Panasonic TX-20LA5F Service Manual

Also see for TX-20LA5F: Operating instructions

Contents

Panasonic TX-20LA5F Service Manual Manual pdf 2 page image

CONTENTSSAFETY PRECAUTIONS ......................................................................................................................................................... 2GENERAL QUIDE LINES.................................................................................................................................................... 2TOUCH – CURRENT CHECK............................................................................................................................................. 2PREVENTION OF ELECTROSTATIC DISCHARGE (ESD) TO ELECTROSTATICALLY SENSITIVE (ES) DEVICES ........... 3ABOUT LEAD FREE SOLDER (PBF)....................................................................................................................................... 4SUGGESTED PB FREE SOLDER...................................................................................................................................... 4SERVICE HINTS ...................................................................................................................................................................... 5SETTING INSPECTION............................................................................................................................................................ 6SELF-CHECK ........................................................................................................................................................................... 6ALIGNMENT SETTINGS .......................................................................................................................................................... 7BLOCK DIAGRAMS.................................................................................................................................................................. 8PARTS LOCATION................................................................................................................................................................. 11REPLACEMENT PARTS LIST................................................................................................................................................ 12SCHEMATIC DIAGRAMS....................................................................................................................................................... 19CONDUCTOR VIEWS ............................................................................................................................................................ 25SAFETY PRECAUTIONGENERAL GUIDE LINES1. When servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheatedor damaged by the short circuit.2. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properlyinstalled.3. After servicing, make the following leakage current checks to prevent the customer from being exposed to shockhazards.4. Always ensure panel TKKL5290 is correctly replaced before returning to customer (see Fig.1).TOUCH-CURRENT CHECK1. Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.2. Connect a measuring network for touch currents between each exposed metallic part on the set and a good earthground such as a water pipe, as shown in Fig. 2.3. Use Leakage Current Tester (Simpson 228 or equivalent) to measure the potential across the measuring network.4. Check each exposed metallic part, and measure the voltage at each point.5. Reserve the AC plug in the AC outlet and repeat each of the above measure.6. The potential at any point (TOUCH CURRENT) expressed as voltage U1 and U2, does not exceed the following values:For a. c.: U1 = 35 V (peak) and U2 = 0.35 V (peak);For d. c.: U1 = 1.0 V,NOTE:The limit value of U2 = 0.35 V (peak) for a. c. and U1 = 1.0 V for d. c. correspond to the values 0.7 mA (peak) a. c. and2.0 mA d. c.The limit value U1 = 35 V (peak) for a. c. correspond to the value 70 mA (peak) a. c. for frequencies greater than 100kHz.7. In case a measurement is out of the limits specified, there is a possibility of a shock hazard, and the equipment shouldbe repaired and rechecked before it is returned to the customer.2Fig. 1