 Abbreviations 3 Pin placements 4 1. RTC 6 2. Keyboard 8 3. Display 13 4. Charging 18 5. Illumination and buzzer 23 6. Doesn't start 28 7. SIM fault 37 8. No serv 41 9. Audio 45 10. Spare part list 53 1 Troubleshooting guide 4/00021-2/FEA 209 544/6 C Component classes. All the components in the phone are divided into classes and after every component in the troubleshooting guide you have a class written. The components are divided into four classes: A, B, C and D.The class of the component depends on how much of the phone's performance is affected when replacing it. Class A and B: A test call towards the "real" net (not only towards a GSM test instrument) and run it through the normal tests is enough to verify the functionality since the performance of the phone is only slightly affected. Class C: Since the tolerances of the component are so great it can substantially affect the performance of the phone you need to calibrate it at station level after replacing the component. Class D: Class D components need to be calibrated at board level using very advanced equipment and may therefore not be replaced. 2 4/00021-2/FEA 209 544/6 C Troubleshooting guide Abbreviations. A: The power module at some phones. B: Crystal. C: Capacitor. D: Digital circuit. F: Over voltage protection. G: VCO. H: Buzzer, LED, pads for display. J: Connector. L: Coil. N: Analogue circuit. R: Resistor. S: Keyboard pads. U: BALUN. A circuit that converts a signal from balanced to unbalanced or the opposite. V: Transistor or diode. X: Contact surface at the circuit board. Z: Filter. AGND: Ground for analogue signals. DCIO: DC voltage used for charging the battery through the syste