Samsung ML-4500/XAA Service Manual

1-2 Samsung ElectronicsPrecautions1-2 ESD PrecautionsCertain semiconductor devices can be easilydamaged by static electricity. Such components arecommonly called “Electrostatically Sensitive (ES)Devices”, or ESDs. Examples of typical ESDs are:integrated circuits, some field effect transistors, andsemiconductor “chip” components.The techniques outlined below should be followedto help reduce the incidence of component damagecaused by static electricity.CAUTION: Be sure no power is applied to thechassis or circuit, and observe all other safetyprecautions.1. Immediately before handling a semiconductorcomponent or semiconductor-equipped assembly,drain off any electrostatic charge on your bodyby touching a known earth ground. Alternatively,employ a commercially available wrist strapdevice, which should be removed for your personalsafety reasons prior to applying power to the unitunder test.2. After removing an electrical assembly equippedwith ESDs, place the assembly on a conductivesurface, such as aluminum or copper foil, orconductive foam, to prevent electrostatic chargebuildup in the vicinity of the assembly.3. Use only a grounded tip soldering iron to solderor desolder ESDs.4. Use only an “anti-static” solder removal device.Some solder removal devices not classified as“anti-static” can generate electrical chargessufficient to damage ESDs.5. Do not use Freon-propelled chemicals. Whensprayed, these can generate electrical chargessufficient to damage ESDs.6. Do not remove a replacement ESD from itsprotective packaging until immediately beforeinstalling it. Most replacement ESDs arepackaged with all leads shorted together byconductive foam, aluminum foil, or a comparableconductive material.7. Immediately before removing the protectiveshorting material from the leads of a replacementESD, touch the protective material to the chassisor circuit assembly into which the device will beinstalled.8. Maintain continuous electrical contact betweenthe ESD and the assembly into which it will beinstalled, until completely plugged or solderedinto the circuit.9. Minimize bodily motions when handlingunpackaged replacement ESDs. Normal motions,such as the brushing together of clothing fabricand lifting one’s foot from a carpeted floor, cangenerate static electricity sufficient to damage anESD.1. Exercise caution when replacing a supercapacitor or Lithium battery. There could be adanger of explosion and subsequent operatorinjury and/or equipment damage if incorrectlyinstalled.2. Be sure to replace the battery with the same orequivalent type recommended by themanufacturer.3. Super capacitor or Lithium batteries contain toxicsubstances and should not be opened, crushed,or burned for disposal.1-3 Super Capacitor or Lithium Battery Precautions