Panasonic CT-27C8G Service Manual

Also see for CT27C8G - 27" COLOR TV: Operating manual Service manual

Panasonic CT-27C8G Service Manual Manual pdf 3 page image

Unplug the A.C. cord and connect a jumper between the two plug prongs.Measure the resistancebetween the jumpered AC plug and expose metallic parts such as screwheads, antennaterminals, control shafts, etc. If the exposed metallic part has a returnpath to the chassis, thereading should be between 240k and 5.2M . If the exposed metallic part does not have areturn path to the chassis, the reading should be infinite.Leakage current hot checkPlug the AC cord directly into the AC outlet. Do not use an isolation transformer during the check.Connect a 1.5k 10 watt resistor in parallel with a 0.15 F capacitor between an exposedmetallic part and ground. Use earth ground, for example a water pipe.Using a DVM with a 1000 ohms/volt sensitivity or higher, measure the AC potential across theresistor.Repeat the procedure and measure the voltage present with all other exposed metallic parts.Verify that any potential does not exceed 0.75 volt RMS. A leakage current tester (such aSimpson model 229, Sencore model PR57 or equivalent) may be used in the above procedure, inwhich case any current measure must not exceed 0.5 milliamp. Ifany measurement is out of thespecified limits, there is a possibility of a shock hazard and the receiver must be repaired andrechecked before it is returned to the customer.Hot check circuitInsulation testConnect an insulation tester between an exposed metallic part and A.C. line. Apply 1080VAC/60Hz for 1 second. Confirm that the current measurement is 0.5mA ~ 2.0mA. Repeat test withother metallic exposed parts.X ray radiationWARNINGThe potential source of x ray radiation in the TV set is in the high voltage section and the picturetube.NOTEIt is important to use an accurate, calibrated high voltage meter.Set the brightness, picture, sharpness and color controls to minimum.3