Repairing a Bad Case of Cataracts on an ADM-3A Terminal

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  • Опубликовано: 14 дек 2024

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  • @ernstoud
    @ernstoud Год назад +101

    “It will give us an error hopefully.“, (c) usagi 2023.

    • @Stoney3K
      @Stoney3K Год назад +12

      "Task failed succesfully."

    • @jurjenbos228
      @jurjenbos228 Год назад +1

      And further progress is getting a different error message.

    • @FireStormOOO_
      @FireStormOOO_ Год назад +2

      Lol, I've been there. Sometimes any output at all is a win.

  • @The8BitGuy
    @The8BitGuy Год назад +193

    Great job! You lucked out finding that missing chip. And the screen looks absolutely beautiful now! I don't even see any burn-in on it.

    • @UsagiElectric
      @UsagiElectric  Год назад +40

      Thanks!
      I should have gotten on the restore a little sooner so we could have had it up and going for your video! Though, your video was the inspiration I needed to get to work on it, haha.

    • @PCBWay
      @PCBWay Год назад +15

      Caught you here A bigg helllo from PCBWayyyyy

    • @minty_Joe
      @minty_Joe Год назад +4

      @@PCBWay I ❤ PCBWayyyyyy!

  • @liquidsonly
    @liquidsonly Год назад +51

    I like how the Centurion has gone from a pile'o'bits to become the reference machine to test all the new projects with.

  • @rivards1
    @rivards1 Год назад +113

    A couple of cautions about cataracts - different manufacturers used different glues, so not all removals will be this easy. Also, prying and stressing a CRT in the wrong place can lead to implosion, so be careful! Lastly, I'd suggest re-sealing the edge of the re-installed cover all around with tape or even silicone. The static of a CRT will pull dust and dirt into any opening, then you've got debris between the CRT and shield again.

    • @KameraShy
      @KameraShy Год назад +11

      Shango066 uses silicone around the edges, leaving no gaps. Offhand I forget which brand/type he recommends.

    • @EndOfLineTech
      @EndOfLineTech Год назад

      Ah there’s the know it all boomer who thinks no one else knows anything. It’s not a proper comment section with out you. Thanks 😀
      It’s pretty obvious he knows what he’s doing, he didn’t use the wire throughout, didn’t use a metal screwdriver but a bondo spatula which is plastic, flexible, and soft just in case you didn’t know I thought I’d mention that. (See degrading and disrespectful right?). You can also tell by his confidence, and knowing exactly what to do without explaining how he knows this that he’s probably done this more times then you. So sit down.
      Lastly I’d suggest closing your mouth for a change. You got a few comments on this channel going “um excuse me retard… you know…” This is likely the one of few time it will ever be turned on again, it doesn’t matter if it’s “done right” when even your way is a hack and also not “done right” just in case you didn’t know the whole thing was glued for a reason and for shock resistance. Anything just around the edges “makes this potentially dangerous”. Just so you know 😉 anything hitting that shield hard enough will crash it into the CRT and potentially cause it to go boom. Just so you know. Oh but that’s right it’s going to be a “museum” piece so none of that really matters. Dummy

    • @EndOfLineTech
      @EndOfLineTech Год назад

      In short: your advice wassnt asked for, needed, or required. What’s up with all you old people that know everything and can’t wait to force it down everyone’s necks? It’s a dislike able trait. I can imagine you now at Christmas dinner ranting and babbling as no one pays you any attention and just goes “uh huh” “uh huh” “oh yeah..” “that’s cool”

    • @RingingResonance
      @RingingResonance Год назад +8

      @@KameraShy He also uses small bits of wood to more gently and slowly pry the shield from the tube, and lets it sit while he is away from it in case of an implosion.

    • @steve6375
      @steve6375 Год назад +6

      bugs (e.g. small thrips) can get in there too. All gaps should be sealed.

  • @mikeselectricstuff
    @mikeselectricstuff Год назад +9

    10:02 - RAM size - 24x80 = 1920 characters, 14 RAM chips is 2 banks of 1Kx7 bits per character=2048

    • @Peter_S_
      @Peter_S_ Год назад +1

      If you bought the budget version, it came without 2 of the RAM chips and the lowercase character ROM. Memory in that case was 2048 x 6 bits.

    • @8bitwiz_
      @8bitwiz_ Год назад

      @@Peter_S_ The budget-budget version only had 6 RAM chips, and displayed every other line of text. I'm going to guess it's rare to find a 12-line version in the wild, since it's so easy to add the rest of RAM and set the right DIP switch.

  • @johnm2012
    @johnm2012 Год назад +49

    10:05 14 RAM chips is 2 kilowords of 7-bit memory. ASCII only needs 7 bits to represent upper- and lower-case letters, numbers and control codes. 24 rows of 80 characters is 1920 in total.

    • @Peter_S_
      @Peter_S_ Год назад +10

      As a side note: The standard memory configuration was only 2K x 6 bits wide and the terminal came with 12 RAM chips. Two additional RAM chips and the character generator ROM gave the upgrade to display lower case.

    • @halfsourlizard9319
      @halfsourlizard9319 Год назад +6

      @@Peter_S_ Different times, eh? You want lower-case characters? Need a hardware upgrade for that schmanciness!

