Rejuvenating a Macintosh CRT with equipment from 1969

[@greedj]

I used to be a TV repair guy back in the 80s and 90s (I'm now a computer engineer). I used that exact tester (B&K actually sold additional updated modern adapters for a while with updated cross reference guides). I rejuvenated many many CRTs with that tester and I would estimate about 75% of the time the CRT remained functional for years after. The other 25% of the time there was either no change or the CRT would completely fail. The spark you hear is normal when rejuvenating and I had the best success using 3 quick taps in a row and then checking emission. It is not doing anything to the heater, it is causing an ARC across the electron gun (usually visible when pressing the rejuvenate button) that exposes fresh surface on the coating of the cathode.

[@filter4now]

Thanks that answers my question. Is the heater necessary at all in the rejuvenating state or just when actually testing emissions or watching the CRT?

[@andymouse]

" Rejuvenation" means increasing the filament current a bit, and or more extraction voltage to "blow" any surface crud of the filament and basically increase the amount of electrons liberated from the filament, this works and is used in old electron microscopes as a last resort before looking the customer in the eye and telling them how much a new filament is ! however filament lifetime after this is a bit of a lottery, also there is a risk that the crud (filament) you removed went further in and caused problems down the line, so all in all, in your situation you did the right thing and you couldn't replace the filament anyway..i'm betting you get years out of it ! and from now it could actually improve a bit more...I'm a "glass half full guy"...cheers.

[@TheEmbeddedHobbyist]

just what I was going to say Andy, years ago a friend had a tv rental company, which would rent tv's cheap to people who the main stream rentals would not touch. The sets were ex rental which I help fix up, good clean inside and out and a tube boost would see them running for up to about a year, only had to last 3 months to pay for themselves.

[@luminociter]

So I guess this is the old extraction potential trick due to surface degradation... I have seen people use this also in old filament gas displays that are no longer produced and used in traditional lab instruments from the 60s to 90s... I guess the filament gets worn out during the process and the times you can repeat it is limited. Nice to see it working though, would be cool to also know what voltage/current it applies during this process.

[@SidneyCritic]

@@TheEmbeddedHobbyist Did you have to hit the button a lot, or just enough to get to good. Basically will more blasts make it better.

[@tekvax01]

@@SidneyCritic, if you hit the grid with HV too much you can completely destroy the CRT!

[@EsotericArctos]

It does work but you never know how long for, but even if you only get another 6 months out of it, it only cost a little bit of time.

[@patrickbuckland5849]

Truly fascinating stuff. And good to see you using Crystal Quest (which I wrote)! Electronics were my original passion actually before getting into programming mainly because I couldn't afford electronic components or test equipment as a kid. Then I realised that I programming was my calling. I was 22 when I originally wrote 'Quest. Currently working on a new version :)

[@mitfreundlichengrussen1234]

you have cost my brother and me several months of productive life - we played on a Mac Plus, the high score was around 1.7 million points and seemed to be unbeatable in the first week - until - I came home and my brother laid 2.1 mio. on me - at the end we reached something over 21 mio points, the game was so slow on the Mac Plus (because there was so much graphics going on) that one game lasted about 6 hours or more ... We´ve both learned a lot about addictions. What a great game it was, cheers from Southern Bavaria, where the beer is cold and the girls are pretty.

[@ltdees2362]

🤣...someone mentioned they had used one of these "crt rejuvenaters" I have one also and would give it bout 60% success rate back in the day, saving your customer considerable expense...also, if this was the only repair and the customer had brought the TV to my shop, I would not charge them...Back in the 60"s we generally made house calls as TV's were just to heavy and bulky to load up and take to a repair shop...I had my tube-case, VOM, solder iron, cheater-cord and few basic tools...$3 house call plus parts...the good times...

[@andymouse]

yes they were.

