[HN Gopher] The Secret Life of XY Monitors (2001)
___________________________________________________________________
The Secret Life of XY Monitors (2001)
Author : ibobev
Score : 79 points
Date : 2024-03-11 14:42 UTC (8 hours ago)
(HTM) web link (www.jmargolin.com)
(TXT) w3m dump (www.jmargolin.com)
| h2odragon wrote:
| > Very likely, the real story is simply that the potting material
| used in the transformers was not up to the task. Regardless of
| the cause, by the time the problem appeared the Operators had
| already made a good return on their investment. That was good
| news for the Operators but bad news for those of us trying to
| keep their 17 year-old Star Wars games alive.
|
| I was a big fan of the "star wars" consoles; and they _all_ had a
| peculiar smell. now i know what that was. cooking flybacks.
| onetimeuse92304 wrote:
| > It's also a safety issue, since the Cathode voltage might be
| substantial.
|
| When I was a small kid, my father had a TV set repair side
| hustle. I was 7-8yo but I would sometimes be called to help him a
| bit. Once he asked me to clean a bunch of CRT tubes from
| substantial amount of dust. What he forgot is that he was just
| testing one of them and the charge wasn't properly dissipated and
| it did not have time to dissipate on its own.
|
| I got hit with a spark so powerful, that it must have temporarily
| disrupted my brain because for a brief moment I was completely
| stupefied, and then I just resumed cleaning it. Then I got hit
| for the second time, then for the third time. Only after third
| time I realised that me cleaning the tube has something to do
| with it. Probably the discharge was much less powerful the third
| time and did not stun me completely.
|
| I can tell you the voltage and amount of charge on these things
| is no joke. Multiple tens of thousands of volts is enough to stun
| you temporarily. Probably not enough to cause lasting damage
| unless you are extremely unlucky about where the discharge went
| (stun guns usually have higher voltage _and_ capacity), but
| enough for you to lose control of your body, fall and hurt
| yourself.
| colechristensen wrote:
| >Probably not enough to cause lasting damage unless you are
| extremely unlucky about where the discharge went
|
| You don't have to be that unlucky. Discharge across your heart
| can stop it, no problem. It is not at all difficult for that
| energy to route through your chest. You were lucky.
| onetimeuse92304 wrote:
| Well... one difference between a stun gun and CRT tube is
| that in a stun gun you usually have both terminals relatively
| close to each other. Little chance of the main pulse going
| deep across the chest. On the other hand working with the CRT
| you are likely using both hands and that makes the signal go
| through your upper chest, by default. So yeah, there is
| something to it.
|
| One thing I learned as amateur EE is to always use just one
| hand to probe the device under test if there is any high
| voltage or AC involved. You put the other hand behind you so
| that there is no chance you create a short right through your
| chest.
| Scoundreller wrote:
| And have someone nearby with a 2x4 to beat you off whatever
| you might be gripping/fell onto.
| sowbug wrote:
| Just to add a bit more color here: most flexor muscles in
| your body are a lot stronger than the corresponding
| extensors, so when an external command comes in telling
| both to contract, for example from electricity in the
| thing you're working on, gripping wins. You can't let go.
| Great for grabbing a branch as you fall out of a tree.
| Not so great for repairing a power line.
|
| Late edit: I've heard you can use this factoid to your
| advantage to avoid being eaten by an alligator or
| crocodile. Wrap your arms around its snout and hold on
| for dear life. Their jaws are strong enough to snap you
| in two, but not enough to force themselves open when
| you're holding them shut. I don't know what Step Two is,
| unfortunately.
| jareklupinski wrote:
| > I don't know what Step Two is, unfortunately.
|
| step two is waiting for the aforementioned 2x4 wielder
| "to beat ... whatever you might be gripping/fell onto"
| rzzzt wrote:
| "Mother" on speed dial maybe?
| hallway_monitor wrote:
| The bit about holding an alligator's mouth closed is
| correct and I remember Step Two from an alligator
| wrestling demonstration: flip it over. They lose
| consciousness if you can hold them in an inverted
| position.