    • @8bitwiz_
      @8bitwiz_ Год назад +3

      The second row of RAM was actually optional. The super-cheap version only displayed every other line of text. Apparently that was a thing before 24x80 became the standard size for terminals.

  • @EmperorKonstantine01
    @EmperorKonstantine01 Год назад +20

    The Design Concept of these terminals were way ahead of their time, kind of like futuristic space age technology. Not only were they smart looking but they were also made to be very serviceable. Tremendous Job, well done!

  • @Rob2
    @Rob2 Год назад +22

    Well, William Lear was no stranger to operating in wildly different markets!
    Besides making jet planes and data terminals, he also created the 8-track audio tape system that once was popular in the USA.

    • @Colaholiker
      @Colaholiker Год назад +2

      Thanks! When he mentioned Lear, I was like "wait, there was something else completely unrelated that Lear was involved in", but for the life of me, I couldn't remember what it was. You nailed it!

    • @w9gb
      @w9gb Год назад +3

      Bill Lear grew up in Hannibal-Quincy area, at beginning of Radio Age (not far from where I grew-up).
      He moved to Chicago and became acquainted with Gavin -
      and became one of co-founders of Motorola.
      He migrated to Wichita (near my Dad’s family 1880s homestead), entered Airplane mfg.
      In early 1960s, he created the 8-track tape format for automotive industry.
      The Lear-Seigler was split-offs of business units in early 1970s.

    • @friedrichhayek4862
      @friedrichhayek4862 Год назад

      Person or company?

  • @hanksmith3628
    @hanksmith3628 Год назад +17

    Just as an FYI, back in the day (early eighties) we did a lot of development work and would need to change the baud rate, # of bits, etc., very often. So we just used a clear tape hinge up top of the DIP switch cover so we would not have to unscrew and re-screw the cover ALL. THE. TIME. Not elegant but functional. The previous owner may have had the same problem and just chucked the cover.

    • @dcmoisan
      @dcmoisan Год назад

      At my school, people just snapped the plates off.

  • @a_funyun
    @a_funyun Год назад +25

    Wow! The inside looked amazing after cleaning, you weren't kidding when you said brand new.

    • @UsagiElectric
      @UsagiElectric  Год назад

      Yeah, I was a little blown away at how well the inside cleaned up!

  • @leftyxbuffalo
    @leftyxbuffalo Год назад +22

    They became popular because they were also offered in kit form ($995) vs assembled ($1195). I built one for the Byte Shop in Raleigh NC (1974-5), and only missed one solder joint!

    • @tommythorn
      @tommythorn Год назад +1

      Oh, wow as a kit!? I would have loved that. Pray tell, what year was this?

  • @Telewaifus
    @Telewaifus Год назад +18

    For the cataract, my suggestion is first to use a body protection suit and an eye protection mask. The square CRTs in some cases don't react well if their bonding agent is removed. When reassemble the protection glass don't use the tape but silicone, so the dust don't go between the glass :)

    • @iamjadedhobo
      @iamjadedhobo Год назад +6

      Instead of silicone I'd recommend optical bonding adhesive. That will remove all reflections on the glass - air - glass transitions.

    • @SeekingTheLoveThatGodMeans7648
      @SeekingTheLoveThatGodMeans7648 Год назад +1

      Tape is good for spacing.

    • @SeekingTheLoveThatGodMeans7648
      @SeekingTheLoveThatGodMeans7648 Год назад +2

      A face mask and lab coat should suffice.

    • @8bitwiz_
      @8bitwiz_ Год назад +2

      Whatever you use to replace the original goo still needs to be about 2mm thick so that the curvature matches. Sticky foam happens to be just right, and a lot less messy than trying to put more goo in there.
      As for the strength of the glass, this is specifically for implosion protection (which is why you want to put it back!), so it's not going to suddenly explode on you.

    • @JamesChurchill
      @JamesChurchill Год назад

      OCA isn't magic, it works because it has the same refractive index as the glass it is bonded to. It's not going to be right for high-lead CRT glass and plastic, even if the shield was the right shape for it to attach directly...

  • @Peter_S_
    @Peter_S_ Год назад +47

    The chips in the ADM 3A you identify as ROM are the character generator ROMs. The chip closest to the edge is a 2513 CGR-001 which was also used in the Apple 1 and Apple ][ through the rev. 4 motherboard. This contains 64 uppercase ASCII characters. The CGR-002 next to it contains the lowercase letters and a set of special characters (including the characters to display sexadecimal values).

    • @UsagiElectric
      @UsagiElectric  Год назад +9

      Oh, wow, that's really interesting that the same ROM was used on the Apple 1 and ][ motherboards! Although, with the Apple being 40 columns (I think, it's been a while since I've seen an Apple II in person), it would have taken me a little bit to make the connection that the fonts are the same.

