Main Board Section - Panasonic KX-MB2061CXB Service Manual

KX-MB2061CXB/KX-MB2061CX2/KX-MB2062CXB
16.6.3. How to Install the Shield Case
Note:
• If you don't have special tools (ex. Hot air disordering tool), conduct the following operations.
• Shield case's No. : PNMC1013Z
1. Put the shield case.
2. Solder the surroundings.
16.7.

Main 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 ROM) malfunctions are extremely rare after
installation in the product.)
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