[@Starphot]

Yes, been there, done that. My buddy and I opened a shop in his garage after serving in the military in 1977. We made house calls in the late 1970's. 10 bucks. This lasted a year until we went separate ways due to other opportunities and overhead costs. Also we bought our rejuvenator and a tuner tester from another small shop going out of business. Most of the mom and pop repair shops went out of business as 1980 approached. If you have to move the console TV sets, that meant you will have to go over the solder joints and burn test the TV for a day before sending it back to the customer. The point-to-point solder joints go bad over time due to the heating and cooling of the filaments and the current draw within the tubes. A little better with the semiconductor boards.

[@Walczyk]

wow i wish i could learn this art today

[@mr-meek]

@@Walczyk You can if you really want to. Check out Mr Carlson's Lab, Glasslinger, Shango006, Uncle Doug, etc, etc... so many resources =)

[@okaro6595]

I did not even know there were any such thing. All out TVs broke other ways than becoming dim. They might have been likely fixed but there always was new technology that made purchasing a new one attractive.

[@MatroxMillennium]

Combining two of my major hobbies: Vintage computers and vintage television repair!

[@luke9511]

these things are used a lot by people who work on and repair and restore old arcade games and they have had good results with it

[@AiOinc1]

They're also used a lot by people in the vintage television community who knows their intended purpose is a band aide until the shop has a new or rebuilt tube ready for the customer.

[@AdolphusOfBlood]

@@AiOinc1 What does rebuilding one entail?

[@lelandclayton5462]

@@AdolphusOfBlood They leak the Vacuum out of the CRT slowly, cut the tail end off and remove the Gun assembly. In some cases they even remove the phosphor and put in a new layer. Add a new Gun assembly then put it on what looks like a lathe and heat the glass tube to the new tail end and slowly create a new vacuum. kzbin.info/www/bejne/jWSqaJVjeciChZY

[@krnlg]

@@lelandclayton5462 Wow, I hope they're still doing this. Its a pleasant surprise to see that people might actually still be making/restoring CRTs in this way!

[@thomassmith4999]

@@krnlg The people that have the equipment in that video have since (recently) successfully rebuilt a tube using it.

[@dschult3]

When you hit the dynamic intensifier button for the first time, someone started up their lawnmower in the neighborhood while I was watching it. That threw me for a loop for a second there!

[@adriansdigitalbasement]

Ah funny I didn't hear that while editing. Good ears!

[@mrnmrn1]

Wow, when I recommended you under the previous video to rejuvenate it, I thought you will need someone's help who has a rejuvenator, I had no idea you already have one. Rejuvenation is usually a temporary fix, but there are exceptions. I guess this will have a long term effect. If not, try the high setting next time. Why I'm thinking it will last? In my opinion, this CRT was not tired, it had cathode poisoning. Because the way these Macs work with the black border around the picture, if this tube was used a lot, it would have a burn-in mark on the screen which resembles this black border, but I can't see any burn-in. Remember, the power supply was giving a low voltage on the machine in which this CRT was installed. This is one way to give a CRT cathode poisoning: run it on too low heater voltage for a long time. There are some other possible reasons, like slight gassiness, if that's the case, it will get poisoned again, it might need a getter re-firing with an induction heater. Good work!

[@electronicengineer]

I agree with your opinion of cathode poisoning being the underlying problem with this CRT. Reflashing the getter would most likely eliminate the cathode poisoning long term and add many years to the life of this CRT. Nice job Adrian!

[@HaveYouTriedGuillotines]

Doooo iiiit...~ As far as I'm aware, there aren't really good solutions for replacing the CRT in these old all-in-ones. Maybe there will be a good LCD solution in the long term, or something involving a full rehousing for the motherboards... But for now, it's better to try and get the CRT fully running again.

[@stevethepocket]

So a "tired" CRT is one that basically has burn-in all over instead of in a pattern?

[@mrnmrn1]

​@@stevethepocket No. Well, yes, if it has so many hours on it, the phosphor will degrade on the whole screen, but it affects the brightness just slightly. A CRT is being tired if the emitting material got worn off on the cathode(s), and it's no longer able to emit enough electrons. This will cause low brighness, and when you try to compensate for it by boosting up the contrast and brightness settings, the CRT will smear the high brightness parts of the picture, and becomes blurry. On some extreme cases, the high brigtness areas will turn to negative.

