Panasonic SA-AK230PL Service Manual

Also see for SA-AK230: Operating instructions Operating instructions Service manual Service manual

Contents

Panasonic SA-AK230PL Service Manual Manual pdf 4 page image

1 Before Repair and AdjustmentDisconnect AC power, discharge Power Supply Capacitors C5820 and C5840 through a 10Ω, 5W resistor to ground.DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy solid state devices.After repairs are completed, restore power gradually using a variac, to avoid overcurrent.Current consumption at AC 120V, 60 Hz in NO SIGNAL mode (volume min at CD mode) should be ~ 600mA.2 Protection CircuitryThe protection circuitry may have operated if either of the following conditions are noticed:· No sound is heard when the power is turned on.· Sound stops during a performance.The function of this circuitry is to prevent circuitry damage if, for example, the positive and negative speaker connection wires are“shorted”, or if speaker systems with an impedance less than the indicated rated impedance of the amplifier are used.If this occurs, follow the procedure outlines below:1. Turn off the power.2. Determine the cause of the problem and correct it.3. Turn on the power once again after one minute.Note :When the protection circuitry functions, the unit will not operate unless the power is first turned off and then on again.3 Prevention of Electro Static Discharge (ESD) toElectrostatically Sensitive (ES) DevicesSome semiconductor (solid state) devices can be damaged easily by electricity. Such components commonly are calledElectrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effect transistors andsemiconductor “chip” components. The following techniques should be used to help reduce the incidence of component damagecaused by electro static discharge (ESD).1. Immediately before handling any semiconductor component or semiconductor-equiped assembly, drain off any ESD on yourbody by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging ESD wrist strap,which should be removed for potential shock reasons prior to applying power to the unit under test.2. After removing an electrical assembly equiped with ES devices, place the assembly on a conductive surface such as aluminiumfoil, to prevent electrostatic charge build up or exposure of the assembly.3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.4. Use only an anti-static solder remover device. Some solder removal devices not classified as “anti-static (ESD protected)” cangenerate electrical charge to damage ES devices.5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.6. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it. (Mostreplacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminium foil orcomparable conductive material).7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protective materialto the chassis or circuit assembly into which the device will be installed.CautionBe sure no power is applied to the chassis or circuit, and observe all other safety precautions.8. Minimize body motions when handling unpackaged replacement ES devices. (Otherwise harmless motion such as the brushingtogether of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity (ESD) sufficient todamage an ES device).4SA-AK230PL