    • @Peter_S_
      @Peter_S_ Год назад +13

      @@UsagiElectric There was also a CM8400 version of the 2513 which contained 64 Katakana characters.
      The original full part number of the CGR-001 was the 2513CM2140 from Signetics circa 1970 and it features the 1967 version of ASCII. You have a General Instruments 2nd source for LSI with the CGR-001 part but the data is identical. The lowercase chip is house numbered with an LSI part number of 129323-02 CGR-002 and that is a VERY rare chip. I've never seen a dump of it (before a few minutes ago) and I've never seen one in the wild without it sitting next to a CGR-001. It appears to be a semi-clone of the Signetics 2513CM3021 which actually doesn't contain a 2nd copy of the punctuation but instead includes a new set of glyphs including an underlined U, V, W, X, Y, and Z to display sexidecimal numbers (See Dave Plummer's vid on sexidecimal).
      I have a vague memory of the underlined W, X, Y, etc. on a screen but I don't recall the terminal I last saw them on; possibly a Hazeltine 1510 or a Televideo 950.
      When Apple switched motherboard designs to remove the 4K DRAM addressing they also replaced the PMOS 2513CM2140 with a copy of the same data in an NMOS 2316 mask ROM, now with an Apple part number and supporting 128 (or 256?), 7 pixel wide glyphs. The uppercase is identical to Apple's font on the unenhance //e and before, but the lowercase is completely different.

    • @joe--cool
      @joe--cool Год назад +1

      @@Peter_S_ I can't seem to find the Dave's Garage video you mentioned. Do you remember the name?

    • @Peter_S_
      @Peter_S_ Год назад +1

      @@joe--cool Yes, the video is from about a year ago and it's called "HAL 9000 and the Sexadecimal Mystery - Finally Explained!"
      Sorry, I should have named it in the original post.

    • @joe--cool
      @joe--cool Год назад +1

      ​@@Peter_S_ Cool thanks a lot. The title seems to make it hard to find. Dumb algorithms.😄

  • @tommythorn
    @tommythorn Год назад +18

    I’n my 2nd year at my uni (1988) I joined the IT staff and got this very ADM3A on my desk, hooked up to a Sun 3/50. It was … ok … but a bit lacking in controls for Emacs. I vaguely recall programs using it had to use a trick to write the very last char on the screen without scrolling: write it to the penultimate position, back up, write an insert char to move it into place.
    Despite its limitation and lack of speed, I did appreciate two things that made me use longer than you would expect: it was SILENT (fanless) and it took up little space on my desk, compared to a Sun 3. (I have a soft spot for this and would love to get my hands on one)

    • @ms_nop
      @ms_nop Год назад +1

      Wow we're almost the same age! I went to UNLV back in 1989 & the library had rows of terminals, most of them ADM3a! They weren't as fun to type on but I didn't know the history at the time. The back end, through a network terminal server, was a hopelessly overloaded (during the day anyway) MicroVAX-2 which would slow to a crawl with 3 simultaneous compilations. Laid my eyes on it once on a data center tour.
      I bought from my high school a couple years back a truly rare terminal, a Liberty Freedom 100, that I used in my dorm room with a modem while there besides usual BBS duty. I want to say there was a termcap for it on the VAX but don't remember. It didn't have many emulations def not VTs. Fortunately Linux does but I no longer own it.

    • @rhialtothemarvellify
      @rhialtothemarvellify Год назад

      I think that must have been a different terminal. The Adm-3A doesn't have an insert-character functionality. That it could move the cursor to random places on the screen was already quite advanced :)

    • @tommythorn
      @tommythorn Год назад

      @@rhialtothemarvellify Apparently so! Thanks. For the record, the best information about the Adm 3A I could find was here which of course agree with you: www.bitsavers.org/pdf/learSiegler/ADM_3/DP2880486F_ADM3A_UM_Apr86.pdf

  • @available898
    @available898 Год назад +2

    Nice video about this great terminal. Back in the days when I was a student our university had rooms filled with these adm3a's which we called 'eitjes' in dutch (translates to 'little eggs'). The faculty board selected this model because they were the only ones that were 'student proof'. You could literally sit (or stand) on top of them, without breaking them. I spend years using them every day, hooked up to our pdp11 systems and IBM370 mainframe. Those where the days!

  • @JacGoudsmit
    @JacGoudsmit Год назад +6

    4:22 I don't know if anyone already mentioned it but the "integral implosion protection" refers to the metal band around the CRT, not the glass screen and the mouldy glue.
    By the way that sticky tape that you used, will probably get brittle over time and because you didn't close off the space hermetically, there will eventually be dust between the glass and the tube.

    • @8bitwiz_
      @8bitwiz_ Год назад +1

      That glass plate is designed to block shrapnel if the front of the CRT breaks during implosion. It is made of much better glass than is possible with CRT glass.

    • @retrozmachine1189
      @retrozmachine1189 Год назад +2

      @@8bitwiz_ Glue on shields are surprisingly ineffective really. The integral implosion protection refers to the metal tension band, as in it's an integral part of the assembly unlike the glue on shield. It's intended to make it more difficult for the tube to spontaneously collapse from the front, the weakest part. If you don't believe me refer to literally any CRT TV service manual. CRTs are remarkably abuse tolerant because of that tension band.
      You can see the difference between a CRT without a glue on shield and those with. Note, a glue on shield, not integral ceramic panels. Either way it goes if you are right beside it when it goes off your day just got a whole lot worse. It's not just big chunks moving around, it's all the glass powder. Breathe that in and you have a considerable problem and will need hospital attention. It's not pretty.

  • @MrDeelightful
    @MrDeelightful Год назад +9

    Ohhh, that's really cool. I love the shape of it. The way the CRT housing slopes down in the back, it's so atomic age it hurts. Love seeing your uploads!