[@compwiz101]

Rather reminds me of why most nixie clock designs will have an "anti poisoning" mode where it will cycle through all of the numbers (even those not normally used) at full brightness to prevent this very issue.

[@Sheevlord]

It would be cool to know if this lasts if you keep using it. Maybe make a follow-up video several months later comparing the performance. Also, it would probably be a good idea to replace the rest of the capacitors just in case. It doesn't matter that they seem to be working now - they are over 50 years old at this point, so they probably won't last much longer

[@oldestgamer]

words of wisdom

[@Fly0High]

@@oldestgamer If your a Mr Carlson's Lad regular, you'll know those caps are leaky.

[@classiccomputers6211]

They're dry electrolytics, they are probably fine. I've found plenty in old equipment that still test new and I have not yet had any fail on me in service.

[@AiOinc1]

For equipment you care about keeping for a long time, yes you should probably replace all of the capacitors and the resistors right now to prevent future problems. Old resistors fail very often in these types of devices as well as the capacitors. But that's not diagnostics, that's full on restoration at that point. CRT restore/rejuvinate is pretty widely known in the television community to be a gimmick. It's just a band aid to give you enough life to get the customer a working television while the shop orders or rebuilds another tube for them. It's similar to a CRT brightener - You're not supposed to keep using it for so long after.

[@Sheevlord]

@@classiccomputers6211 Well, given that one of them failed right in the video I'd say that replacing the rest is a good idea.

[@JamesPotts]

You snagged a rejuvenator at a thrift shop?!?!?!

[@laurensa.1803]

You stumble upon the weirdest things at thrift shops. Is this an unfamiliar experience to you?

[@AiOinc1]

Tube testers and brighteners are extremely common, they were service grade equipment and lots of people had them.

[@Damaniel3]

I hit up Portland area thrift shops all the time and don't find anything nearly as cool (probably because Adrian's picking it all up).

[@iamdarkyoshi]

One of my friends got a 90's tester/rejuvenator for 15 bucks, it's 400$+ on ebay right now If you go thrifting, go everywhere and go often

[@mrnmrn1]

Yep, I wish we had thrift shops like this here in Hungary, and I wish CRT and tube testers to be this common like in the US. In here, they were never a common thing. Only the government/military had tube testers, and even they had just a few. Some of the biggest post offices had tube testers (for maintenance of the telecom systems), where they also tested your tubes for a fee. CRT testers/rejuvenators started to occur about in the mid '80s, but they were very expensive, so only a few repair shops bought them. Then in the early '90s, someone probably here in Hungary copied a Spanish Promax RT-501B CRT tester/rejuvenator, and sold them as "Sam's CRT regenerator" m.blog.hu/tu/tubemania/image/img_2435.JPEG . There are not much of these around, it is very difficult to get one second hand, and also quite expensive, so I will probably build one, the schematics are available.

[@abc-ni9uw]

I was reading somewhere ( 3 years ago ) about a trinitron that needed rejuvenation In 1977 tv was only 6 years old but worked for another 30 years before it was junked

[@ramakrishnamishra8179]

Trinitrons are the best CRT TVs ever made!

[@abc-ni9uw]

@@ramakrishnamishra8179 that's why I have a huge collection of pvms and bvms

[@Naitrio]

@@abc-ni9uw Oh sweet i'd like to get a Sony PVM or BVM one day.

[@ramakrishnamishra8179]

@لای آسمووونی yes!! That is engineering!

[@ramakrishnamishra8179]

@@Naitrio yes they are great sd monitors!! Check out my channel where I hace content on them!

[@kuro68000]

Didn't it say wait 15 seconds before doing medium, I guess to let the cap charge? Anyway interesting result!

