I'm getting ready to replace the DSP chip in a Yamaha AVR. There are YouTube videos but they're all lacking in the details like what temp to set the rework station to, etc. I've searched in vain for a written overview but have come up empty. Looking for tricks traps, advice or links to sites that cover the details. The one issue I'm in the dark about is this chip has a metal center section on the bottom that solders to a corresponding metal plate on the circuit board, I need to know the proper technique to handle this.
If you have no experience in working with SMD chips, I recommend to practice first on scrap boards.
If the chip has no metal pad underneath, removing the IC is a pretty simple job. For desoldering, get some good flux and Chip Quick solder. Generously cover all pins, in the flux and ChipQuick, make sure that the solder is liquid on all sides, and remove the chip. After removal, clean the flux with isopropyl alcohol, and clean the pads well using solder wick. Place the new chip, and solder it down. ChipQuick is a low melting point solder, which will stay liquid for long enough to heat all sides and remove the chip.
Use solder wick to clean the pads. Put the wick on the pad, press gently with soldering iron, wait until the solder melts, and drag along the length of the pad. Don't try to drag across the pads, it's too easy to damage them. Repeat until all pads are clean. Flux the pads again, put some solder on the tip, drag along the pads to wet them, and clean again.
There is a simple trick, which makes mounting the new chip a breeze: Flux the pads well, put enough solder on the tip to make a big drop, and drag it along the pins holding the tip submerged in the molten solder, but without touching the pins. Don't worry about bridging pins, you can clean bridges later. Search YT for "drag soldering".
As for temperature, for leaded solder I heat up the soldering iron to 300-320C, Occasionally I'll bump the temperature to 350C if 300 is not enough.
The operation gets more complicated if the chip has a thermal pad underneath. With enough experience it is possible to replace it with just a hot air station, but you have a very good chance of damaging the board.
I highly recommend preheating the board before the rework. If you don't have a board preheater, you can use an electric skillet. The point is to keep the board warm during the entire operation. There is a big plane of copper under the chip which drains away the heat, and it is difficult to heat up the pad through the chip to the point of melting solder.
I usually heat the board up to 150-200C before using hot air. With a warm board, a light blow of hot air is usually sufficient to melt the solder.
Once the chip is removed, clean the solder with a wick.
Soldering the thermal pad is tricky. Since you can't access it from outside, you have to put some solder on the pcb before mounting the chip, and reflow it by heating the chip from the top. It has to be the right amount of solder: too little will result in a poor thermal connection, too much will float the chip too high to solder the pins to the board, and can result in shorts. Once again. I recommend practicing on scrap boards.
I set the hot air temperature and flow rate by experimenting. Set the temperature by trying to melt a piece of solder on a sheet of paper. Flow rate has to be big enough to deliver enough heat, but not too big, to not blow other components off the board. Again, practice on scrap boards.
It is a good idea to cover components around the chip with a kapton tape, or aluminum foil.
After mounting the chip, you have to clean the board. I use a tooth brush, isopropyl alcohol, and clean water.
Start by scrubbing the board with IPA and the brush until there are no residues of the flux on the board. Rinse with IPA frequently during the operation.
After you're done, rinse again with clean IPA, and then rinse the IPA with water. After rinsing in water, rinse again in IPA and let the board dry.
Water removes the dirty IPA, and clean IPA removes water.
As you may have noticed, I mentioned flux many times. Good flux is the key to success when working with SMD components, don't be shy with it. I use Kester 186 for all my work. It is tacky, and requires cleanup after work but holds the components during soldering.
Good luck!