Схема сотового телефона Other ERICSSON GF 788/768/788e

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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.
Ground for analogue signals.
DC voltage used for charging the battery through the system connector.
Logical signal from the processor that keeps the phone running after you've released the On/Offkey.
Input signal at the system connector that the processor uses to determine if there's any externalaudio equipment attached.
EXTAUDI: The same signal as the EXTAUD signal but at the processor side.GND:
Logical signal used to activate the background illumination.
Voltage from the On/Off key that starts the phone.
Input signal at the system connector that the processor uses to determine if there's any handsfreeequipment attached.
The same signal as PORTHF but at the processor side.
Logical signal that activates the voltage regulators.
Real time clock. The clock that keeps track of time and date.
Clock signal from the processor used for communications with the SIM.
Data signal from the processor used for communications with the SIM.
Reset signal from the processor used for communications with the SIM.
Feed voltage for the SIM.
Switched VBATT.
DC voltage for the analogue part of the logic (N800).
Battery voltage.
DC voltage for the processor and memory.
DC voltage for the DSP (Digital Signal Processor).
DC voltage for the display that controls the contrast.
DC voltage for the radio part except the synthesizer.
DC voltage for the radio part in D600 (also used for the top diode and the buzzer).
DC voltage for the real time clock.
VSIMPAD: VDIG voltage that has been switched up to 5V used for SIM.VVCO:
DC voltage for the synthesizer.
Two line serial communications standard using one clock and one data line.
Local oscillator.
Pulse width modulation.