Curing CRT Cataracts Freshens Up Retro Roundy TVs

September 29, 2024 by Dan Maloney 12 Comments

It’s been a long time since the family TV has had a CRT in it, and even longer since that it was using what was basically an overgrown oscilloscope tube. But “roundies” were once a thing, and even back in the early 80s you’d still find them in living rooms on TV repair calls, usually sporting a characteristic and unsightly bullseye discoloration.

Fast-forward a few decades, and roundy TVs have become collectible enough that curing their CRT cataracts is necessary for restorationists like [shango066], a skill he demonstrates in the video below. The defect comes from the composite construction of CRTs — a safety feature added by television manufacturers wisely concerned with the safety aspects of putting a particle accelerator with the twin hazards of high vacuum and high voltage in the family home. The phosphor-covered face of the tube was covered by a secondary glass cover, often tinted and frosted to improve the admittedly marginal viewing experience. This cover was often glued in place with an epoxy resin that eventually oxidized from the edges in, making the bullseye pattern.

The remedy for this problem? According to [shango066], it’s heat, and plenty of it. After liberating the tube from the remarkably clean TV chassis, he took advantage of a warm summer’s day and got the tube face cooking under a black plastic wrap. Once things were warmed up, more heat was added to really soften the glue; you can easily see the softening progress across the face of the tube in the video below. Once softened, gentle prying with wooden chopsticks completes the job of freeing the safety lens, also in remarkably good shape.

With the adhesive peeled off in an oddly satisfying manner, all that’s left is a thorough cleaning and gluing the lens back on with a little silicone sealant around the edges. We’d love to see the restored TV in operation, but that’s left to a promised future video. In the meantime, please enjoy a look at the retro necessities TV owners depended on in the good old days, which really weren’t all that good when you get down to it.

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Original Game Boy Gets Display “Upgrade”

August 13, 2024 by Bryan Cockfield 17 Comments

Before LCD and LED screens were ubiquitous, there was a time when the cathode ray tube (CRT) was essentially the only game in town. Even into the early 2000s, CRTs were everywhere and continuously getting upgrades, with the last consumer displays even having a semi-flat option. Their size and weight was still a major problem, though, but for a long time they were cutting edge. Wanting to go back to this time with their original Game Boy, [James Channel] went about replacing their Game Boy screen with a CRT.

The CRT itself is salvaged from an old video conferencing system and while it’s never been used before, it wasn’t recently made. To get the proper video inputs for this old display, the Game Boy needed to be converted to LCD first, as some of these modules have video output that can be fed to other displays. Providing the display with power was another challenge, requiring a separate boost converter to get 12V from the Game Boy’s 6V supply. After getting everything wired up a few adjustments needed to be made, and with that the CRT is up and running.

Unfortunately, there was a major speed bump in this process when [James Channel]’s method of automatically switching the display to the CRT let the magic smoke out of the Game Boy’s processor. But he was able to grab a replacement CPU from a Super Game Boy, hack together a case, and fix the problem with the automatic video switcher. Everything now is in working order for a near-perfect retro display upgrade. If you’d like to do this without harming any original hardware, we’ve seen a similar build based on the ESP32 instead.

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Pixel Art And The Myth Of The CRT Effect

August 3, 2024 by Maya Posch 61 Comments

The ‘CRT Effect’ myth says that the reason why pixel art of old games looked so much better is due to the smoothing and blending effects of cathode-ray tube (CRT) displays, which were everywhere until the early 2000s. In fits of mistaken nostalgia this has led both to modern-day extreme cubism pixel art and video game ‘CRT’ filters that respectively fail to approach what pixel art was about, or why old games looked the way they did back with our NES and SNES game consoles. This is a point which [Carl Svensson] vehemently argues from a position of experience, and one which is likely shared by quite a few of our readers.

Although there is some possible color bleed and other artefacts with CRTs due to the shadow mask (or Sony’s Trinitron aperture grille), there was no extreme separation between pixels or massive bleed-over into nearby pixels to create some built-in anti-aliasing as is often claimed unless you were using a very old/cheap or dying CRT TV. Where such effects did happen was mostly in the signal being fed into the CRT, which ranged from the horrid (RF, composite) to the not-so-terrible (S-Video, component) to the sublime (SCART RGB), with RGB video (SCART or VGA) especially busting the CRT effect myth.

