Fluke 8050A LED Conversion

A common problem with Fluke 8010A, 8012A, and 8050A bench/portable DMMs is the LCD will ‘bleed’ or turn completely dark.  Replacements are hard to come by.  But if some common 7-segment LCD displays are hacked in, you get a meter that can be read in the dark.

I did this project before starting this blog and did not fully photo-document the process.  But you get the idea.

This is not an original idea.  More 8050A LED conversions from around the web:

 

18 Responses to Fluke 8050A LED Conversion

  1. Sean says:

    Have you ever done a conversion for an 8010a? Do you have any suggestions or ideas?
    Thanks

  2. William Tang says:

    My Fluke 8050A meter head (LCD) is not showing any digits and I believe the meter is perfectly functional. If I can convert the display to LED, it will be great. Is any circuitry involved and if so can you send me that circuitry so that I can do some conversion of my meter to LED display.

    Thanks and regards

    William

  3. Rob says:

    modemhead,

    Just wondering: Did you make or buy the power supply in the photos? If the later, which make/model is it? Great work with the display. I have an 8050A and the display is in very good shape. I use it all the time and, though it’s a manual ranging DMM, I still enjoy it. Great performance for such an old design. Thanks for publishing this.

  4. Alex says:

    I just purchased an 8050a with a dying LCD. Thinking about using your guide to swap for an LED. Is the schematic in the first picture all that needs to be done? Besides the pull up resistor and trace cut on the reverse of the board.

  5. Jaco says:

    Hi,

    Thanks for this mod, it really works very well.

    I would like to know if I can use this post and or content to publish it in our HAM Radio Club News Letter called “QRX” we normally have about 4 publications and we share what we have done in the past quarter.

    Thank you..

  6. Ron says:

    Hello.

    Great work Mr Modemhead! In the diagram, what resistor wattage are you using and is it necessary to insulate all the resistors? How is the LED display board fastened to the front panel? Is it hot glue? Thanks.

    Ron

    • modemhead says:

      Thanks, it was kind of a bodge job, but even after 3+ years, it’s still working great. The resistors are 1/8 watt. I insulated the connections just to keep them from accidentally shorting to adjacent wire. Probably overkill.

      The LED board is indeed fastened with a small bead of hot glue. You can barely see it in image #10. And if I recall correctly, that excess board sticking out on the left had to be trimmed off because it bumped into something.

  7. Ron says:

    Hello!

    I purchased the prototype boards, resistors and LED’s. The only thing left for me to buy is some hookup wire. What gauge and wattage do you recommend? Thanks.

    Ron

  8. AC says:

    With the design shown on another web page http://lous.home.xs4all.nl/fluke/Fluke8050Asite.html, the circuit for “+” and “-” used a BS170 MOSFET. You chose to use 3 transistors (2N3906, 2N3904). Is there an advantage to either design or are they pretty much the same?

    It’s difficult to see in the picture, in your final installation, is there plastic film or similar material used as a clear protective cover?

    • modemhead says:

      I just used the BJT’s because I had a drawer full of them. I added drivers for the b&c (1) segments so that one CD4054 pin wouldn’t have to provide current for two segments. Those CD405x drivers are pretty weak, they’re meant for LCDs.

      The “cover” is a piece of translucent plastic salvaged from the front of an old VCR. Remember those?

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