The IBM 1401 Demo Lab and Restoration Project
Computer History Museum

  • 1st IBM 1401 from Hamm, Germany (built 1964)
  • 2nd IBM 1401 from Darien, Connecticut (built 1961)
  • Card Equipment: 077 Collator, 083 Sorter, 513 Reproducer, 026 Keypunches

The 1401 Demo Lab is open
    whenever the Museum is open
Live demonstrations Wednesdays 3:00 to 3:30,
Saturdays, 11 - 11:30 Museum Schedule

For group demos, contact
Kate McGregor, 650-810-2729
New entries - also Tony Sale Award

  • Table of Contents
  • Daily Reports
  • Restoration & Docent Team Bios
  • 1950s Teams Bios
  • MajorEvents
  • Reunion & 50th Anniversary of the IBM 1401
  • 1401 Demo Lab Renovation and Grand Opening
  • Stan's 1401 restoration activity blog
  • Contacts, IBM 1401 Restoration and Presentation
    Team Chief Robert Garner (w) 408-927-1739, robgarn @ mac . com
    CHM Staff Liaison Kate McGregor (w) 650-810-2729
    Web "Master" Ed Thelen (c) 510-828-7673,
    Presentation on monitors in 1401 Room
    Image permissions, Donations

    General Pictures
    Recent visitors experiencing the memorable sights and sounds of our two working IBM 1401 mainframes at the Computer History Museum.

    Grand Opening,
    Bill Worthington
    Jim Strickland

    That looks like fun,
    can I try ??

    Jim Strickland
    w printout

    Steve Russell
    w tape cable

    Ken Ross & Dave Bennet

    Telepresent guests


    Steve & Janet Wozniak

    More Families



    WOW !!

    And fun along the way :-))

    Larger image 1.6 MB

    1401 Inspired Music
    1401 Film Trailer

    1401 Team
    Dec 2013

    Larger image 500 k bytes

    Team - 2009

    Team - 2013

    CHM Mission

    1401 Operators Panel

    Gene Amdahl, May 2010

    Doug Englebart w Bob E.

    Women brave our culture ;-)

    We have fun ;-)

    I'm not so sure!! ;-))

    Nov 2008

    IBM CEO Ginni Rometty
    visits on 11/2014

    IBM CEO Sam Palmisano
    visits 8/2011

    Joe Preston and
    Frank King

    Matthais Goerner

    full scale Founders

    full scale Founders


    1401 Demo Lab movie:
    1401 Project images from Marcin Wichary - 1, 2, 3, 4, 5, 6
    1401 inWikipedia "Our" Jim Hunt is shown working on our German IBM 1401 - And Ron Williams appears :-))

    Table of Contents - Major Topics
    Project, & Daily Reports 1403 printer General Hardware Other & Award
    Origins & Design
    also People and stories
    729 tapes 1401 Software Devel. & ROPE Demo & Education
    Continuing Maintenance
    What is an IBM 1401? Auxiliary Equipment Geek fun, Software, Apps 1401 Stories
    1401 Hardware System, Patents Core Memory Geek fun, Hardware 1401 Movies and Music ;-)
    1401 Processor SMS Cards 1401 Inventory/location Nov 10, 2009 Reunion & 50th Anniv.
    1402 Card Reader/Punch Components/Devices Related Restorations & 1440 Unit Record Equipment

    Table of Contents - Detail
    Please note: Users of dial-up lines report troubles accessing Adobe .pdf files larger than about 1 megabytes. The symptom they see indicates file corruption. The "corruption" seems to be time-outs or transmission problems. Adobe employees claim using Reader version 7 is better - or download the whole file first to your system then access it with Adobe Reader. :-((


    CHM mission statement:

    "Our Mission
    "The mission of the Computer History Museum is to preserve and present for posterity the artifacts and stories of the information age. As such, the Museum plays a unique role in the history of the computing revolution and its worldwide impact on the human experience."
    Our efforts aid the presentation efforts of the above statement.

