Skip to main content Skip to main navigation menu Skip to site footer
labor, arcade, CRT, cathode ray tube, repair, television, rejuvenator

Tools of the Trade

How a Device Called the Rejuvenator Is Keeping the Technology of Yesterday Alive Today

Scott Stilphen (Independent Researcher)


I’ve been an arcade technician both professionally and personally for nearly thirty years. When I went to college, I intended to have a career fixing computers rather than games. It was only after I purchased an arcade game for myself that I made the connection between the two. When I was a kid, I would often repair my controllers and those of my friends—or at least try to. Back then, video games were to be played, not fixed, and any repairs I did were out of necessity because buying a new controller every few weeks wasn’t an option. My curiosity to open gadgets up and see how they worked soon had me opening not just controllers, but cartridges, game consoles, clocks, radios, and even TVs. I wasn’t sure what I wanted to do when I got older, but I was reasonably sure it would involve repairing or building something.

I first saw an arcade game in the basement of a friend’s girlfriend (ca. 1990–91). Her house certainly gave one the impression that her family was well-off and could afford to own one, even though it was an older game (Centuri Phoenix, 1980). A few years later, I met someone who would become a good friend, and he had two games in his garage: a video game (Atari’s Breakout) and a pinball game (Bally Harlem Globetrotters on Tour, 1979). Although these were both several years older than Phoenix, I decided to look around and see if there were any others for sale locally. To my surprise, they were sometimes extremely affordable to buy, as operators at the time were all too happy to sell off (or even give away) old games that had long stopped earning money for them and instead were only costing them money by taking up valuable space in their warehouses. With my first purchase in 1994 (Atari Asteroids, 1979) and a basic understanding of electronics, I set out to learn how the magic worked. Within a year, I was working for a local arcade operator as a technician and reading through issues of Star-Tech Journal and soaking up as much information as I could.

As I gained experience with repairing arcade games, I acquired some useful tools, including an obscure device known as a cathode ray tube (CRT) rejuvenator. As the name suggests, this device rejuvenates old CRTs, thereby extending an old television set’s life. Much like a defibrillator, a rejuvenator generates an electric shock to a TV’s heart. As I will explain, using this device requires more than simply reading the manual because what’s not in the manual is often just as important as its contents, and what you don’t know can do much more harm than good.

The goal of this article is to briefly describe the history of those old CRT television sets, and how one of the tools created to service them still serves a useful purpose in the restoration and operation of CRT-based arcade machines. I hope to convey how much the maintenance and restoration of old TV hardware depends upon the skill of the operator as much as the tools themselves. A rejuvenator is not as useful or as commonplace as a multimeter, but for a certain subset of games, it’s just as valuable and useful. I will then conclude by reflecting on the status of arcade conservation and how the rejuvenator can continue to keep game history alive today.

How a CRT Works

A CRT is essentially a large vacuum tube with a phosphorescent-coated screen on the display end and a cathode on the other end comprised of one or three electron guns. These guns fire electrons toward the screen, creating a magnetic field that guides the electrons toward the screen.1 If you’ve ever held a magnet by the CRT TV screen when it’s on, you’ll see a rather psychedelic display of colors. That’s because you’re affecting the TV’s own magnetic field and causing the electrons to strike the screen where they’re not supposed. The electron guns paint the screen one line at a time, sixty times a second. This is necessary to generate a stable and flicker-free image, as the glowing phosphors only stay lit for a split second. The glow you see at the end of the CRT when it’s on is a heater filament. With time and usage, the cathode will eventually become less effective at operating the electron guns, as the guns themselves become worn or dirty, which results in a dim image or one with weak colors. Think of the CRT as being akin to your eyeball. As one ages, bits of the fluid inside your eye start to bind together and cast a shadow over your retina at the back of the eye. These shadows are what we call floaters. With CRTs, the phosphor coating on the inside of the tube doesn’t react to the electron guns as effectively as it previously did, or some of the coating may have flaked off and ended up on the electron guns themselves. Unlike the issue with floaters, a handy rejuvenator may rectify these issues with CRTs.

