Samsung MH026FNCA Service Manual

Also see for MH026FECA: Service manual

Samsung Electronics9-189-4 PCB Inspection9-4-2 Procedure12-4-2 The parts should be replaced in the following procedure.1. The human body carries much static electricity.Before touching a part for repair, replacement or thesimilar purpose, be sure to touch a grounded metal-lic portion by hand to let the static electricity gothrough the metallic portion to the earth.Especially when handling any micro computer or IC,carefully remove such static electricity before touch-ing them.2. When repairing any part on a work bench, be sureto place an insulative sheet on the bench and alwayskeep the sheet surface neat without any metal frag-ments. If any such fragment touches a part, a sec-ondary trouble will possibly be caused in the part.3. Before replacing any parts, be sure to turn off thepower supply. If such replacement is done with thepower supply kept on, an electric shock, short circuitor destruction of a part may result.4. During replacement or repair of a part, carefully han-dle it : The printed circuit board has fine lead wires(jumper wires) and glass-made parts (diode) on itssubstrate.So if a circuit board is roughly handled, such leadwires and parts will be easily broken or damaged bybending or shock.5. When soldering the lead wires of any new part, besure to polish them using an emery paper or the likebefore soldering them.Since the lead wires of any new part are coveredwith an oxide film, solder cannot adhere to the leadwires if not polished.6. When soldering any part, care should be exercisednot to apply any high-wattage soldering iron to thepart for a long time. Some parts are of so low a heatresistance that they may be broken or have theproperties changed if a soldering iron is so applied(Otherwise, the pattern may possibly be separatedand raised).7. The heat of the soldering iron should be transferredto the entire object to be soldered. If the solderpieces are not well fused due to insufficient transferof the heat from the soldering iron, no satisfactoryelectrical continuity can be assured even if the sol-dered objects appear well connected to each other.8. The solder used should be limited to a minimum.If excessive solder is used, it will cause inter-patterncontact, which may cause malfunction of the circuit.9. Although some part of the PCB surface are coatedwith coating material for protection from dust anddirt, soldering is also available to the coating part.Because this coating is thin and is weak for solder-ing heat.But coating material remaining on the solder partshould be cleaned up before soldering a newcomponent to prevent the solder part from becomingbad conduction.The repair is completed.Check the operation of the new part.Replace it with a new part.Detach the faulty part.Check for any faulty part.9-4-1 Cautions for Part Replacement