My Most Obsolete Skill: Delta-Gun Convergence

In a lifetime of working with electronics we see a lot of technologies arrive, become mighty, then disappear as though they had never been. The germanium transistor for instance, thermionic valves (“tubes”), helical-scan video tape, or the CRT display. Along the way we pick up a trove of general knowledge and special skills associated with working on the devices, which become redundant once the world has moved on, and are suitable only reminiscing about times gone by.

When I think about my now-redundant special skills, there is one that comes to the fore through both the complexity and skill required, and its complete irrelevance today. I’m talking about convergence of the delta-gun shadow mask colour CRTs that were the height of television technology until the 1970s, and which were still readily available for tinkering purposes by a teenager in the 1980s.

Delta-gun shadow mask operation. By User:Tirante (Own work) [CC BY-SA 3.0], via Wikimedia Commons
Delta-gun shadow mask operation. By User:Tirante (Own work) [CC BY-SA 3.0], via Wikimedia Commons
A shadow mask colour CRT has three electron guns, one for red, one for green, and one for blue. There is a grid of red, green, and blue phosphor dots on its screen, with a metal plate full of holes – the mask – aligned just behind it such that each colour phosphor can only be seen by its corresponding electron gun. As the three electron beams are traced in a raster across the screen, their relative intensities can synthesise any visible colour for your eye.

The problem facing the designer of a shadow-mask CRT is that of aligning electron guns, mask, and phosphor dots so that the alignment is perfect at all points on a screen which is not equidistant from the guns at all points. If you supply a poorly aligned CRT with a picture that is entirely white it would deliver a picture mostly white but with spots of colour, and when a TV picture is shown then it would feature magenta, cyan, and yellow shadows around its subjects.

Shadow mask CRTs developed from the mid-1960s onwards solved this problem mechanically, by clever shadow mask designs, different phosphor dot patterns, and careful alignment of all the components with the three electron guns in a line across the neck of the tube. Earlier tubes had their electron guns mounted in a triangular delta in the neck of the tube, and relied on complex arrangements of electronics, magnets, and electromagnets to actively correct the misalignment as the beams traversed the screen. It is the skill of making these adjustments that is the subject of this piece.

The daddy of all delta-gun CRTs, the RCA CT-100. By HumanisticRationale - CC BY 3.0
The daddy of all delta-gun CRTs, the RCA CT-100. By HumanisticRationale – CC BY 3.0 (Wikipedia)

Broadcast colour TV has its roots in the years following the Second World War, with the first commercial sets both being American 525-line NTSC, the Westinghouse H840CK15 and RCA CT-100 from early 1954. (I should be using Noah Webster’s spelling color in those cases.) Earlier sets had round CRTs, but by the time we Brits got our 625-line PAL colour TV in the late 1960s the world had moved on to the curved-edge rectangular screens you will probably be familiar with.

To illustrate this piece I pulled out my last remaining delta-gun TV from storage. It’s an ITT CVC5 that came into my hands some time in the 1990s, it was made in 1972 and I hung on to it because I guessed it would be the last delta-gun that would come my way. It’s been in the wars – I should have held on to one of the many far nicer examples I ripped apart in the ’80s – but I got it working at the time with some repairs to a cracked PCB and replacement of a blown rectifier. Sadly it has now lost its field oscillator, so there’s a repair job for a future idle time.

Opening up the CVC5, you start to understand why these sets were so expensive when they were launched. It’s got a Mullard delta-gun CRT, a chassis that has a couple of square feet of resin-bonded-paper PCB densely covered in discrete components and tubes hinges down in front of you, a chunky PAL delay line and a large metal enclosure for the 25 KV EHT circuitry. It’s a live-chassis design, so extreme care is the order of the day if it’s connected. On the neck of the CRT is the deflection assembly, and behind it the convergence yoke attached by an umbilical cable to a large plastic convergence box containing a bank of pots and variable inductors. These and the adjustable magnets on the convergence yoke form the basis of the convergence adjustment.

The CVC5 convergence yoke with coloured arrows showing what each control does.
The CVC5 convergence yoke with coloured arrows showing what each control does.

The convergence yoke takes the form of an inverted Y (a ⅄) of coil and magnet assemblies, which put a magnetic field in the path of each of the electron beams when correctly placed. Each arm of the ⅄ has a rotatable magnet which moves the corresponding beam along the axis of the arm. On top is blue, bottom right is red, bottom left is green. There is also another adjustable magnet clamped to the top of the tube neck just behind the convergence yoke. This has the effect of moving the blue beam from side to side.

