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Fluke 8060a Custom LCD

I've had a number of 8060s with failed displays and always wanted to design a replacement... so I did!

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I first got my hands on a Fluke 8060A multimeter in 1990, and 30+ years later I began "collecting" them... at one point I had over 25! I've since pared way down but have kept a few, my favorite being a blue IBM branded unit that came with the original soft case, England leads and the notorious screen bleeding affliction that is common to these older devices. After working through a variety of different display ideas and exercises, I finally bit the bullet and designed a drop-in LCD replacement.

Coming around to designing a custom LCD for the Fluke 8060a took a few failed starts.  

Years ago I saw a post on ModemHead's awesome blog where a user named Dmitri built a custom LED-based display for his 8060.  I thought this was extremely cool so I reached out to ModemHead and he put me in contact with Dmitri who told me more about his display.  I struggled with cutting a test template on a crude drill press "mill" and ultimately tabled the idea while I explored fitting the 8060 with an OLED instead.  That was a non-starter because of the hardware required to convert the LCD drive signals to data for the OLED, and that it would have to fit and operate in a battery powered meter that doesn't have a lot of extra interior space.

Then one day while scrolling through Hackaday I saw a charlieplexed display by Bobricius, where he used the fabricator to cut segments into a pcb!  That gave me the idea to merge Dmitri's display concept with Bobricius's build technique... My new plan was to build a display using 2 layers of pcb and some translucent epoxy.  The top pcb would be routed out in the shapes of the digits and other indicators I needed, and would be attached to the lower pcb which would mate with the multimeter's existing LCD pads on one side and host 40-something tiny LEDs on the other.  The slots would be filled with the epoxy to diffuse the LEDs, and the whole assembly installed into the existing display carrier.  

I started a prototype before getting any boards manufactured, but the tiny LEDs were too fiddly for me to work with and I realized I didn't have enough time, patience, or skill to build them.  I had 4 meters left that needed new displays and without any real smd tools (stencils, reflow oven, pick and place etc) the work would have been extremely tedious... so I tabled that idea too.

Some time later I stumbled across an eevblog video series Dave did on making custom LCDs, and I figured what the heck - why not give it a shot?  This project is the result of that effort.

  • Testing the samples!

    ogdento11/17/2022 at 05:31 0 comments

    I sent my custom LCD plan off to a few different manufacturers, some I never heard back from but I did finally get a quote I was comfortable with.  After finalizing some details regarding order quantity and price, and actually paying for the samples, it was a not-too-long wait for them to arrive.  I was a happy guy when the samples arrived!

    Included in my quote were new elastomeric strips, but I messed up one dimension of the strip and they didn't fit, so I need to re-measure and get new samples of those.  Apparently you're supposed to allow some extra percentage for the eventual compression of the strip, but I allowed too much.  Live and learn.

    In any case, I was able to re-use the original elastomer from the display - which happened to be the older round/hollow elastomer vs the newer pink foam sided strip that seems to be more common nowadays.  As this was the first LCD I'd ever designed and had manufactured, I was over the moon when I popped my first sample onto the meter and powered it up... I immediately saw the power on test with all segments on, and breathed a very happy sigh of relief!

    I was pretty pleased with how it came out - especially since I'd never attempted this before!  The digits are a little taller and a little skinnier - more like the Fluke 83/5/7 iii series, but I think they look good on the 8060a.  The font I chose is a touch larger than the original but is clear and easy to see.  Considering I didn't take an exact copy from the manual or a photo - which would have been easier than drawing it all myself - I quite like it!

    Now I've got to wait for new elastomers and get to fitting some replacement LCDs in my remaining meters.  I'll eventually make these available for sale, but I'm a little ways off yet.

  • Designing the custom LCD

    ogdento11/17/2022 at 05:21 0 comments

    Dave at eevblog posted an excellent video series on designing custom LCDs, so I watched those a number of times.  I also found another eevblog user who posted a great writeup of a replacement LCD he designed for his Tandy/Radio Shack TRS-80 PC-1 (coincidentally I desperately wanted one of these when I was a kid).

    The Fluke 8060a manual has a pretty good image of the display... it's not exactly the same as what you see on the glass, but it would have been close enough to use for a replacement.  However, I didn't feel quite right copying the work done in the manual, and I wanted to make a few of my own tweaks anyway so I created my own graphics for the LCD.  