| HeyLaughingBoy wrote:
| So do chickens, but they're a lot easier to wrestle.
| TFortunato wrote:
| Related fun fact - On many industrial robots that I've
| worked with, the teach pendant (the handheld controller
| you drive it around with), requires you to hold a 3
| position spring-loaded switch in a middle position for
| the robot to operate, which requires you to hold with a
| rather precise amount of force. Squeeze it either too
| loosely or too tightly and the robot disables.
|
| The idea being that not only will you dropping the
| pendant disable the robot, but it will also disable if
| you accidentally touch energized equipment and your hand
| clenches, or (more likely) you panic and squeeze the
| controller too tightly.
|
| https://us.idec.com/idec-us/en/USD/Safety-
| Components/Enablin...
| close04 wrote:
| > One thing I learned as amateur EE is to always use just
| one hand to probe the device under test
|
| I was taught to use the back of my hand to avoid gripping
| the damn thing and never letting go.
| renewiltord wrote:
| Same. And I do it like a superstition now.
| mauvehaus wrote:
| You're describing the well-known Alanis Morissette
| technique for electrical work:
|
| "I got one hand in my pocket, and the other one holding a
| DMM"
| dmoy wrote:
| > One thing I learned as amateur EE is to always use just
| one hand to probe the device under test if there is any
| high voltage or AC involved.
|
| I remember in some EE course, the prof randomly stopped in
| the middle of a lecture and said roughly
|
| "Ok now that you all know this theory, I need to remind you
| that you should not go do your own home electrical work,
| because you will get ahead of yourself and die from some
| kind of electric shock"
|
| The implication being:
|
| 1. You're trained, but for EE not electrician work
|
| 2. You'll think you know what to do, even if you don't
| it'll cloud your judgement
|
| 3. As an EE you will make enough to pay a real electrician
| to do your electrical work
|
| Needless to say in the real high power EE courses (t lines,
| grid, etc), this wasn't even mentioned, because it was just
| implicitly known that all that stuff was in the realm of
| "Don't physically touch this stuff in the real world ever
| because it will kill you and it will hurt the whole time
| you're dying".
| onetimeuse92304 wrote:
| I did not mean doing home electrical work. That I do
| leave to professionals.
|
| But there are times I have a device on my bench that is
| consuming 230V AC.
|
| I have a 3kVA separation transformer set up, which makes
| it safer for me to work with the device (there is no
| potential between the DUT and the ground).
|
| Technically, even without the transformer the residual
| current protection should kick in and prevent you getting
| killed between device and the ground. I have tested mine
| couple of times to check whether it works. But I somehow
| still feel better with a separation transformer.
|
| But there is still the problem that I could touch
| different parts of the device that are at different
| potential and then I could get zapped this way. There is
| not much protection there. Solution -- If you must, don't
| ever touch more than one place at a time.
| Cthulhu_ wrote:
| That said, direct current is "safer" than alternating
| current; AC makes your muscles (and heart) spasm/contract 50
| or 60 times a second like it's fibrilating, DC locks
| everything up like a defibrilator.
|
| I recommend neither though.
| Zardoz84 wrote:
| high frequency alternate current is the safest, in the
| sense that the skin effect enters in effect, and the
| current doesn't touch your muscles (or at least your
| hearth). However, the danger of burns persists.
| dfox wrote:
| The nasty thing about HF burns is that you often do not
| notice that something is wrong until you either smell the
| burnt skin or the burn starts to deep enough to become
| acutely painful. It is perfectly possible to burn 1mm dia
| hole completely through you thumb and nail by inadvertly
| placing your thumb over output connector of CCFL inverter
| without you noticing that this is happening.
| kloch wrote:
| > Discharge across your heart can stop it, no problem. It is
| not at all difficult for that energy to route through your
| chest. You were lucky.
|
| As my dad used to say "It's volts that jolts, but mills that
| kills!"
