Analog Oscilloscope

Discussion in 'General Electronics Chat' started by dukeman, Dec 20, 2012.

  1. dukeman

    Thread Starter Member

    Feb 7, 2009
    13
    0
    Hi,
    I have a old Beckman 20MHz analog. Recently, I found out that the trace is not stable. For instance, the ground trace can not stay at the center line, and it keeps moving up.
    Is there way to fix it? Or should I just get rid of it?

    Best,

    Dukeman
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    You need a circuit to help fix this...
     
  3. crutschow

    Expert

    Mar 14, 2008
    13,028
    3,237
    Does it eventually stabilize?
     
  4. nado

    Member

    Dec 17, 2012
    40
    1
    Any thing is fixable. They will help you along the way. But it's not worth your money or time. Sell at the eBay. There plenty of people who can fix easy at no time.
     
  5. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    A drifting trace usually indicates drift of the balance in the various differential amplifiers OR lack of stability of power supplies. Search the internet with the model number of the scope and if you are lucky, a service manual may be available.

    Back in the day, we had machines that had vacuum tube differential amplifiers. Balance on these was checked/adjusted at least every 8 hours since it would have an effect on machine position accuracy.
     
  6. dukeman

    Thread Starter Member

    Feb 7, 2009
    13
    0
    After turning around the volt/div knobs several times, taking from a suggestion from a friend of mine, the traces would get stabilized after the scope is sitting with power on for a while. I decided to keep the scope.

    Thanks for all our suggestions.

    Best
     
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