    List of Daily Reports:
    2004, Jan, ... Jun, Jul, Aug, Sep, Oct, Nov, Dec
    2005, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec
    2006, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sept, Oct, Nov, Dec
    2007, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sept, Oct, Nov, Dec,
    2008, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sept, Oct, Nov, Dec
    2009, Jan, Feb, Mar, Apr, May, June, July, Aug, Sep, Oct, Nov, Dec,
    2010, Jan - no more daily reports, the end -
    A 1401 restoration activity blog started October 2010

    Light at the end of the tunnel.
    As the astronomers call it
    First Light. - Oct 19, 2005

    - the 1403 printer works in all 132 columns - Jan 18, 2006
    - all basic and installed optional instructions (including Multiply and Divide) work - April 26th, 2006
    - the Overlap feature is no longer stuck "ON" interfering with programmed card reading - May 27th, 2006
    - the 1402 card reader and card punch are correctly aligned and working well - mid August, 2006

    Scheduled Work Days

    The main group meets at 10 AM Wednesdays at the 1401 restoration room at the Computer History Museum, Shoreline and Hwy 101, Mountain View, Ca.

    How to visit us informally. -

    Come Wednesday at 1 P.M. for a tour of the Computer History Museum, Map of 1401 N Shoreline Blvd Mountain View, CA 94043 or this map. (The guest entrance is on the *North* side of the building.) Ask your docent to include a view of the 1401 room in the tour. Come early as some of us start leaving at 3:00 to avoid the commute traffic.

    House Rules

    1. We are dealing with artifacts of considerable rarity and historical interest, to be kept in historically accurate status as possible/practical.

    2. from "CHM Restoration Guidelines"
      "At least TWO team members must be present whenever the work on major components or the system has potential dangerous energy (either electrical or mechanical) exposure. Team members can include a member of the curatorial staff. Work is ideally conducted as a team and with a partner to share knowledge, responsibilities and to provide project continuity. Good engineering judgment and practices are to be used when working on any aspect of the machine or system or operating the machine and its peripherals.

      from Grant Saviers, Chm, Restoration Committee
      " The intent is to explicitly permit solo work on a PC, or programming, demonstration, or other cosmetic activities on systems by individuals, as long as no "dangerous energy (either electrical or mechanical) exposure" is present."
      "I would add [...] that those working on restorations do have a responsibility pro-actively notify docents and visitors of any hazardous situations. Volunteers can not be so singularly focussed on restorations that they fall short of helping to create a safe and great visitor experience.
      Also, I believe personnel safety and welfare matters should be directed to Gary Matsushita or John Hollar and if there are debates about these, they should be the arbiters."

    3. Log "everything". You might forget how some wire or structure was connected, diagram and/or photograph it.

    4. Our "official Museum contact" is Karen Kroslowitz.

    5. Emergency phone numbers, in priority order

    People and Stories

    Action Groups

    - IBM 1401 C.E.s were trained on, and expected to fix, all the below.

    1401 Processor w/ 1406 added memory, 1402 Card Reader/Punch, 1403 Printer
    729 Tape Units, Software

    Our "working" environment, - er - Play Room,

    decorations by Ron Williams, Master Welder, Court Jester, Jack of All Trades, ... ;-))


    Ed's Citation

    Amnesty ;-))

    Nov. 2005
    Mascot w Bug ;-))

    The Baby Mascot on the left was given by Ron Williams to Betsy Toole on her retirement as CHM Volunteer Coordinator. Betsy, you were so helpful, cheerful and warm - Thank You.
    New Baby Mascot

    Teasing Allen

    More Teasing Allen
    Better View

    Bug Stalking

    May 2012
    Bug stalking the Bug Stalker (already caught in another bug's web of deception) :-(( The world missed a great artist and wit :-((
    But at least fixing stuff usually pays regular :-))

    More environment, but not by Ron Williams
    < In the 1960s Camille Bounds of Gilroy made Christmas wreaths from IBM cards to help pay for her husband's tuition at Caltech. Photo credit: David A. Laws A CHM staff member said that since we are men, working with machinery, the air must turn blue occasionally. Oddly, there is no "blue air" in our 1401 room. The IBM folks said that profanity or vulgarity (especially near a customer) was grounds for instant dismissal.