[@zaprodk]

It's to let the filament get to a stable temperature

[@IlBiggo]

"This thing is from the '60s so it's definitely really old." Me, a man from the '60s: T_T

[@adriansdigitalbasement]

Haha yeah I realized that came across wrong after I said it! Old for technology :-) Not humans hehe

[@marco_evertus]

Me, a man from the late ‘90s: yes you are

[@IlBiggo]

@@marco_evertus When this equipment was new I would have called you an old man .-P

[@KennethPlaysOfficial]

@@IlBiggo your as old as my grandpa

[@IlBiggo]

@@KennethPlaysOfficial Maybe I *am* your grandpa.

[@frankowalker4662]

O.K. Two things.... 1) I love the way you have got 'chapters' on your YT vids, very clever. 2) Replace ALL the cap in that test/rejuvenator set and it will last another 50+ years.

[@dschult3]

I was incredibly impressed with the chapters as well! What a nice detail!

[@AiOinc1]

The capacitors in this device are probably fine - None of them are particularly critical and their values drifting won't cause many issues. Resistors are what you'll worry about for devices this old. They can start to drift or fail in other ways that would make the results inaccurate or could damage the tube you're testing. You don't *need* to replace all of them. Replacing all of the parts is not diagnostics and it's a waste of time and money if they work. If you used a device like this daily or wanted a display piece then yes you should probably replace all of them now.

[@tactileslut]

@@AiOinc1 Maybe it doesn't matter on an uncalibrated intermittent duty piece, but DC leakage can be happening at the operating voltage without it showing up on a low voltage meter.

[@adriansdigitalbasement]

I tested them all with my LCR meter and replaced the on that had failed. The rest mesure within spec (reistors and capacitors.) Yeah I only replace stuff that has failed... not stuff that "might fail" at some point in the future.

[@My_Op]

@@adriansdigitalbasement I'm delighted to read that. I have the same opinion and I'm a bycicle mechanic. (Digression: I wish I could send you some old computer stuff from Belgium so I could add some traditional candies!)

[@GadgetUK164]

Excellent video Adrian! I've been hoping to see a video on this subject for a while! I remember when I was in the trade my boss had a DIY rig that he had built himself, it comprissed of a light bulb (presumed to limit current) and a transformer. I think he basically powered the heater and drove some high voltage through each of the guns. I saw him use it on colour monitors back then and I was amazed how much brigher they were afterwards.

[@nuclearmonster]

Love this episode and seeing that wonderful old tester still working and helping that slightly younger tube come back to life!

[@mymessylab]

Nice and helpful instrument. As tv rapairman I’ve used many times successfully. Good idea to get it👍🤗

[@seshpenguin]

Wow, thats an interesting piece kit! Your right, this CRT is the perfect one to test on, it was going to be thrown out so there is nothing to lose. And hey, you may have a working CRT now!

[@jjock3239]

Great video. An excellent site to watch for old electronics, is Mr Carlson's Lab. I know there are many more, but he is my favourite. A very close friend of mine, long since departed, spent his whole career, from the early 50s, as radar tech and instructor in the RCAF. After he retired, to keep occupied, he made a hobby, then a business, out of repairing tube type and solid state TVs that other techs had failed to repair. After restoring life to the TVs back to life, his last trick was, to use a version of a B&K rejuvenator similar to the one you have, to attempt to improve the brightness of the CRT I used to marvel at what he could bring back to life. As some of your other commenters have mentioned below, his success rate using the rejuvenator was about 75%, and this step was probably going to be enough to last the operational life of the TV. I had to chuckle, when I saw that you had blown a capacitor on the rejuvenator. I still play with a lot of old crap like that, (I am still using a tube type Tektronics 545b scope as one of my toys), and the first thing that needs to be done with those old beasts, is to re-cap them. If they haven't been used in a long time, I also plug them into a variac, and warm them up on a lower voltage, to allow the capacitors to re-form. That way, a lot fewer components (electrolytics) fail and require replacing.

[@FyberOptic]

There's so much science and technology in tube displays, it's a real shame that we've reached a point where you see them sitting on the curb often nowadays.