As can be seen from the picture, the blue electron beam can be adjusted in two axes while the other two only have one axis. To perform basic adjustment of convergence you turn off the blue gun and move the blue and green to the point at which they align, then turn the blue back on and move it as needed in both directions until it meets the other two. Ideally this should be done with a test pattern generator, but as a teenager such a device was far beyond my reach and I used Testcard F. Thank you BBC 2, for transmitting that!

Of course, with basic convergence done, you discover just how lousy the convergence of a delta-gun CRT is. You will still have coloured shadows on almost everything around the edges of the screen, each of the three rasters may be aligned in the centre but they still all have different shapes. It’s time to reach for the electronic convergence panel, and enter the black art of adjusting all those pots and inductors to drag the three images into line.

The ITT CVC5 convergence panel
The ITT CVC5 convergence panel

The convergence panel is always designed to be accessible from the front of the set, you need to have a good view of the screen to use it. On some sets it’s accessible behind a panel on the front, on others it’s a PCB that hinges up, but on the CVC5 it’s a plastic box that lives in a slot inside the case and can be brought out on an umbilical cable.

On the front are the array of convergence controls, each helpfully labeled by colour and area of the screen. There are also adjustments for the beam intensity to set up the grey-scale performance, and switches to turn off both blue and green guns for adjustments that don’t need them.

My reaction on looking at a convergence panel for the first time in years is that maybe this is a skill I *used* to have and have now lost. But in reality the controls are logically arranged, and rather than  going crazy twiddling pots the technique is to make small adjustments in response to convergence problems on the screen. There is almost certainly a recommended progression, but if I had it in the first place I’ve lost it somewhere in the last twenty years. I do remember learning how to do this by trial and error on an endless succession of scrap sets back in the 1980s, first getting it spectacularly wrong and then progressively getting better at the job.

So there you have it, complex adjustments on a very old version of a now completely redundant technology — my most obsolete skill. What’s yours?

It’s worth taking a moment to delve into retrotechtacular territory and look at some other shots of the CVC5. Some close-ups of the colour decoder and timebase circuitry, and the high-voltage enclosure. The PL509 line-output tube, flyback transformer and EHT tripler. My personal favourite though is the focus pot, 5 KV across an open rod resistor, with the wiper adjusted by a long thin piece of fibreglass PCB material through a slot in a live chassis. Seems safe to me.

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90 thoughts on “My Most Obsolete Skill: Delta-Gun Convergence

  1. That is a pretty cool skill! To bad is useless now. But who knows, maybe you can build some sort of device that may require an electrons beam to work. Maybe the next holographic display where two or more electron beams collide with each other in a vacuum-sealed-chemicalX-rich environment forming light dots in the air and forming 3d images when arranging them together, or anything else we hadn’t imagined yet.

    1. I would love to have that knowledge :) I looked ~ a year ago for glide tutorials/dev tools and couldnt find anything :(
      I was interested in hacking some ancient dos games to add 3d acceleration. Both Mame and dosbox support 3dfx emulation now (full hardware and glide overlay), so glide sounded like the easiest option, that is until I realized this knowledge is dead now.

  2. I remember back in my early days as an AV installer converging monstrous 3-gun projectors. Back then we had just discovered fire…so if you needed more throw (any therefore more light) you had to “stack” projectors. The most extreme was a “quad stack”, 2 projectors wide and 2 projectors tall, of Runco DTV-1200s; these thing weighted hundreds of pounds each. As you can imagine it was quite the process to mechanically align the projectors together using the green guns only, then converge all of the guns into one image.

    The Runcos only accepted 1080i in the days when the best source was a laser disc player, a good one was 1080i but most were 480i, so we had to run line quadruplers which cost something absurd like $20K to quad scan the 480i into 1080i. Ahh the good old days for rich people yelling “SHUT UP AND TAKE MY MONEY”…and there were no HDMI connectors

    1. I got my first CRT projector back in the late 90s from the local university’s surplus auction. I was in junior high. It was a Barco data 800, good for 480i. I must have spent hundreds of hours learning to tune and converge that thing.

