John Wiltrout's Blog

  • Vacuum Chamber for Pulling Wires through a Sheath

    jw0752
    This is my first Blog in over a year so you will probably not see any improvement in my style or deliver from previous attempts. I have a hobby business where I repair or recondition specific parts for various pieces of Dental Operatory Equipment. On...

  • Grafting 2 Damaged Circuit Boards

    jw0752
    In the picture above we have two circuit boards from two Dental Table Top Sterilizers. The board on the left has had a solder joint crystallize, arc out, and set fire to the back of the board. The board's logic section is still working properly b...

  • Solder Wick Repair of Damaged Circuit Board

    jw0752
    The circuit boards used in the counter top sterilizers of the medical and dental industries are subjected to a lot of stresses. The high moisture content in the air combined with the heating and cooling inherent in their operation puts them at higher...

  • Climate Change Anyone?

    jw0752
    This is about 5 weeks early even for us:   Slip or get your feet wet I refuse to shovel in October! John

  • Repair of a Burned Circuit Board using Grafting Technique

    jw0752
     This is the main circuit board from a Dental Clinic Sterilizer. It is a very popular brand that has been sold extensively across the USA as well as internationally. One of the power outputs of the board is controlled by a 30 amp relay that powe...

  • Lie Detector  Fact Checker and Commentator

    jw0752
    Recently I have been having a hard time watching my television. There are a lot of people on the TV lately who like to make up things and tell lies or at least bend the truth around so that one can not tell which end of the horse to kiss. These alter...

  • How I poked out an Eye of my Oscilloscope - A cautionary tale

    jw0752
    For about a year I have owned a Hantek 8060 dual channel oscilloscope. I have been very pleased with the scope as it is well suited to my needs. I use it in my simple experiments and I use it for helping me diagnose equipment that is in need of repai...

  • Repairing an Inexpensive Scope Probe

    jw0752
    Recently my scope and I had an unfortunate encounter with some high voltage and it left me with one channel out. I am slowly working through the process to see if I can fix the scope. I will blog about my journey at a later date whether I can fix it ...

  • A Do Nothing Machine

    jw0752
    The Thinker Revisited            The Thinker Revisited is an Electronic Sculpture built on an X-Ray Control circuit board. I usually salvage these boards for the parts but since I had already taken a ...

  • World Tour

    jw0752
    I got the idea for this Blog from . Since the Covid 19 has kept us from getting out and traveling I thought it might be fun to give you a short tour of my home town Chippewa Falls Wisconsin USA and to invite you to add your own tour of your ...

  • Anyone seen circuit modules like this before?

    jw0752
    I am busy salvaging circuit boards while my mind resets and a new idea for a build takes form. Yesterday I disassembled a circuit board from a Planmeca X-Ray machine (a company from Finland) that dated from the 1990s. Among the salvaged components we...

  • Playing with Circuit Boards while the Virus Storm Passes

    jw0752
    I am very lucky to have a son in the Dental Equipment Service Business who faithfully watches for circuit boards that he can salvage from discarded equipment and deliver to the old man (me). Here is the cache that I got on Friday.  Sometime...

  • Making a Load Bulb for Board Output Testing

    jw0752
    Today I am working on a circuit board from a Dental Statim Sterilizer. This sterilizer is unique in that it doesn't work by heating water inside the sterilization chamber but rather it has a separate boiler. Water is injected into the boiler and ...

  • AC Optocoupler LTV 814

    jw0752
    When I used to repair dental chairs it was very common to find a logic circuit communicating with a line voltage triac through an opto-coupler. The chair's actuators were typically 115 Volt AC motors. These opto couplers had an internal LED tied to a...

  • One of My Favorite Building Blocks

    jw0752
    I like to think of the parts and pieces in my shop as building blocks. I very seldom design my creations from the ground up. Like the Borg, I prefer to assimilate technology. Once I have a board or circuit that I find a useful building block I go to ...

  • Cheap Chinese Volt Amp Panel Meter won't zero

    jw0752
     A while back I bought 8 of these small 0 to 30 Volt 0 to 10 Amp panel meters from China. I like to use them in my builds because they have in the past worked well for my needs and they are very inexpensive. The other day when I needed one for a...

  • Exploring an Inexpensive Thermal Imager

    jw0752
    In early November told us that his NVR had died. In the course of the discussion and Ralph's experiments it was speculated that there was a short on the board that was pulling down the power supply. Over the years as I have serviced equip...

  • Walking in the Dark - Voice Activated Flashlight

    jw0752
    If you have followed my blogs you may know that I like to walk at night. During the summer months I always have a small flashlight in my pocket or in my hand. Since I dress in black or dark colors and I am sometimes in the roadway, the flashlight all...

  • "The Squealer", an Invention that didn't make it to market

    jw0752
    In January of 2009 my wife Millie and I were the owner operators of a small Dental Equipment service business. We operated out of our home town and drove 100 miles in any direction to the dental clinics of our customers to repair their chairs, lights...

  • Indianhead Electronics in Storage

    jw0752
    As I have mentioned in some of my previous posts I have been having a good time until recently trying to keep a small electronic parts house alive in the neighboring city of Eau Claire Wisconsin. Indianhead Electronics has been the business of Judy f...

  • Shop Tips - Bread Board Alligator Clips

    jw0752
    Recently I was working on a bread board circuit provided by . One of the things that I find very convenient when wiring up a bread board are short wires with an alligator clip on one end and a bread board pin on the other. I use these cables t...

  • Repurposing Salvaged Circuit Board

    jw0752
    I recently bought a power control module from a Chinese source. All I needed to do was provide the input power, up to 75 volts at 12 Amps and the module would allow me to output a digitally controlled voltage or current up to 60 Volts and 12 Amps. I ...

  • Walking in the Dark

    jw0752
    One of the things that I like to do each day is go for a nice long walk. What makes me a little unusual is that I like to do it at night when it is quiet and dark. I typically leave the house about 11 PM and walk for about an hour and a half. My rout...

  • Strain Relief Extractor

    jw0752
    If you do any service work on electrical or electronic devices you have undoubtedly run into strain reliefs on power or control cords that had to be removed and replaced.  I have found these devices very frustrating. They are made of a very...

  • Incorporating a PWM Control Module into a New Test Device

    jw0752
    Several weeks ago I purchased a couple of Modules that were advertised as able to provide 1 Hz to 150 kHz signal with a 0% to 100% duty cycle control.    The modules were able to be powered with 3 volts to 30 volts and would output a sign...