I had to replace the Volume/On/Off switch in many Motorola radios, to include the 6000 series Trbo radios and many XTS1500/2500's. This is a common issue as this switch and the PTT are the most used, and wear out often. Like others have said, an "Air Dragon" chip remover or some type of unit that spreads the heat around will make removal of broken parts easier. Newer Motorola radios sometimes also suffer from cold solder joints on some of the solder connections at the top of the mina board. It's like the flow soldering does not reach the middle board connections well enough, causing a poor connection with the channel selector contacts or volume contacts.
The parts are on auction sites, expect to pay $5-20 in some cases. If you have more than one radio, it saves to buy parts in bulk, as these parts may fail on others as well. Good luck on the repair. I actually prefer the XPR6550's to the XPR7550's in many ways....as my end users do not need a color display, WiFi and Bluetooth connectivity, or even things like text messaging. In hindsight, Model I's may have been an even better option.