I chose the Panasonic KX-TGA660 cordless telephone handset to tear down. The phone was part of a set that included the base and charging cradle. I used a plastic pry tool on the case and a small screwdriver and needle nose pliers for the rest. 
Inside the handset were once two rechargeable AAA batteries. To open the phone, I had to pry the two sides open by sliding the plastic pry tool along the seam. There was a light adhesive that popped free with some work. 
Inside the phone is the mainboard and it is connected to the receiver (hidden in this view, but the top wires go through the board at the top) and the speaker is connected to the back of the phone. The two sets of blue and orange wires go to the receiver and speaker. The board is screwed down to the front case of the phone with three small screws. 
Removing the three screws frees up the front of the phone. This reveals the silicon keypad, and the speaker mounted at the top of the board. The two metal pieces are the contacts for the charging base that detach as the bottom screws are removed. 
Fully disassembled front and back of handset. Board view shows the contacts for the buttons and the round black speaker at the top and the small black microphone at the bottom of the screen. 
Getting ready to remove the components soldered on the board. 
The board freed from the case. Showing the speaker and microphone connected by the blue and orange wires. 
Freeing the screen by pulling free the flexible flat cable from the board. 
The screen removed from the board and the white plastic holder. 
All the parts of the screen disassembled. 
(1,2,3) cabinet – plastic (4) dial keypad – silicon (5) navigator key – plastic (6) main pc board (7) antenna – metal wire (8) 1.8″ monochrome LCD panel (9,10) LCD mounting bracket – plastic (11) black film (12) small processing board (13) receiver – magnetic (14) speaker – magnetic (15) speaker clip – plastic (16) microphone (17) 2.5mm headset jack and rubber cover (18) charge terminals – metal (19) charge terminal holder (20) 220 6S. E01 capacitors (21) IC (22) crystal oscillator (23) sticky foam strips (24) main flat IC chip 
reverse view of disassembled handset
The part that interested me the most was the crystal oscillator (22). It is more accurately referred to as a piezoelectric resonator. It is marked ECEC for the manufacturer: the East Crystal Electronic Company and also marked 13.824H1. The 13.824H1 indicates the frequency. A crystal oscillator uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. Crystal oscillators contain a wafer of synthetic quartz crystal and trace amounts of silver and gold.