Panasonic KX-DT543-B Service Manual

Also see for KX-DT543: Quick reference card Quick reference card Quick reference card Quick reference card Quick reference card

Panasonic KX-DT543-B Service Manual Manual pdf 42 page image

42KX-DT543/KX-DT543-B/KX-DT546/KX-DT546-B10.2. How To Replace a Flat Package ICEven if you do not have the special tools (for example, a spot heater) to remove the Flat IC, with some solder (large amount), a sol-dering iron and a cutter knife, you can easily remove the ICs that have more than 100 pins.10.2.1. Preparation• PbF (: Pb free) Solder• Soldering IronTip Temperature of 700F ± 20F (370C ± 10C)Note: We recommend a 30 to 40 Watt soldering iron. Anexpert may be able to use a 60 to 80 Watt iron where some-one with less experience could overheat and damage thePCB foil.• FluxRecommended Flux: Specific Gravity  0.82.Type  RMA (lower residue, non-cleaning type)Note: See About Lead Free Solder (PbF: Pb free) (P.4).10.2.2. Removal Procedure1. Put plenty of solder on the IC pins so that the pins can becompletely covered.Note:If the IC pins are not soldered enough, you may givepressure to the P.C. board when cutting the pins witha cutter.2. Make a few cuts into the joint (between the IC and itspins) first and then cut off the pins thoroughly.3. While the solder melts, remove it together with the ICpins.When you attach a new IC to the board, remove all solderleft on the land with some tools like a soldering wire. If somesolder is left at the joint on the board, the new IC will not beattached properly.10.2.3. Procedure1. Tack the flat pack IC to the PCB by temporarily solderingtwo diagonally opposite pins in the correct positions onthe PCB.Be certain each pin is located over the correct pad on the PCB.2. Apply flux to all of the pins on the IC.3. Being careful to not unsolder the tack points, slide the sol-dering iron along the tips of the pins while feeding enoughsolder to the tip so that it flows under the pins as they areheated.10.2.4. Removing Solder From BetweenPins1. Add a small amount of solder to the bridged pins.2. With a hot iron, use a sweeping motion along the flat partof the pin to draw the solder from between the adjacentpads.