    What is an IBM 1401?

    A 1401 - History and Fundamentals by Robert Garner

    I (Ed Thelen) am qualified to tell you because I used to maintain G.E. Computer equipment trying to compete with the 1401 - and I know all too well!
    Basic IBM 1401
    with added memory 16,000 characters max.

    this system had tapes

    a guide to the drawings

    1401 Core

    Simon Barratt image
    The 1401 computer, introduced in 1959, used discrete transistors to provide decimal (0-9) addressing and arithmetic. It provided an effective way for card data processing shops to convert to "computers". The 1402 card reader/punch was excellent, the 1403 printer was superb. Interfaces to magnetic tape drives, discs, and other peripherals were available.
    The 1401 software was very "primitive". No operating system, no graphical user's interface, no windows, - in other words, only your code was running, and you had a chance of knowing what was going on. :-))
    Obviously things had to get better, and we can now blame Bill Gates for everything - everyone agrees this is an improvement??
    The 1401 system was really "user friendly" - say the machine stopped because there were no cards in the card reader. You looked at the Operator's Panel, and there was the Card Read instruction. You the operator put a tray of cards into the card reader, depressed a button, the machine started to run again - and life was good - and simple :-)
    Why did we have to "improve" things?
    The 1401 has an unusual architecture, which uses "word marks" to show the end of numbers or fields. It is easy to play with *big* exact numbers. Say you have two 30 digit numbers on an 80 column IBM card. You want to multiply them and print the result. You issue a card read instruction, and the two numbers are read into memory, in decimal format. You set two word marks to define the high ends of the 30 digit input numbers, and set a word mark in the print area to define the high end of the resultant 60 digit multiply. Do a multiply sending the result to the print area, and issue a print command and the 60 decimal digit answer is on the paper in the printer. - Just try that with your 32 bit binary word Pentium C++ Windows GUI machine.
    Folks interested in the definition and development of the 1401 computer and the 1403 printer are recommended to "IBM's Early Computers" by Bashe, Johnson, Palmer & Pugh, 1986, MIT Press, pages 459-495. (Available 2nd hand) - to whet your appetite - The French proposed the transistor technology, ferrite-core memory and variable-word-length characteristic in a June 1955 conference in Sindelfingen Germany. The Americans worried about offshore development in small laboratories and did the design in Endicott. The 702-705 field terminating character was replaced in the 1401 by a special (8th) bit. It was also determined that a plug board added a great deal of cost and was eliminated. :-))

    System Characteristics of our 1401 system, summary

    1401 computer
    1,400 to 4,000 character memory, clock speed 87.5 kilohertz, time to get one character from memory is 11.4 microseconds, time to fetch a seven character instruction is 80 microseconds.

    Using a seven character add instruction (including six characters of source & destination addressing) to add two positive 6 character numbers took the above 80 microseconds, plus 2 times 11.4 microseconds to check the signs of the operands, plus 3 times 11.4 microseconds per character giving 309 microseconds. (If an addition results in a negative, more time is required to adjust the result.)

    DTL (Diode Transistor Logic) using Alloy junction transistors is mounted on SMS cards. Two styles of logic are used, "T" and "U", each having different "1" and "0" voltages. About 3,000 SMS cards are used.

    1402 Card Reader, Card Punch
    Card reader speed is 800 cards/minute (if you issue the next read fast enough) else lower per minute.

    Card punch speed is 250 cards/minute

    1403 Printer
    600 132 character lines per minute - normal alphabetic printing. Our 1403 controller has a buffer permitting concurrent computing and printing.

