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I bought today a very old second hand oscilloscope (Philips PM 3253), see picture below.enter image description here

I put the probe into a +5v circuit before a LED inside an Arduino breadboard (and checked with a multimeter +5v was on that circuit).

However, whatever knobs I turn or switches on the oscilloscope I set, the horizontal line always stays in the middle (except when I change the position knob on the bottom left).

It's my first-ever oscilloscope ... what switch/knob should I set to get a reading of +5v ... or is the oscilloscope broken?

@Update: It works now (sort of). I noticed there was a multiplication of 10 switch on the probe itself (so the difference between 0 and +5v was not visible), and had to change the main amplitude knob and the inner knob (whatever it means) and also the 0 X B Bal knob ...

But the most important is, that it works, now I have to learn what all knobs mean :-)

I made a new question, since I got some major problems using it: Oscilloscope makes my mains (fuse box) group go down (maybe problem solved)

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    \$\begingroup\$ fwiw, it's very encouraging that something comes up at all, you probably just need to dial it in correctly. you have a fun afternoon ahead of you. congrats on the equipment acquisition. btw, you have it ac coupling in the photo, but you want to measure DC... \$\endgroup\$
    – dandavis
    Commented Apr 26, 2017 at 20:18
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    \$\begingroup\$ Make sure you have a common ground. \$\endgroup\$
    – stark
    Commented Apr 26, 2017 at 20:25
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    \$\begingroup\$ What a beauty you got there! \$\endgroup\$
    – winny
    Commented Apr 26, 2017 at 20:41
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    \$\begingroup\$ It appears to be an old analog **storage \$\endgroup\$
    – glen_geek
    Commented Apr 26, 2017 at 21:33
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    \$\begingroup\$ Appears to be an old analog storage 'scope. Your photo looks to have the whole screen stored. Play with the persistence knob to keep from flooding the screen with green background. Hope you can find some info on how analog storage works - it is a very neat feature. \$\endgroup\$
    – glen_geek
    Commented Apr 26, 2017 at 21:37

4 Answers 4

Reset to default
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Try moving the switch above your probe to DC

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  • \$\begingroup\$ Just tried, but no difference, see update in 1 minute \$\endgroup\$
    – Michel Keijzers
    Commented Apr 26, 2017 at 20:22
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    \$\begingroup\$ Well it certainly needs to be in DC mode. What happens when you turn the amplitude knob to the left of your probe \$\endgroup\$
    – BertVano
    Commented Apr 26, 2017 at 20:28
  • \$\begingroup\$ That did the trick (+ the inner knob and the O X B Bal knob). \$\endgroup\$
    – Michel Keijzers
    Commented Apr 26, 2017 at 20:29
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See that BNC connector on the left, labeled "Cal."? "Cal." is short for "Calibration". Stick the tip of your probe into that (thanks to Peter Bennet for this clarification). It provides a square wave signal that's intended for calibrating probes. If you see the signal, the scope is working. If you don't see it, the calibration output might not be working, or the scope itself might not be working.

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  • \$\begingroup\$ How should I hook that up? I mean I can connect the probe connector to it, but where should I contact the end of the probe with? \$\endgroup\$
    – Michel Keijzers
    Commented Apr 26, 2017 at 21:54
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    \$\begingroup\$ @MichelKeijzers: just stick the tip of your probe into the center contact of the BNC "Cal" connector. \$\endgroup\$
    – Peter Bennett
    Commented Apr 26, 2017 at 22:14
  • \$\begingroup\$ I can try (but I'm afraid the fuse will go down again), it happens now even when not really changing a setting or putting the probe to anything). \$\endgroup\$
    – Michel Keijzers
    Commented Apr 26, 2017 at 22:15
  • \$\begingroup\$ @PeterBennett I got two lines when I tried, which seems like a square wave, however, whatever I tried with the Time knobs, I always got two lines, not any square wave. After 5 minutes the oscilloscopes set my house fuxe box group down (see question at end of my post above). \$\endgroup\$
    – Michel Keijzers
    Commented Apr 26, 2017 at 22:28
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    \$\begingroup\$ Set the main trigger mode to "Auto", trigger source switch to Ya or Yb, depeding on which channel your probe is in, set the main timebase to 1 mS/div, and adjust the Trigger Level to get a stable square wave display. The scope should not cause the main fuse to trip. \$\endgroup\$
    – Peter Bennett
    Commented Apr 26, 2017 at 22:48
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Been a while since I've used an analogue scope but try the following:

  • Connect your probe to channel B as channel A might be blown.
  • You may have a trigger enabled, use the 'level' knobs on the right to make sure it is within range. It could be expecting an external trigger so test it by applying a voltage to the Trigger BNC input
  • The switch at the top, move it from LF to DC.
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  • \$\begingroup\$ I already got it working, now I have problems with the fusing (or lack of it), and having my house fuse box go down \$\endgroup\$
    – Michel Keijzers
    Commented Apr 26, 2017 at 23:11
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You're looking at a DC signal, you need to change the coupling mode from "AC" to "DC" (switch in the middle).

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  • \$\begingroup\$ Just tried, but no difference (see update in 1 minute) \$\endgroup\$
    – Michel Keijzers
    Commented Apr 26, 2017 at 20:22

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