Panasonic CT-25G6E Service Manual

Also see for CT27G6DE - 27" COLOR TV: Operating instructions Service manual

Panasonic CT-25G6E Service Manual Manual pdf 4 page image

- 4 -Service NotesLeadless Chip Component(surface mount)Chip components must be replaced with identical chipsdue to critical foil track spacing. There are no holes inthe board to mount standard transistors or diodes.Some chips capacitor or resistor board solder padsmay have holes through the board, however the holediameter limits standard resistor replacement to 1/8watt. Standard capacitor may also be limited for thesame reason. It is recommended that identicalcomponents be used.Chip resistor have a three digit numerical resistancecode - 1st and 2nd significant digits and a multiplier.Example: 162 = 1600 or 1.6kΩ resistor, 0 = 0Ω (jumper).Chip capacitors generally do not have the valueindicated on the capacitor. The color of the componentindicates the general range of the capacitance.Chip transistors are identified by a two letter code. Thefirst letter indicates the type and the second letter, thegrade of transistor.Chip diodes have a two letter identification code as perthe code chart and are a dual diode pack with eithercommon anode or common cathode. Check the partslist for correct diode number.Component Removal1. Use solder wick to remove solder from componentend caps or terminal.2. Without pulling up, carefully twist the componentwith tweezers to break the adhesive.3. Do not reuse removed leadless or chipcomponents since they are subject to stressfracture during removal.Chip Component Installation1. Put a small amount of solder on the boardsoldering pads.2. Hold the chip component against the solderingpads with tweezers or with a miniature alligator clipand apply heat to the pad area with a 30 watt ironuntil solder flows. Do not apply heat for more than3 seconds.How to Replace Flat-IC- Required Tools -1. Cut the pins of a defective IC with wire cutters.Remove IC from board. If IC is glued to the board,heat the IC and release the IC. See Note above.2. Using soldering iron and needle nose pliersremove the IC pins from the board.3. Using de-soldering braid and soldering iron removesolder from affected are on board (pads).4. Position the new Flat-IC in place (apply the pins ofthe Flat-IC to the soldering pads where the pinsneed to be soldered). Determine the positions ofthe soldering pads and pins by correctly aligningthe polarity symbol. Solder pin #1 first, align the IC.Solder the pin opposite to pin #1. This will assistpositioning the IC.5. Solder all pins to the soldering pads using a finetipped soldering iron.6. Check with a magnifier for solder bridge betweenthe pins or for dry joint between pins and solderingpads. To remove a solder bridge, use a de-solderbraid as shown in the figure below.Note: Some components may be affixed with glue. Be careful not to break or damage foil under the componentor at the pins of the ICs when removing. Usually applying heat to the component for a short time whiletwisting with tweezers will break the component loose.Chip Components• Soldering iron • De-solder braids• Needle nose pliers • Magnifier• Wire cutters (sharp & small)Flat ICSolderingIronSolderingIronDe-solderingBraidPolaritysymbol 1st solder2nd solderSolder SolderingIron