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    #141
    Re: PC Restarting/ Shutting off abruptly.

    I turned off the alarm clock that way once.
    Once.
    Mann-Made Global Warming.
    - We should be more concerned about the Intellectual Climate.
    -
    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
    - Dr Seuss
    -
    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
    -

    Comment

      #142
      Re: PC Restarting/ Shutting off abruptly.

      Really saggy-looking AC mains sinusoid - the top portion 'clipped' off due to ... extensive use of peak-rectifying power supplies (all kinds of consumer electronics?):

      http://www.youtube.com/watch?v=ozzp4RW5G54

      This is the result of being on kind the long-end of a power distribution line -

      - and something that PFC (which draws current during the entire 360 degrees of the AC sinusoid, rather than just during the peak and 'clipping' the incoming AC wave, as peak-detecting or peak-rectifying Power Supplies do using only diodes and caps ...

      Comment

        #143
        Re: PC Restarting/ Shutting off abruptly.

        Or it might be that a Tektronix 453 is a 1960's design they quit making in the 70's.
        Mann-Made Global Warming.
        - We should be more concerned about the Intellectual Climate.
        -
        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
        - Dr Seuss
        -
        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
        -

        Comment

          #144
          Re: PC Restarting/ Shutting off abruptly.

          Originally posted by everell View Post
          ...Air circulation is MUCH better, and notice the clever job of modifying the heat sink!
          This is why they don't let me have pistols anymore.
          veritas odium parit

          Comment

            #145
            Re: PC Restarting/ Shutting off abruptly.

            Originally posted by PCBONEZ View Post
            Or it might be that a Tektronix 453 is a 1960's design they quit making in the 70's.

            Comment

              #146
              Re: PC Restarting/ Shutting off abruptly.

              Originally posted by PCBONEZ View Post
              Or it might be that a Tektronix 453 is a 1960's design they quit making in the 70's.
              Old proverb say.........If you shoot at nothing, you will hit nothing (George Henry 10-14-11)

              Comment

                #147
                Re: PC Restarting/ Shutting off abruptly.

                IMO, He's speaking to the age/reliability of the test equipment.
                veritas odium parit

                Comment

                  #148
                  Re: PC Restarting/ Shutting off abruptly.

                  The age/reliability of the oscilloscope is probably the reason why we see the interference exactly in the place where switching PSU's make it? Or even every other oscilloscope has the same problem thus showing intereference where is actually none?
                  Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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                    #149
                    Re: PC Restarting/ Shutting off abruptly.

                    Originally posted by Behemot View Post
                    The age/reliability of the oscilloscope is probably the reason why we see the interference exactly in the place where switching PSU's make it? Or even every other oscilloscope has the same problem thus showing intereference where is actually none?
                    You mean that exact place where Voltage regulators on turbine generators make it?

                    Oh yeah, and an old scope would never clip anything....
                    Especially when the probes are properly compensated.

                    I didn't see a sticker. - Has it been cal'ed since the 60's?

                    .
                    Last edited by PCBONEZ; 08-29-2010, 12:09 PM.
                    Mann-Made Global Warming.
                    - We should be more concerned about the Intellectual Climate.
                    -
                    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                    - Dr Seuss
                    -
                    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                    -

                    Comment

                      #150
                      Re: PC Restarting/ Shutting off abruptly.

                      No I mean where switching power supplies without APFC and appropriate transient filtering make it...
                      Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                      Exclusive caps, meters and more!
                      Hardware Insights - power supply reviews and more!

                      Comment

                        #151
                        Re: PC Restarting/ Shutting off abruptly.

                        Exactly same place.

                        That trace has more problems than just being clipped which suggest the scope is AFU.
                        The rise-fall is a flat line.
                        Mann-Made Global Warming.
                        - We should be more concerned about the Intellectual Climate.
                        -
                        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                        - Dr Seuss
                        -
                        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                        -

                        Comment

                          #152
                          Re: PC Restarting/ Shutting off abruptly.

                          Originally posted by Toasty View Post
                          IMO, He's speaking to the age/reliability of the test equipment.
                          That thought never entered my mind; everything I've got here indicates a true representation as displayed by the Type 453 O-scope in the video ...

                          If he would prefer, I think I've got an old Eico or Heathkit that *does* have a dynamic range/compression issue ...

                          BTW, how does one post an image/still picture (jpg) on the forum? Guess I'll go check the FAQ for that ...

                          Comment

                            #153
                            Re: PC Restarting/ Shutting off abruptly.

                            Originally posted by GX270_user View Post
                            That thought never entered my mind; everything I've got here indicates a true representation as displayed by the Type 453 O-scope in the video ...

                            If he would prefer, I think I've got an old Eico or Heathkit that *does* have a dynamic range/compression issue ...

                            BTW, how does one post an image/still picture (jpg) on the forum? Guess I'll go check the FAQ for that ...
                            As I was saying ... I can view the 'signal' six ways from Sunday, swap channels, et cetera, the AC Mains signal always has the peaks clipped:





                            The 'clean' sinewave (for comparison) was generated by this instrument (note: It too is not currently certified to an NIST-traceable standard, but I have a warm fuzzy feeling it's working okay and would even 'fly' with it):



                            Jim
                            Attached Files

                            Comment

                              #154
                              Re: PC Restarting/ Shutting off abruptly.