      I’ve upgraded through a half dozen models over the years and finally reached the pinnacle of CRT projector technology just six months a Sony G90. Gorgeous, silky smooth 1080p with literally perfect black levels and amazing greyscale detail that even the best new home theater projectors these days can’t touch, and it was built in the very early days of the DVD.

      I must have tinkered with every part of five or six different models of CRT projector now. I’ve replaced dozens of components, swapped out a pile of tubes, machined custom parts and built custom signal processing boards… let the smoke out of some stuff…. I’m something of a master technician… now that they are antiques. But for my money, they are still by far the best home cinema experience!

      I’m keeping an eye out for another G90 so I can set up a stack :)

      1. I can definitely get behind your experience with the G90. I have aligned many of them, as well as the full line of Sony projectors. I was a product support engineer at the San Jose, CA Sony office. Although projectors were not my primary responsibility, I had the knack to do the alignment on some of the projectors for shows and conventions. The most challenging however, was projector cubes of 3×3 or larger. Not only is the alignment of each projector required, but integration of a single image on the combination of cubes.

        1. Oh god, I almost lost my mind messing with a 2×2…a 3×3 system would have driven me over the edge.

          We used to mount them in these equally huge lift assemblies and when they motored down it look like(and sounded like) the entire ceiling in the room was moving.

      2. CRT projectors were great…many will argue against their greatness, but to this day some of the best setups I have seen were built around CRT devices.

        Good luck with setting up your own stack, it’s tricky but so worth it.

      3. I had a Sony VPH1031Q I picked up cheap at a ham fest a while ago. It was a great machine for a broke high school student. I would just about kill anyone that bumped it though! Bank of pots to do all the alignment…. I got rather quick at it. It has since moved on to a friend’s house to play vintage video games!

        1. Awesome to here it’s still in use…if you don’t burn the phosphors they’ll last >25yrs easy. Maybe a few electrolytics to replace here and there but the tubes have staying power.

    2. Projector stacking is still common… today I stack 3-4 Barco large venue laser projectors, turn them on and then run the align program from the web interface. all the projectors use motors to line them selves up. Takes less than 2 minutes, it takes longer getting the union electricians to run a freaking extension cord.

      1. It’s cool to know stacking is still done in practice…but I assure you it was no 2 minute process in the home theater industry. We didn’t have motorized and automated systems. We had to mechanically align them to within an 1/8″ and then use the adjustment range built into the CRT guns to finsh. Normally it took a few passes to get everything converged and correct any geometry issues that happen when the projectors aren’t centered on the screen (left and right mirror images).

        I could probably still be done faster than any required union work…

  3. I’ve seen (and messed up) convergence boards with quite a lot more twiddles than that.
    One cool thing I learnt a while ago is how they make the tubes and get the phosphor dots lined up with the mask. Apparently they coated the face with one phosphor, then exposed it to UV from the gun position, which shines through the mask and hardens the phosphor in the positions for that gun, then repeated for the other two colours.

    1. So have I, this is one is rather spartan in its design compared to some of the era. But ti’s the only one I still have, so it has to serve for the purposes of this article.

  4. I can fix almost anything in my house. The only things I didn’t play with are gas stove and gas heater. I fixed and attempted making furniture, fixed electrical installation, did plumbing, repaired washing machines, TVs, tiled both floors and walls, did floor and wall panels, glued wallpapers, These are skills that everyone used to have. Nowadays people call electricians to replace burned light bulbs…

    1. I had some mild concern swapping out my gas water heater a few weeks ago, turns out gas lines are much more forgiving than supply side water plumbing (and much less messy that return side plumbing). Most important difference is that you shouldn’t use a torch when doing gas line work, threaded pipe shouldn’t need it any how.

      Natural gas lines run as a fairly low pressure, the pipes are thick, and a bit of yellow teflon tape seals up threaded joints nicely….. just make sure to use some soapy water on the joints afterward to check for leaks.

      1. Just ran some flashshield CSST this weekend. I had to break the black iron pipe supplying gas to my furnace, install a ‘T’ and run the CSST to my new gas range. CSST has to be bonded and grounded back to your main ground at the electrical panel for lightning protection, so I did that too. You can use yellow Teflon tape to seal BIP, but pipe dope is better. But yeah, gas is scary, but if you do a little research and use common sense, it can be tackled by us mortals! Poking around in the 200 AMP service box to get the ground wire in there was perhaps even more nerve wracking.