|
| (you can survive a jolt very large voltage, but only a few
| milliamps across the heart can kill you)
| ryanjshaw wrote:
| Not just heart-stopping-dangers! I had a dishwasher whose
| wiring was damaged by a rat. I unplugged the dishwasher, and
| started working on the wires - maybe 1mm thickness. Next
| thing I know, I've punched myself in the face and knocked
| myself to the floor from something discharging, and need an
| ice pack on my lip.
| QuercusMax wrote:
| I had a dishwasher whose wiring wasn't installed properly,
| and it eventually caught fire. Seeing smoke and flames come
| out of a running dishwasher is something I won't soon
| forget!
| LorenPechtel wrote:
| But that takes current, not merely voltage. It's very hard to
| do with the discharge of static energy.
| orbital-decay wrote:
| I also touched a CRT anode when fiddling with a TV set when I
| was 12. I was aware of the danger and scared of that thing (it
| was _huge_!) but still forgot to discharge it. Despite the
| ~26kV nominal voltage there was only enough charge to make me
| jump to the ceiling, or at least I thought so. It 's a lesson
| you never forget.
| LorenPechtel wrote:
| I got zapped once as a kid. My grandfather's TV, I was pulling
| the tubes to take them to the testing machine. Fairly small
| screen but I knew it probably had some residual charge that I
| most definitely didn't want to come into contact with. The
| layout was such that I could pull the tubes while staying far
| away from it. It never occurred to me that safety would require
| keeping him from looking on in curiosity and bumping my arm.
| (He was impatient about getting his TV fixed, I saw that
| whoever designed it had had the courtesy to put the tubes in an
| area where even if your hand slipped it wouldn't approach the
| tube. That was no protection against my hand getting moved in a
| direction I was not applying force, though.)
|
| I don't think such things are actually capable of direct
| lasting damage but you do lose control--I slammed my hand into
| the cabinet pretty hard, completely involuntary. My
| understanding is that tasers are AC, thus involuntary movements
| will be back and forth rather than just in one direction.
| lttlrck wrote:
| I was thrown across a room twatting around in the back of a TV.
| Many years later I still wonder if there were any sdiefeftcs.
| tyingq wrote:
| Oscilloscopes are mentioned a few times, but not for the main
| reason I assumed they would be.
|
| Many of them include an x/y mode to use them as vector displays,
| even some of the cheap ~$150 ones.
| theamk wrote:
| TIL: even today, they still make analog oscilloscopes [0]
|
| The are not cheap though - almost $1000 for a 30MHz model which
| is super expensive, especially compared to digital model. I
| assume "$150" refer to price for a used oscilloscope.
|
| [0] https://www.bkprecision.com/products/data-acquisition-
| record...
| tyingq wrote:
| $150 for a new, cheap/small digital oscope that supports an
| X/Y mode. Yes, it's not truly a vector display, but accepts
| vector x/y input and rasterizes it. Not all of these have an
| X/Y mode though, so check first.
|
| But, yes,old oscopes with CRTs is an option also.
| RespectYourself wrote:
| The glow of CRTs creates an atmosphere that's surely missed by a
| lot of those who enjoyed arcades.
| RetroTechie wrote:
| It's a pity such monitors aren't made any more.
|
| In the late 80s, I owned a small (12..13" or so) amber monochrome
| CRT monitor. Lovely phosphor color, non-flickering superb for
| text-based work, single composite video input.
|
| Let go when it didn't seem to matter much, and CRTs were still
| everywhere.
|
| But today I'd love to have such a screen. Commercially this would
| be a small niche market, but probably a _stable_ one. And
| regardless of modern LCD /LED screens, such antique monochrome
| CRTs have properties that no modern flatscreen can match. As an
| in-between, LCD/LED screen _designed_ for ~0 lag & X/Y vector
| input (monochrome or color), would be nice too. Doesn't exist
| afaik?
| autoexec wrote:
| When LCD monitors/TVs came out they were a huge step backwards
| in terms of quality. They were relentlessly pushed on consumers
| because they were cheaper to make, cheaper to ship, and took up
| less space in stockrooms and on store shelves. I doubt the CRT
| will make a comeback. Even today's TVs are inferior to CRTs in
| some ways and so we're still compromising, but at least current
| LCD screens are so much better now than they were when they
| were replacing CRTs.