                              GX270_user; As the author of that video you linked himself shows in the comment the reason for the resonance on his powerline was a failed connection, he later found it by radio direction finding a mile down his powerline, and gives a youtube link for this aswell
                              http://www.youtube.com/watch?v=uhaMJD57QwA
                              "The one who says it cannot be done should never interrupt the one who is doing it."

                              Comment

                                #155
                                Re: PC Restarting/ Shutting off abruptly.

                                Originally posted by GX270_user View Post
                                As I was saying ... I can view the 'signal' six ways from Sunday, swap channels, et cetera ...


                                I should add, I try to verify proper test equipment operation by either verifying with another instrument - or by cross checking with another type of instrument (perhaps a PC based scope or spectrum analyzer) ... I'm sure everybody does this ... right?



                                In the case above, swapping between CHs 1 and 2 on the O-scope resulted in the 'distorted' waveform always being associated with the AC Mains signal ...

                                Jim

                                Comment

                                  #156
                                  Re: PC Restarting/ Shutting off abruptly.

                                  Originally posted by Per Hansson View Post
                                  GX270_user; As the author of that video you linked himself shows in the comment the reason for the resonance on his powerline was a failed connection, he later found it by radio direction finding a mile down his powerline, and gives a youtube link for this aswell
                                  http://www.youtube.com/watch?v=uhaMJD57QwA

                                  I don't quite understand ... but, the issue with the flat-topped mains remains today (see posted image above, for instance), and was not due to the 'arcing' across an 1" air gap on an un-used circuit a mile away (the pole-pig shown fed an unused riser to an empty lot where a house had been removed). Good work hunting that down BTW. I have a full report how all this was down, BTW, in PDF format if one is interested ...

                                  Regards, Jim

                                  Comment

                                    #157
                                    Re: PC Restarting/ Shutting off abruptly.

                                    The scope isn't showing you what you think it is.

                                    1- The grid has 100's & 1000's of generators running in parallel. They aren't all going to be perfectly in sync, there will be load shifting between generators through the grid, and expecting a clean sine-wave on the grid is nothing less than naive.

                                    2- When you have to send voltage very long distances over wire, in order to have the correct voltage at the distant point from the source you have to crank up the voltage at the source. This means that loads near the source require a means of reducing the voltage is required. They aren't going to use an AC motor to spin another generator just to get a nice clean sine-wave at the correct voltage. They regulate it at the sub-stations and the method is to clip it.
                                    .
                                    Last edited by PCBONEZ; 08-29-2010, 05:01 PM.
                                    Mann-Made Global Warming.
                                    - We should be more concerned about the Intellectual Climate.
                                    -
                                    Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                    - Dr Seuss
                                    -
                                    You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                    -

                                    Comment

                                      #158
                                      Re: PC Restarting/ Shutting off abruptly.

                                      Originally posted by PCBONEZ View Post
                                      The scope isn't showing you what you think it is.

                                      1- The grid has 100's & 1000's of generators running in parallel. They aren't all going to be perfectly in sync, there will be load shifting between generators through the grid, and expecting a clean sine-wave on the grid is nothing less than naive.

                                      2- When you have to send voltage very long distances over wire, in order to have the correct voltage at the distant point from the source you have to crank up the voltage at the source. This means that loads near the source require a means of reducing the voltage is required. They aren't going to use an AC motor to spin another generator just to get a nice clean sine-wave at the correct voltage. They regulate it at the sub-stations and the method is to clip it.
                                      .
                                      Right.

                                      I suspect 'out there' on the 14 kV riser off the main 3-phase things are a lot 'cleaner' so to speak; however, it isn't true here near the end of a long residential spur feeder off that line (did I *did* mention being near the end of long spur by any chance?) ... in fact, for some reason this is one of the longer spur lines in this subdivision ... this as they say a "Power Quality" issue but I digress ... I'm going to take this up with out local 'provider' too I think ...

                                      I'm familiar with transmission and distribution too. And generation. I don't guess I mentioned that any where else so it's probably fair to mention it here ... beware how far you might go out on a limb (fair 'warning' notice given) ...

                                      One of my research activities has been to look at the lead-lag action of 'the grid as loads (and generator dispatch) change throughout the day (we here in Texas have our *own* grid; I suspect you know that already) and other assorted oddities ... one of the results of that work is a software app shown in the vid below which displays/logs the number of cycles gained/lost over a period of time ... it's interesting to see how the 'dynamics' of the system reacts over a 24 hr period:

                                      http://www.youtube.com/watch?v=W-K35uYV9UI

                                      (Note the 'reference' used is GPS-disciplined/phase-locked 10 MHz timebase)

                                      Regards,
                                      Jim



                                      Tagline: In lieu of evidence, measurements, data or facts: use conjecture, resort to extraneous or tertiary fact recitation, construct needless hypothesis and as a last resort filibuster.

                                      Oh - and move the 'goal posts' if all else fails ... (or pick another target/area of apparent weakness) ...
                                      Last edited by GX270_user; 08-29-2010, 05:30 PM. Reason: Added

                                      Comment

                                        #159
                                        Re: PC Restarting/ Shutting off abruptly.

                                        Originally posted by GX270_user View Post
                                        I'm familiar with transmission and distribution too. And generation.
                                        I did it for a living.
                                        Mann-Made Global Warming.
                                        - We should be more concerned about the Intellectual Climate.
                                        -
                                        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                        - Dr Seuss
                                        -
                                        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                        -

                                        Comment

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