    2. My opinion about fixing stuff in the house is that I won’t touch anything, that will be in the wall. I could probably do it OK. But I don’t want to touch anything in the wall for at least ten years, and OK might not be enough for that.

    3. Indeed, It is easy to change the gas heater, or to fix the electrical installation. Till… an insurance event happenes (fire etc). Since the work was not done by certified technitian, guess who will pay the bill + the reast of expenses…

  5. My entire career is obsolete. Since they change programming languages/methodologies/platforms/whatever every two years, I was always retraining. Now I’m retired and obsolete. But I still know how to do an insert on a keypunch machine :)

    1. I was interested in programming after getting a z80 based computer at school and learning machine code programming.

      Then I launched my career by starting EE.

      Then later in life I turned back to programming as a hobby (as well as the electronics) as the two go hand in hand now.

      I am still studying and learning. As a hobby I have done probably over 100 languages now from HTML to VHDL.

    2. In the book, “Anything can Happen”, the author recalls that his father told him back in Georgia (the country) around the 1900’s, “learn two skills, if one fails, you can fall back on the other”. Eventually, he emigrates to America around 1920.
      He is interviewed for work placement, “What is your profession?”; “I make swords”; “We have no need of that, what else can you do?”; “I know how to elaborately braid riding crops!”
      B^)

  6. I know people say CRTs are a dead technology, but one niche hobby where CRT use is still heavily favored and desired is video arcade game collecting. Many would pay dearly for a quality 19″ or 25″ tube, depending on the type, and where CRT convergence is still a necessary skill.

    1. Maybe I should advertise my services, contract rate :)

      I’ve encountered one or two cabinet builds in my time, but the ones I’ve seen have tended to have Japanese preconverged inline-gun tubes. Probably an indicator of what my friends can afford.

    2. There are other uses too. No LCD monitor can show as true colors and as perfect picture as one of those reference monitors used in broadcasting and video editing industry. Plasmas are good too, but only because they are basically the same technology in different package.

      1. today reference monitors are usually some form of LCD(at least for field work where i have encountered it, never worked in a permanent studio), since color management is done to exhaustion in those environments all that really matters is that no post processing is done and that the full color space one wants to work with is available.

    3. >CRT convergence is still a necessary

      but not an issue needing fixing/tuning. Newer trinitrons/diamondtrons/whatevertrons use electronic compensation and keep perfectly sharp picture on whole screen including edges.

  7. I’m old enough to know about/appreciate the “alignment voodoo” (albeit I’ve never been trained on, nor had to do it).

    But then on another thought: why did it take so much time after the introduction of LCD screens for computers to transit from analogue VGA signals to digital ones?
    (after all, EGA the precursor of VGA was already digital, sort of…)

    Anybody remembers LCD based (see-through) panels to put onto the overhead projectors?
    Phase adjust problems *shudder* (pricey like a small car and produced images pale like washed out T-shirts…)

    1. Those overhead projector LCD panels were awful… didn’t matter how much you paid for one, it still sucked… and badly. Seems like it should have been viable, but a lot of R&D budget apparently got thrown at proving that it wasn’t!

  8. My obsolete skill is configuring emm386 and loading tsrs into high memory in the right order to get enough free main memory and extended memory configured to launch various gamea from the 90s while still loading the appropriate mouse, sound and CD-ROM drivers.

    1. I used to pride myself a bit on being able to get that all set up, with significantly more free memory than any of the automated configuration software could.

      How about writing text files with COPY CON or EDLIN? Using DEBUG to low level format MFM hard drives. The 80’s and early 90’s were truly hands on times for computer users.

      1. Ah.. I miss that. There was a long time between when everything started swithching to PnP and when PnP actually started working worth a crap. I remember for a while avoiding any new expansion cards or paying extra for one that still gave the option of setting jumpers because it was almost a gaurantee that if you let the BIOS/cards set their own stuff you would end up with an IRQ or memory address conflict.

        I remember the first time I saw two devices actually sharing an IRQ# and still working properly… I almost thought it was witchcraft!

  9. Since the three-gun shadow-mask approach is how I’ve always seen color CRTs described, I’m curious what replaced it by the ’90s. Trinitron’s aperture-grille wasn’t patent-free until 1996.