Where the pixel art of yester-year shines is in its careful use of dithering and anti-aliasing to work around limited color palettes and other hardware limitations. Although back in the Atari 2600 days this led to the extreme cubism which we’re seeing again in modern ‘retro pixel art’ games, yesterday’s artists worked with the hardware limitations to create stunning works of arts, which looked great on high-end CRTs connected via RGB and decent via composite on the kids’ second-hand 14″ color set with misaligned electron guns.

This Home Made Mac Has A Real CRT

July 30, 2024 by Jenny List 14 Comments

Cathode-ray tube (CRT) televisions may no longer be in production, but its last bastion came in the form of extremely cheap little Chinese portable sets with a black-and-white tube. They’re now useless for broadcast TV, so can often be had for next-to-nothing. [Action Retro] has a video showing a Mac Classic clone using one, and with a built-in Raspberry Pi and a copy of RiscOS it almost makes a usable computer.

The video below the break is a little heavy on the 3D printer sponsor and the Mac case comes from a Thingiverse project, but it’s well executed and we’re grateful for being introduced to that original project. We’d have gone for a period-correct beige filament rather than the glow-in-the-dark green one used here.

We’re guessing that more than one reader will have a few of those TVs around the place, such is their ubiquity. Is it worth making this as a novelty item? It depends upon your viewpoint, but we can’t help liking the result even if perhaps it’s not for us. If RiscOS isn’t quite the thing, there’s an option a little closer to the real thing.

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You Can Use A CRT As An Audio Amplifier Tube

July 11, 2024 by Lewin Day 36 Comments

When we talk about audio amplifier tubes, we’re normally talking about the glass little blobby things you might find in a guitar amplifier. We’re not normally talking about big ol’ color CRTs, but apparently they can do the job too. That’s what [Termadnator] is here to show us.

The CRT in question is a 14″ unit from a common garden variety Philips color TV. [Termadnator] pulled out the TV’s original circuitry, and replaced much of it with his own. He had to whip up a high-voltage power supply with a 555 and a laptop power supply, along with a bunch of fake MOSFETs pressed into service. He also had to build his own Leyden jar capacitor, too. The specifics of converting it to audio operation get a bit messy, but fear not—[Termadnator] explains the idea well, and also supplies a schematic. Perhaps the coolest thing, though, is the crazy color pattern that appears on the display when it’s working as an amp.

Sound output isn’t exactly loud, and it’s a little distorted, too. Still, it’s amusing to see an entire TV instead doing the job of a single amplifier tube. Video after the break.

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All About CRTs

June 25, 2024 by Al Williams 76 Comments

For old-timers, CRTs — cathode ray tubes — were fixtures as kids sat in front of TVs watching everything from Howdy Doody to Star Trek. But there’s at least one generation that thinks TVs and computer monitors are flat. If that describes you, you might enjoy [The 8-Bit Guy’s] coverage of how CRTs work in the video below.

CRTs were heavy, took high voltage, and had a dangerous vacuum inside, so we really don’t miss them. The phosphor on the screen had a tendency to “burn in” if you showed the same image over and over. We don’t miss that either.

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Tight Handheld CRT Asteroids Game Curses In Tuscan

June 12, 2024 by Elliot Williams 5 Comments

How many Arduini does it take to make a tiny CRT Asteroids game? [Marco Vallegi] of MVV Blog’s answer: two. One for the game mechanics and one for the sound effects. And the result is a sweet little retro arcade machine packed tightly into a very nicely 3D printed case.

If you want to learn to curse like a Tuscan sailor, you can watch the two-part video series, embedded below, in its entirety. Otherwise, we have excerpted the good stuff out of the second video for you.

For instance, we love the old-school voice synthesis sound of the Speak and Spell. Here, playback is implemented using the Talkie library for Arduino, and [Marco] is using the BlueWizard software on a dated Macbook for recording and encoding. (We’d use the more portable Python Wizard ourselves.) Check out [Marco] tweaking the noise parameters here to get a good recording.

And since the Talkie Arduino library uses PWM on a digital output pin to create the audio, the high-frequency noise was freaking out his simple transistor amplifier. Here, [Marco] adds a feedback capacitor to cancel that high-frequency hash out.

The build needs to be quite compact, and the stacked-Arduino-with-PCB-case design is tight. And the 3D-printed case has a number of nice refinements that you might like. We especially like the use of thin veneers that cover the case all around with the build-plate’s surface texture, and the contrasting “Asteroids” logos are very nice.

All in all, this is a really fun build that’s also full of little details that might help you with your own projects. Heck, even if it just encourages you to play around with the Talkie library, it’s worth your time in our opinion. And while you’re at it, you can turn on the subtitles and pick up some vocab that’ll make your nonna roll over in her grave.

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