120
KX-FC265GR-T
12.5.5. 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 mal-
functions 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 sol-
dering 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 (IC10) controls all the other digital ICs. When the power is turned on, the ASIC retrieves the operation code stored in
the FLASH ROM (IC16), 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).
Содержание KX-FC265GR-T
Страница 13: ...13 KX FC265GR T 4 2 1 2 Error Messages Report 4 2 2 Cordless Handset ...
Страница 22: ...22 KX FC265GR T 6 4 2 Block Diagram ...
Страница 24: ...24 KX FC265GR T ...
Страница 37: ...37 KX FC265GR T b Redundancy Compression Process Coding Mode This unit uses one dimensional MH format ...
Страница 61: ...61 KX FC265GR T Note Refer to Program Mode Table P 102 ...
Страница 69: ...69 KX FC265GR T 11 2 Cordless Handset ...
Страница 72: ...72 KX FC265GR T 11 3 2 Service Mode Settings Note The above values are the default values ...
Страница 80: ...80 KX FC265GR T Countermeasure ...
Страница 81: ...81 KX FC265GR T REFERENCE Test Mode P 62 ...
Страница 82: ...82 KX FC265GR T REFERENCE Test Mode P 62 ...
Страница 83: ...83 KX FC265GR T REFERENCE Test Mode P 62 ...
Страница 84: ...84 KX FC265GR T REFERENCE Test Mode P 62 ...
Страница 85: ...85 KX FC265GR T ...
Страница 86: ...86 KX FC265GR T REFERENCE Test Mode P 62 ...
Страница 87: ...87 KX FC265GR T REFERENCE Test Mode P 62 ...
Страница 91: ...91 KX FC265GR T ...
Страница 116: ...116 KX FC265GR T ...
Страница 123: ...123 KX FC265GR T I O and Pin No Diagram ...
Страница 126: ...126 KX FC265GR T 12 5 5 2 NG Example ...
Страница 130: ...130 KX FC265GR T 12 5 7 2 Troubleshooting Flow Chart ...
Страница 136: ...136 KX FC265GR T 12 5 11 Thermal Head Section Note Refer to Thermal Head P 23 ...
Страница 145: ...145 KX FC265GR T 13 Service Fixture Tools ...
Страница 149: ...149 KX FC265GR T 14 2 5 Cordless Handset Section REFERENCE E 1 How to Remove the Cordless Handset Board P 173 ...
Страница 150: ...150 KX FC265GR T 14 3 Disassembly Procedure 14 3 1 How to Remove the Image Sensor CIS ...
Страница 151: ...151 KX FC265GR T 14 3 2 How to Remove the Thermal Head ...
Страница 152: ...152 KX FC265GR T ...
Страница 153: ...153 KX FC265GR T 14 3 3 How to Remove the Bottom Frame ...
Страница 154: ...154 KX FC265GR T 14 3 4 How to Remove the P C Boards and Speaker ...
Страница 155: ...155 KX FC265GR T 14 3 5 How to Remove the Power Supply Board and AC Cord ...
Страница 156: ...156 KX FC265GR T 14 3 6 How to Remove the Gear Block and Separation Roller ...
Страница 157: ...157 KX FC265GR T 14 3 7 How to Remove the Gears Motors and Arms of the Gear Block ...
Страница 158: ...158 KX FC265GR T ...
Страница 159: ...159 KX FC265GR T 14 3 8 How to Remove the Charger Board A ...
Страница 160: ...160 KX FC265GR T 14 3 9 How to Remove the Back Cover ...
Страница 161: ...161 KX FC265GR T 14 3 10 How to Remove the Platen Roller and Lock Lever ...
Страница 162: ...162 KX FC265GR T ...
Страница 163: ...163 KX FC265GR T 14 3 11 How to Remove the Pickup Roller and Antenna ...
Страница 164: ...164 KX FC265GR T 14 3 12 How to Remove the Operation Panel ...
Страница 165: ...165 KX FC265GR T 14 3 13 How to Remove the Operation Board MIC Board and LCD ...
Страница 166: ...166 KX FC265GR T 14 3 14 How to Remove the Separation Holder and Exit Roller ...
Страница 167: ...167 KX FC265GR T 14 3 15 Installation Position of the Lead Wires 14 3 15 1 Lower Section ...
Страница 168: ...168 KX FC265GR T ...
Страница 169: ...169 KX FC265GR T ...
Страница 170: ...170 KX FC265GR T ...
Страница 171: ...171 KX FC265GR T 14 3 15 2 Operation Panel Section ...
Страница 172: ...172 KX FC265GR T 14 3 15 3 Back Cover Section ...
Страница 173: ...173 KX FC265GR T 14 3 16 How to Remove the Cordless Handset Board ...
Страница 174: ...174 KX FC265GR T 14 3 16 1 How to Replace the LCD ...
Страница 196: ...196 KX FC265GR T 16 2 3 4 Copying Note See Sensor Locations in Sensor and Switches P 28 REFERENCE Sensor Section P 133 ...
Страница 203: ...203 KX FC265GR T 17 1 7 Cordless Handset Board ...
Страница 208: ...208 KX FC265GR T 17 4 Test Chart 17 4 1 ITU T No 1 Test Chart ...
Страница 209: ...209 KX FC265GR T 17 4 2 ITU T No 2 Test Chart ...
Страница 210: ...210 KX FC265GR T 17 4 3 Test Chart ...
Страница 211: ...211 KX FC265GR T Memo ...
Страница 224: ...224 KX FC265GR T Memo ...
Страница 243: ...243 KX FC265GR T Memo ...
Страница 261: ...261 KX FC265GR T Memo ...
Страница 271: ...271 KX FC265GR T ...
Страница 272: ...272 KX FC265GR T K T KXFC265GRT ...