[@Quickened1]

Its called progress... In their day, they were a marvel, but by today's standards, they are energy hogs and polluted boat anchors... Some things are best left behind, with a small remnant to remind us where we came from...

[@FalconFour]

oh this is so cool to see. I recently got an RCA TV from 1974 that was apparently put in storage as it stopped working - no red. That experience familiarized me with CRT rejuvenators. I got a Heathkit tester/rejuvenator off eBay for $100. That fixed it right up, good as new! But mine had very specific, meticulous instructions for use, and I followed every step. It had two modes - cleaning and rejuvenating. Cleaning is what fixed the gun, rejuvenating brightened and sharpened it. On mine, you hold the function button for much longer, as you adjust the heater voltage. It had a lot more features than this one though (it was also 1975~ vintage). It also had an elaborate build guide with tons of illustrations, because evidently the "kit" in "Heathkit" is literal - sold as a kit! At least, before it got to me fully assembled.

[@batlin]

Have to say that was more exciting than I expected! Great work improvising the adapter!

[@grantbyers7625]

Fantastic! We had an old Rank Arena set rejuvenated in the mid to late 80's. It lasted another 30 years.

[@Aruneh]

Very interesting to see "ancient" tech like this being used and not just sitting in a museum!

[@alancordwell9759]

Where I used to work we used to get 12in B&W CCTV monitors coming into the shop that had been sitting switched on 24/7 for decades, some of the CRTs were so bad you could hardly see an image at all (apart from the permanently burnt on one of course!) so we used to 'give them a zap'. I would have said that 8/10 of them came up to a perfectly usable level of brightness, and a few came up like new. The 'repair' was permanent enough for it to be worth doing and it saved the cost of a new CRT. Loving this series of videos, Adrian. Best wishes from Sheffield, UK.

[@adriansdigitalbasement]

Cool! I can see that if this was a TV that you used 10 hours a day every day -- the fix might seem temporary, but for something like a retro computer which only sees occasional use -- even 1000 hours of bright image might last me 20 years. :-)

[@69Dartman]

I used to repair TVs back in the crt days and I was given a Beltron crt rejuvenator that was beat to death but still worked by one of the repair shops I got my sets from as their customer rejects. I made a pin adapter setup I could put on any newer crt and it increased my decent looking set output probably 60 percent because I could bring back marginal tubes to looking like new again. There is really a art to using one so it doesn't blast the guns too hard and it goes backwards and dies quickly. Some sets and the tubes they used almost always turned out great after usually just a cleaning cycle. Zenith used to have really good quality tubes that had a lot of emissions materials on the guns and usually a quick cleaning would bring them back, if not do a rejuvenation and do it similar to what you did. Push the button for a sec or a quick hit and see the crap blow off the guns with a light show inside the neck. Sometimes it would kill it, many times it would bring it back. Then you push the emissions button and watch how long it takes the meter per gun to drop to zero. The longer it holds, and if they dropped fairly evenly the better it was. If all the guns show the same level of emissions and its way up in the green the better. If one gun is way higher it would be hard to get a balanced black and white picture and the colors would be tilted towards the best gun. I much later found a totally rebuilt and fully updated Beltron on eBay for like 25 shipped in the early 2000s and last set I used it on was a 36" Sony HD set my mom had been given several years ago when it was looking horrible. It did bring it back and I was very careful but true to every Sony tube I've done it lasted about 6 months and was awful again. That Beltron had every newer crt socket adapter available and some internal upgrades and complete new manual for the newest tubes out before everything went lcd flat screens. I also have several military and high end tube testors and bixes if tubes I collected to repair TVs back in the day. I'm actually local to Portland if you ever run into needing any old tubes tested or a different crt testor to play with. I knew when I bought that last Beltron that I probably would never or very rarely use it but I couldn't let it go for the money and everything it could do. I MAY even have one of those B&K testors just like you have, but I didn't like it as well as the Beltron I knew how to use. I can't remember what I did with it but it may still be here stashed in my shed with the others. Shango is the man when it comes to troubleshooting any old stuff and getting it running, or restoring it if it's worth it. He likes the B&K rejuvenators best and has a Beltron as well he occasionally uses but every one likes what they are comfortable with so if you understand how to use it they all can work. Not many shops or repair guys do component level repair, they just replace the bad board and see if it works these days. That was fun to watch and brings back memories of all the sets I fixed.

