6.6.7. DIGITAL BOARD SECTION
When the unit fails to boot up the system, take the troubleshooting procedures very carefully. It may have a serious problem.
The symptom: No response when the power is turned on. (No LCD display, and keys are not accepted.)
The first step is to check the power source. If there is no problem with the power supply unit, the problem may lie in the digital
unit (main board).
As there are many potential causes in this case (ASIC, DRAM, etc.), it may be difficult to specify what you should check first.
If a mistake is made in the order of checks, a normal part may be determined faulty, wasting both time and money.
Although the tendency is to regard the problem as a serious one (IC malfunction, etc.), usually most cases are caused by solder
faults (poor contact due to a tunnel in the solder, signal short circuit due to solder waste).
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 DRAM and FLASH ROM) malfunctions are extremely rare
after installation in the product.)
This may be repaired by replacing the IC, (DRAM etc.). However, the real cause may not have been an IC malfunction but a
soldering fault instead.
Soldering faults difficult to detect with the naked eye are common, particularly for 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 presented below.
Don’t replace ICs or stop repairing until checking the signal lines.
An IC malfunction rarely occurs. (By understanding the necessary signals for booting up the unit, the “Not Boot up”
display is not a serious problem.)
What are the main signals for booting up the unit?
The ASIC (IC501) controls all the other digital ICs. When the power is turned on, the ASIC retrieves the operation code stored
in the FLASH ROM (IC523), 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 designates the location inside each IC. And the data bus reads or writes the data in
order to transmit the instructions from the ASIC to the ICs.
These signal lines are all controlled by voltages of 3.3V (H) or 0V (L).
Between the DRAM (IC503), Gate Array IC (IC520) signal lines are controlled by voltages of 5V (H) or 0V (L).
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KX-FP342BX
Summary of Contents for KX-FP342BX
Page 21: ...4 1 2 COMPONENT LOCATIONS 21 KX FP342BX ...
Page 33: ...5 2 2 HOW TO REMOVE THE OPERATION PANEL BLOCK 33 KX FP342BX ...
Page 34: ...5 2 3 HOW TO REMOVE THE OPERATION BOARD AND LCD 34 KX FP342BX ...
Page 35: ...5 2 4 HOW TO REMOVE THE IMAGE SENSOR CIS 35 KX FP342BX ...
Page 36: ...5 2 5 HOW TO REMOVE THE THERMAL HEAD 36 KX FP342BX ...
Page 37: ...5 2 6 HOW TO REMOVE THE PLATEN ROLLER AND BACK COVER 37 KX FP342BX ...
Page 38: ...5 2 7 HOW TO REMOVE THE PICKUP ROLLER 38 KX FP342BX ...
Page 39: ...5 2 8 HOW TO REMOVE THE CASSETTE LEVER 39 KX FP342BX ...
Page 40: ...5 2 9 HOW TO REMOVE THE BOTTOM FRAME 40 KX FP342BX ...
Page 41: ...5 2 10 HOW TO REMOVE THE DIGITAL ANALOG POWER SUPPLY SENSOR BOARDS AND AC INLET 41 KX FP342BX ...
Page 42: ...5 2 11 HOW TO REMOVE THE MOTOR BLOCK AND SEPARATION ROLLER 42 KX FP342BX ...
Page 43: ...5 2 12 HOW TO REMOVE THE GEARS OF MOTOR BLOCK 43 KX FP342BX ...
Page 44: ...5 3 INSTALLATION POSITION OF THE LEAD WIRES 44 KX FP342BX ...
Page 57: ...6 5 2 SREVICE MODE SETTINGS Note The above values are the default values 57 KX FP342BX ...
Page 71: ...71 KX FP342BX ...
Page 85: ...85 KX FP342BX ...
Page 86: ...CROSS REFERENCE TEST FUNCTIONS P 50 86 KX FP342BX ...
Page 87: ...CROSS REFERENCE TEST FUNCTIONS P 50 87 KX FP342BX ...
Page 88: ...CROSS REFERENCE TEST FUNCTIONS P 50 88 KX FP342BX ...