History of B&K Precision

The explosion of TV ownership after the Second World War (and the finicky nature of analog TVs) led to the need for a new occupation—that of the TV repairman. And this new profession would need somebody to make specialized tools for TV repair: enter B&K Precision Corporation. Founded in 1948 under the name Central Television Service Company, B&K Precision was the typical American garage startup company.2 Chicago-based entrepreneurs Philip Ban and Carl Korn set out to fill the market void for repair parts. According to B&K representative Greg VonRehder,3 the company started as a small TV repair shop, where Ban and Korn learned how to repair TVs. From that experience, they designed and built a machine to help with repairs. They showed their machine (their model 465 rejuvenator) to Sears, which was also based in Chicago, and ended up becoming their first customer. From there, B&K started selling their product to other TV repair shops throughout the US, at which point the company was renamed B&K Precision Corporation as it expanded into offering electronic test equipment (see fig. 1). VonRehder was unsure when the 465 model was first commercially sold (possibly sometime in the 1960s), but it was discontinued in 1974.

B&K’s line of products expanded into devices for record players such as wow and flutter meters. B&K’s engineers earned several patents, and some of their equipment became the standard for use at several universities and vocational schools. In 1961, Korn instituted Dynascan, an umbrella corporation housing several electronics firms, with B&K being one. Korn eventually sold off B&K to focus on another company under Dynascan, Cobra Electronics. Dynascan would eventually be renamed Cobra Electronics. Both B&K Precision and Cobra Electronics still exist today.

Figure 1

Instruction manual for B&K Precision’s cathode ray tube tester/rejuvenator model 470 (Image courtesy of author)

Rejuvenators had many uses and users, particularly as the decades wore on and TV sets aged. In the middle of the first decade of the 2000s, for instance, the Salvation Army was one of the biggest customers for CRT rejuvenators, buying twenty at a time approximately every six months. They would receive funding to open up training centers for people to learn how to rejuvenate old TV sets that were donated to them, so that they could turn around and sell or donate them.

B&K sold a number of different rejuvenator models over the decades, only ceasing production in 2007 thanks to the advent of digital sets and some interference by Sony. Since, as we’ll see shortly, different sets required different attachments for the rejuvenator, CRT manufacturers would often provide all the technical information B&K needed to incorporate into their design. Sony, however, saw TV repair as cutting into profits and stopped providing their sets’ information to B&K, leading to a decline in usefulness for the device.

Tools of the Trade

Rejuvenators, in brief, allow a technician to measure the output of the cathode and repair the electron guns (fig. 2). This restoration process is subtractive, meaning its use doesn’t add any additional emitting material to the electron guns; instead, it removes some of the existing material from the guns, thereby exposing new or fresh material to be used. This is done by running the electron guns at a slightly higher voltage, which in turn burns off any oxidation and material. The upside is that if a tube is weak or missing colors, careful use of a tube rejuvenator may bring the colors back. This is not an exact science by any means, and it’s very easy to permanently damage a CRT using one of these.

Figure 2

B&K Precision’s cathode ray tube tester/rejuvenator model 470 (Image courtesy of author)

Besides B&K Precision, Heathkit, Promax, and Sencore also made CRT rejuvenators, but those by B&K are the most commonly used in today’s arcade industry, as they were the leader in that field. Those who grew up in the so-called golden age of video games usually prefer using CRTs, particularly with arcade games, making rejuvenators an invaluable tool to the contemporary operator. Some technicians prefer certain makes and models of rejuvenators over others because most techs become familiar with a specific model and thus favor that one over a different one, but the different models all function on the same principle.

Other common devices used by CRT technicians are a degaussing coil and a tube brightener (see fig. 3). The degaussing coil is simply a coil of wire that is plugged into a standard wall outlet. This creates a magnetic field and is used to help with CRTs that have become magnetized, which causes color distortions on the screen. Most TV and arcade monitors include their own degaussing coils around the edge of the tube, but those that don’t have them or have ones that are not connected or working properly will likely require use of a degaussing coil.