    • @8bitwiz_
      @8bitwiz_ Год назад

      Sexiest. Terminal. Ever.

  • @bborkzilla
    @bborkzilla Год назад +4

    I saw quite a few ADM-3's attached to Altairs and IMSAIs in the late 1970's and early 1980's. Not a single one of them had the cover over the dip switches!

  • @frankowalker4662
    @frankowalker4662 Год назад +4

    Lear invented the cartridge player for cars, too. Which became 8-Track cartridges.. 👍

  • @ForgottenMachines
    @ForgottenMachines Год назад +39

    Oh, Dave you are seriously producing some amazing results here...both with this terminal AND with this video! A double bonus! So cool! Makes me proud to know you... 😉😉

    • @UsagiElectric
      @UsagiElectric  Год назад +9

      Thanks so much man!
      With our powers combined, we're keeping these weird old machines alive, one by one!

  • @Starchface
    @Starchface Год назад +1

    I cannot believe how *mint* this 3A turned out! Separating the front "shield" from the CRT was particularly satisfying to watch. I am interested to see how you tackle the missing key caps and DIP-switch covers. Truly this is a magnificent data terminal. Gorgeous.

  • @ltsiver
    @ltsiver Год назад +14

    I'm surprised you didn't use the Shango066 method of de-cataracting. He also uses the heat of the day, but is a lot more careful with the extraction of the glue, resorting to wire knife in order to not put pressure on the CRT. After cleanup, he uses a silicone based adhesive to remarry the lens to the CRT, only with a single bead on the outside edge of the CRT.

    • @IgnacyG1998
      @IgnacyG1998 Год назад +2

      He does it on large 1950s CRTs with no anti-implosion band and possibly a different glue formulation. This one was a much safer job, but not sealing the corners is still a blunder.

    • @8bitwiz_
      @8bitwiz_ Год назад +1

      I did mine this way a few years ago, except I was being careful and only nibbled away a little at a time with a hook-end tool. That spatula thing did it much faster. But yes, the big difference is that this is a much smaller screen, so no need for a heat gun. And the edges do need to be sealed to keep dust from getting in. I used clear packing tape on mine, no need to be perfect because the lid hides so much of the CRT edge.

    • @hotsauce2446
      @hotsauce2446 Месяц назад

      Glad to see Shango mentioned here.

  • @Gannett2011
    @Gannett2011 Год назад +1

    In the 80s, we had a PRIME minicomuter system that used these terminals at our college. Lovely keyboards and bright, clear green phosphor screens. About 2 years later I went for a job interview at the same college, and saw all these monitors outside just thrown in a dumpster/skip. If only I had been able to save at least one!

  • @TheOwlman
    @TheOwlman Год назад +1

    8:16 That is a KSR33 (no tape reader/punch) and it is the model used as ICL operators' terminals from the 1900 series, including volume knob to listen to the processor being stuck in a loop 😁 Actually, we used to be able to tell when the highways department were running an illicit number intensive job from their MOP terminal, which interfered with payroll and creditor processing until they finally stumped up and paid for a floating point unit and an extra 32K of core! Happy days.

  • @dlt4videos
    @dlt4videos Год назад +4

    Back in the day to test these, we would use the rs232 serial loop back, as you did. Then type a [ U ] and an [ * ] (asterisk) would give you a data stream of 01010101 or 10101010, therefore one could check all data lines to make sure everything was working correctly, This method will find bad RAM memory bits also.

  • @8bitwiz_
    @8bitwiz_ Год назад +1

    Glad to see you finally got to work on this, and glad to hear that my "Texas sun" suggestion back at VCFSW worked for you! Funny about the UART chip hiding like that, but at least you have your lowercase ROM. I had to make an EPROM adapter board because mine was missing. Also my lid doesn't have those retaining ring thingies, the hinge rods are part of the lid and it just slides off sideways. All your chips are socketed, so I think yours is an earlier design. My case is brown, while you have what I think is the better blue color.
    And I'm glad mine wasn't anywhere near that dirty and had all the key caps! But I did have to swap a few keyboard plungers (the hollow square that goes up and down) from a junk keyboard because the corners were splitting. As for the glass, I didn't use as much sticky foam, you did a much better job. Seeing that raster is a wonderful thing, because you know that all the analog stuff is working! The good side of that shorter brightness pot is that it doesn't stick out where it can get bumped.
    EDIT: you might want to seal the edges of the CRT glass by wrapping clear packing tape around the edges. That keeps dust from getting in through the gaps of your foam. The screen frame has a surprising amount of overlap, so you can be sloppy by at least half an inch without it showing.
    You don't really need that 2-3 jumper to do local mode, there's a dip switch for that in there somewhere. (Also don't use a pencil to flip the switches, it actually says so in the manual!)
    The SRAM is 7 bits wide, with the second row being the difference between the 12 line version and the 24 line version, and the 7th bit for the lower case option. It's more obvious when most of the chips aren't socketed, and unlike yours, mine only has sockets for the big chips and 8/14 of the SRAM.
    And speaking of lowercase, you need to get yours showing some! The ADM-3A lowercase font is a bit unusual and distinctive, it sticks up by a scan line to give more room for descenders.

