2.3.6. DIGITAL BOARD SECTION
One of most difficult problems to deal with is when the system will not boot up.
The symptom: No response when the power is turned on. (No LCD display, keys are not accepted.)
Note:
1. Electrical continuity may have existed at the factory check, but a faulty contact occurred as a result of vibration, etc.,
during transport.
2. Solder waste remaining on the board may get caught under the IC during transport, causing a short circuit.
Before we begin mass production, several hundred trial units are produced at the plant, various tests are applied and any
malfunctions are analyzed. (In past experiences, digital IC (especially SRAM and ROM) malfunctions are extremely rare after
installation in the product.)
This may be repaired by replacing the IC, (ASIC etc.). However, the real cause may not have been an IC malfunction but a
soldering fault instead.
Soldering faults which are difficult to detect with the naked eye are common, particularly for an ASIC and RA (Resistor Array).
But if you have an oscilloscope, you can easily determine the problem site or IC malfunction by checking the main signal lines.
Even if you don´t have such a measuring instrument, by checking each main signal line and resoldering it, in many cases the
problem will be resolved.
An explanation of the main signals (for booting up the unit) is below.
What are the main signals for booting up the unit?
Please refer to the DIGITAL BLOCK DIAGRAM (P.57).
The ASIC (including the CPU) (IC1) controls all the other digital ICs. When the power is turned on, the ASIC (CPU) retrieves
the operation code stored in the ROM (IC2), then follows the instructions for controlling each IC. All ICs have some inner
registers that are assigned to a certain address.
It is the address bus by which the ASIC (CPU) designates the location inside each IC. And the data bus reads or writes the data
in order to transmit the instructions from the ASIC (CPU) to the ICs.
These signal lines are all controlled by voltages of 5V (H) / 3.3V (H) or 0V (L).
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Страница 3: ...1 1 LCD MESSAGE 1 INTRODUCTION 3 KX FT72BR G ...
Страница 8: ...1 11 TEST CHART 1 11 1 ITU T NO 1 TEST CHART 8 KX FT72BR G ...
Страница 9: ...1 11 2 CCITT NO 2 TEST CHART 9 KX FT72BR G ...
Страница 10: ...1 12 LOCATION OF CONTROLS 1 12 1 OVERVIEW 10 KX FT72BR G ...
Страница 28: ...2 3 4 2 DOCUMENT JAM CROSS REFERENCE SENSOR SECTION P 72 DISASSEMBLY INSTRUCTIONS P 84 28 KX FT72BR G ...
Страница 29: ...2 3 4 3 MULTIPLE FEED CROSS REFERENCE DISASSEMBLY INSTRUCTIONS P 84 29 KX FT72BR G ...
Страница 30: ...2 3 4 4 SKEW CROSS REFERENCE DISASSEMBLY INSTRUCTIONS P 84 30 KX FT72BR G ...
Страница 34: ...CROSS REFERENCE DISASSEMBLY INSTRUCTIONS P 84 34 KX FT72BR G ...
Страница 37: ...2 3 5 1 2 SOMETIMES THERE IS A TRANSMIT PROBLEM CROSS REFERENCE LCD MESSAGE P 3 37 KX FT72BR G ...
Страница 39: ...2 3 5 1 4 THE UNIT CAN COPY BUT CANNOT TRANSMIT RECEIVE 39 KX FT72BR G ...
Страница 45: ...45 KX FT72BR G ...
Страница 46: ...CROSS REFERENCE TEST FUNCTIONS P 82 46 KX FT72BR G ...
Страница 47: ...CROSS REFERENCE TEST FUNCTIONS P 82 47 KX FT72BR G ...
Страница 48: ...48 KX FT72BR G ...
Страница 49: ...CROSS REFERENCE TEST FUNCTIONS P 82 CROSS REFERENCE TEST FUNCTIONS P 82 49 KX FT72BR G ...
Страница 50: ...50 KX FT72BR G ...
Страница 51: ...51 KX FT72BR G ...
Страница 52: ...CROSS REFERENCE TEST FUNCTIONS P 82 52 KX FT72BR G ...
Страница 58: ...58 KX FT72BR G ...
Страница 59: ...Normal Wave Patterns 59 KX FT72BR G ...
Страница 61: ...CROSS REFERENCE NG EXAMPLE P 63 CHECK THE STATUS OF THE DIGITAL BOARD P 64 61 KX FT72BR G ...
