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Drama, of a sort, in the AT&T power room

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  • albertjlafrance@cs.com
    The introduction to a March 1968 Bell System publication titled TD2 DC-DC Converter, Instructor Outline contains this scenario to help the instructor
    Message 1 of 2 , Jun 5, 2001
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      The introduction to a March 1968 Bell System publication titled "TD2 DC-DC
      Converter, Instructor Outline" contains this scenario to help the instructor
      impresses on his students the importance of being able to fix the converters,
      which supplied 250 volt DC power for the vacuum-tube transmitter amplifiers
      in the TD-2 (4 GHz) microwave radio equipment:

      BEGIN QUOTE from pp. G1-5 to G1-7, my comments in [brackets]:

      General ...

      Place yourself in this condition...
      3:30 PM - Friday

      Out of a crew of 10 craftsmen...
      6 are out on the road
      2 are on day offs
      1 is routining FM terminals [performing routine maintenance on the equipment
      which converts baseband multiplexed voice circuits to/from the TD-2 radio's
      70-MHz intermediate frequency input/output.]
      The other is on the test bench

      You are preparing your weekly summary

      A major failure alarm comes in...
      Power room alarms
      TD-2 bay alarms

      The loud speaker comes on from the order wire
      TD-2 system failures

      Phones start ringing

      You send your man to report on 0001 [the Official Message Network,
      Teletypewriter Circuit 0001 - a company network for reporting major outages]

      You and the craftsman go to the power room

      All DC-DC converters are down...
      Other supervisors arrive on the scene
      The Plant Manager wants to know what happened

      DC-DC converts down...

      What should be done?...
      Stop...
      Has this happened to you?
      What was your reaction?
      What did you do?
      If this hasn't happened to you...
      Don't think it cannot

      In the Midwestern Area we have had several failures to date.

      The last failure was very severe...
      30 terminal MUR's [Message Unit Radio - a single one-way radio channel
      between two terminal stations]...
      Interrupted from 84 minutes to 107 minutes
      8 through MUR's and 1 wideband data channel...
      Interrupted for 1 minute and then degraded service during the restoration
      process

      Knowledge and confidence is required...
      To handle the above situation...
      As a professional

      END QUOTE
    • ozob99@yahoo.com
      ... DC-DC ... instructor ... converters, ... amplifiers ... equipment ... radio s ... outages] ... channel ... restoration ... The TD2 plant i believe was type
      Message 2 of 2 , Jun 6, 2001
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        --- In coldwarcomms@y..., albertjlafrance@c... wrote:
        > The introduction to a March 1968 Bell System publication titled "TD2
        DC-DC
        > Converter, Instructor Outline" contains this scenario to help the
        instructor
        > impresses on his students the importance of being able to fix the
        converters,
        > which supplied 250 volt DC power for the vacuum-tube transmitter
        amplifiers
        > in the TD-2 (4 GHz) microwave radio equipment:
        >
        > BEGIN QUOTE from pp. G1-5 to G1-7, my comments in [brackets]:
        >
        > General ...
        >
        > Place yourself in this condition...
        > 3:30 PM - Friday
        >
        > Out of a crew of 10 craftsmen...
        > 6 are out on the road
        > 2 are on day offs
        > 1 is routining FM terminals [performing routine maintenance on the
        equipment
        > which converts baseband multiplexed voice circuits to/from the TD-2
        radio's
        > 70-MHz intermediate frequency input/output.]
        > The other is on the test bench
        >
        > You are preparing your weekly summary
        >
        > A major failure alarm comes in...
        > Power room alarms
        > TD-2 bay alarms
        >
        > The loud speaker comes on from the order wire
        > TD-2 system failures
        >
        > Phones start ringing
        >
        > You send your man to report on 0001 [the Official Message Network,
        > Teletypewriter Circuit 0001 - a company network for reporting major
        outages]
        >
        > You and the craftsman go to the power room
        >
        > All DC-DC converters are down...
        > Other supervisors arrive on the scene
        > The Plant Manager wants to know what happened
        >
        > DC-DC converts down...
        >
        > What should be done?...
        > Stop...
        > Has this happened to you?
        > What was your reaction?
        > What did you do?
        > If this hasn't happened to you...
        > Don't think it cannot
        >
        > In the Midwestern Area we have had several failures to date.
        >
        > The last failure was very severe...
        > 30 terminal MUR's [Message Unit Radio - a single one-way radio
        channel
        > between two terminal stations]...
        > Interrupted from 84 minutes to 107 minutes
        > 8 through MUR's and 1 wideband data channel...
        > Interrupted for 1 minute and then degraded service during the
        restoration
        > process
        >
        > Knowledge and confidence is required...
        > To handle the above situation...
        > As a professional
        >
        > END QUOTE


        The TD2 plant i believe was type 425 , usually located in the radio
        room in a central office,but not always.A power survey was done at
        each station & terminal periodically,putting the plant on battery
        discharge to verify normal operation over the few hours of design
        time;contactors were used in the 12V feed to cut resisters out &
        maintain filament voltage during discharge.The tube cooling
        blower(turbine)had a DC motor for backup during emergency AC
        power failures,and was checked at this time.The emergency engines at
        radio stations were test run(remotely) weekly.
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