    • @beenine5557
      @beenine5557 9 месяцев назад

      What is it with the UART chips that they liked to go walkabout?

  • @InCaldera
    @InCaldera Год назад +1

    The aesthetic of the terminal is *chefs kiss*

  • @DavePKW
    @DavePKW Год назад

    Brings back a lot of memories. I used one in the early 80’s for assembly language programming for many years. Thanks for the trip back in time.

  • @williamtell1477
    @williamtell1477 4 месяца назад

    Im just glad someone gives these cool old gadgets the love they deserve! Engineering/tech history is AWESOME!

  • @andydragon69
    @andydragon69 Год назад +1

    I think the implosion protection is the metal implosion band around the cap of the CRT, not the glue or shield (I worked in a CRT factory in my late teens). The implosion band helps to keep the screen from flexing and when the CRT does shatter, it helps to contain the energy imparted through the glass. When CRT's impose without the band, glass goes flying everywhere - at 3am on midnight shift, an implosion will wake you up in a hurry.

  • @Unfinished80
    @Unfinished80 Год назад +4

    That was really cool and the bunny flop at the end was adorable. Thanks!

    • @UsagiElectric
      @UsagiElectric  Год назад +1

      I love it when they flop like this, it's the most adorable expression of being happy and relaxed!

  • @ahbushnell1
    @ahbushnell1 Год назад +3

    I used one of those when I was in school in the 70's. It was great. It replaced a Teletype terminal that was slow and noisy. We still had to run a paper tape to load code. We used a HP2100 computer.

  • @EsotericArctos
    @EsotericArctos Год назад +1

    Shango does a lot of cataract repairs, as he does a lot of older tube TV's. He usually uses a silicon around the edge to completely seal it as if there is any gap, like corners with double sided tape, it can allow dust to get in and I can imagine dust between the CRT and the shield would likely be really annoying.
    Looks like you have a bit more work to do on this terminal to just get it 100%, but I think finding the missing key may be a the hardest thing of this., but it really is fantastic to see it up and running. If I recall this could be even sharper than how you have it with a little tweek of the focus. Going on memory, I think these had a very sharply focused CRT.

    • @eDoc2020
      @eDoc2020 Год назад

      Maybe it could have been sharper but I could see the gaps between the scanlines.

  • @dhpbear2
    @dhpbear2 Год назад

    14:37 - Molex connectors are NOTORIOUS for flaky connections! IIRC, Southwest Technical Products' 6800 system (1975) in their infinite wisdom, used Molex connectors for data and address lines!

  • @RichMye-wx1ob
    @RichMye-wx1ob 7 месяцев назад

    I left school at 16 but my learnings back then of 74series TTL and 4000 cmos still stands me in today with restoring old equipment.. :)

  • @dcmoisan
    @dcmoisan Год назад +3

    Don't worry about the missing DIP switch cover. Most of the terminals at my school (in 1987) were missing it, most usually because people tinkered with the duplex settings. It was fun when people used ballpoint pens, or worse, pencils to set the switches!

  • @happycomputerguy
    @happycomputerguy Год назад +9

    Awesome to see those cataracts fixed! Great job!

    • @UsagiElectric
      @UsagiElectric  Год назад

      Thanks! And thanks for the hook up!
      Let me know when that ADDS terminal comes up, I'd love to see its white phosphor displaying text in 80 column glory too!

  • @Clavichordist
    @Clavichordist Год назад +2

    I was really excited seeing this terminal come to life. It's amazing how the terminal works without a CPU and only utilizes TTL logic. Video terminals played a big part in my early tech days. I worked for Visual Technology, as I mentioned before, building, testing, and eventually repairing various models as well as their PC-like equipment and later the Ontel Corp terminals and systems.
    The keyboard switches look familiar. I think they may also be used on some of the early Atari computers, not the later 800 X/L which was made with far less quality.

    • @8bitwiz_
      @8bitwiz_ Год назад +1

      The keyboard switches are the old Stackpole type with the copper fingers. They were used on TRS-80 Model I (early versions), Atari 800, and TI 99/4A.

    • @Clavichordist
      @Clavichordist Год назад

      @@8bitwiz_ Thanks. That's what I thought because I had an old Atari 800 and they looked familiar. I also remember seeing those on the old Ontel Corp. keyboards as well. I used to repair those after Visual acquired the company.

  • @JohnKiniston
    @JohnKiniston Год назад +15

    Woah, I didn’t know CRT’s with that damage could be fixed, great video!

    • @bzuidgeest
      @bzuidgeest Год назад +2

      There have been videos on how to do that on RUclips for years. You must not have been looking very hard. I have to warn you though. He had an easy one. Some are really stubborn and he should have worn eye protection.

    • @UsagiElectric
      @UsagiElectric  Год назад +6

      Thanks!
      Initially I thought this type of CRT problem was un-saveable too, but it turns out, the hot Texan sun was the trick all along, haha.

    • @stevem.1853
      @stevem.1853 Год назад +4

      Shango066 has done several of these operations on old TV's I think..

    • @ironhead2008
      @ironhead2008 Год назад +2

      Yep, Shango066 has done a lot of these. And blistering southern heat and A LOT of patience is the key

    • @minty_Joe
      @minty_Joe Год назад

      @@UsagiElectric CRT Cataract problem? Shango066 to the rescue!! Complete with "Shango-isms". Hahaha!!