    1. What took over from the delta or dot triad shadow mask was the slot mask. It was sort of a mashup of the two. Take a Trinitron aperture grille then put small bridges across the vertical wires, with each column offest up/down halfway from the column next to it. The phosphors were put onto the inside of the glass in vertical stripes just like a Trinitron.

      Then came the ‘true flat’ CRT which heated and stretched the slot mask then molded a glass ring around its edge. That assembly was then bonded between the tube body and a double layer front glass.

      Having grown up in the 70’s with used 25″ delta phosphor TVs, I was rather unimpressed by the screen door appearance of the slot mask televisions. The arcade games of the 80’s often used especially crude, low resolution slot mask CRTs, which is where I first encountered them.

      But now I have a 40″ Samsung 4K LED backlit LCD Smart TV. :) CRTs can suck it…

  10. “Throwing a chain” as in surveying with a chain and transit. Surveyor’s chains have been steel tapes for a very long time, but the name never changed. The dark art was how to “throw the chain” into a figure 8 that collapsed into a smaller circle. If you get it wrong it becomes a terrible tangle with you wrapped inside. With practice it’s a quick flick of the wrist.

    I’m not sure CRT convergence is an obsolete skill. The real skill in doing it is problem solving which never becomes obsolete. I just accepted adjusting the convergence on CRTs as part of the overall problem. But I didn’t get into it to the level that folks working on projectors did.

  11. Ah those neck magnets, one of which is very close to the horizontal deflection coil connections!!! Many rude awakenings there.

    I’m color blind so this was a little harder for me. Geometry was easy but shade was hard.

    There were also a lot of other adjustments that were easier to do while looking *at* the screen so I had a mirror permanently attached to the wall behind the work bench. I also had three color filters (Red Green Blue) arranged into a panel that would sit on top of the TV as it faced away from me and towards the mirror. I used the filters for shade (drive) adjustments.

    Here’s the (far better) test card we had –

    This is not actually the one but it’s very close.

    In the same workshop I did all the other era things to – early computers, VHS and Beta Video Cassette Recorders, boom box stereos, CD players, Cassette Tape players, component stereos, microwaves and any other domestic electronics.

    For me convergence adjustments are a skill that still pays off because it taught me how other people see color. I use this learnt skill now with any programming to do with color like HTML bgcolor=”#A52A2A”

    He had PAL B/G here. It’s only different to PAL I in that it has a different audio sub-carrier frequency. Far better system than Never Twice the Same Color.

    Obsolete skills – fixing “line” printers and still having some hearing left lol. Replacing pins in dot matrix print heads. Anything to do with valves, oh yeah, you could mention that an old CRT tube is literally a big valve. Those old network sub-networking points (sector controller) that had 8 inch disks. Wave guides that you could walk through. Water cooled Radio transmitter valves that were 5 foot tall.

    1. I learnt QBasic which was much the same. It was my introduction to the IBM clone (XT) we had XT’s at work to use as work (flow) stations. I always vied them as toy computers because my job there was to maintain a computer that was three stories big.

        1. What I loved about old QBasic wasn’t QBasic alone. It was the era when you could access all the hardware directly (bypassing the Operating System DOS) and do things like use the pins of the parallel port as GPIO.

  12. Carburetor diagnosis and rebuilding. They were complex mechanical devices with multiple fuel circuits, honestly the last gen Japanese stuff from the late 80’s was beyond me. I mean truly rebuilding, not just spraying some carb clean in the throttle body. Diagnose problem, remove the whole thing from the vehicle, tear the carb down apart (don’t lose any fidly bits!) and soaking in some rather noxious solvents. Setting float height, checking the choke pull-off and idle cut off solenoid among many other steps. Put it back in and cross your fingers. Pretty much worthless.

    1. I used to do that too, along with all the other auto mechanical stuff. Still do all the work on my own cars.

      Now If only I could figure out why my 1982 GMC 1 ton flatbed that I’ve done a TBI transplant from a 1991 Chevy will run if I pour some gas down the throttle body, but flat our refuses to open the fuel injectors. It ran great in the donor truck.

      1. the GM TBI (toilet bowl injection) swaps were common in the 90’s because they were cheap and pretty much the only thing available. there are much, much better EFI alternatives today. for instance, you could get a microsquirt, plus the required GM sensors/ignition coils off of a car at the junkyard, for <$400. you'll end up with something much easier to setup, diagnose, and most importantly, tune.

