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Full teardown of a cordless phone and accessories from 2001.

Bu teardown bir tamir kılavuzu değildir. GE 27990G3 Cordless Phone cihazınızı onarmak için, servis kılavuzumuzu kullanın.

  1. GE 27990G3 Cordless Phone Teardown, GE 27990G3 Cordless Phone Teardown: adım 1, 3 resimden 1. GE 27990G3 Cordless Phone Teardown, GE 27990G3 Cordless Phone Teardown: adım 1, 3 resimden 2. GE 27990G3 Cordless Phone Teardown, GE 27990G3 Cordless Phone Teardown: adım 1, 3 resimden 3.
    • 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.

  2. GE 27990G3 Cordless Phone Teardown: adım 2, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 2, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 2, 3 resimden 3.
    • Part I: The Handset.

    • Remove the battery door on the back.

  3. GE 27990G3 Cordless Phone Teardown: adım 3, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 3, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 3, 3 resimden 3.
    • Use needlenose pliers to disconnect the battery connector.

    • The battery is a 3.6V Nickel-Cadmium rechargeable battery made up of 3 AAA-sized cells

  4. GE 27990G3 Cordless Phone Teardown: adım 4, 1 resimden 1.
    • Remove 2 phillips screws inside the battery compartment.

  5. GE 27990G3 Cordless Phone Teardown: adım 5, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 5, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 5, 3 resimden 3.
    • After some aggressive spudgering (the pictures make it look much easier), the back of the case can be removed.

  6. GE 27990G3 Cordless Phone Teardown: adım 6, 1 resimden 1.
    • The charging contacts can now be easily removed.

  7. GE 27990G3 Cordless Phone Teardown: adım 7, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 7, 2 resimden 2.
    • Remove 2 screws on what appears to be the wireless board.

  8. GE 27990G3 Cordless Phone Teardown: adım 8, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 8, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 8, 3 resimden 3.
    • The wireless board can be flipped up, but is still attached to the main board by a short ribbon cable.

    • Remove 2 screws on the main board.

    • Remove 2 screws on the speaker.

  9. GE 27990G3 Cordless Phone Teardown: adım 9, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 9, 2 resimden 2.
    • The mainboard assembly can now be removed from the front case.

  10. GE 27990G3 Cordless Phone Teardown: adım 10, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 10, 2 resimden 2.
    • The wireless board is attached by a soldered and hot-glued in ribbon cable, which must be cut off to remove.

  11. GE 27990G3 Cordless Phone Teardown: adım 11, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 11, 2 resimden 2.
    • Components on the main board:

    • Speaker

    • Message indicator LED

    • Ringer switch

    • Electret microphone

    • Unknown potted 'Blob' IC

    • Piezo buzzer for ringer

  12. GE 27990G3 Cordless Phone Teardown: adım 12, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 12, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 12, 3 resimden 3.
    • 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.

    • The shield took about 20 minutes to remove with diagonal cutters, 2 pairs of pliers, and 3 metal spudgers.

    • Needless to say, the shield is irreversibly damaged and the wireless module will probably never work again.

  13. GE 27990G3 Cordless Phone Teardown: adım 13, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 13, 2 resimden 2.
    • Components inside the wireless module:

    • Toshiba TB31261AF cordless telephone RF chip

    • Ceramic resonators

    • Unidentified square ceramic components with 2 cylindrical holes in them horizontally (anyone who has an idea what they are, please comment.)

    • 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.

    • Interestingly, the Toshiba TB31261AF is designed for a 900MHz cordless telephone, but this is a 2.4GHz model.

  14. GE 27990G3 Cordless Phone Teardown: adım 14, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 14, 2 resimden 2.
    • Repairability score: 6/10

    • Phone is held together with only phillips screws.

    • Battery, the most likely part to fail, is a standard component and is easily replaceable.

    • Case is difficult to open.

    • Wireless module is very hard to replace and impossible to repair.

    • All wires (except for the battery) are soldered to the circuit board instead of using connectors.

  15. GE 27990G3 Cordless Phone Teardown: adım 15, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 15, 2 resimden 2.
    • Part II: The Secondary Base Station

    • Remove 2 phillips screws on the bottom.

  16. GE 27990G3 Cordless Phone Teardown: adım 16, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 16, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 16, 3 resimden 3.
    • The top case can be removed with some spudgering.

  17. GE 27990G3 Cordless Phone Teardown: adım 17, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 17, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 17, 3 resimden 3.
    • Remove 1 screw to remove the wireless module.

  18. GE 27990G3 Cordless Phone Teardown: adım 18, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 18, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 18, 3 resimden 3.
    • 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.

    • Remove 2 screws that hold down the main board.

  19. GE 27990G3 Cordless Phone Teardown: adım 19, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 19, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 19, 3 resimden 3.
    • The main circuit board can be removed from the bottom case.

    • Remove 4 screws holding in the button board and charging contacts from the top case.

  20. GE 27990G3 Cordless Phone Teardown: adım 20, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 20, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 20, 3 resimden 3.
    • The wireless module can be cut away from the logic board.

    • 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.

  21. GE 27990G3 Cordless Phone Teardown: adım 21, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 21, 2 resimden 2.
    • Remove 2 screws to remove the support for the wireless module.

    • The plastic pieces used to hold down the board can also be removed.

  22. GE 27990G3 Cordless Phone Teardown: adım 22, 1 resimden 1.
    • The button board contains a lonely button, 2 LEDs, and is connected with a soldered ribbon cable reinforced with hot glue.

    • This board appears to have been manufactured on April 17, 2001.