| bombcar wrote:
| The problem is that the available market for CRT screens (and
| it does exist!) is well supplied for now by used and other
| older models.
|
| Modern screens are better in many ways, but like CRTs, there
| are tradeoffs and many things are not yet designed around
| those tradeoffs.
| actionfromafar wrote:
| Not well supplied at all. None of the three sub-sects are
| well provided:
|
| a) high-quality video monitors like Sony PMW, great for
| gaming and old-school video
|
| b) slow amber screens like mentioned above
|
| c) large TV sets with good colors (and no semi-digital
| stuff messing with quality like 100Hz)
|
| None of those can be easily found, especially not in
| working condition.
|
| Oh, forgot about the substantial
|
| d) Gaming CRT with insane refresh-rate and true blacks!
|
| Of these, I think only monochrome sets and maaaaaaybe PMW-
| style sets have any inkling of a chance of new manufacture.
| Probably only monochrome monitors, they are much simpler to
| get right.
| theamk wrote:
| I don't remember LCDs needing any "push" in the customer
| segment, and they certainly co-existed for a while, until
| people stopped buying CRTs.
|
| Initially they were wildly expensive, so all we could do is
| to sit and watch; but the moment they got affordable, people
| just started buying them. I remember swapping my CRT for a
| (smaller) LCD.. the extra space on my desk was so nice! And
| in a few years, I bought an LCDs display that was much larger
| than any CRT I could ever afford and fit on my desk...
|
| And yes, viewing angle restriction was annoying. Also
| magazines would keep writing about latency, but I didn't care
| - I was not a gamer, I was a programmer, big size + desk
| space was much more important.
| autoexec wrote:
| The sales pitch was that "HD" was all anyone was supposed
| to care about. What we got in exchange for HD and some
| extra desk space was terrible color accuracy, worse
| contrast and grey blacks, low refresh rates, high
| latency/input lag, motion blur, dead/stuck pixels, poor
| viewing angles, fixed resolutions, backlight bleed, and
| DRM. We also lost the degauss button. Kids today will never
| know how fun that was.
|
| Some of that has gotten better over time, but it'd be nice
| if in 2024 we had screens at least as capable as what we
| had several decades ago.
| didntcheck wrote:
| Perhaps I just had poor ones, but my memory of CRTs was
| inferior blacks in practice due to the much higher
| reflectiveness of the glass surface. So while
| _technically_ it was a perfect black in terms of direct
| emissions, it didn 't help much when I could see the room
| behind me reflected in that "black" patch. In a dark
| arcade it's fine of course, but most of my monitor use is
| in a well-lit room. And I still dislike glossy modern
| monitors
| autoexec wrote:
| It's true that there were CRTs that performed worse than
| others and that glare was an issue. CRTs could develop
| some weird image issues when they started failing too so
| for a lot of people used to old CRTs that needed repair
| getting a new LCD probably did seem like an upgrade. Very
| few people who'd been using a well functioning Sony
| Trinitron would have felt that way though.
| NikkiA wrote:
| As someone that had a 22" Sony trinitron monitor on my
| (sagging) desk in the late 90s, no, I was glad to switch
| to LCD.
| HeyLaughingBoy wrote:
| There's a Sony Wega that's been sitting outside my back
| door for 10 years because it could only handle a toddler
| pouring apple juice inside it twice. Should probably make
| a trip to hazmat drop off one of these years.
|
| Anyway, no. The reason said toddler was able to damage it
| was because I replaced that sucker with an LCD TV the
| instant they didn't cost an arm and a leg and moved the
| CRT into the basement for the kids to watch.
| EvanAnderson wrote:
| I'd post it on your local craigslist, etc, as a free
| pickup. No more Trinitron tubes are being made. It's
| possible it has value to somebody. No point in it going
| to landfill if somebody can make something good out of it
| (and you potentially don't have to move it).
| HeyLaughingBoy wrote:
| > been sitting outside my back door for 10 years
|
| I'm thinking you missed that part :-)
|
| He and I talked about it today and it's probably been out
| there for closer to 12 years.