[@enzoperruccio]

Now it's just a matter of how long the effect will last before the crt goes dim again!

[@dan_loup]

We will know the how long now.

[@enzoperruccio]

@ungratefulmetalpansy Yeah I've seen some videos. The technique is called crt rebuilding, and it's almost a form of art because of the amount of time and skill it requires. Either way, the end result was always a like-new picture tube.

[@MurderMostFowl]

what an awesome goodwill find! Glad that it ended up in good hands instead of a dumpster

[@lorenzoporciani]

Would be nice if you got someone to reverse engineer it! Having a modern open source crt tester would be a saving grace on those aging tubes! Also, ask a certain Mr Carlson to see if you have to swap out those caps, because they seem those old cardboard ones!

[@henriqueolifiers6400]

That. Would love a 'rejuvenator' like this around!

[@ForgottenMachines]

Oh, but I DO love this video...first time I've seen one of these rejuvenators in action, nicely done! You've demystified a LOT here for me, even though you were learning on it yourself at the time, I followed right along with you...very helpful! Keep doin great stuff like this, Adrian!!!!

[@ArixZajicek]

Whoa, I've never seen the segment feature on KZbin before, neat!

[@Maoyon28]

When I saw the title I guessed that your just going to add 2-3 more volts on the filament, to my surprise there's that machine that you have that I never heard or read about at school. This has been educational for me, thank you.

[@anumeon]

My heart honestly skipped a beat when i saw that thing.. Ohh,, so cool

[@askhowiknow5527]

I can’t wrap my head around how not a single one of the wires on that adapter has continuity

[@SeanBZA]

Heavy oxide layer on the pins will do that, and perhaps the potting has shrunk with time and snapped off the internal wiring as well.

[@mrnmrn1]

Possibly they used some agressive, corrosive (acidic) flux to solder the wires. I've seen this before with figure-8 type power cables.

[@maxpowers2168]

With content like this no wonder is my favorite tech channel

[@XnoobSteve]

This was amazing, thank you. I can only imagine the satisfaction you got from this

[@tomcarlson3913]

As a vintage TV collector/restorer I can say: These old testers will have lower heater voltage with the heater connected than without. CRT heaters are not nearly as delicate as you think (except for some low current heaters some portable micro TVs)...Case in point there were devices called CRT brighteners common in the 40's-70's that would step up heater voltage by 40%, and the manual for my B&K 466 reccommends doing that as a first step...It is the gentlest form of rejuvination. CRTs that have sat for months to decades unused develop what TV collectors call "sleeping sickness". The cathode is made of a reactive substance that emitts electrons easily when heated. CRTs must be under HIGH near perfect vacuum inorder to function properly but there is always stray gas molecules floating around. There is usually a brown or black spot inside the glass aroung the electron gun called the getter that is a reactive metalic film designed to collect gas molecules... The cathode also acts as a getter, but regular use cleans the gas off of it....When it sits the gas that bonds to it builds up an insulative film that blocks emission....That film is the root cause of sleeping sickness. The safest way to wake up a sleeping CRT is to test it under normal parameters and if after an hour long emission test it does not wake up bump the heater to 1.4x-1.6x its rated voltage and check back every 5-15 minutes for a ~2 hour span...If that fails doing a rejuvination like you did is the next step. Doing a rejuvination is sometimes aided by at the same time as the button press gently taping the neck of the tube with a wooden dowel (be careful not to break the glass). There were various rejuve circuits from different makers common back then was to cahrge up a large cap and dis charge it across the cathode and a grid to create a brief spike in cathode current to blast the surface contamination off...Many testers elevate heater voltage during rejuvination. The emissive cathode coating is thin and will be blown off its metal substrate if too many rejuves occur or if too many hours are put on the CRT. Good life test is 3-11 seconds before the needle hits zero. All the lytics should be changed if you plan to use that tester regularly. Brighteners were usually step up transformers for the heater AC holtage (some also or exclusively did isolation to fix heater-cathode shorts). Most brighteners only worked on 60Hz AC because most sets that old used a 60Hz heater transformer. In the mid 70's-mid 80's TV/monitor makers switched from linear 60Hz power supplies (feed wall voltage into a transformer distribute it to loads and rectifiers that power everything) to 17KHz switch mode power supplies (rectify and filter line voltage use, use a transistor to create 17KHz AC by switching that on and off, use a 17KHz transformer to step it up then distribute and or rectify and distribute that to everything that needs power). Transformers don't like to opperate at frequencies substantially different than design so if you find a 60's vintage brightener installing that in your mac will cause damage. There were some 17KHz brighteners made but they are very rare.