  23. GE 27990G3 Cordless Phone Teardown: adım 23, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 23, 2 resimden 2.
    • Components on the main board:

    • 4 MHz crystal

    • Reed relay

    • Variable capacitor

    • Small audio transformer

    • Miniature fuse

    • Varistor for surge protection

    • This board was manufactured on September 3, 2001.

  24. GE 27990G3 Cordless Phone Teardown: adım 24, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 24, 2 resimden 2.
    • Repairability Score: 4/10

    • Secondary base station is assembled with only phillips screws.

    • Circuit boards use mainly through-hole parts, so repair of individual components is easier.

    • Case requires lots of spudgering to open.

    • Removing the board requires a long screwdriver.

    • Wireless module is very hard to replace and impossible to repair.

    • All wires and ribbon cables are soldered to the board and reinforced with hot glue.

  25. GE 27990G3 Cordless Phone Teardown: adım 25, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 25, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 25, 3 resimden 3.
    • Part III: The Main Base Station

    • First step: remove 4 screws.

  26. GE 27990G3 Cordless Phone Teardown: adım 26, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 26, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 26, 3 resimden 3.
    • The case for the main base station can be opened, but it requires 2 spudgers and much more force than the other one.

    • Remember how I said soldered ribbon cables were becoming a theme here? I was right.

  27. GE 27990G3 Cordless Phone Teardown: adım 27, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 27, 2 resimden 2.
    • Remove the buttons from the side of the case.

  28. GE 27990G3 Cordless Phone Teardown: adım 28, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 28, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 28, 3 resimden 3.
    • Remove 2 screws holding down the wireless module.

    • Remove 2 more screws holding down the plastic pieces attached to the circuit board.

  29. GE 27990G3 Cordless Phone Teardown: adım 29, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 29, 2 resimden 2.
    • Remove another 2 screws on the other side of the board.

    • Remove the microphone from its holder.

  30. GE 27990G3 Cordless Phone Teardown: adım 30, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 30, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 30, 3 resimden 3.
    • 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.

    • All of the cables to the main board can now be cut and the wireless module can be cut off of the main board.

  31. GE 27990G3 Cordless Phone Teardown: adım 31, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 31, 2 resimden 2.
    • Components on the main board:

    • LM324 Quad Operational Amplifier

    • Electret microphone

    • Small audio transformer

    • Reed relay

    • Same potted 'Blob' IC found in the handset

    • HEF4053 triple SPDT analog switch

  32. GE 27990G3 Cordless Phone Teardown: adım 32, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 32, 2 resimden 2.
    • 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.

  33. GE 27990G3 Cordless Phone Teardown: adım 33, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 33, 2 resimden 2.
    • Remove 2 screws to remove the charging contacts in the upper case.

  34. GE 27990G3 Cordless Phone Teardown: adım 34, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 34, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 34, 3 resimden 3.
    • Remove 3 screws to remove the speaker cover.

    • 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.

  35. GE 27990G3 Cordless Phone Teardown: adım 35, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 35, 2 resimden 2.
    • The upper case board can be removed by removing 5 screws.

  36. GE 27990G3 Cordless Phone Teardown: adım 36, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 36, 2 resimden 2.
    • Remove 4 screws on the mysterious metal box.

  37. GE 27990G3 Cordless Phone Teardown: adım 37, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 37, 2 resimden 2.
    • 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.

  38. GE 27990G3 Cordless Phone Teardown: adım 38, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 38, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 38, 3 resimden 3.
    • So what is inside the mysterious metal box?

    • Samsung K9F4008W0A-TCB0 512x8 Kb (512 KB) flash memory (designed for digital audio recording)

    • Crystal oscillator, covered in the same unusual substance found on the main board.

    • Unknown IC D16529CAC11CQC. Googling it turns up nothing that makes any sense.

    • This board is probably where the messages are stored.

  39. GE 27990G3 Cordless Phone Teardown: adım 39, 3 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 39, 3 resimden 2. GE 27990G3 Cordless Phone Teardown: adım 39, 3 resimden 3.
    • The major components on the top case board:

    • Dual 7-segment display

    • LM386 audio amplifier

    • Message indicator LED

    • This board was manufactured on July 27, 2001.

    • The speaker is a standard 2" low profile 8 ohm 0.25 watt speaker.

  40. GE 27990G3 Cordless Phone Teardown: adım 40, 2 resimden 1. GE 27990G3 Cordless Phone Teardown: adım 40, 2 resimden 2.
    • 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.

  41. GE 27990G3 Cordless Phone Teardown: adım 41, 1 resimden 1.
    • Repairability Score: 3/10

    • Base station is only held together with phillips screws.

    • Circuit boards use mainly through-hole parts, so repair of individual components is easier.

    • Removing the top circuit board is difficult because the buttons are attached to the top case with clips.

    • Opening the case requires 2 metal spudgers and a lot of force.

    • Removing the bottom circuit board is difficult because the case is still attached with soldered ribbon cables.

    • Wireless module is very hard to replace and impossible to repair.

    • All wires and ribbon cables are soldered to the board and reinforced with hot glue.

  42. GE 27990G3 Cordless Phone Teardown: adım 42, 1 resimden 1.
    • Overall repairability score: 5/10

    • The handset battery, the most likely part to fail, is a standard component and is easily replaceable.

    • Circuit boards use mainly through-hole parts, so repair of individual components is easier.

    • Entire phone is held together with phillips screws

    • Cases are difficult to open and require heavy spudgering.

    • Most parts were not designed to be repaired.

    • All wires and ribbon cables are soldered to the board and reinforced with hot glue.

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jdp23

Üyelik tarihi: 22-08-2013

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