    2. I have a carburetor to be re-kited in a ute (pick up) that I am rebuilding to go bush in. No dependence of any “black boxes” to leave me stranded 1000’s of miles from anywhere.

      1. So instead you have a shiny box (with lots of holes) that has lots small passageways to get clogged and is always worse for fuel economy and has constant trouble starting in the cold/extreme heat? If were talking literal thousands of miles, the fuel economy is something that should not be overlooked, a “reliable” car that get’s you only half the way is just as useless as a broken one…

        You can take spares with you if you are worried about the black box giving up, you can take spares with you.
        Never saw that happen, it was either something mechanical that broke, be it a pump, injector, sensor… or something that was made too sketchy, like a cheap coilpack…all I did see was the black box switch to “limp mode” and limp the car home. Then to wherever you went to get it fixed.

        1. Yeah, um no. My country is NOT like yours lol.

          By thousands of miles, I mean thousands of miles of nothing not even a road! No gas stations (you take what you need) no humans unless you brought them with you. Nothing that is created by human beings.

          The bush here is a graveyard full of electronically controlled vehicles that used to belong to people that have the confidence you have lol.

          I can fix a carby with minimal tools – do that with a black box – I can take a spare carby.

          The required electrics are one wire from the battery / alternator to the coil. One from there to the points and 5 spark plug wires and a dizzy.

          So if you want a *brand new* electronically controlled 4WD then come to Australia we have thousands of them stuck in the bush. All you need is a $2,400,000.00 helicopter ride to get them out.

          And limp mode doesn’t work when the front half of the vehicle is missing.

          1. Carbs are less reliable than all but the worst fuel injection systems. o2 and maf sensors aren’t needed for a fuel injection system to work and the ecus themselves are usually bulletproof. Of course there are many modern cars that integrate fuel injection into the main computer and they aren’t always reliable, but there are many good fuel injection systems (such as Bosch’s old 2.4 LH-Jetronic) that never fail.

          2. @[John] Quote: “Carbs are less reliable than all but… ”

            Are you comparing 50 year old carbs with fresh off the showroom floor ECU’s. Or is it that you simply are not old enough to have any experience with Carbs???

            If I fully kit a carb then it is going to run for 20 years plus or minus a clean here or there (Just as you clean injectors). No blown FETs, No corroded through PCB traces, No dry joints!!!

            My countryside is testament to the FACT that “broken” electronics is going to leave your show pony thousands of miles from anywhere until it rusts into the ground (If it’s not completely plastic).

            This is how it goes in the bush … If YOUR vehicle *breaks* then YOU fix it because NO-ONE is going to come and fix it for you. If YOU CAN’T fix it then it stays where it is!!!! and there are thousands of vehicles exactly where they broke down just rusting into the ground. Why is no-one going to fix it for you??? because the closest person who CAN is 20,000 km away and has better things to do with their time unless your offering say $15,000 to $20,000

            But you know that’s not the big point here. Because if you can’t fix it then your dead. You can’t call a taxi, you can’t call emergency services because the last place your phone worked was 10,000 km ago!!!

            The last plane that went over was 150 years ago and your standing on ground that hasn’t been stood on by a human for over 2000 years. We call this area “bush”. ie NOT a picnic in a park.

          3. I’m not arguing with you about the abandoned vehicles being there. I’ve never been to see. But.. what you are saying doesn’t make a lot of sense for a couple of reasons.

            First reason, I drive a lot of old cars. (but still new enough to have electronic ignitions). The only one I ever had a computer go out on still had a carburetor! No, I’m not really even sure what the ‘black box’ in that particular one did but apparently it was important enough to stall the car. Anyway.. sure.. I wasn’t driving through the outback, I am surounded by infrastructure. But.. it’s not like I am ever actually using that infrastructure to get my ‘black box’ serviced. Like I said.. I only replaced one and that was on a vehicle from 1984! All my cars since have gone over 100k and some over 200k. There are countless other parts that do tend to wear out that have nothing to do with carburetors or black boxes. I imagine those don’t grow wild in the outback either. What do you do when your _____ goes out? You don’t take extras of everything do you? I would hope that you have a radio and somebody with a working car to call!

            Second.. why is it easier to take a replacement carburetor than a replacement ‘black box’? You mention the presence of only one wire. So? While I may not ever replace the black box in all my cars I do still see them when I take the car apart to replace less reliable things. They may have several wires but those wires all come to a point at one, maybe two multi-pinned connectors. It’s not like replacing it means cutting the wire harness and individually hand soldering 1000 tiny wires into place. You just unplug the old, plug in the new.