[@WalnutSpice]

Aight as a 22 year old reading some of these, we really need to have an archived CRT info website. Just full of random stuff like this. Can't let this knowledge/ decades of experiences die or become simply impossible to find

[@tomcarlson3913]

@@WalnutSpice Videokarma.org is such a place. I'm only 6 years older than you and picked up much of what I know about TV repair in the last 15 years reading there (getting my bachelors in EE in the middle of that also helped).

[@one_b]

This makes me think of my grandfather. He had incredible knowledge from a career in the Navy. He would have loved this video.

[@adriansdigitalbasement]

He probably would have had so much good information to share too. So much of this type of knowledge is lost.

[@delorean00]

Great job!! As for how long it will last, we have lots of CRTs in TVs that are rejuvenated that have hundreds of hours of use and still look great. It really comes down to the age of the CRT, how dead it was when you started, along with a bit of luck. Also in the beginning when you said it would get brighter the longer it ran before your rejuvenated, that is really common with CRTs, some will warm up after not being used a long time and never dim back out. I suggest if you have a dim CRT on a machine that works, let it run for a few hours a day for a couple days and see if it gets better and stays that way. Sometimes the CRT just goes to sleep when they sit.

[@PaulinesPastimes]

This is the first time I have seen an objective test of this function and it is fascinating. You didn't have any expectation bias and just gave it a go. It's a great result. Cheers

[@ksaspectre]

Wow, I can't believe how much of an improvement that was. And it's awesome that it got saved from e-waste.

[@RavenWolfRetroTech]

I's love to see how this does down the road. Awesome video!

[@saxonian]

Hi Adrian, I've seen some videos from a German TV technician explaining all the rejuvenating stuff. Here is what I've learned from that videos. The cause of the tube getting darker is some oxidation at the surface of the cathode that builds up over time. The rejuvenation is the process of removing this layer. If you turn down the lights you might even see the dirt flying of the cathode and being burned away. So what you did was basically correct. In the video he was also talking about the different tubes and the different voltages of the different color and much more. This is kind of a science of its own. Btw he was not to hesitate about pushing the button ;-) Starting at low and tying to burn away the stuff a few times. If it wasn't enough he used medium. High seem to be really aggressive and the tube might not take it well. But if it's not working with medium the tube is almost toast anyways.

[@OzRetrocomp]

19:59 "It looks so much brighter, it's shocking". I see what you did there lol

[@HermannR-o6h]

Hello Adrian. CRT rejuvenation is an analog process, that takes a little time. That means, the button should be pressed for at least 1 to 2 seconds in the low or medium settings (count "21 .. 22" while pressing the button). The definition of "briefly" as it says in the manual is vague at best, but the thing is one should not exceed about 5 seconds as that can make matters actually worse. Excellent video and my best wishes for 2024.

[@kirishima638]

Possibly your coolest video. Incredible.

[@bigpapab]

That was really cool. I did not know of that device. Excellent video on how to bring back old tech, with old tech to fix it. Keep it up my friend!

[@carlosbragatto]

Absolutely gobsmacked how well this turned out. Great video!