Figure 3

GC Electronics degaussing coil model 9317 (Image courtesy of author)

The other device I mentioned, a tube brightener, was sometimes installed by TV shops. These were small transformers that attached to the CRT socket and would slightly raise the heater-filament voltage. The short-term result would be a brighter picture, but the long-term result would be a briefer lifespan for the tube. Tubes for which the rejuvenator’s effects only lasted a short time (measured in weeks or months), these brighteners were probably a cheap work-around when the only other option would be to either replace the tube or buy another TV.

What none of these devices can repair is the far more common issue of tubes having images burned into the phosphor. Tubes with burn on them result when the CRT displays a static image for too long, and the image will effectively get burned into the phosphor coating. This was a significant issue with early home game consoles, as the dedicated or single game systems didn’t cycle the colors if the game was on and wasn’t being played. Those who frequently traveled by air back when airport terminals used CRT displays to show flight information will probably recall how badly burned those displays were, as they typically showed bright white text against a black background. This was also a major issue with early dedicated video game consoles such as Odyssey and Pong. Atari was the first company to address this issue with their Atari Video Computer System (VCS), as programmers included code that would cycle the screen colors after a few minutes if the game was left idle.4 Screen burn is not an issue solely with CRTs as it can still affect newer LCD-based TVs for the same reason.

Using a Rejuvenator

Before discussing how the rejuvenator is used, I need to note something that isn’t covered in the manual: CRTs are inherently dangerous items. For one, they can store a significant amount of voltage—at least twenty thousand volts—even when they are off and unplugged. Some tubes discharge themselves as soon as they are powered off, but some don’t and may hold a charge for hours or even days, so you can’t assume anything. For that reason, a technician must first discharge the voltage before doing anything else. Plenty of articles and videos online show how to do this, but the most important thing to keep in mind when discharging one is to keep one hand behind your back. Doing so prevents voltage from going across your chest and possibly stopping your heart should you be accidentally shocked. This is why devices such as TVs and arcade machines are often marked that only qualified technicians should be working on them.

Another dangerous aspect of CRTs is they are also at risk of imploding if broken. The front or face of the tube is quite thick and very difficult to break, and for good reason: that’s usually the only visible part. The back of the tube, called the neck, is where the glass is the thinnest, and it’s all too easy to crack this part. Arcade techs refer to doing this as necking the tube, and it usually happens when you’re handling the tube outside of the cabinet, or in the process of removing or installing it into a cabinet. Once cracked, you’ll hear the unmistakable sound of air rushing into the tube (remember, the tube is a vacuum internally), and at that point, the tube is worthless and cannot be repaired.

The rejuvenator is relatively simple to operate with literally just the push of a button. However, all the controls to set it up are analog (dials and gauges), with some models using separate gauges for each gun, which introduces added complexity to a rejuvenator’s actual use. Above all else, using a rejuvenator requires that it be properly configured for the tube being used, as not all tube makes and models are exactly the same. The rejuvenator also needs the correct adapter to connect it to the tube’s neck (see fig. 4). For example, with most arcade games, a number 23 adapter fits nineteen-inch standard-resolution color monitors.

Figure 4

B&K Precision CRT adapter 23 (Image courtesy of author)

With the rejuvenator connected to the tube and the tube’s own monitor chassis disconnected from the tube, the device is ready to be configured (see fig. 5). This process varies depending on the make of the device (e.g., the setup process for a B&K is different from a Sencore). The rejuvenator’s manual often includes a list of the most common tubes that were used at the time, but since most of these devices were produced years or decades earlier than the tubes found in most arcade games, the manual often won’t have the needed information. To address this issue, an online searchable database called Tubular was created.5

Figure 5

Instructions for restoring a picture tube using a B&K rejuvenator (Image courtesy of author)

