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Scanner light bar - harmufull or not?

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    Scanner light bar - harmufull or not?

    Hi everybody,

    I recently had a chance to get rid of some older HP printer/copier/scanner device. Therefore i have kept some parts like scanner light bar (i assume it is fluorescent light bar), few borads with components, 2 motors and 2 stepper motors.

    After i removed scanner light bar and its inverter, i noticed some strange things.
    1) The light source is strong when i look at it. It definitely gives me an unpleasant feeling in my eyes like if I was staring at something very bright. But if i try to light my room with it it is not so strong anymore. For close up lighting it is very good.
    What is it that is hurting my eyes? Is it the whiteness, the brightness, the wrong wavelength? Is it worth trying to find a filter for it?
    2) I just checked the output of inverter for curiosity.. Set my DMM to 600V AC, but no luck in there - just as i touch one of the terminals of transformer output with the lead of dmm it gives a constant little spark there of some frequency and the light goes of while i touch and it is sparking there
    It is easier with light bulb disconnected, it is not as sparky anymore, but i can't see any voltage with my dmm. is shows 0,2V form time to time but that is it. Why is it behaving like that? Is my dmm way too stupid for this frequency? I have no idea what voltage i am playing with but i am sure it might bite my finger a bit if i touch it.
    3) The voltage i am feeding the inverter with is 15V but it works on as low as 4,3V (haven't tried less) with less of the bar glowing. I gave it 15V because what is what i measured on the input of the inverter while the scanner was still somewhat functional. It was jumping between 12-17V, so i gave it the average value. What voltage should i run it normally? It has a 25V lytic cap on the input, so it should be not more than that.


    It says 94-0V on the inverter. So is it the voltage i am working with??
    Attached Files

    #2
    Re: Scanner light bar - harmufull or not?

    The voltage when the tube is not conducting will be around 1000 volts at 30 kHz or something like that.

    DMM are not designed to measure voltage like that especially at that frequency.
    My pc
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      #3
      Re: Scanner light bar - harmufull or not?

      not harmful just has very high surface brightness.
      i make emergency/closet/outhouse/ect lights for solar homes with them.free from any broken office in a box junker.most are 12v.

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        #4
        Re: Scanner light bar - harmufull or not?

        you are overdriving the inverter, standard voltage is 12v but running it at 15v for testing wont kill it. just dont have it ta 15v forever.
        Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

        "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

        Excuse me while i do something dangerous


        You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

        Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

        Follow the white rabbit.

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          #5
          Re: Scanner light bar - harmufull or not?

          I agree, run it at 12v.

          DUDE! I wonder if you have destroyed your meter. They are NOT meant to measure a few thousand volts!
          Muh-soggy-knee

          Comment


            #6
            Re: Scanner light bar - harmufull or not?

            ok, thanks for answers. I ran it from crappy power supply so on load the voltage would drop to 12.something volts anyway. But it was funny as while the scanner was somewhat functional the voltage would go as high as 17.something volts before the inverter for a moment, than drop down to 12-13. I will run it from 12V form now on anyway!

            Regarding the dmm those are really rigid for this kind of abuse, and mine is fused. Or it was just me that was lucky with it? 'cause it happens that i push it to the limits once in a while But again, if i knew it was 1000s of volts at 30khz freq i wouldn't have tested it like that. It has a limit of 600V AC.

            Any ideas how to convert it to a nice workshop light? I mean what kind of filter to make it more pleasant for the eyes?

            Comment


              #7
              Re: Scanner light bar - harmufull or not?

              just place it where it cannot be looked at directly in ordinary use.
              not a lot of lumens but fine for task lights and things like closets,outhouse,ect.
              also note they need to warm up.might be nice for the nighttime outhouse run so your eyes adjust.

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                #8
                Re: Scanner light bar - harmufull or not?

                Originally posted by kc8adu View Post
                just place it where it cannot be looked at directly in ordinary use.
                not a lot of lumens but fine for task lights and things like closets,outhouse,ect.
                also note they need to warm up.might be nice for the nighttime outhouse run so your eyes adjust.
                Outhouse?! Your a century behind bro!

                You can put a diffuser over the light too, so the light will be not as bright when you look at it.
                Muh-soggy-knee

                Comment


                  #9
                  Re: Scanner light bar - harmufull or not?

                  many solar installs are way off the beaten path and away from any utilities.this includes sewer service!

                  Comment


                    #10
                    Re: Scanner light bar - harmufull or not?

                    My HP 7400 scanner has some sunburn on the lid from the light bar being on in the same position for some time.
                    My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

                    Comment


                      #11
                      Re: Scanner light bar - harmufull or not?

                      Originally posted by japlytic View Post
                      My HP 7400 scanner has some sunburn on the lid from the light bar being on in the same position for some time.
                      It's the plastic yellowing due to UV light.
                      Muh-soggy-knee

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