NEC Confidential & Proprietary
Semiconductor devices are easily damaged by electrostatic discharge. Many of the
procedures detailed in this manual involve disassembly of the equipment and therefore
handling of the printed circuit boards.
To protect these devices from ESD a wrist strap connected to ground must be worn. In
addition to this the work surface must be covered with an anti-electrostatic mat, which
should also be grounded.
If printed circuit boards are to be stored without being re-assembled into their
equipment, then they must be kept in an anti-electrostatic bag.
Grounding:
Each piece of test equipment should be electrically grounded. A third (grounding) pin is
provided as a safety feature. Ensure that the electrical outlet also contains this feature.
Cosmetic Protection during Repair Work:
Always ensure that the working surface is kept clean and free from abrasive materials.
The LCD is very susceptible to scratches and damage. It should be covered with clear
adhesive vinyl while the equipment is disassembled.
Storage of Faulty Components:
Any components that are replaced due to failure should be kept safely in an anti-
electrostatic container. NEC’s Quality or Research & Development Departments may
require them to make quality and reliability investigations.
No Fault Found Equipment:
In some cases the reported symptom may not be apparent. You may subject the
equipment to a controlled amount of stress, vibration and temperature variation to see
if the fault occurs.
Care should be taken not to apply excessive stress or vibration or extreme temperature
variations as further faults may develop.
Soldering and Disordering :
Fast, accurate and high quality soldering is required to minimise the risk of heat damage
to the electronic components.
The soldering tip should not be in contact with components or PCB tracks for longer than
2 seconds.
Heat the pad on the PCB and the lead, quickly apply solder, remove heat and cool.
After soldering is complete, ensure that all solder joints are of good quality - no dry
joints, solder bridges, cracks or excess solder.
