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Engagement
  • Author Author: three-phase
  • Date Created: 29 Jan 2018 9:24 PM Date Created
  • Views 624 views
  • Likes 8 likes
  • Comments 4 comments
  • voltage_probe
  • proving unit
  • kew 1700
  • test for dead
  • kewtech
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Uh-oh broken my voltage probe

three-phase
three-phase
29 Jan 2018

This wasn't supposed happen - there I was happily sorting through my tools ready for a job tomorrow and my trusty old Kewtech KEW1700 voltage probe decided to exit the tool bag in two parts.

 

This is the test apparatus that I use for the test for dead procedure utilised to prove a circuit is de-energised before I start work on it. It does however have more functionality that a voltage probe and will test continuity, phase rotation and detect voltage on a single probe.

 

Kewtech KEW1700 Brochure.       Kewtech KEW1700 Manual.

 

imageimage

I am sure I put it in the tool bag in one piece? Must have been those pesky side cutters attacking it when I wasn't looking. Oh well, its useless to me now and will have to be replaced, may as well take a closer look at things!

 

image

The front is mostly shrouded by the faceplate for the LEDs that also houses the little buzzer and probe light button. The barrel at the top houses the two AAA batteries required to power it. Over on the left hand side you can just see the clip that connects to the probe within the housing. The other probe comes in on the lead on the right hand side and goes into the voltage dropper circuit.

 

image

It looks like the first component the lead goes to is an inductor and then the capacitor voltage dropper for AC voltage detection is next to it. On the opposite side the inductor feeds into a series resistor network in parallel with the capacitor circuit that looks to be the voltage dropper for DC voltage detection.

image

Not much going on underneath the LED housing, they are all surface mount LEDs with a lens cover over them, but you can now seen the probe connector much more clearly, the probe light button and continuity buzzer.

 

imageimage

The component side reveals a few more surface mount components and the main chip. The main chip looks to be some type of microcontroller. Its main identification is 38003A40V, but is also stamped KEW 1710, so looks to be bespoke made / marked for Kewtech. There is a crystal there but I cannot make out its frequency. The other 8 pin chip is 285-12 which I believe to be a voltage reference, but am not sure. The rest of the components seem to be a mixture diodes, transistors, resistors and capacitors.

 

Texas Instrument LM285-1.2.

 

imageimage

 

Looking back through my records, I seem to have purchased the Voltage Probe and Proving Unit as a pair back in 2010, so it has done a lot of work and definitely paid for itself. Looks like Have some shopping to do......

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Top Comments

  • genebren
    genebren over 5 years ago +2
    Donald, It is a shame that a fully functional device has suffered a plastics failure (case breakage). Good luck on finding a suitable replacement. In the meantime be safe when it comes to dead circuit…
  • three-phase
    three-phase over 5 years ago in reply to genebren +1
    Many thanks Gene, It does just seem like the case has split at its joint, but I cannot actually see what held it together in the first place. There are no internal clips, it just appears to be a tight…
  • mcb1
    mcb1 over 5 years ago +1
    Nice breakdown ... well not the actual cause but the parts inside. I cannot actually see what held it together in the first place I suspect it would be glued as there are no field serviceable parts, and…
  • three-phase
    three-phase over 5 years ago in reply to mcb1

    Many thanks for reading. It probably was glued, with such a low cost of these voltage probes, I would imagine they tend to get recycled rather than repaired.

     

    Kind regards

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  • mcb1
    mcb1 over 5 years ago

    Nice breakdown ... well not the actual cause but the parts inside.

    I cannot actually see what held it together in the first place

    I suspect it would be glued as there are no field serviceable parts, and if necessary the manufacturer would simply replace the palstic piece after repair.

     

    The main chip looks to be some type of microcontroller

    It has a lot of spare pins ....

     

    Nice to see you've sorted a replacement My new voltage probe has arrived

     

    Mark

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  • three-phase
    three-phase over 5 years ago in reply to genebren

    Many thanks Gene,

     

    It does just seem like the case has split at its joint, but I cannot actually see what held it together in the first place. There are no internal clips, it just appears to be a tight fit over a lip and possibly a single drop of glue just above the probe light button.

     

    I always have a backup voltage detector to put into service, so there will be no problems.

     

    Kind regards.

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  • genebren
    genebren over 5 years ago

    Donald,

    It is a shame that a fully functional device has suffered a plastics failure (case breakage).  Good luck on finding a suitable replacement. In the meantime be safe when it comes to dead circuit testing.

    Gene

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