Page 89: ...CROSS REFERENCE TEST FUNCTIONS P 50 89 KX FP342BX ...
Page 90: ...90 KX FP342BX ...
Page 91: ...91 KX FP342BX ...
Page 92: ...CROSS REFERENCE TEST FUNCTIONS P 50 92 KX FP342BX ...
Page 96: ...96 KX FP342BX ...
Page 100: ...I O and Pin No Diagram 100 KX FP342BX ...
Page 104: ...6 6 7 3 NG EXAMPLE 104 KX FP342BX ...
Page 109: ...6 6 9 2 TROUBLESHOOTING FLOW CHART 109 KX FP342BX ...
Page 115: ...6 6 13 THERMAL HEAD SECTION Refer to THERMAL HEAD P 129 115 KX FP342BX ...
Page 116: ...7 CIRCUIT OPERATIONS 7 1 CONNECTION DIAGRAM 116 KX FP342BX ...
Page 118: ...7 2 1 GENERAL BLOCK DIAGRAM 118 KX FP342BX ...
Page 120: ...7 3 2 MEMORY MAP 120 KX FP342BX ...
Page 128: ...7 4 2 BLOCK DIAGRAM 128 KX FP342BX ...
Page 131: ...TIMING CHART i Print Duty 50 or less ii Print Duty more than 50 131 KX FP342BX ...
Page 150: ...150 KX FP342BX ...
Page 159: ...8 REFERENCE MATERIAL DATA 8 1 TERMINAL GUIDE OF THE ICs TRANSISTORS AND DIODES 159 KX FP342BX ...
Page 162: ...8 3 TEST CHART 8 3 1 ITU T No 1 TEST CHART 162 KX FP342BX ...
Page 163: ...8 3 2 ITU T No 2 TEST CHART 163 KX FP342BX ...
Page 164: ...9 FIXTURES AND TOOLS 164 KX FP342BX ...
Page 165: ...10 CABINET MECHANICAL AND ELECTRICAL PARTS LOCATION 10 1 GENERAL SECTION 165 KX FP342BX ...
Page 166: ...10 2 OPERATION PANEL SECTION 166 KX FP342BX ...
Page 167: ...10 3 BACK COVER SECTION 167 KX FP342BX ...
Page 168: ...168 KX FP342BX ...
Page 169: ...10 4 UPPER CABINET SECTION 169 KX FP342BX ...
Page 170: ...10 5 LOWER CABINET P C BOARD SECTION CROSS REFERENCE MOTOR SECTION P 171 170 KX FP342BX ...
Page 171: ...10 6 MOTOR SECTION 10 7 ACTUAL SIZE OF SCREWS 171 KX FP342BX ...
Page 172: ...11 ACCESSORIES AND PACKING MATERIALS 172 KX FP342BX ...
Page 180: ...8 REFERENCE MATERIAL DATA 8 1 TERMINAL GUIDE OF THE ICs TRANSISTORS AND DIODES 159 KX FP342BX ...
Page 183: ...8 3 TEST CHART 8 3 1 ITU T No 1 TEST CHART 162 KX FP342BX ...
Page 184: ...8 3 2 ITU T No 2 TEST CHART 163 KX FP342BX ...
Page 185: ...9 FIXTURES AND TOOLS 164 KX FP342BX ...
Page 186: ...10 CABINET MECHANICAL AND ELECTRICAL PARTS LOCATION 10 1 GENERAL SECTION 165 KX FP342BX ...
Page 187: ...10 2 OPERATION PANEL SECTION 166 KX FP342BX ...
Page 188: ...10 3 BACK COVER SECTION 167 KX FP342BX ...
Page 189: ...168 KX FP342BX ...
Page 190: ...10 4 UPPER CABINET SECTION 169 KX FP342BX ...
Page 191: ...10 5 LOWER CABINET P C BOARD SECTION CROSS REFERENCE MOTOR SECTION P 171 170 KX FP342BX ...
Page 192: ...10 6 MOTOR SECTION 10 7 ACTUAL SIZE OF SCREWS 171 KX FP342BX ...
Page 193: ...11 ACCESSORIES AND PACKING MATERIALS 172 KX FP342BX ...