About

From an early age, I was always fascinated by all things electronic, electrical and mechanical.  I have always wanted to know how things work.  And when things don’t work, it’s a personal challenge to make it work again.

I am young enough to barely avoid the vacuum-tube era, but old enough not to be interested in Arduinos and USB-connected gadgets containing legless microscopic bits that I can’t see without the aid of optics.  Instead I am drawn to the technology of the time when I was discovering the most about electronics.  Repairing 8-track tape players in high school, hanging out at Radio Shack, and later earning an electrical engineering degree.  Yeah, I was a geek before being a geek was cool.

Fluke 70 Series DMMPresent day, enter eBay.  An endless resource of broken and derelict things that don’t work.  Fluke, Tektronix, and Hewlett-Packard equipment that can still stand as premium examples of design, engineering and reliability.  You know, from back when the USA actually made stuff.  Available for pennies relative to the prices they once commanded, not all that long ago.

Herein are a few chronicles of repair, restoration and appreciation of that technology.  I hope you find it interesting…

12 Responses to About

  1. Harvey says:

    Dear mrmodemhead

    Wondered if you would mind me asking a question, you really seem to enjoy repairing things like me, but im stumped this time 🙁

    I have a fluke 8050a bench multimeter and on the 2m ohm resistance range it has a mains pickup problem, or thats what it looks like.

    If i put say a 680k resistor direct to the com/v/a/ohm terminals it reads the value fine, but when its leads are pluged in and the resistor on the probes it wanders around in reading, and putting my hands on the leads just upsets it more.

    have you seen this problem before, does yours do it?

    Its a smashing meter, i just cant see why its doing it.

    Tryed different mains cables and different mains outlets, same result, different probe cables tryed as well, the unit is dry and the psu seems fine, im confused 🙁

    Any answer would be appreciated, even if its “Go away” 🙂

    • modemhead says:

      Welcome friend.

      Try using alligator clips to connect the resistor and then stand back. If the meter reads steadily, then it’s OK.

      For anything over about 500K I can only get a stable reading by using clip-on leads, or by holding the probes VERY firmly and VERY still. Just waving my hand about affects the reading, and this is true for any whiz-bang meter I have here, not just the 8050A.

      Let’s do some math. When I hook up a 680K resistor to my 8050A, I read 83mV across it (with another DMM). 83mV/680K is around 122 nA. That’s nano-amps. A very tiny current. It’s no wonder that the readings are easily influenced, considering I can read several volts off the end of my finger with a 1Meg oscilloscope input. That’s at least two orders of magnitude more voltage than the 8050A is using to measure the resistor…

  2. Harvey says:

    Thank you for your kind reply about my 8050a fluke 🙂

    I suppose its just me being daft and comparing it to the much higher current resistance range of cheaper meters, i think ill nip outside and shoot myself 🙂

    Perhaps over the years ive never needed to test higher values to any close accuracy, and i must have used my very old decrepit micronta 22-191 digital to do quick yes/no checks.

    Thank you for your time and patients for my stupid brain 🙂

    • modemhead says:

      Don’t beat yourself up. It’s an interesting question and the concepts may not be immediately obvious until you think of the scale of the currents and voltages involved in having a single instrument measure anything from 0.1 ohm to 20 Megohms. I use resistors mounted on dual banana plugs to check multimeters. If a meter can read a 10 ohm and a 10 Megohm resistor correctly, it’s probably in pretty good shape.

      Also, I’ve noticed that mains-powered meters are more susceptible to noise issues, presumably due to being more capacitively coupled to the mains. I have had my 8050A couple noise into a circuit I’m working on. It’s always good to have a reliable battery-powered floating meter at hand. Or maybe several… 🙂

  3. harvey says:

    Yes i have to agree, some days the brain is very crispy and can see the light, and other days i would not trust myself to stur a cup of tea lol 🙂

    I have an old avo model 8 for peaking analog i.f strips in radios, or just to see a wandering voltage, digitals are great for static voltage but this old avo i repaired 6 years ago is still a great tool 🙂

    I also have a few of the cheap-n-cheerfull £5 icl7106 based meters, yes they are very cheap but for general go/no go checks they perform really well for what they are.
    Checking bits in cars mostly, resistance/voltage mainly.

    You have a great site, ive been though your repairs with great interest, ive allways been a nosey person cracking the case open of a new device and wearing the components out with my eyes lol, love seeing people succeed to repair things 🙂

  4. Nathan says:

    I have thoroughly enjoyed your site. Sincere thanks for sharing with us all. At 46 years old it appears all of my favorite test instruments are no longer in production. I still use the Hioki 3211, Beckman HD100, Tif 1000, Wavetek 2020, and 3M Scotchtrak TK-6B circuit tracer. The Tif with it’s easily discernible red led display being a particular favorite.

    Regards,
    Nathan

  5. Richard says:

    I have a DVOM, not a fluke but the jacks are similar… But each is a single jack with plastic locator pins and 2 soldered connections to the board. Is there anywhere these can be stolen bought or bribed for?

    I am having no luck and this far I sacrificed a set of leads and have them soldered to the DVOMs circuit board.

  6. mark hodsman says:

    Hello to you!
    Just wondered if you had any donor parts for my 8060A?

    the rear battery case hatch is struggling to do its job properly. Also the display plastic outer is badly scarred. Don’t know how to post images here so description only…

    Have to say this has fulfilled my needs for 20 years. Not tempted by auto flukes or scope meters just yet….
    If I do get one one day I will pass this on to you no charge.
    Thanks for your blog!

  7. mark hodsman says:

    aargh…cannot believe this. Just plugged an unpowered jack into the right socket and 8060A has just died. Could be diodes I guess near the socket but I have no meter now.

    This is the 3rd failure of stuff in two days. An arduino that fails to communicate a bench power that generated the magic smoke and now this.

  8. Eric jacobs says:

    Just read your article it was great I have an 8060a that I can’t seem to get the polarity indicator I cleaned the contacts on the board and the tiny contacts on the back of the LCD which fixed the digits but I still get no polarity any thoughts thank you in advance

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