    Noise, with the cover closed, at about 2 feet in front is about 85 dbA. With cover open, about 94 dbA. (for details)

    1406 Extended Memory
    An added 4,000 to 12,000 characters of memory, in 4,000 character increments. Permitting a maximum memory in a 1401 system of 16,000 characters. This addition also added the Modify Address command.
    729 Magnetic Tape Drives

    Other input/output devices

    "IBM 1405 Disk Storage", based on the 350 Disk Storage (RAMAC) announced 1960
    1407 Inquiry Terminal, with typewriter
    from Bill Worthington August 1, 2008 Updated August 3, 2008
    There was also a plethora of other input/output devices which attached to the 1401. ... from 1401 manuals that I have in my stash.
    • 1009 Data Transmission Unit
    • 1011 Paper Tape Reader
    • 1012 Paper Tape Punch
    • 1301 Disk Storage (See comment below too.)
    • 1404 Printer
    • 1407 Console Inquiry Station (It was not an operator's console.)
    • 1418 Optical Character Reader
    • 1428 Alphameric Optical Reader
    • 1412 Magnetic Character Reader
    • 1419 Magnetic Character Reader
    • 1026 Transmission Control Unit
    • 1231 Optical Mark Page Reader
    • 1285 Optical Reader
    • 7740 Communication Control System
    • 7770 Audio Response Unit

    Of the machines above, I programmed the 1401 to support the 1412 and 1419 while working for a bank. While working as a Systems Engineer for IBM, I supported customers who had 1404, 1418, and 1231 machines installed. I installed the first fiber-optic version of the 1231. It was hand-carried from Rochester, MN to a college in RI.

    The 1301 Disk Storage looked a lot like the 1405, but had at least two actuator arms.
    ... the 1311 Disk Storage was much more widely used than the 1301 or 1405 Disk Storages.

    The 7330 Magnetic Tape Unit was a low cost alternative to the models of the 729.

    1401 Product Mix

    From Justin McCarthy, 3/2/2009
    - I remember the original base 1401 system was advertised to be a single cube with 1,400 Bytes of memory. However, from day one, almost every 1401 was a 2 cube system with 4K of memory. Very few 2K systems. I only remember seeing 2 single cube 1,400 Byte, 1401 Systems on the Endicott manufacturing floor. I am not sure who ordered them.

    - I believe one of the most significant options was the TAU (729 Tape) option in the second cube. Card I/O was already on the way out. Most of the large customers had large inventories and processed many transactions. The media of choice during the front end of the 1401 era, before the removable disk came into play, was magnetic tape.


    From Robert Garner, 3/2/2009

    Thanks for your reply.

    Interesting how few 1400-character machines were shipped! Although it was good there was a low-entry "proof" price point, it seems the market was lusting for a reliable stored-program core-memory machine (at a reasonable price) with mag tape to rid themselves of all their punched-card processing! (Something that Shel has told us wasn't realized by the marketing/planning folks, including himself -- who nevertheless helped to convince IBM that the 1401 was going to sell like hot cakes.)


    Looking at the monthly ship figures (I'll share graphs later this week), it looks like there was a long lead time between the 360 announcement and first 360 ship. During that time 1400 systems continued to ramp (the 1440 esp). There were several months in late 1965 where 48% of all computers in the world were 1400-family machines!

    - Robert

    From Bill Worthingon, 3/2/2009

    ... there were lots of features for customers to chose from.

    Do I want Multiply/Divide?
    Do I want Advanced Programming?
    Do I need tape?
    Do I need 4K or 8K of memory?
    Do I need 100 or 132 print positions? Etc.

    Jud adds "one of the biggest RPQ?s was the color of the top band around the covers of the cube(s). The standard color was blue, but almost every color in the book could be made available. Red was quite common, I believe yellow was next, and I saw a few others like a white, a lavender and etc."

    This meant that manufacturing was presented with lots of variations on the base product. It also meant that each system had to be tested in Endicott before it was shipped to the customer which added to the complexity. I was a customer during this time and, with each feature and component of the 1401, we were allocated x hours of test time at any IBM test center.

