Introduction
Full teardown of a cordless phone and accessories from 2001.
Tools
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            This is a teardown of a GE 27990G3 cordless phone system from 2001. Sadly, while it still works, its 2.4 GHz wireless transmitter interferes with WiFi. 
 
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            Use needlenose pliers to disconnect the battery connector. 
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            The battery is a 3.6V Nickel-Cadmium rechargeable battery made up of 3 AAA-sized cells 
 
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            After some aggressive spudgering (the pictures make it look much easier), the back of the case can be removed. 
 
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            The wireless board can be flipped up, but is still attached to the main board by a short ribbon cable. 
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            Remove 2 screws on the main board. 
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            Remove 2 screws on the speaker. 
 
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            The wireless board is attached by a soldered and hot-glued in ribbon cable, which must be cut off to remove. 
 
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            Components on the main board: 
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            Speaker 
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            Message indicator LED 
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            Ringer switch 
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            Electret microphone 
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            Unknown potted 'Blob' IC 
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            Piezo buzzer for ringer 
 
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            Whoever designed the wireless module really didn't want anyone to know what was inside. The very thick EMI shield is soldered, crimped, and epoxied on. 
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            The shield took about 20 minutes to remove with diagonal cutters, 2 pairs of pliers, and 3 metal spudgers. 
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            Needless to say, the shield is irreversibly damaged and the wireless module will probably never work again. 
 
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            Components inside the wireless module: 
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            Toshiba TB31261AF cordless telephone RF chip 
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            Ceramic resonators 
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            Unidentified square ceramic components with 2 cylindrical holes in them horizontally (anyone who has an idea what they are, please comment.) 
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            The back of the board says that it was manufactured on August 29, 2001, making the phone 14 years old at the time of writing. 
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            Interestingly, the Toshiba TB31261AF is designed for a 900MHz cordless telephone, but this is a 2.4GHz model. 
 
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            Repairability score: 6/10 
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            Phone is held together with only phillips screws. 
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            Battery, the most likely part to fail, is a standard component and is easily replaceable. 
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            Case is difficult to open. 
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            Wireless module is very hard to replace and impossible to repair. 
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            All wires (except for the battery) are soldered to the circuit board instead of using connectors. 
 
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            Just like in the handset, the wireless module is connected to the main board with a soldered ribbon cable. I'm sensing a theme here. 
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            Remove 2 screws that hold down the main board. 
 
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            The main circuit board can be removed from the bottom case. 
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            Remove 4 screws holding in the button board and charging contacts from the top case. 
 
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            The wireless module can be cut away from the logic board. 
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            This wireless module is identical to the one in the handset except for the fact that it used coiled wires instead of straight wires for antennas. 
 
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            Remove 2 screws to remove the support for the wireless module. 
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            The plastic pieces used to hold down the board can also be removed. 
 
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            The button board contains a lonely button, 2 LEDs, and is connected with a soldered ribbon cable reinforced with hot glue. 
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            This board appears to have been manufactured on April 17, 2001. 
 
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            Components on the main board: 
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            4 MHz crystal 
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            Variable capacitor 
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            Small audio transformer 
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            Miniature fuse 
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            Varistor for surge protection 
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            This board was manufactured on September 3, 2001. 
 
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            Repairability Score: 4/10 
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            Secondary base station is assembled with only phillips screws. 
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            Circuit boards use mainly through-hole parts, so repair of individual components is easier. 
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            Case requires lots of spudgering to open. 
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            Removing the board requires a long screwdriver. 
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            Wireless module is very hard to replace and impossible to repair. 
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            All wires and ribbon cables are soldered to the board and reinforced with hot glue. 
 
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            The case for the main base station can be opened, but it requires 2 spudgers and much more force than the other one. 
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            Remember how I said soldered ribbon cables were becoming a theme here? I was right. 
 
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            Remove 2 screws holding down the wireless module. 
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            Remove 2 more screws holding down the plastic pieces attached to the circuit board. 
 
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            Remove another 2 screws on the other side of the board. 
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            Remove the microphone from its holder. 
 
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            In order to remove the board from the bottom case, you have to carefully reach in and free each one of the plastic pieces attached to the board from a clip on the bottom case. 
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            All of the cables to the main board can now be cut and the wireless module can be cut off of the main board. 
 
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            The main board in the base station has patches of an unknown yellowish-brown substance on it that appears to be some kind of weak adhesive, and it seems to be scattered in no obvious pattern. 
 
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            Remove 3 screws to remove the speaker cover. 
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            This speaker cover appears to have been designed to accomodate both a low-profile speaker and a speaker with a larger magnet on the back. 
 
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            The entire top case assembly can be removed from the printer after using a spudger to free the large buttons from clips in the top case. 
 
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            So what is inside the mysterious metal box? 
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            Samsung K9F4008W0A-TCB0 512x8 Kb (512 KB) flash memory (designed for digital audio recording) 
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            Crystal oscillator, covered in the same unusual substance found on the main board. 
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            Unknown IC D16529CAC11CQC. Googling it turns up nothing that makes any sense. 
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            This board is probably where the messages are stored. 
 
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            All of the boards in this phone system have terrible solder quality. I was able to cleanly remove the 7-segment display, about 20 capacitors, 3 voltage regulators, 1 transformer, and 2 crystal oscillators without damaging them using needle nose pliers. 
 
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            Repairability Score: 3/10 
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            Base station is only held together with phillips screws. 
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            Circuit boards use mainly through-hole parts, so repair of individual components is easier. 
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            Removing the top circuit board is difficult because the buttons are attached to the top case with clips. 
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            Opening the case requires 2 metal spudgers and a lot of force. 
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            Removing the bottom circuit board is difficult because the case is still attached with soldered ribbon cables. 
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            Wireless module is very hard to replace and impossible to repair. 
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            All wires and ribbon cables are soldered to the board and reinforced with hot glue. 
 
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            Overall repairability score: 5/10 
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            The handset battery, the most likely part to fail, is a standard component and is easily replaceable. 
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            Circuit boards use mainly through-hole parts, so repair of individual components is easier. 
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            Entire phone is held together with phillips screws 
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            Cases are difficult to open and require heavy spudgering. 
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            Most parts were not designed to be repaired. 
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            All wires and ribbon cables are soldered to the board and reinforced with hot glue. 
 
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