  • @2packs4sure
    @2packs4sure Год назад +2

    Great job on the cataract repair but you really should seal that thing ...
    Those open corners,,, something's gonna get in there and it's gonna be visible and drive you nuts..
    Put a little silicone from double stick to double stick and seal that thing.... :)

  • @lesdmark
    @lesdmark Год назад +3

    Another fun fact about Lear-Siegler is a lot of the upgrade seats in GM products from the 80's and early 90's were produced by them. So the 12 way and such seats with the fancy lumbar.

  • @JamesHalfHorse
    @JamesHalfHorse Год назад

    The chassis color and everything about it is a product of it's time when business machines were art... and it's glorious. Even cars like computer hardware kinda all looks the same now. Dealing with a 5 volt rail in something that ran the regulator hot enough to turn the screw to charcoal and what I think is a dead op-amp in some radio station gear while watching this. Keep up the awesome content. Just like in my industry while some of the hardware is getting rare but the people that know everything about it are even more so. Us young... ish.. guys have to learn this stuff and archive it the things that ain't in the manuals before it's gone. Glad you and other youtubers I already see in the comments are a part of that.

  • @jurjenbos228
    @jurjenbos228 Год назад

    The fact that the screen doesn't clear brings you right into the wonderful world of TERMCAP files. The Centrurion must have something like that, too.

  • @SteveRowe
    @SteveRowe Год назад

    Makes me so happy to see this tech history get brought back to life!

  • @roysmith5902
    @roysmith5902 Год назад +1

    Glad you got it going. These were awesome terminals when they came out. A huge step up from working on an ASR-33! I remember there was a big divider chain that generated all the frequencies from a single crystal; vertical and horizontal sync, dot clock, baud rates (getting 110 was complicated), all the way down to the cursor blink.
    These were also famous for having primitive keyboards with no debounce circuitry. Sometimes pressing a key once would generate a bunch of that character. The "debounce" (such as it was) was provided purely by a capacitor somewhere in the key scan circuitry. And the fix was just to replace it with a larger capacitor. I don't remember the details, but it should be pretty simple to figure out if you've got the schematics. I think LSI even provided a retrofit kit.

  • @lurkersmith810
    @lurkersmith810 Год назад

    I love it when the item you're working on gives back the missing parts. I've had two recently purchased wind-up phonographs cough up missing parts that would have been a pain to find. I don't even ask how it got there, I just thank the part for showing up again so it can get back to work! (I have radios older than that Bendix computer. Wait: I think one of my tube radios IS a Bendix!)

  • @KeritechElectronics
    @KeritechElectronics Год назад +3

    A fantastic restoration of a beautifully designed device. They really put some thought into making it serviceable.
    "Asbestos a can", eh? Nicely cleaned. Winner winner, chicken dinner :)
    My goodness, 43 friggin' degrees? That's wireless energy transfer from a fusion reactor after all ;)

  • @joehoser6313
    @joehoser6313 Год назад

    Brings back memories. I worked at Lear Ziegler in the late 1970s. I tested ADM-1, ADM-2, and ADM-3As.

  • @TheJensenInterceptor
    @TheJensenInterceptor Год назад

    So good, made me so happy, brings back some amazing memories of being an engineer 40 years ago

  • @Rich-on6fe
    @Rich-on6fe Год назад +5

    Nice work. Might be worth closing the air path into the cavity between crt and front glass : this will stop it filling up with new dust and grime (as it will probably tend to with the influence of the high voltage)

  • @franklincerpico7702
    @franklincerpico7702 Год назад +1

    Bro you are amazing at bring back these historic items.

  • @beamsio
    @beamsio Год назад

    Finally a good use for all this Texas heat! Well done.

  • @kellingc
    @kellingc Год назад +1

    My first experience with the ADM 3A was in 1985/1986 at SUNY at Buffalo. Along with VT220s and over VT100 compatible terminals was how we interfaced with the VAXes. It's also how we registered for classes.
    I never really took to them because I couldn't use the full screen editor mode of EDT.

  • @antonnym214
    @antonnym214 Год назад +1

    Very nice restoration. I'm amazed how good that Simple green worked on the power supply parts. You got super lucky with the finding of the missing chip. That text looks great on there and the keyboard works great after 47 years!

  • @nicolesi2201
    @nicolesi2201 Год назад

    I used to sit around in the university library in my hometown, in the early 90s, playing DikuMUD on an engineering student's Apollo Domain 2500 that he somehow managed to get hooked up in the data center, via an ADDS Viewpoint 3A+. At the time, the library's "computer lab" was entirely populated with ADDS terminals hooked up to a concentrator via Gandalf connections.

  • @KennethScharf
    @KennethScharf 6 месяцев назад

    Many people remember the ADM-3. There was an earlier model ADM-1. Digital Equipment is famous for their VT-100 and VT220 series terminals, but their line started with the VT05, VT50 and VT52 terminals. The VT52 was the first to have an 80 column screen with lower case display. I had a VT05 terminal back in the late 70's. Actually, I had a VT05 terminal case with a monitor and keyboard, but the electronics inside was missing. I had planned on building a small computer inside of the terminal case.

