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Re: Reforming Capacitors: EAI Analog Computer TR-48

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  • joshbensadon
    ... Good point. I ll take them out of circuit and ramp the voltage up through a 20K resistor while monitoring current. I ll not go past say 2mA? I have a home
    Message 1 of 31 , Oct 11, 2012
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      --- In midatlanticretro@yahoogroups.com, David Gesswein <djg@...> wrote:
      >
      > Normally you either want to ramp the voltage up or if out of circuit
      > use a series current limit resistor to keep the reforming current low.

      Good point. I'll take them out of circuit and ramp the voltage up through a 20K resistor while monitoring current. I'll not go past say 2mA?

      I have a home made ESR meter, need to run tests on it to verify it's range and accuracy. I also have an LCR meter.

      > Sometimes you also get visual hints

      Nothing wrong visually.

      > Does the documentation you have specify the allowable supply
      > ripple? If you have a fixed load current you can estimate what ripple you
      > should have based on the capacitance.

      No documentation. I'm just winging it.
      There are 2 power supplies for this unit. The first one has 4 output voltages (don't recall them yet). The second power supply is smaller and has 2 output voltages, 1 is a weird voltage.

      -8V @3Amp and +2V @500mA.


      What can you do with 2V at 500mA?

      Anyway, thanks for your input. It will be a couple of weeks before I get this on my bench.

      Cheers,
      Josh
    • Bill Dromgoole
      ... Yes, In my opinion you are correct. In the early years of semiconductors most parts have three digit date codes. You have to know the approximate decade
      Message 31 of 31 , Oct 18, 2012
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        >
        > Here's a transistor with 430 on it. Would that make it 1964, week 30?
        > Transistor part number is 2N1218. Or does the 430 refer to the factory the
        > transistor was made? or other?
        >
        > Photo of transistor posted in the photos/Josh Bensadon folder of this group.
        >
        > I've seen some IC's with only a 3 digit code on them (not part of this analog
        > computer). Case in point is the following:
        >
        > CD4023BE
        > RCA H 650
        >
        > Is that to mean 1976 week 50?
        > H being the factory where it was made?
        >
        > Cheers,
        > Josh
        > ------------------------------------

        Yes, In my opinion you are correct.
        In the early years of semiconductors most parts have three digit date codes.
        You have to know the approximate decade the part was first produced to get the
        correct date.

        Sometimes you have trouble telling the part number apart from the date code.
        In the 1970s a lot of the 7400 series ic's had date codes like 7414 and a part
        number like 7404.
        I was always having trouble with those.

        A good history of early transitor marking can be found here.
        http://transistorhistory.50webs.com/index.html

        billdrom
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