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RK05 battery pack for emergency head retraction

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  • B. Degnan
    Found from the manual that the batteries are associated with the H743 voltage regulator.
    Message 1 of 6 , Dec 27, 2012
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      Found from the manual that the batteries are associated with the H743
      voltage regulator.
      http://bitsavers.trailing-edge.com/pdf/dec/disc/rk05/DEC-00-RK05-DA_RK05main
      t_72.pdf

      thanks for the tip, I do run the system somewhat frequently, but I never
      thought about the batteries in each drive's power supply system. They
      probably will not leak unless they're incredibly old, I *assume* the
      previous owner replaced them, but I will make this a priority to address.

      Bill
    • David Gesswein
      ... They are nickel cadnium so will leak after enough time though not as bad as some other types and only metal below them. The origional has a plastic sleve
      Message 2 of 6 , Dec 28, 2012
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        On Thu, Dec 27, 2012 at 11:08:08PM -0500, B. Degnan wrote:
        > Found from the manual that the batteries are associated with the H743
        > voltage regulator.
        > http://bitsavers.trailing-edge.com/pdf/dec/disc/rk05/DEC-00-RK05-DA_RK05main
        > t_72.pdf
        >
        > thanks for the tip, I do run the system somewhat frequently, but I never
        > thought about the batteries in each drive's power supply system. They
        > probably will not leak unless they're incredibly old, I *assume* the
        > previous owner replaced them, but I will make this a priority to address.
        >
        They are nickel cadnium so will leak after enough time though not as bad
        as some other types and only metal below them. The origional has a plastic
        sleve around the entire pack which also contained most leakage. Next time
        I replace them I probably will see if supercaps will provide enough energy
        so the repair is permanent.
      • B. Degnan
        ... retraction ... http://bitsavers.trailing-edge.com/pdf/dec/disc/rk05/DEC-00-RK05-DA_RK05main ... never ... address. ... plastic ... time ... energy ... By
        Message 3 of 6 , Dec 30, 2012
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          -------- Original Message --------
          > From: "David Gesswein" <djg@...>
          > Sent: Friday, December 28, 2012 9:30 AM
          > To: midatlanticretro@yahoogroups.com
          > Subject: Re: [midatlanticretro] RK05 battery pack for emergency head
          retraction
          >
          > On Thu, Dec 27, 2012 at 11:08:08PM -0500, B. Degnan wrote:
          > > Found from the manual that the batteries are associated with the H743
          > > voltage regulator.
          > >
          http://bitsavers.trailing-edge.com/pdf/dec/disc/rk05/DEC-00-RK05-DA_RK05main

          > > t_72.pdf
          > >
          > > thanks for the tip, I do run the system somewhat frequently, but I
          never
          > > thought about the batteries in each drive's power supply system. They

          > > probably will not leak unless they're incredibly old, I *assume* the
          > > previous owner replaced them, but I will make this a priority to
          address.
          > >
          > They are nickel cadnium so will leak after enough time though not as bad
          > as some other types and only metal below them. The origional has a
          plastic
          > sleve around the entire pack which also contained most leakage. Next
          time
          > I replace them I probably will see if supercaps will provide enough
          energy
          > so the repair is permanent.
          >

          By the way, thanks for the great web site, I really appreciate the time and
          effort put into putting all this together...I am getting closer to having a
          "DEC teletype" set up, by following these directions
          http://www.pdp8online.com/pdp8cgi/query_docs/tifftopdf.pl/CHD/LT33_print_set
          .pdf

          Right now my teletype is stock, and only capable of receiving, but at least
          that part works great now.

          Bill
        • David Gesswein
          ... Thanks ... I was recently looking at that and either missed it or didn t see the schematic for the 4915 board. I did find a version here
          Message 4 of 6 , Dec 30, 2012
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            On Sun, Dec 30, 2012 at 02:31:11PM -0500, B. Degnan wrote:
            >
            > By the way, thanks for the great web site, I really appreciate the
            > time and effort put into putting all this together.
            >
            Thanks

            > I am getting closer to having a
            > "DEC teletype" set up, by following these directions
            > http://www.pdp8online.com/pdp8cgi/query_docs/tifftopdf.pl/CHD/LT33_print_set
            > .pdf
            >
            I was recently looking at that and either missed it or didn't see the
            schematic for the 4915 board.

            I did find a version here
            http://so-much-stuff.com/pdp8/cad/boards.php
            The free version of Eagle will dispaly them. I put a PDF copy here in
            case you don't wish to download Eagle.

            http://www.pdp8online.com/ftp/misc/4915/

            I was reparing some of my spare cards and noticed that the reader run
            drive signal was going way negative at turnoff. When I originally did it
            many years ago I didn't put a diode across the relay coil. Adding that
            made it stop abusing the drive transistor.

            > Right now my teletype is stock, and only capable of receiving, but at least
            > that part works great now.
            >
            Thats good. Hopefully you will have it fully functional. It should
            transmit without the mod, just the paper tape reader may loose characters
            and won't turn on automatically.

            Those bus bars they used on cards for power distribution are annoying
            me. One card had an intermittent where one of the pins has bad solder
            joint. Another card several of the pins were broken off entirly that
            was a pain to fix.
          • Dave McGuire
            ... Seconded! It s great stuff. In fact when I first met you in person at VCF-E in 2011, I felt a bit of celebrity shock . :) -Dave -- Dave McGuire, AK4HZ
            Message 5 of 6 , Dec 30, 2012
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              On 12/30/2012 04:15 PM, David Gesswein wrote:
              >> By the way, thanks for the great web site, I really appreciate the
              >> time and effort put into putting all this together.
              >>
              > Thanks

              Seconded! It's great stuff. In fact when I first met you in person
              at VCF-E in 2011, I felt a bit of "celebrity shock". :)

              -Dave

              --
              Dave McGuire, AK4HZ
              New Kensington, PA
            • David Gesswein
              ... This may have been unclear. It is referring to the reader run mod. Teletypes had lots of options so it can be configured such that it doesn t work. The
              Message 6 of 6 , Dec 30, 2012
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                On Sun, Dec 30, 2012 at 04:15:19PM -0500, David Gesswein wrote:
                > It should
                > transmit without the mod, just the paper tape reader may loose characters
                > and won't turn on automatically.
                >
                This may have been unclear. It is referring to the reader run mod. Teletypes
                had lots of options so it can be configured such that it doesn't work. The
                teletype does need to be set to passive transmit loop (just contact closure).
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