Once all the device’s controls are set according to the instructions, the first step is to test the tube. Based on the initial test results, the operator will decide at what level to rejuvenate the tube: remove any shorts (in the electron guns), clean or restore, or full rejuvenation. With each of those, the operator must decide how long to run the process, as the intensity of the process depends on how long the operator runs it. Each time one runs the rejuvenator, one has to wait for the tube to cool down before doing anything else with it. Because the device is running the TV set at a higher voltage than normal, it’s very easy to cause permanent damage. It’s like walking on a beam—there’s a fine line between staying on or falling off. Perhaps a more accurate analogy would be comparing open-heart surgery as it’s done today to how it was done fifty years ago: there’s a fifty-fifty chance you’d survive the procedure, and if you did, you’d likely only live for another year or two. While the odds of the CRT surviving the rejuvenator process are better now, the process uses up more of the tube’s life each time it’s done, and the tubes are only getting older. As those who are experienced in using it in the arcade community like to say, if the tube dies during the process, chances are it was going to fail soon anyway, regardless of whether or not you tried to save it.

The real key to rejuvenating CRTs has less to do with the rejuvenator than with the knowledge of the operator. For example, I can take a perfectly good tube and render it useless within seconds if the rejuvenator is used incorrectly. Rejuvenating a tube is a destructive process that lessens the life of the tube and should only be done as a last resort. Fully recapping (replacing all the major capacitors) a monitor chassis is often the first step in repairing CRTs and will solve some of the more common issues. Only use the rejuvenator after you’re sure that the tube is the issue and that a rejuvenator can fix it.

As I mentioned, a rejuvenator should be used in increments, starting with the least destructive option and working up from there. This is because a more mild option might be sufficient to correct the issue you’re having. Choosing to use the most intense option could do more harm than good. Technically, the rejuvenation process heats the barium coating on the cathodes. Over time, this barium layer is worn away from the tips, which is the source of electrons needed to create a picture, and the process liquefies an extremely thin layer of this barium. Most technicians will operate the rejuvenator with either the tube still mounted in the cabinet or placed on a work bench, but one trick is to have the CRT facing down during the process. This ensures that the liquefied barium flows from the cathode’s base to its tip, where the material is needed.

The Arcade Connection

The first two video games created were American physicist William Higinbotham and engineer Robert Dvorak’s Tennis for Two (1958) and Steve Russell’s Spacewar! (1962).6 Both actually used oscilloscopes, or vector monitors, but these were simply CRTs that were driven by different electronics. Ralph Baer and his colleagues’ early efforts with his Odyssey home game units first led to repurposing TVs for home gaming for millions of people. With the rise of the video arcade games in the early 1970s, starting with Nolan Bushnell and Ted Dabney’s Computer Space by Nutting Associates in 1971,7 CRTs were by far the most common type of displays used. In the early days of the arcade industry, the monitors used in the arcade cabinets were in fact actual TVs that could be found at any local store! For example, Atari’s Pong by Allan Alcorn used various thirteen-inch black-and-white (b&w) models, and other than being modified to accept the composite video signal from the game board, the TVs were stock with their antennas and carrying handles still intact (see fig. 6).

Figure 6

Atari’s Pong arcade game showing two different black-and-white TVs being used (Images courtesy of author)

In our interview, VonRehder admitted that B&K’s CRT rejuvenator business isn’t what it once was, but the requests they get these days for technical support for them are almost all for arcade repair. Arcade techs in the 1980s wouldn’t have had a rejuvenator because most of the games they worked on were new. Only in the 1990s when folks started looking into buying and collecting older games did word get around that such a device existed and could be used. I worked as an arcade tech for several years before even becoming aware of the existence of rejuvenators, and then only from the online arcade community (the arcade-related newsgroups), where some of the techs mentioned using them; none of the arcade operators I worked for even had one! TV repair shops were few and far between, with the industry moving from CRT-based TV sets to flat screens (LCD, plasma, etc.), so any training or knowledge about using a rejuvenator was mostly anecdotal.

