DMM probes are loose after some time?

Discussion in 'General Electronics Chat' started by smilem, Nov 6, 2010.

  1. smilem

    Thread Starter Active Member

    Jul 23, 2008
    Hi, I read that DMM probes gets loose after a while if left connected to multimeter while not in use. In other words it will prolong probe (connector life) if you you disconnect them from actual DMM while not working with it.

    Has anyone any experience with this ?
    I mean springs could loosen after a while what do you think?
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    No they do not.
    I always have them inserted. But it does get loose if I unplug them often.

    But one can always tighten them, it's quite easy,
    Take a look inside the plug, u will get the idea
  3. marshallf3

    Well-Known Member

    Jul 26, 2010
    I rarely unplug my leads unless I need to change to a high current range or borrow them for another meter or piece of test equipment. Common movement in the socket usually keeps the contact fairly clean although I've been known to lightly swipe the plugs with 400 sandpaper as they age and pick up oxidation.

    Let's face it - some test leads are many steps above others, I kind of miss the old days when the ends & wire were all replaceable.
  4. smilem

    Thread Starter Active Member

    Jul 23, 2008
    Thanks, I think I'll leave them plugged in.
  5. someonesdad

    Senior Member

    Jul 7, 2009
    It depends on the construction. Cheap leads are often a cylinder of metal that are slit in two directions. Those will relax and eventually not fit well in the DMM's hole; they're easy to fix by prying apart a bit. You don't see these much anymore since shrouded plugs became popular.

    Better plugs use Be-Cu springs in their banana plugs. The springs also can relax over time and they can be fixed with some judicious prying with a small screwdriver. Be careful -- if you go a little too far, they're easy to break. I've got some 40+ year old Pomona plugs that are still working fine. With shrouded plugs, however, you'll have to cut the shrouds off to get access to the springs.

    A properly designed spring/banana plug won't be stressed beyond its elastic limit, so leaving it in the meter is fine. I have a Fluke DMM I've used for 20+ years and its plugs still work fine. Of course, the tips wear down over the years and you need to sharpen them.