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Safety Precaution for Repair
1-1 Cautions
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts have special safety-related characteristics. These are often not
evident from visual inspection nor can the protection afforded by them necessarily be obtained by using
replacement components rated for a higher voltage, wattage, etc. Replacement parts which have these
special safety characteristics are identified in this Service Manual. Electrical components having such
features are identified by marking with a on the schematics and the parts list in this Service Manual.
The use of a substitute replacement component which does not have the same safety characteristics as
the HITACHI recommended replacement one, shown in the parts list in this Service Manual, may create
shock, fire, or other hazards. Product safety is continuously under review and new instructions are issued
from time to time. For the latest information, always consult the current HITACHI Service Manual. A
subscription to, or additional copies for, HITACHI Service Manual may be obtained at a nominal charge
from HITACHI SALES CORPORATION.
1-2 Electrostatic Protection Measures
Semiconductor components can be damaged by static electricity charged on clothes, human body,
etc. Take great care when handling components to avoid electrostatic damage, and perform
servicing in an environment where grounding is complete.
(1) Grounding work bench (Fig. 1-2-1)
Lay out an antistatic mat on work bench, and then use the ground plate to ground the work bench.
(2) Grounding human body (Fig. 1-2-2)
Use an antistatic wrist strap to discharge any static electricity charged on the body. Also, use a
tester for wrist strap to make sure that the wrist strap is working normally. Note, however, that
static electricity charged on clothes will not be discharged by wrist strap: Therefore do not allow
your clothes to touch the semiconductor components.
Antistatic mat
Antistatic wrist strap
Ground
Fig. 1-2-1 Grounding Work Bench Fig. 1-2-2 Grounding Human Body
1M ohm
1 - 1
Safety Precaution for Repair > Lead-Free Solder
1-3 Lead-Free Solder
The printed circuit board that uses lead-free solder is adopted. To protect the global environment,
use the recommended lead-free solder also during servicing.
Read and observe the following before soldering:
Caution
ALWAYS wear protective goggles during soldering so that no solder smoke or scattered solder
enters the eye. Lead-free solder may scatter at high temperatures of 600°C.
(1) Identification of circuit boards that use lead-free solder
“F” is stamped or noted with pattern letter on circuit boards that use lead-free solder.
(2) Characteristics of lead-free solder
The components of lead-free solder used are as follows. The melting point of lead-free solder is 3040°C higher than that of lead based solder:
Point to be soldered
For reflow
For dip
Composition of alloy (wt%)
Solder paste: Sn-3Ag-0.5Cu
Bar solder: Sn-0.6Cu
Melting temperature: Approx. 220°C
(3) Lead-free solder for servicing
Use the following lead-free solder for servicing:
Recommended lead-free solder and composition of alloy (wt%): Sn-3.0Ag-0.5Cu or equivalent
Information:
For composition of alloy, Sn is tin; Ag is silver; Cu is copper; Bi is bismuth; Pb is lead.
(4) Soldering iron for servicing
The temperature of soldering iron tip must be adjusted according to the points to be soldered: Use
an antistatic soldering iron with thermal control function.
When removing components, take care not to damage any surrounding component or pattern. When
attaching components, observe the heating time in the following table so that the components are
not destroyed by heat.
Tip temperatures for different soldering points:
Point to be soldered
Surface-mounted (chip) parts [other than
those shown below]
Surface-mounted (chip) parts [for DVD
cameras, cellular phones only]
Discrete parts
Chassis, metal shield, etc.
320 ± 30°C
[heating time: less than 5 seconds]
350 ± 10°C
[heating time: less than 3 seconds]
380 ± 30°C
420 ± 30°C
Tip temperature
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