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  • Glass capacitor

    I'm working on a vintage organ and it has glass capacitors. I am not sure if I'm reading the value right. This one has 200 on it and the tolerance below. What is the value of this capacitor?

    Thanks.
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  • #2
    Looks like a diode to me.

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    • #3
      A diode wouldn't have a tolerance right? I'm pretty sure it's a vintage glass cap.

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      • #4
        Glass? Looks like polystyrene to me

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        • #5
          Originally posted by frus View Post
          Glass? Looks like polystyrene to me
          Polystyrene gets my vote too. Sometimes they fail with age, sort of prematurely. They were a bugaboo in Klark-Teknik graphic EQ's. I'm guessing yours is 200 pF. Typically the voltage spec is on the low side, 63V is common. They're also sensitive to being overheated when leads are soldered.

          Likely any competent 200 or 220 pF cap will work as a replacement if yours is bad.
          This isn't the future I signed up for.

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          • #6
            Thank you Leo_Gnardo!

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            • #7
              Looks like a 200pF/160V polystyrene ("Styroflex") capacitor. The red band denotes the voltage rating (160VDC).
              These are high quality/precision caps often found in oscillator circuits. They rarely fail but typically don't stand temperatures above 70°C.
              Last edited by Helmholtz; 07-25-2019, 03:28 PM.
              - Own Opinions Only -

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              • #8
                Originally posted by Helmholtz View Post
                Looks like a 200pF/160V polystyrene ("Styroflex") capacitor. The red band denotes the voltage rating (160VDC).
                These are high quality/precision caps often found in oscillator circuits. They rarely fail but typically don't stand temperatures above 70°C.
                That's good to know, thanks Helmholtz! Maybe K-T bought a dodgy batch way back in the 80's.

                If the suspect cap is part of an oscillator it may be best to stick with polystyrene.
                This isn't the future I signed up for.

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                • #9
                  If the suspect cap is part of an oscillator it may be best to stick with polystyrene.
                  ...and match the cap value as it may determine oscillator frequency.
                  - Own Opinions Only -

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                  • #10
                    Originally posted by Helmholtz View Post
                    Looks like a 200pF/160V polystyrene ("Styroflex") capacitor. The red band denotes the voltage rating (160VDC).
                    These are high quality/precision caps often found in oscillator circuits. They rarely fail but typically don't stand temperatures above 70°C.
                    Thank you Helmholtz. The lead broke off the one I'm replacing so it most likely didn't fail.

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                    • #11
                      Îf the circuit requires 200pF, you may wire a 220pF in series with a 2.2nF cap.
                      - Own Opinions Only -

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                      • #12
                        +1 vote for styroflex.

                        We had a local factory of very high quality Mallory Styroflex caps , so good that the main Moog oscillator one was an Argentine made one ... I guess they had closed the USA plant and sourced those made here, "the old way".

                        Then Reaganomics hit us and we lost all of our Electronics Industry and the little which survives, is run by stubborn greybeards like me who donīt know anything else so canīt switch to, say, coding (as was suggested to US coal miners ).

                        Of course, in, say, 20 years tops, even these little resistance pockets will also disappear.
                        Juan Manuel Fahey

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                        • #13
                          Originally posted by J M Fahey View Post
                          Then Reaganomics hit us and we lost all of our Electronics Industry and the little which survives, is run by stubborn greybeards like me who donīt know anything else so canīt switch to, say, coding (as was suggested to US coal miners ).
                          Or... those coal miners could become endive farmers. Yeh, that always works! Big market going unfilled for endives. Plus, it's best to give endives a spell in the dark before harvest, coal miners definitely have an advantage there.

                          This isn't the future I signed up for.

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                          • #14
                            With the value of 200 on the polystyrene cap, that could well be 20pF, where 201 would 200pF, 202 being 2nF and so on. I've been burned by those assumptions before, thinking it was 200pF.
                            Logic is an organized way of going wrong with confidence

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                            • #15
                              Originally posted by nevetslab View Post
                              With the value of 200 on the polystyrene cap, that could well be 20pF, where 201 would 200pF, 202 being 2nF and so on. I've been burned by those assumptions before, thinking it was 200pF.
                              I have an assortment of Styroflex caps from the 80s (as well as databooks). Those were/are all labelled in plain pF values.
                              - Own Opinions Only -

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