EEVblog #406 – Keithley 480 Picoammeter Teardown & Calibration

Teardown and calibration checking of a Keithley 480 Picoammeter Dave got from ebay.
This was supposed to be a repair and troubleshooting as well, but Murphy had other ideas.

Keithley 480 User & Service Manual

Forum Topic HERE

Be Sociable, Share!

    About EEVblog

    Check Also

    EEVblog #1029 – BGA PCB Fanout

    Dave looks at some issues with fanning out tiny 0.4mm pitch BGA packages, via pad ...

    • Hi Dave,
      Bruce Jones here, had a lot of experience with those pushbuttons back in the 70’s & 80’s. They are notorious for getting oxidized during storage, and acting just like your Keithley meter did. (Or in reverse, ‘Works OK”, take it off the shelf, and NG) A drop of contact cleaner on that power switch’s contacts, work it in for 10-20 pushes, and Bob WILL be your Uncle- Thanks for the great videos & site.

      • Thanks for the verification!

    • agussug

      Can not download the file.
      redirect to

      Best Regards

      • Yes, both and was hacked! Now fixed.

    • Jean

      Hi Dave,

      The phenomen yu experienced, when your signal calble was moved, it is called triboelectric effect.

      The world below 1pA is an interesting one.
      You won’t find too many players in this field. Just try a google search for Teraohms, femtoamperes and so.
      Maybe it worths a dedicated video?

      • f4eru

        The input wire on separate wire is to avoid the leak in the FR4 / solder stop, etc.
        Also, some guy measuring femtoamperes say that the teflon also leaks at that level…

        • f4eru

          For the best op amp : LMP7721
          Plain crazy.

    • Great video Dave, entertaining and illuminating.
      I always enjoy your teardowns of exotic old equipment.

    • @BrianJHoskins

      Hi Dave – interesting video. One small point; I noticed the manual claims 4½ digits accuracy. That’s slightly misleading of course – it really means 4½ digits resolution.

      • @BrianJHoskins

        Ah hang on I got ahead of myself there – the manual I was referring to was actually the datasheet for the ADC chip, not the manual for the instrument.

    • Uran0s

      Hey Dave,

      nice Teardown & Repair video. But it would be nice if you mark all repair videos. Would be easier to search for them.

    • Nick

      More informatio on the flying wire can be found here:

    The EEVblog Store generally ships twice a week, on Tuesdays & Fridays, Sydney time. Dismiss