Keithley 135 DMM

Keithley 135 4½-digit DMM.  The LCD is completely ruined.  Replacement with a generic LCD may be possible.  Stay tuned…

Update: After obtaining a 4½-digit generic LCD, it appears that to get it to fit, the LCD and the range selector knob would have to occupy the same space. Back to the drawing board…

8 Responses to Keithley 135 DMM

  1. Harvey says:

    I must have missed this one, did you ever come close to fitting another display later on?

    It looks like a good old unit, bet it was expensive in its day.

    • modemhead says:

      No the generic 4-1/2 LCD looked like it would take too much of a hack job to fit. These models seem to be quite rare, so getting an exact replacement is unlikely. I’ve seen some “Tegam” and “Omega” units that look like Keithley re-brands, but they were just 3-1/2 digit.

      Using a scope I figured out that the rest of it is probably working.

      • Harvey says:

        What a dam shame, perhaps you could post dimensions and pinouts for the type of display required, someone may find a compatable 🙂

        I did look through R.S, but they seemed pointless.

  2. Mark Hughes says:

    You could probably hack surface mount LEDs into 7 segments and still have room to for some surface mount chips to glue it to the main board.

  3. Emi Bemol says:

    Have you had any luck with this project?

    I’ve recently got an identical Keithley 135 with the same LCD issue. It’s a shame to waste an entire functional DMM because of some crappy LCD that didn’t withstand time 🙁

  4. Frank says:

    I also have a Keithley 135 DMM that has a bad LCD display. Pity there is no replacement. A long time ago I ordered one from Keithley which was then supported by Fluke and they sent me a LCD for a Fluke 8020A DMM. It does not fit.
    Please post if you ever find a solution.

  5. EB5AGV says:

    One more to the queue… I have just found today a fleamarket Keithley 130 with a completely darkened LCD :-(. It has been just 2.50€ but it is a pity it is not useful due to the LCD.

    Please, any news will be welcomed.



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