    Remember too that when S/360 was announced, the average time between order and delivery was about 18 months. Having joined IBM just before the announcement, I remember justifying this as a time for customers to prepare for the S/360 by using the IBM Datacenters to test their programs so that, when the S/360 arrived, it could go into immediate production. IBM also dropped two models of S/360 -- the models 60 and 62 -- and replaced them with the models 65 and 67 because those models didn't meet performance expectations. (The model 67 had virtual addressing capability and was planned to run Time Sharing System/360 [TSS].

    Reliability of the 1401 System

    From Justin McCarthy, 3/2/2009
    - As for 1401 24/7: After the 1401, I was involved in the 1440 / 1460 development and then the 360 Model 30. After the Sys /360 Model 30 was developed and in manufacturing, I spent a few years as a Product Field Engineer, chasing field problems on new 360 / Mod 30 Systems. In almost every major customer situation, the customer's first statement would be "I have run my 1401 & 1460 systems for 3 or more years at 24/7 without a trouble call, and now this new /360 (that replaced 2 of my 1400 systems) fails every other day". Many of the customers, five years after initial installation, were still running 1401 units 24/7 with little to no need for service.
    Regards ---- Jud

    from Robert Garner 3/2/2009

    Most of our 1401 restoration guys similarly cared for 360s in the field, and they've mentioned how unreliable the initial 360s were, and that they frequently were running 1401 programs (partially because OS/360 was so late along with no apps). Your summary of the situation is very compelling.

    Some IBM 1401 web links:

    1964 Ballistic Research Labs report, IBM, Columbia University, Tom Van Vleck, Van Snyder's 1401 links, mine
    LaFarr Stuart has a web page What makes the 1401 so interesting?,
    Movie of Jan 18, 2006 - progress, see #3, IBM 1405 disk storage
    1401 Data Processing System from IBM web site

    1402 Card Reader Character Set
    NO 0 1 2 3 4 5 6 7 8 9 3-8 4-8
    12 "X"& +0 A B C D E F G H I . "lozenge"
    11 "Y"- -0 J K L M N O P Q R $ *
    0 xxx xxx / S T U V W X Y Z , %
    NO blank 0 1 2 3 4 5 6 7 8 9 # @
    xxx is an illegal punch combination
    # is an = in the Fortran character set
    Mike Albaugh comments
    " [your web page] calls the 12-4-8 punch a "square". We always called it a "lozenge" Also, the "commercial" and "Scientific" character sets for the 026 were different, although at this point I only remember that the commercial '&' (12-only) was a scientific '+', and that the '#' was "something else" :-) I could have sworn that 12-6-8 was a '+' in 029 code, but you show it as "Less than", albeit unprintable."

    John Van Gardner points out

    The earliest machine that I know of that used the 7 bit BCD code was the 702 which evolved from TPM (Tape Processing Machine). The seven track 726 Tape drives used on the 702, 704 and 705 had the tape tracks labeled as 1248ABC. Your 729s have inherited this.

    Attached is a pdf file of pages 31-33 of the 702 Preliminary Manual found at: I have highlighted in yellow the pertinent part about the code.

    There is some good information about the TPM and 702 around page 213 of the book "IBM's Early Computers" by Emerson W. Pugh.

    A list of all 64 6 bit codes for the IBM 1401 in binary and collating order from Stan Paddock.

    From Bill Worthington, a reference card, ,

    And a 1401 card code from Bob Feretich

    A 1401 Card Code from Robert Garner

    HTMLized and Sorted by BCD or OCTAL value


    (from Part No. 451424 - Diagnostic Function Test)
    -LEFT PARENTHESIS 12 5 8     MZ-MINUS ZERO 11 0  
    -TAPE SEGMENT MARK 0 7 8     DE-DELTA 11 7 8
    -GROUP MARK 12 7 8     PZ-PLUS ZERO 12 0  
    -RIGHT PARENTHESIS 11 5 8     TM-TAPE MARK   7 8
    SE-SEMICOLON 11 6 8     CO-COLON   5 8
    LT-LESS THAN 12 6 8                    
    Standard Fortran printer carriage control, 1st character:
    blank, single space;
    1, top of form;
    0, double space;
    +, overprint (not supported everywhere).
    Feel free to consult your friendly Unix man page for the program 'asa' for further reference.