| nyanpasu64 wrote:
| [delayed]
| toast0 wrote:
| LCDs do give consistent color convergence over the whole
| display, and perfect vertical and horizontal lines. That
| counts for something, although you're certainly right
| about the cons.
| theamk wrote:
| Wait what, "HD"? Sales pitch where? I don't think I ever
| watched traditional ads for monitors, it was always
| catalogs (with dry specs) and computer magazines /
| friends (which always mentioned latency). And if there
| were any resolution-related acronyms, it would be SVGA,
| XGA and other weird things no one took seriously.
|
| Here is a period shopping catalog: https://archive.org/de
| tails/computer_shopper_2000-07/page/n5... (page 5). Note
| you had a choice PerfectFlat E2 CRT panel (1280x1024, 17"
| viewable) and ViewPanel LCD (with same spec). At that
| time (2000's), LCDs were 2x-3x times more expensive than
| CRTs, so most people would still go with CRTs.
|
| HD is a relatively new term which I think appeared when
| LCD came for consumer TVs? By that time, LCD monitors has
| long ago became prevalent with the PCs.
| xcv123 wrote:
| I remember the constant eye strain from years of CRT
| monitor use. Blurry and flickery pieces of shit. I dumped
| mine in the trash and never looked back. Good riddance.
|
| > it'd be nice if in 2024 we had screens at least as
| capable as what we had several decades ago
|
| You don't know what you're talking about. Try using a
| high end LCD that was manufactured in the past 10 years.
| The screens today are way better than the shit we were
| forced to use in the 90s.
|
| https://www.apple.com/pro-display-xdr/
| autoexec wrote:
| I fully admit that they have improved. i haven't tried
| that particular model. I'm unwilling to pay the $1,000
| for the monitor stand, but I'll have to stop into an
| apple store sometime to see in it in action.
| kjkjadksj wrote:
| Lcds were way better than the crts consumers had. Most
| desktop crts were absolutely massive and took up the entire
| desk. We had to install special drawers in our desks that
| slid out and held a keyboard because there wasn't room
| otherwise on most desks. The lcds that replaced them were far
| lighter, my grandparents could actually move them for once,
| they took up probably three inches of the desk, and they were
| bigger diagonally too with more io accepted.
|
| For tvs flat screens only really started replacing crt and
| plasma when they were hd. Even a 720p tv looked a lot better
| than a crt and once again, was much lighter, was much bigger,
| and had way more io (early flatscreens had even more than
| today usually). Crts sucked, thats why everyone happily threw
| them to a curb.
| autoexec wrote:
| LCDs were garbage at just about everything. It was so much
| worse when the screens were new, but even today I have yet
| to see an LCD screen that can display an image with even a
| single solid color accurately. Correctly representing an
| image on a screen is their one job and they still fail at
| it.
|
| See my reply here
| (https://news.ycombinator.com/threads?id=autoexec#39670782)
| for a list of just some of the ways LCD screens were worse
| than CRTs
| xcv123 wrote:
| > even today I have yet to see an LCD screen that can
| display an image with even a single solid color
| accurately
|
| Have you tried professional calibrated monitors?
| https://www.eizo.com/products/coloredge/
| autoexec wrote:
| I doubt it. They aren't even terribly expensive.
| xcv123 wrote:
| Well those cost tens of thousands of dollars. But even a
| cheap (by comparison) Apple XDR display is properly
| calibrated and surpasses the color gamut of professional
| CRT monitors. (100% of DCI-P3
| https://en.wikipedia.org/wiki/DCI-P3)
| gwbas1c wrote:
| > Even today's TVs are inferior to CRTs in some ways
|
| Get a high-end OLED. Totally exceeds the real and imagined
| advantages of CRT.
| layer8 wrote:
| Motion blur is an area where impulse displays like CRTs
| still excel compared to sample-and-hold displays like LCD
| and OLED.
| kjkjadksj wrote:
| I turned on a crt recently and it was so noisy I could hear it
| outside, through the walls. My cat ran and hid. Did we really
| all collectively just tolerate that noise back then, or do
| these things decay over time somehow and get louder?
