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The Secret Life of XY Monitors (2001)

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Re: The Secret Life of XY Monitors (2001)

#21

Post by theamk »

tyingq wrote: post #8

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.

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...

Re: The Secret Life of XY Monitors (2001)

#22

Post by kloch »

colechristensen wrote: post #4
onetimeuse92304 wrote: post #3

> 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…

>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.

> 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)

Re: The Secret Life of XY Monitors (2001)

#23

Post by rbanffy »

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).

Re: The Secret Life of XY Monitors (2001)

#24

Post by dfox »

Zardoz84 wrote: post #19
Cthulhu_ wrote: post #6

Earlier quoted context omitted.

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.

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.

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.

Re: The Secret Life of XY Monitors (2001)

#25

Post by actionfromafar »

bombcar wrote: post #18
autoexec wrote: post #15

Earlier quoted context omitted.

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…

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.

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.

Re: The Secret Life of XY Monitors (2001)

#26

Post by kjkjadksj »

RetroTechie wrote: post #14

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…

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?

Re: The Secret Life of XY Monitors (2001)

#27

Post by dn3500 »

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.

Re: The Secret Life of XY Monitors (2001)

#28

Post by autoexec »

theamk wrote: post #20
autoexec wrote: post #15

Earlier quoted context omitted.

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…

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 disp…

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.

Re: The Secret Life of XY Monitors (2001)

#29

Post by kjkjadksj »

autoexec wrote: post #15
RetroTechie wrote: post #14

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…

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…

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.

Re: The Secret Life of XY Monitors (2001)

#30

Post by dfox »

rbanffy wrote: post #23

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).

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.

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