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What you need

This teardown is not a repair guide. To repair your Fnirsi FNB58, use our service manual.

  1. Fnirsi FNB58 USB tester Teardown, Remove screws: step 1, image 1 of 2 Fnirsi FNB58 USB tester Teardown, Remove screws: step 1, image 2 of 2
    • Start with the back side and use a TR6 bit to remove the four screws (circled in red).

  2. Fnirsi FNB58 USB tester Teardown, Remove covers: step 2, image 1 of 3 Fnirsi FNB58 USB tester Teardown, Remove covers: step 2, image 2 of 3 Fnirsi FNB58 USB tester Teardown, Remove covers: step 2, image 3 of 3
    • Remove first cover by carefully prying (e.g. with an old (credit) card)

    • It should not take much force

    • In the created opening, roughly where the red square marking is, there is a small plastic latch/hook.

    • Lightly press it down and pry on the back cover with the bluetooth logo.

    • This is the hardest step. Be patient and careful.

    • There is two more latches/hooks, these should not pose a big problem once the first one came lose.

  3. Fnirsi FNB58 USB tester Teardown, Remove electronics: step 3, image 1 of 3 Fnirsi FNB58 USB tester Teardown, Remove electronics: step 3, image 2 of 3 Fnirsi FNB58 USB tester Teardown, Remove electronics: step 3, image 3 of 3
    • Carefully slide out the electronics.

    • You can see a screen on a PCB in a black plastic frame.

    • Remove the PCB from the frame

    • Remove the black foam tape

    • Remove the two screws (redcircles) next to the USB-A connectors.

    • Carefully bend the plastic (pink rectangle) on the menu select button to remove the PCB.

    • If you have the FNB58B variant you should see the bluetooth module remain in the frame (green square).

  4. Fnirsi FNB58 USB tester Teardown, Reverse engineering: step 4, image 1 of 3 Fnirsi FNB58 USB tester Teardown, Reverse engineering: step 4, image 2 of 3 Fnirsi FNB58 USB tester Teardown, Reverse engineering: step 4, image 3 of 3
    • Screen labelled "NFP200H-20A", could not identify further. Probably some standard TFT display with SPI/I2C.

    • Backside main PCB:

    • Red square: Artery AT32F403A CGT7 (Main microcontroller) with orange square: W25Q128JV (128M-bit Serial Flash Memory with uniform 4KB sectors and Dual/Quad SPI)

    • Blue square: 3PEAK TPA626 TPA626 (Bi-Directional Current and Power Monitor)

    • Green square: RS2228 MCO7117 (High-Speed USB 2.0 (480-Mbps) 1:2 Multiplexer/Demultiplexer Switch). Probably to switch between the USB micro and -C inputs.

    • Pink square: IC labelled IV7NS. I think it might be a MPS MP2451DT step-down converter. Probably to always provide the 3.3V logic-level voltage for the ICs.

    • Yellow squares: could not identify. One (presumably) QFN14 labelled "UAAC CEH" and one with unknown form factor "WL5 J3".

    • Bluetooth board: pogo-pins to make contact to main board and Tuya BEKEN BK3432

Rene

Member since: 12/12/16

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