  • @LMacNeill
    @LMacNeill Год назад

    Wow!! That turned out *really* well! Can't believe the missing IC was just lying in the bottom of the case, and that it worked perfectly fine! Very nice!

  • @andypughtube
    @andypughtube Год назад

    I remember using a Tektronix storage-screen terminal (I think it was a 4014) during my PhD. I used it because I nobody else wanted to. This was in 1991, so it really was a relic of a bygone age at the time.

  • @thomashowe855
    @thomashowe855 Год назад +3

    Great job! My only concern is that humid air could enter the space between the CRT and the protective glass and condense. It is amazing though, and it shaped up well!

    • @8bitwiz_
      @8bitwiz_ Год назад

      Condensation isn't much of a problem as long as it can breathe. A bigger worry is dust, with static charge helping pull it in. Just needs some tape wrapped around the edges.

  • @ClausB252
    @ClausB252 Год назад

    You took me back to fall '76, when I first met my school's new Altair 8800a computers, one on an ASR33 and the other on an ADM3A. Cool!

  • @sellophanesun
    @sellophanesun Год назад

    Saw your gaff on 8 Bit Guy so I get why yr rabbit is that relaxed! Thank you for making the technical understandable!

  • @markwatson9816
    @markwatson9816 Год назад +1

    Spent the first couple of years as an EE using one of those to work on several computers including DEC 11/23s to program Fortan IV, assembly, and early CP/M computers to program assembly language on 8039 micros, and maybe other stuff - can't remember after 40 years 😂

  • @JohnJones-oy3md
    @JohnJones-oy3md Год назад +3

    8:54 - Someone was allowed to really flex their industrial design degree on this one.

  • @PplsChampion
    @PplsChampion Год назад

    11:28 this is so satisfying there should be entire channels of this

  • @KurtisRader
    @KurtisRader Год назад

    Great video. I've seen a few of your videos but this is the first one that caused me to subscribe. I'm old enough to have used many of the terminals mentioned. Including a Teletype ASR 33 with paper tape punch used in my first programming course in 1976 as a high school sophomore. I used to subscribe to the ACM Annals of the History of Computing journal because I think there is value is understanding the history of modern computers.

  • @Slim_Chiply
    @Slim_Chiply Год назад +1

    Living in Houston and also suffering this unbearable heat, I'm glad at least one good thing has come from this misery

  • @katho8472
    @katho8472 Год назад

    I've had issues with caps in a 1958 tube/valve radio and also on an MD recorder - supplying caps with power for a while or switching on and off will usually caps that are still sleeping because of not being used in ages.

  • @michellelawson4267
    @michellelawson4267 Год назад

    When I worked for Dictaphone, we had a dictation management system that was built around the Intel SBC 80/20 and there were two ADM-3A terminals. They had a dark grey base and a light grey top, but I forget where the Disctaphone logo was placed. I loved those terminals. Wish I had one now.....

  • @davida1hiwaaynet
    @davida1hiwaaynet Год назад

    Amazing fix! I agree that it seemed a lot easier than I would have expected!
    We've been having triple-digit temps here in AL as well. This makes my antique refrigeration projects seem that much more rewarding LOL!

  • @audenlundquest5211
    @audenlundquest5211 Год назад

    I started watching your videos when you did a cameo with the 8bit guy and at first I thought your videos were too long but now I am hooked! Plz feel up the good work!

  • @robertdutcher8081
    @robertdutcher8081 Год назад +1

    You have such great skills on these old machines. Love watching your videos.

  • @RWBHere
    @RWBHere 4 месяца назад

    Nice job!
    The 110°F isn't so bad in itself, but the accompanying 85% Relative Humidity is the killer. 🥵

  • @dlt4videos
    @dlt4videos Год назад +1

    This unit looks great and your video was awesome. I used to work on these in the early 80s and the unit you have is in extremely good shape even compared to the ones I was working on 40 years ago great job

  • @RaymondHng
    @RaymondHng Год назад

    Nice design. I couldn't afford an ADM-3A terminal. So I bought a Heathkit H9 terminal and assembled it. It had 7 circuit boards: power supply circuit board, keyboard circuit board, RAM and counter circuit board, input/output circuit board, character generator circuit board, timing and processing unit circuit board, and video circuit board.

  • @efkastner
    @efkastner Год назад +1

    Lear was also behind the 8-track tape format! (Sorry if it’s mentioned already, I didn’t look through all the comments)

  • @FirstLast-vr7es
    @FirstLast-vr7es Год назад

    I've watched a bunch of cataract removal videos from Shango066 here on the 'Tube. Never saw him de-cataract a terminal though; Just antique televisions. Great work. Love this channel!

  • @MichaelEhling
    @MichaelEhling Год назад +2

    Nice work! I had no idea that glue could come off so cleanly. (OT: all the cowboy cred points to you! 11:16: jeans in 110F...here in Toronto, we're tapping out at 85F~30C.)

    • @8bitwiz_
      @8bitwiz_ Год назад

      It's only been around 105F in San Antonio during this heat wave, so even that freaked me out a little.