            Anyway.. drive whatever floats your boat. If you like a carburetor then go for it. It’s your car!

            “So if you want a *brand new* electronically controlled 4WD then come to Australia we have thousands of them stuck in the bush. All you need is a $2,400,000.00 helicopter ride to get them out.”

            Why not go in with a working vehicle, identify what part is broke then come back with one on a second trip? Sounds like you could make yourself some money!

            “And limp mode doesn’t work when the front half of the vehicle is missing.”
            WTF Does your ‘black box’ contain C4 or something? You might want to have a chat with your car dealer!

          4. Good old fashioned fully mechanical Diesel Engine with Inline fuel-pump, IMHO better than any spark-plug/petrol motor for reliability, You don’t even need a battery or alternator once its running–For use where you don’t ever want to break down–like 100’s K from anything!….

    3. You could still get a job at NASA. Well.. you could if they still made rockets anyway. They have to use carburetors still because the computers controlling electronic emission systems tend to fail when subjected to cosmic rays.

  13. We still use CRT projectors extensively in the commercial flight simulator industry. Doing convergence adjustments tonight as a matter of fact. Lately the trend has been towards LCOS projectors but we still have plenty of sims here with 300+ lb projectors sitting on top of them. We go CRT Projector to a BP (basically a rear projected dome) which is reflected by a mylar mirror to provide a feeling of depth to the final projection. Works really well.

  14. In our TV, the grid would shift and throw the colour completely off. So I guess I was also ‘calibrating’ when I would smack it in just the right way to fix it. Many fond hours of the whole family sitting dead still because stepping heavily or sneezing would be enough to mess everything up. Also, not to brag or anything but we only upgraded that old set <5 years ago!

  15. Assembly programming… 8031s PICs x86… no need for it anymore. But as the saying gos… He who have never programmed in assembly has no soul, and he who still does has no brain. While there are still some fringe cases where assembly may be of use, the biggest use of assembly programming is in structuring the programmers brain into thinking like the processor does.

    1. Isn’t the 8031 a ROMless 8051? An old CISC? I thought there were faster pipelined versions available. If there is room for a 20 MIP ATmega in the world then surely there is some room for a faster CISC?

  16. When I started doing lighting for live theatre, I used a 36 channel manual desk – 2 banks of 36 faders, top was switched a/b, bottom c/d, then there were 4 master faders: a,b,c,d. The art was in distributing the lights onto the masters to minimize the amount of fader adjustments needed for each cue, especially when some might be only 10 seconds apart. One dance performance I lit, I only ever saw snippets of – most of the time I was head down over the desk, flat out shifting faders.

    1. Heh, that brings back some memories. In high school we had an old analog pre-DMX setup that had seen far better days.

      Over the years, the analog control voltages were no longer properly calibrated – so 0% at the desk would end up being a slightly lit lamp on stage, even color washes were near impossible &c.

      I remember taking advantage of Radio Shack’s generous 30-day loan program to get my hands on an RMS meter and spending hours backstage adjusting the variacs(?) with a handful of dejanews printouts and a screwdriver. Ended up pretty well.

  17. This reminds me of the day all TV sets and other devices came with full schematics, parts list and aligning instructions, so that knowledgeable people were encouraged to perform repairs themselves, and you could even mail (email? ..what email?) the manufacturer asking for hints or suggest improvements.
    Those days are long gone; today there is something a lot worse than being able to repair a cool but obsolete technology: it’s being prevented to do that on current technologies because of laws bought by corporations.

      1. He means like your 42″ LCD panel. When that 20c part dies then you need a new screen because you’re never going to find *which* 20c part died without a schematic.

        Today all repairs are *replace board* like a computer *replaced mainboard* or *replaced video card*. There was a time when one would replace only the faulty part on the board. As in *Replaced Bios Chip on main board*, *Replaced SOIC socket on video card” but to do this you need a schematic (realistically).

        The new way is great for Corporations and they are the cause of it but it is destroying our environment with toxic landfill.

    1. Dear Mr. Muntz,

      You know.. if you added a bypass capacitor here and a choke there your TV would perform a whole lot better….

      LOL, I wonder how many people will get this

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