Страница 62: ...CROSS REFERENCE CHECK THE STATUS OF THE DIGITAL BOARD P 64 62 KX FT72BR G ...
Страница 63: ...2 3 6 2 NG EXAMPLE 63 KX FT72BR G ...
Страница 66: ...2 3 7 2 DEFECTIVE ITS INTEGRATED TELEPHONE SYSTEM SECTION 66 KX FT72BR G ...
Страница 68: ...2 Troubleshooting Flow Chart 68 KX FT72BR G ...
Страница 69: ...69 KX FT72BR G ...
Страница 73: ...2 3 11 READ SECTION Refer to SCANNING BLOCK P 112 73 KX FT72BR G ...
Страница 79: ...2 4 5 SERVICE MODE SETTINGS Example of a printed out list 79 KX FT72BR G ...
Страница 84: ...3 DISASSEMBLY INSTRUCTIONS 3 1 HOW TO REMOVE THE HANDSET CRADLE CABINET HOOK BUTTON AND SPEAKER 84 KX FT72BR G ...
Страница 85: ...3 2 HOW TO REMOVE THE OPERATION BLOCK 85 KX FT72BR G ...
Страница 86: ...3 3 HOW TO REMOVE THE OPERATION BOARD AND LCD 86 KX FT72BR G ...
Страница 87: ...3 4 HOW TO REMOVE THE BOTTOM FRAME AND ANALOG BOARD 87 KX FT72BR G ...
Страница 88: ...3 5 HOW TO REMOVE THE DIGITAL POWER SUPPLY BOARD AND AC INLET 88 KX FT72BR G ...
Страница 89: ...3 6 HOW TO REMOVE THE MOTOR BLOCK AND SEPARATION ROLLER 89 KX FT72BR G ...
Страница 90: ...3 7 HOW TO REMOVE THE MOTOR AND GEARS OF MOTOR BLOCK 90 KX FT72BR G ...
Страница 91: ...3 8 HOW TO REMOVE THE IMAGE SENSOR CIS 91 KX FT72BR G ...
Страница 92: ...3 9 HOW TO REMOVE THE DOCUMENT FEED ROLLER 92 KX FT72BR G ...
Страница 93: ...3 10 HOW TO REMOVE THE THERMAL HEAD 93 KX FT72BR G ...
Страница 94: ...3 11 INSTALLATION POSITION OF THE LEAD WIRES 94 KX FT72BR G ...
Страница 96: ...4 3 FLAT PACKAGE IC INSTALLATION PROCEDURE 4 4 BRIDGE MODIFICATION PROCEDURE 96 KX FT72BR G ...
Страница 97: ...5 CIRCUIT OPERATIONS 5 1 CONNECTION DIAGRAM 97 KX FT72BR G ...
Страница 99: ...5 2 1 General Block Diagram 99 KX FT72BR G ...
Страница 109: ...5 4 2 BLOCK DIAGRAM 109 KX FT72BR G ...
Страница 111: ...111 KX FT72BR G ...
Страница 117: ...5 4 6 3 4 COPYING CROSS REFERENCE SENSOR SECTION P 72 117 KX FT72BR G ...
Страница 126: ...b Redundancy Compression Process Coding Mode This unit uses one dimensional MH format 126 KX FT72BR G ...
Страница 132: ...5 10 1 CIRCUIT DIAGRAM 132 KX FT72BR G ...
Страница 135: ...5 12 POWER SUPPLY BOARD SECTION 135 KX FT72BR G ...
Страница 137: ...6 TERMINAL GUIDE OF THE ICs TRANSISTORS AND DIODES 137 KX FT72BR G ...
Страница 138: ...7 FIXTURES AND TOOLS 138 KX FT72BR G ...
Страница 139: ...8 CABINET MECHANICAL AND ELECTRICAL PARTS LOCATION 8 1 OPERATION PANEL SECTION 139 KX FT72BR G ...
Страница 140: ...8 2 UPPER CABINET SECTION 140 KX FT72BR G ...
Страница 141: ...8 3 LOWER CABINET P C B SECTION CROSS REFFERENCE MOTOR SECTION P 142 141 KX FT72BR G ...
Страница 142: ...8 4 MOTOR SECTION 142 KX FT72BR G ...
Страница 143: ...8 5 ACTUAL SIZE OF SCREWS 143 KX FT72BR G ...
Страница 144: ...9 ACCESSORIES AND PACKING MATERIALS 144 KX FT72BR G ...
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