    I used Inkscape to draw the segments how I wanted them... I increased the digit size a tiny bit and also dropped the continuity bar down a little bit from the top of the display so I'd be able to see it better.  (with the original display I sometimes struggled to see if the continuity bar was ON, since it wsa so close to the display bezel which often cast a shadow on the top of the LCD)

    The LCD details are:

    1. Display Type - TN/Positive
    2. Polarizer Type - Reflective
    3. Drive Mode - 1/2 Bias, 1/2 Duty
    4. Operating Voltage - 3V
    5. Viewing Direction - 6 o'clock
    6. Connector Type - Elastomer

    The 8060 display pinout is:

    pin  H1    H2
    ---------------
    1    H1
    2    cont  bar
    3    rel   audible
    4    A0    B0
    5    G0    C0
    6    E0    D0
    7    F0    DP0
    8    A1    B1
    9    G1    C1
    10   E1    D1
    11   F1    DP1
    12   A2    B2
    13   G2    C2
    14   E2    D2
    15   F2    DP2
    16   A3    B3
    17   G3    C3
    18   E3    D3
    19   F3    DP3
    20   1/2   1/2
    21   BT    NEG
    22   K     HZ
    23         H2

    The Inkscape image, the LCD details and the pinout then went into a document that I could send off to an LCD fabricator for a quote.

  • Scoping the display driver

    ogdento11/17/2022 at 05:02 0 comments

    The display in the 8060 is driven by a Sharp SM4a "4-bit microcomputer" which can do up to 68 segments with a 1/2 duty 1/2 bias drive.  I didn't have a clear picture in my mind of the waveform that drives the display segments so I poked around a bit with my scope.  

    The drive signal is 0 to about -3.2v overall.  The segment waveform is a ~156hz square wave, and the H1/H2 are stepped and out of phase with each other.  When H1 or H2 and the segment waveform have a 3.2v difference (this will be for half of the H1/H2 cycle), that segment is ON.  The other half of the cycle has a difference of 1.3/1.8v and the segment is OFF.  The average voltage for the cycle is zero - otherwise the LCD would be damaged.

    Here's a shot showing the drive signal for turning on the Rel segement, which is connected to the H1 common (notice that there is a delta of 3.2v - so it's ON - for 1/2 of the cycle):

    Here's the signal when the segment is off (notice that no segments have a 3.2 volt delta):

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saileshchhatpar wrote 01/18/2024 at 05:33 point

I had issue of LCD blackening, long back, it's the glue on the polarizer, at the back of LCD which hardens (humidity plays a big role in it). I removed the polarizer with thin aluminum foil on it and replaced with another non-sticking polarizer and aluminum foil (mounting

them is a bit tricky). Replaced the front polarizer too.

If the LCD is not broken and u need to reuse it then cleaning the stuck glue is not as easy job. It took me about 1 hr to do so with isopropyl alcohol.

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Zero Mho wrote 01/17/2024 at 00:18 point

I have a couple of 8060A meters, both of which have failing displays. I was contemplating doing exactly what you have done here having also seen Dave's LCD videos.  Fortunately, I just stumbled on your excellent project.  Since you've already done the heavy lifting, there's little point in me duplicating your successful effort.  Would you consider getting another small batch made and make them available for purchase by 8060 fans like me? (and @Anders Dinsen ?)  Thanks!

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Anders Dinsen wrote 11/20/2023 at 06:13 point

Impressive and nice work you've done there! I have an 8060a with the display working well except that the elastomeric strip has been deformed and doesn't connect well any more. I'm trying to solve that. I'm interested in buying a replacement LCD as a spare to keep my meter going. Do you have any left?

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ogdento wrote 12/11/2023 at 01:14 point

Hey Anders, I haven't got any left at the moment but I'll reach out once I get more.

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Anders Dinsen wrote 12/11/2023 at 18:08 point

Great, thanks, please do! :)

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Bharbour wrote 11/17/2022 at 14:10 point

Good writeup, Thanks! I have 2 of the 8060's in my shop, both still look good.

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ogdento wrote 11/17/2022 at 16:33 point

Thanks so much @Bharbour.. I actually checked out your home made led displays back when I started down this rabbit hole.  I just re-visited your project and chuckled when you mentioned how much of a pain they'd be to assemble!

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