Maintaining these older arcade games in the present day introduces new issues, with owners seeing parts breaking that either never broke before or weren’t common issues until recently. For example, the twenty-three-inch b&w CRTs (the specific tube model is 22VATP4) that were often used in games in the 1970s (such as Atari’s Basketball and Football games) are increasingly hard to find in working condition (working monitors currently sell for at least $250 on the secondhand market), because the phosphor coating on the inside front of the tubes has or is close to breaking down. The materials used to create it have degraded to the point that it’s flaking off from the inside of the tube and rendering the tube nonfunctional.

When I finally got myself a rejuvenator, I first started experimenting with tubes at work that were either known to be bad (i.e., bad color gun) or were so burned in that they couldn’t be used for anything. So, for example, if a tube had one bad gun, I could experiment with trying to fix that gun, and if it didn’t work, I could then experiment with a working gun to see how long a certain test would run before it was too long. Once you get comfortable with using them, you can move on to using them with more valuable tubes. But even then, it’s not 100 percent guaranteed that using a rejuvenator won’t damage a tube, especially if it’s an old tube that’s likely at the end of its life, so even briefly using one will cause permanent failure.

The Future for CRTs

The history and use of CRTs now stretches back nearly a hundred years. Although LCDs and other flat-screen technologies have long replaced them in homes and arcades, CRTs are still being produced and used, although for limited applications; Thomas Electronics is one such manufacturer.8 The retrogaming community is certainly keeping CRTs alive. Those who own and operate older video game arcade machines and consoles often prefer CRTs over flat screens, as they grew up with CRTs and are more familiar with them. Speaking as a Gen-Xer who saw the birth of the video game industry, there is something to be said for those warm, blurry screens over the cold, sharp displays of today. Some early game programmers took advantage of the CRT’s display limitations to create colors on-screen that otherwise weren’t possible with the game hardware being used. This is but one example of the continuing relevance of CRT repair to modern games and game history.

When my generation passes, I predict there won’t be many CRTs left in use, and even fewer people who will know how to repair them. After all, that’s how it is with any technology, especially one that’s now become disposable (i.e., buying a new TV is often cheaper than having the old one fixed). But even if I and other operators and collectors maintain these old boxes for a few decades more, who will maintain and repair our tools, like the rejuvenator? Who pass on the knowledge of arcade operations of the generations of arcade operators who learned not only the ins and outs of these machines but also the embodied skill it takes to find just the right intensity for a rejuvenator’s operation? After all, maintenance and repair devices and practices are more than just tools for the preservation of game devices; they are themselves a part of game history worth documenting. I hope that in some small way, this article has done that.


1. ^ For diagrams and other visual aids, see, for example, Marshall Brain, “How Television Works,” How Stuff Works, accessed April 30, 2023,, as well as other information on this website.

2. ^ “About B&K Precision Corp,” About Us, B&K Precision Corporation, accessed April 30, 2023,

3. ^ Greg VonRehder, virtual interview with author, May 24, 2023.

4. ^ “Scott Stilphen asked 3 of Atari’s early VCS/2600 game designers on how 2:16 came to be used,” Atari Compendium FAQ, Atari Compendium, 2023,

5. ^ Tubular, accessed April 30, 2023, Programmer and vintage-game collector Ian Eure created the database.

6. ^ Tristan Donovan, Replay: The History of Video Games (East Sussex, UK: Yellow Ant, 2010), 1–12; and Raiford Guins, Game After: A Cultural Study of Video Game Afterlife (Cambridge, MA: MIT Press, 2014), 94–105.

7. ^ Henry Lowood, “Videogames in Computer Space: The Complex History of Pong,” IEEE Annals of the History of Computing 31, no. 3 (2009): 5–19.

8. ^ “Are CRTs Still Manufactured or Used?,” FAQs, Thomas Electronics, accessed April 30, 2023,