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Continuity Tester Teardown

Written By: Brendon Morey (and 2 other contributors)
Published: October 25, 2019
  • Comments: 0
  • Favorites: 1
  • Views: 678

Continuity Tester Teardown

Written By: Brendon Morey (and 2 other contributors)
Published: October 25, 2019
  • Comments: 0
  • Favorites: 1
  • Views: 678

Teardown

Introduction

This teardown will show the process of taking a continuity tester apart. A continuity tester is a small electronic device that can be used to test a circuit for its open or closed state. The device operates by connecting the positive and negative leads to a circuit and pressing the small black button. If the red light illuminates, the circuit is closed. If it does not, the circuit is open.

This device was fabricated in a Cal Poly Manufacturing Engineering course. All of the resistors, the switch, the LED, and the IC chip were hand-soldered to the PCB.

What you need

This teardown is not a repair guide. To repair your Continuity Tester, use our service manual.

  1. Continuity Tester Teardown, Gather Tools and Device: step 1, image 1 of 2 Continuity Tester Teardown, Gather Tools and Device: step 1, image 2 of 2

    • Not many tools needed here! Just grab your favorite Phillips head screwdriver.

    • The best size for these small screws is a PH1.

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  2. Continuity Tester Teardown, Check for proper function: step 2, image 1 of 2 Continuity Tester Teardown, Check for proper function: step 2, image 2 of 2

    • Connect the positive and negative leads to each other.

    • Press the small black button

    • Does the red light come on?

    • If so, battery is in good condition!

    • If not, time for a new 9V!

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  3. Continuity Tester Teardown, Remove side screw: step 3, image 1 of 2 Continuity Tester Teardown, Remove side screw: step 3, image 2 of 2

    • Start with either side of the device and unscrew the Phillips head sheet metal screw.

    • Remove the screw and set aside in a safe place.

    • These tiny screws are easy to lose, so grab a ramekin or small bowl to keep track of 'em!

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  4. Continuity Tester Teardown, Remove other side screw: step 4, image 1 of 1

    • Flip over the device to the opposite side and repeat the sheet metal screw removal.

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  5. Continuity Tester Teardown, Separate device: step 5, image 1 of 1

    • Separate the top and bottom halves to expose the internals.

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  6. Continuity Tester Teardown, Battery Removal: step 6, image 1 of 2 Continuity Tester Teardown, Battery Removal: step 6, image 2 of 2

    • Remove the battery connection on the top of the battery.

    • Set battery aside

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  8. Continuity Tester Teardown, Unscrew first top screw: step 7, image 1 of 2 Continuity Tester Teardown, Unscrew first top screw: step 7, image 2 of 2

    • Using the same screwdriver, unscrew one of the top screws that holds in the circuit board.

    • Hold the nut on the back with another finger to keep it from spinning.

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  9. Continuity Tester Teardown, Unscrew other top screw: step 8, image 1 of 1

    • Using the same process as step 7, loosen the other top screw.

    • Don't forget to hold the nut on the back of the screw!

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  10. Continuity Tester Teardown, Remove star washers: step 9, image 1 of 1

    • With the nuts off of the screws, remove the two star washers and set them in your bowl of hardware.

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  11. Continuity Tester Teardown, Extract the circuit board: step 10, image 1 of 2 Continuity Tester Teardown, Extract the circuit board: step 10, image 2 of 2

    • With the nuts and washers off, remove the circuit board from the top shell.

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  12. Continuity Tester Teardown, Observe the circuit board: step 11, image 1 of 1

    • This is a resistor. There are 5 of them on this board!

    • Here we see the LED.

    • This is the Texas Instruments IC Chip. It is the brain of the operation.

    • In this device a ON Semiconductor (formerly Fairchild Semiconductor) LM311M voltage comparator was used

    • This is the Panasonic switch.

    • This is a little diode.

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  13. Continuity Tester Teardown, Remove first nylon spacer: step 12, image 1 of 3 Continuity Tester Teardown, Remove first nylon spacer: step 12, image 2 of 3 Continuity Tester Teardown, Remove first nylon spacer: step 12, image 3 of 3

    • These little spacers keep the circuit board from being smashed against the top shell.

    • Using the best tool (your fingers) remove the first spacers from the screw.

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  14. Continuity Tester Teardown, Remove second spacer: step 13, image 1 of 2 Continuity Tester Teardown, Remove second spacer: step 13, image 2 of 2

    • Remove the second spacer from the screw.

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  15. Continuity Tester Teardown, Remove screw from top shell: step 14, image 1 of 2 Continuity Tester Teardown, Remove screw from top shell: step 14, image 2 of 2

    • Take the first screw out of the top shell.

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  16. Continuity Tester Teardown, Remove last screw from top shell: step 15, image 1 of 2 Continuity Tester Teardown, Remove last screw from top shell: step 15, image 2 of 2

    • Take the last screw out of the top shell.

    Edit

  17. Continuity Tester Teardown, Done!: step 16, image 1 of 2 Continuity Tester Teardown, Done!: step 16, image 2 of 2

    • Sit back and observe your hard work.

    • Arrange the parts for a nice pic for your portfolio!

    Edit

Author

with 2 other contributors

Brendon Morey

Member since: 10/25/19

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