| didntcheck wrote:
| It it was that loud then I'd expect something was wrong with
| it. I can no longer hear those frequencies, but I could when
| I was a kid, and I don't remember it being annoying at all.
| Just one of those things you only really notice _after_ it
| stops, like when the fridge stops humming. Our cat also didn
| 't react at all from my memory
| EvanAnderson wrote:
| I tried to show off an Apple II to my then 5 y/o daughter
| using a CRT monitor. She the sound (presumably somewhere
| around 15Khz) and was really annoyed by it and clasped her
| hands to her ears. My wife and I were completely oblivious.
|
| We didn't see if she could acclimate to it. The monitor
| works okay but it's early 1990s stock so, presumably,
| something might be wrong w/ it, too.
|
| I definitely remember hearing CRTs as a kid and adults
| telling me I was making it up.
| vikingerik wrote:
| The horizontal refresh rate (scanlines per second, how
| often the beam retraces horizontally) of NTSC video is
| indeed 15750 Hz, and PAL is 15625. Just about every CRT
| will emit some amount of audio at that frequency, and yes
| that's just at the upper end of the audible range for
| some (mostly young) humans.
| c22 wrote:
| You couldn't hear it over the sound of your PC fans and hard
| drive seeking...
| HeyLaughingBoy wrote:
| Slap it on the side. Coils may be loose due to age and glue
| drying out.
| demondemidi wrote:
| This is a pretty good emulation:
|
| https://github.com/Swordfish90/cool-retro-term
| rbanffy wrote:
| It's a shame that when the SCART connector was conceived they
| didn't include X and Y signals along with the RGB ones. Would be
| cool to have every TV in Europe also being an X-Y monitor (and
| allow an extra cool free visualization mode when the TV is on but
| you are listening to music).
| dfox wrote:
| The deflection circuitry of a TV or raster-scan CRT monitor is
| not designed to be driven by random X-Y signals and optimized
| around the sawtooth patterns of the raster scan. One thing is
| that driving the deflection coils of large-ish CRT at typical
| raster scan frequencies requires considerable power (the
| typical X-Y display cannot draw all the "pixels" each "frame")
| and another is that there is a bunch of analog tricks (funky
| magnetics in the "output filters" and such) where various non-
| linearities of the system partially cancel each other out,
| which works only for the typical saw-tooth-ish deflection
| waveforms.
|
| Another thing is that both CRT monitors and "modern" CRT TVs
| synchronize both their main SMPS and the EHT flyback to
| horizontal frequency of displayed image (one is tempted to say
| that typical CRT computer monitor is in fact one giant
| overcomplicated SMPS). The reasoning is more or less the same
| as to why the TV framerate is related to mains frequency:
| reduction of artifacts that move around in the image. Also,
| this is the reason why out-of-spec signal can damage (old,
| which essentially means not microprocessor controlled) CRT
| displays and TVs.
| dn3500 wrote:
| I used to have a 1948 Hallicrafters TV and it had yet another
| type of high voltage supply. There was a 100 kHz oscillator
| driving an air-core transformer in normal (not flyback) mode. The
| potting had gone bad on the transformer, and I couldn't find a
| suitable replacement, but I did find one that had the right
| secondary winding. Since it was air-core I just cut the secondary
| off that and the primary off the original and glued them
| together. Worked great.
| HeyLaughingBoy wrote:
| Hallicrafters made TVs? I guess I shouldn't be surprised but
| I've only ever heard that name in the context of ham radio and
| shortwave listening.
| xythobuz wrote:
| I just want to mention Oscilloscope Music [1]. You can find other
| artists on YouTube. It can be played on analog oscilloscopes with
| an XY mode. I also recently made a little player with a Raspberry
| Pi [2].
|
| [1]: https://oscilloscopemusic.com/
|
| [2]: https://www.xythobuz.de/osci_music_player.html
| sam1r wrote:
| It's absolutely worthwhile to click the comments link. [0]
|
| [0] https://www.jmargolin.com/mail.htm
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