    Major Equipment Inventory - incomplete

    Product # Name Model Serial # Informal ID
    1401 computer . 1401-40-28421-E4 .
    1406 extended memory . 1406-40-20066-61 .
    1402 reader/punch . 1402-1-1600743-C2 .
    1403 printer . 1403-40-11401-A3 .
    729 tape drive V 0729-3534825B4 Green dot
    729 tape drive V 3534949C4 Red dot
    729 tape drive IV 35-21062-L1 .
    729 tape drive II 21062 .
    729 tape drive II 2012 .
    077 Collator . 077-40-22036 .
    083 Sorter . 33619
    (on casting)
    ?Rusty? ;-))

    Documation Card Reader instructions and software
    From: Bill Selmeier [] 
    Sent: Tuesday, October 10, 2006 4:57 PM
    To: Ronald Mak
    for when you need it, here is the software [] 
    for the Documation Card Reader.  
    Load this to a directory on a  PC, connect the usb cord from 
    the card reader,  fire up cardread.exe. (there are insturctions in 
    the included word file and the pdf) and use deckview.exe to look at 
    the file created on your disk.  Bill Worthington probably remembers 
    how this program runs if you have a problem or describe it and I'll 
    try and help.  But the best support is from Brian Knittle who wrote 
    these programs and made the usb convertor box.  He is a museum 
    volunteer that lives up in  Emeryville.
    Good Luck...

    Source of IBM cards

    THE source of IBM cards in the 1950s was - ?? - correct, IBM ;-))
    This is a receipt for a box (2000) of green 5081 cards, purchased by LaFarr Stuart, during his student days in 1957, from an IBM branch office in Salt Lake City, Utah. It was rather clear to all concerned that this was an unusually small purchase.
    A followup from LaFarr One minor detail. Apparently, IBM sold cards by the thousand which at that time accountants abbreviated with the letter M for a thousand. That is why there is a 2M on the receipt, even though it was just one box.

    I wonder if today anybody still uses M as an abbreviation? Just for fun I checked with a 1973 edition of "The American Heritage Dictionary" and for M it lists 29 uses as an abbreviation. The 28th is: "M Roman numeral for 1,000 (latin for mile)." I guess that is where it came from. Today, I think we have gone to the metric abbreviation. But, sometimes K stands for 1,000 other times 1024. Most computer geeks know which and everybody else is confused.

       Cardamation Company Inc.
       c/o Bob Swartz
    Bob Swartz died in 2011 - Cardamation is no more !!

    Stan Paddock and Robert Garner have been working on getting more unused IBM cards. It turns out that the suggested 3 million cards held by CHM aren't - and that what ever stock is held by CHM is held as "artifact" and not available to the 1401 Restoration Project.

    Stan Paddock wrote a piece appearing in VIE Vol. 4, No. 7 –
    Quoting in part from VIE Vol. 4, No. 7

    Cornering the Market

    In the recent past, the museum bought a pallet of cards left over from Cardamation* in Pennsylvania. At the time, we did not have the time to deal with them so they were placed on an upper shelf in the CHM warehouse.

    Per arrangement with Karen Kroslowitz, I went to the warehouse today where Dennis Cassar was available to lower the pallet to the floor so it could be repacked.

    The pallet contained 18 cartons that each contained 2,000 card boxes. In addition, there were 24 two thousand card boxes, not in a case.

    ... - and picture not reproduced here -

    In total, 130 boxes @ 2,000 cards per box = 260,000 cards (1,443 pounds gross weight). Along with the cards we already have at the CHM, we have a corner on the NOS** punch card market. I would like to thank Karen and Dennis for their help.

