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Oscilloscope Repair?

Discussion in 'Amp Tech Center' started by Faceman, Jan 9, 2020.

  1. Faceman

    Faceman Tele-Meister

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    Hello All,
    I have a Gould 2 channel Oscilloscope that just went down. The CRT no longer displays any line. When I turn it off, a dot appears before the power drains completely. When I opened it up, I saw a 40volt 150 mic cap that is clearly leaking everywhere and will be replaced but I was just curious if anyone has repaired one and has some pointers on what else to look for.

    [​IMG]
     
  2. FenderLover

    FenderLover Poster Extraordinaire

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    If one electrolytic has gone south, the rest of the scope is the same age. I'd go through and replace all of the large electro's at a minimum. Short of tracking down a service manual for it, that may be all it needs.

    I gave a friend a Tek scope a couple years ago and he recently had the same problem. He replaced filter caps and it's back in service.
     
  3. Faceman

    Faceman Tele-Meister

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    Great advice. I’ll start there and hope I have the same outcome as your friend.
     
  4. drneilmb

    drneilmb Tele-Meister

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    The best repair info I've ever seen for oscilloscopes is on the TekScopes email group. They used to be on Yahoo groups and they are now on groups.io I think https://groups.io/g/TekScopes.

    In general, a service or calibration manual with a full schematic is the most important starting point. If you have bad electrolytic caps, replace as many as you can. Then start with the power supply and work your way forward measuring voltages.

    If you can get some dot or line or anything to show up on the screen, then you're way ahead of where you could be because CRTs and they very high voltage components are nearly un-repairable.

    And, sad to say, these days it doesn't make sense to spend too much money on a scope repair because you can get a working analog scope for very cheap on eBay, or a brand new digital one for not much money, especially at bandwidths below HF.

    -Neil N0FN
     
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