  • @jann3109
    @jann3109 Год назад

    I love your show. Amazing job resurrecting those vintage computers - a pure pleasure to watch 🙂

  • @jeromevaneersel8491
    @jeromevaneersel8491 Год назад +1

    Met a few cases of cataracts like these on scopetubes and crt's like yours. I found the easiest way to remove the glass was to slowly heat it with a heatgun to around 60 degrees (Celsius that is..) and it just comes loose. Glued the screen back with optical clear LED potting from Electrolube but it was a tricky job. Some small bubbles came under the glass but luckily you don't see much of it. The screen is to improve the contrast and has nothing to do with implosion protection.(that is the band around the crt). The scope tubes (from Philips) had clear glass screens glued onto the front , these where old model tubes with a rounded front end of the balloon (mold blown in one piece) whereas later models had flat screens fritted to the front. These did not need a glued on screen as they where perfectly flat already.

  • @hannescampidell
    @hannescampidell Год назад +1

    this is the highlight of my day

  • @ChristopherHailey
    @ChristopherHailey Год назад +1

    I used to use those ADM terminals all the time back in the day - they were everywhere. The little cover over the DIP switches was ALWAYS missing, so yours is "period correct" :)

    • @Peter_S_
      @Peter_S_ Год назад +1

      I've got history with them going back to 1977 if not 1976 and I don't know If I've seen more than a couple with switch covers.... ever.

  • @jimruddy6083
    @jimruddy6083 Год назад

    Wow. I used an ASM-3A from 1977 to 1978. Nice little terminal.

  • @IbanNieto
    @IbanNieto Год назад

    Great job restoring this beautiful computer!!

  • @beanMosheen
    @beanMosheen Год назад

    Brave soul with your face that close to the caps first power up!

  • @AgentDiego
    @AgentDiego Год назад +1

    I think you should isolate the space between CRT and the protective glass with the silicone, because of the static electricity will suck all the dust out of and get it between the CRT and that glass. Just like Shango066 always does when he removes cataracts out of his CRTs

  • @electrohustler3621
    @electrohustler3621 Год назад

    Awesome fix for the cataract issue!!

  • @danaeckel5523
    @danaeckel5523 Год назад

    That is a nice looking terminal. Sure does have plenty of 1960's influence in it's design. Good thing for those excessive heat warnings you have been getting down to help out with this project.

  • @Plarndude
    @Plarndude Год назад

    Am I the only one feeling warm fuzzies while watching these machines get a new lease on life instead of rotting in a dump?

  • @rickhole
    @rickhole Год назад

    ADM-3A. I had one connected to the Altair 8800. Then moved it to a CPM-like OS called ISIS. I wish I could remember the manufacturer of that machine. Old memories triggered when that screen lit up!
    My experience with CRTs is more with black & white TV CRTs. When I replaced one and discarded the old I would take it to the dump and knock the neck off with a ten foot pole. I never had any glass shards, the neck popped off cleanly. But I would recommend treating the CRT as if it were a bomb, eye protection at minimum. A face shield would be good.

  • @dr.elvis.h.christ
    @dr.elvis.h.christ Год назад

    I remember these terminals back in high school. They were connected to an HP2000 at another school. Had to love that 30cps output.

  • @tony359
    @tony359 Год назад

    amazing! I was wondering what that instability of the picture was, never would have I thought it could be the HDD!
    One concern about the glass protection is that air can get in and static from the CRT will draw in all sort of dust. At some point you'll have to remove it to clean it again. Maybe you could seal the edges with something, maybe leaving a very small gap to allow a small amount of air to move in and out due to thermal expansion?

  • @seangorry
    @seangorry Год назад +4

    @shango066 Has done many excellent videos on cataracts. Safety is super important. Flying glass is no joke.

  • @NATHANJK3
    @NATHANJK3 Год назад

    Bro amazing as always...too much to learn from you. Salutes from Costa Rica.

  • @chucku00
    @chucku00 Год назад

    If there's some generous French person in this comment section who happens to still have a Minitel he has no use for, please consider offering it to David. I'm sure he'd enjoy the hell outta this landmark of _télématique_ technology...

  • @jugostran
    @jugostran Год назад

    The keyboard in this terminal seems to be Hi-Tek switch grid / Stackpole. Key tops for those aren't that uncommon, so I am sure you can find replacements.
    Great job on the cataracts repair!

  • @mikebarushok5361
    @mikebarushok5361 Год назад +1

    Small correction: The Lear Siegler corporation predates the Learjet corporation and was completely separate. Bill Lear had no connection with Lear Siegler past 1961 and started the Learjet corporation in 1962. Further, Lear Siegler only started making terminals in 1972. And Bill Lear had sold Learjet in 1967.
    As a serial entrepreneur Bill Lear was unique in the variety of areas of interest and invention. But he rarely stayed involved once a business idea was established.

  • @Riiludragon
    @Riiludragon Год назад +5

    you really should have worn a face shield and long sleeved jacket when working on removing the protective glass. If the screen imploded you'd be showered in glass bits.

  • @CasualSpud
    @CasualSpud Год назад +4

    Didn't Lear also create the 8-track?

    • @Peter_S_
      @Peter_S_ Год назад +1

      Yes, at least he lead the consortium which standardized the cartridge and the cartridge was based directly on a Lear product.

  • @neilmayo6868
    @neilmayo6868 Год назад

    Wow, really fun project, thank you.

  • @nrdesign1991
    @nrdesign1991 Год назад

    "Fifty years of grime" - that would be a good title for a book