Hitachi 42HDF52A, Руководство по обслуживанию

Страница: 7 / 44

7
4. Service points
z
Lead-free solder
This product uses lead-free solder (unleaded) to help protect the environment. Please read these instructions
before attempting any soldering work.
Caution:
Always wear safety glasses to prevent fumes or molten solder from getting into
the eyes. Lead-free solder can splatter at high temperatures (600
℃
).
„
Lead-free solder indicator
Printed circuit boards using lead-free solder are engraved with an "F."
„
Properties of lead-free solder
The melting point of lead-free solder is 40-50
℃
higher than leaded solder.
„
Servicing solder
Solder with an alloy composition of Sn-3.0Ag-0.5Cu or Sn-0.7Cu is recommended. Although servicing with
leaded solder is possible, there are a few precautions that have to be taken. (Not taking these precautions
may cause the solder to not harden properly, and lead to consequent malfunctions.)
Precautions when using leaded solder
z
Remove all lead-free solder from soldered joints when replacing components.
z
If leaded solder should be added to existing lead free joints, mix in the leaded solder thoroughly after the
lead-free solder has been completely melted (do not apply the soldering iron without solder).
„
Servicing soldering iron
A soldering iron with a temperature setting capability (temperature control function) is recommended.
The melting point of lead-free solder is higher than leaded solder. Use a soldering iron that maintains a high
stable temperature (large heat capacity), and that allows temperature adjustment according to the part being
serviced, to avoid poor servicing performance.
Recommended soldering iron:
z
Soldering iron with temperature control function (temperature range: 320-450
℃
)
Recommended temperature range per part:
Part
Soldering iron temperature
Mounting (chips) on mounted PCB
320
℃
±30
℃
Mounting (chips) on empty PCB
380
℃
±30
℃
Chassis, metallic shield, etc.
420
℃
±30
℃
( 1) EMI PWB, AUDIO TRANSFER PWB, RS-232 PWB, AUDIO PWB, KEY PWB, IR PWB, I/O PWB,
CONNECTOR PWB, SPEAKER CONNECTOR PWB
(2) MAIN PWB
(3) ATSC BOX(Digital Tuner Module) / TUNER
(4) POWER PWB
(5) PDP MODULE (is all lead free solder. X-SUS PWB, Y-SUS PWB, LOGIC PWB, ADDRESS PWB, SDM PWB)
The PWB assembly which has used lead free solder