Panasonic KX-FT982RU / KX-FT984RU / KX-FT988RU Service Manual ▷ View online
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KX-FT982RU-B / KX-FT982RU-W / KX-FT984RU-B / KX-FT988RU-B / KX-FT988RU-W
12.5.5. Communication Section
Find the problem in the table shown below, and refer to the corresponding troubleshooting procedure in Defective Facsimile
Section (P.84).
Section (P.84).
No.
Symptom
Content
Possible cause
1
The paper is not fed properly when faxing.
(Nor in the copy mode.)
(Nor in the copy mode.)
Troubleshooting
Problem with the feeding mechanism.
2
The fax usually transmits successfully but sometimes fails.
(The unit can copy documents.)
(The unit can copy documents.)
Troubleshooting
Problem with the service line or with
the receiver's fax.
the receiver's fax.
3
The fax usually receives successfully but sometimes fails.
(The unit can copy documents.)
(The unit can copy documents.)
Troubleshooting
Problem with the service line or with
the transmitter's fax.
the transmitter's fax.
4
The fax completely fails to transmit or receive.
(The unit can copy documents.)
(The unit can copy documents.)
Troubleshooting
Problem with the electric circuit.
5
The fax fails either to transmit or receive when making a
long distance or an international call.
(The unit can copy documents.)
long distance or an international call.
(The unit can copy documents.)
Detailed description of the possible
causes (Similar to troubleshooting
items No.2 and No.3.)
causes (Similar to troubleshooting
items No.2 and No.3.)
Problem with the service line.
6
The fax image is poor when transmitting or receiving during
a long distance or an international call.
a long distance or an international call.
7
No.1-No.5
The troubleshooting procedure for
each error code will be printed on
the communication result report.
each error code will be printed on
the communication result report.
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KX-FT982RU-B / KX-FT982RU-W / KX-FT984RU-B / KX-FT988RU-B / KX-FT988RU-W
12.5.6. 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).
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.
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.)
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?
Please refer to Check the Status of the Digital Board (P.111).
The ASIC (IC1) controls all the other digital ICs. When the power is turned on, the ASIC retrieves the operation code stored in
the FLASH 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 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).
The ASIC (IC1) controls all the other digital ICs. When the power is turned on, the ASIC retrieves the operation code stored in
the FLASH 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 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).
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KX-FT982RU-B / KX-FT982RU-W / KX-FT984RU-B / KX-FT988RU-B / KX-FT988RU-W
Digital Block Diagram
Digital board is including analog system. All analog signals (Telephone, CID and TAM) excepting Fax communications. Another
one is ASIC system for mechanical functions: Copy, Fax and UI (LCD/Key). And serial interface (UART) connects both systems.
one is ASIC system for mechanical functions: Copy, Fax and UI (LCD/Key). And serial interface (UART) connects both systems.
Flash memory IC2 in the ASIC system is for software and also for user memory (settings, Phone book, CID memory) DRAM IC4
in the ASIC system is for work memory and also for fax memory.
in the ASIC system is for work memory and also for fax memory.
The signal lines that must be normal for the system to boot up are listed here [List 1].
For signal lines other than these, even if they malfunction they do not directly affect booting up the system.
For signal lines other than these, even if they malfunction they do not directly affect booting up the system.
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KX-FT982RU-B / KX-FT982RU-W / KX-FT984RU-B / KX-FT988RU-B / KX-FT988RU-W
NG Wave pattern
Note:
Refer to NG Example (P.113).
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