0 Replies Latest reply on Jun 28, 2020 5:32 AM by raygen

    Fluke Scopemeter 123


      main unit and LCDHi All,


      Need some help with a faulty Fluke 123 Scopemeter if anyone has had the same issue the scopemeter has been in storage for 20 years it has not been used much in its life and only used on test bench. it was working fine about 10 years ago never had a problem, fluke want $195 just for a quote and then on top of that the repair cost new screen is about $575 US dollars according to fluke there is no serviceable parts then on top there is labour cost not much change from $1000.


      First I went to turn it on and ok dead battery fine understand still the original 20 year old battery. I ordered some new nicad batteries from amazon and I built a new battery pack for it also recycled the internal resistor and thermistor from the old pack. Battery seems to charge ok and so the battery part is fixed.


      Problem I have is with the LCD screen I know there is a few YouTube videos around, about the connection between the LCD and the board issues black lines appearing but this seems to be a different issue the backlight is working ok but nothing on screen it’s all black.


      I can see by plugging in the serial cable to pc the unit is sort of working if I view on the computer screen  using fluke view and I can scroll through the menu I can see the grid.

      I have factory reset I was able to hear the 2 beeps the unit I had still no success

      I applied some pressure near the ribbon cables with no success.


      While I was successful scrolling through the menus viewing from a PC I thought I would try some simple tasks.

      The continuity was acting strange the beep was going on and off and on random when I touch the probes

      I could not get a reading from the probe measuring DC voltage.

      I turned on the unit by disconnecting the battery and running it on just the power supply I believe this also loads the loader program no change so far not successful

      I’m thinking it is a failed component due to age driving the display data or the LCD screen.

      If a LCD is not used for a long period of time do they fail.

      Checked the following test points


      MS406 +5VA for +5V ok

      MS405 +3V3D for +3.3V ok

      MS401 -30VD for -30V (from Fly Back Converter). ok

      MS404 REFPWM1 for +3.3V. ok

      MS422: LCDONOFF for +3.3V ok


      I am looking for anyone that has experienced the same problem  and any suggestions what could be the problem


      Message was edited by: Raymond Genovese added photo