KX-AT7730RU - Panasonic Telephone Service Manual (repair manual). Page 23

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Even if you do not have the special tools (for example, a spot heater) to remove the Flat IC, with some solder (large amount), a 
soldering iron and a cutter knife, you can easily remove the ICs that have more than 100 pins.

• PbF (: Pb free) Solder
• Soldering Iron

Tip Temperature of 700°F ± 20°F (370°C ± 10°C)
Note: We recommend a 30 to 40 Watt soldering iron. An 
expert may be able to use a 60 to 80 Watt iron where 
someone with less experience could overheat and damage 
the PCB foil.

• Flux

Recommended Flux: Specific Gravity 

→ 0.82.

Type 

→ RMA (lower residue, non-cleaning type)

Note: See About Lead Free Solder (PbF: Pb free) (P.4).

1. Put plenty of solder on the IC pins so that the pins can be 

completely covered.
Note:

If the IC pins are not soldered enough, you may give 
pressure to the P.C. board when cutting the pins with 
a cutter.

2. Make a few cuts into the joint (between the IC and its 

pins) first and then cut off the pins thoroughly.

3. While the solder melts, remove it together with the IC 

pins.

When you attach a new IC to the board, remove all solder 
left on the land with some tools like a soldering wire. If some 
solder is left at the joint on the board, the new IC will not be 
attached properly.

1. Tack the flat pack IC to the PCB by temporarily soldering 

two diagonally opposite pins in the correct positions on 
the 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 

soldering iron along the tips of the pins while feeding 
enough solder to the tip so that it flows under the pins as 
they are heated.

1. Add a small amount of solder to the bridged pins.
2. With a hot iron, use a sweeping motion along the flat part 

of the pin to draw the solder from between the adjacent 
pads.