    * Cardamation, of Phonexville, Pennsylvania ceased business in December 2011 when the founder and CEO, Robert Swartz, died.
    ** In the old automobile vernacular, when a person finds a fan belt for a Model T that has never been used, it is “New Old Stock.” These cards were made in the 1980s but never used—NOS.

    The worrysome card shortage for IBM 1401 demonstration purposes appears to be over for the foreseeable future.

    • Assuming the use of 20 cards/week, one box (2,000 cards) should last almost two years.
    • Assuming the 130 boxes, and the above rate of usage, we are "set" for about 250 years :-))
    • By then, I presume the IBM 1401s will be retired from regular use :-((

    Comments about the IBM 1405 by Dave Bennet
    The 1405 was a version of the 10 million character RAMAC that was specially configured to interface with the 1401 system. It was the last version of RAMAC built. It was still in production in 1963 when I transferred into IBM san Jose. It, like other 10 million character RAMACs, used transistors instead of vacuum tubes.

    I think it would be very difficult, if not impossible, to tell any difference in appearance between a 1405 and any other RAMAC, unless you could see the nameplate or knew the differences of the internals. Heretofore, I have not been aware of any surviving 1405s on the planet.

    Dave Bennet

    Image permissions:
    Many of the images on this web site:
    a) were photographed by me (Ed Thelen), with frequent contributions by Robert Garner and others,
    b) are of property (computers) owned by Computer History Museum.
    I am advised by the Museum (July 20, 2006) that
    Judy Strebel is the media archivist at the Museum and in general, handles requests for image usage.

    To donate 1401 specific manuals, equipment or supplies to the project,
    e-mail Robert Garner or Ed Thelen

    To donate general items to the museum - from Karen Kroslowitz, Registrar

    Our curatorial team meets weekly to discuss offers of new donations, following a thorough search of our database to determine whether the Museum's collection may already include representative examples of the material(s) you are offering. Either I or the Associate Registrar will contact you if we require additional information or photographs of your item or when a decision has been reached, typically 1-2 weeks.

    Because specific information is required for the curatorial team to make decisions on donation offers, we encourage prospective donors to review the information and use the easy online donation submission form available at

    Thank you for your interest in the Museum. Our world-class collection would not exist without the generosity of prospective donors like you.

    With thanks and best wishes,


    On Going Maintenance ;-))
    I have down-played On Going Maintenance because:
    1. Afraid of scaring museum staff
    2. Usually kinda booooring, something is intermittent.
      Something reported bad, go to fix it, and it works :-(((
    3. Lots of techie blood and gore - boring for outsiders -
    But some things are "interesting" for insiders and outsiders :-))
    I think this is one

    The tape drive is neither reading nor rewinding, no commands are going to it.
    All this action when the tape drive is just sitting there, idle - no commands -
    Third tape drive on the Connecticut machine doing a dance
    From:	"Stan Paddock" < stpaddock @ sbcglobal . net >	 	 
    Date:	Tue, Mar 24, 2015 11:45 am
    To:	"1401_people"  
    The third tape drive on the Connecticut machine had a problem 
    that Ignacio (Iggy) Menendez identified and later fixed.
    But before he fixed it, 
        I took a video of it and posted it on YouTube.

    Stan Paddock

    The problem turned out to be that a carbon brush to the brake on the clutch/brake assembly for that reel was worn too short, disabling the reel brake action.

    The slight torque from the suction air in the vacuum column pulled the reel to let out tape when it wasn't needed. The tape pulled down past the lower pressure (position) sensing hole, activating the reel clutch to pull tape up in the column.

    When the tape loop was sensed to be between the top and bottom sense hole, the reel clutch should apply the brake, (couldn't) and release the pulling up action.

    some pictures (incomplete) of the clutch/brake assembly
    Simplified exploded view from 729-PartsCatalog-Form123-0405-0-Mod5.pdf


    This page started June 5, 2004
    Updated through April 23, 2015

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