[@garthhowe297]

That was amazing Adrian.Thanks for pursuing trying to fix this "lost cause" CRT. The results were way better than I expected.

[@alexandrecouture2462]

This is so cool! I have never seen such a machine before, or even less know that it exists!

[@frugalprepper]

This is a really cool video. When I first started working as a tech in the 1992 we had one of these on the shelf in the back room. We use to use it on ADDS dumb terminals that the screens got too dim on. I don't think there was ever a time that they came back with a screen to dim again in the 4 or 5 years we did it. Eventually all the customers just left the dumb terminals behind and put in PC's with ProComm though, so they were already well on their way out before I started working there. Great video.

[@eDoc2020]

Great to see how this came out! I have an old portable TV from 1982 with a dim picture I might want to fix up. And in other news, the shorted capacitor in the tester could've been worse. I was working on an old tube intercom and a capacitor failed shorted between the ac input and the metal case. Fortunately I did a quick safety inspection of the internals before plugging it in. I highly recommend anyone dealing with old equipment in unknown condition perform a similar check as well.

[@spishco]

Bringing back memories of Apple repair training from the 90's. Careful of that flyback voltage buddy! :)

[@colinstu]

Curious how those caps test with Carlson's capacitor tester

[@LtKernelPanic]

Toast would be my guess. They need to go IMO.

[@colinstu]

LtKernelPanic agreed. After seeing his tester I’m not sure why anyone would bother with anything else.

[@SidneyCritic]

According to him all wax caps like those would be junk by now, even if new/old stock.

[@DanafoxyVixen]

the problem with Mr with Carlson's capacitor tester is its more of a good/bad tester.. i like looking at numbers..... give me an old Heathkit capacitor tester anyday

[@BEdmonson85]

Honestly, I wouldn't even bother testing those caps. The electrolytic and wax/paper caps are junk after 50yrs, I'd just replace them all.

[@SarahWattCA]

Someone on a forum I read found one of these at a thrift store recently and I was curious about how it worked but I couldn't find any information, so thanks for demonstrating

[@robintst]

Such an interesting intermingling of old tech with even older tech.

[@VladoT]

Its great that you took my advice from the previous video and tried CRT rejuvenation, now you need to buy or build in-circuit ESR meter for you to be able to test caps without removing them from the boards.

[@adriansdigitalbasement]

Oh I show my DE-5000 which I bought which allows me to test in circuit. Also a secret -- I made this video on May 8 -- so it was luck it seemed to be a response to comments. :-)

[@blueribb99]

We used a B&K 467 Rejuvenator for many years. We had very good luck bringing dull CRT's back to life.

[@IrishvintageTVRadio]

Always worth a shot with a tube that's going in the bin anyway. Always a last resort though. Great video and a cool BK.

[@parrottm76262]

...a bad capacitor... Ha! Color me surprised! Love this video. It is like watching the 3rd Indiana Jones movie when Indy was winding his way through all the traps.

[@cablecartman]

Very nicely done. Perseverance pays off!

[@hadireg]

Great stuff!! Thanks for explaining how that process goes! :) pretty shocky indeed! :) 👍

[@xyzconceptsYT]

Oh wow, this reminds me when I used to re-gun CRT's in the mid-'90s. Fascinating process. Oh, and the post oven and vac down spot-knocking process were always fun and firing the getters with a high powered RF induction coil.

[@arfink]

I've been really interested in the re-gun process for some time now, but there's almost no information out there about how it works, what the process is like, or what equipment is used.

[@cee128d]

And if nothing else it was a fun learning experience no matter how long it continues to work.

[@gizcommusic4596]

This doodad is amazing. It really bothers me how many service tools have been forgotten; let alone the principles they operate upon. Great video, man! Not joking, you need to send this to Me. Carlson to tear down in his lab. He would also be able to give a full description of the "Rejuvenate" function and just what it's really doing in there. Maybe even get some pointers for your audience on reverse engineering this thing with mossfets and a PC power supply. Keep doing the Good work, and sharing your valuable accumulated knowledge and problem solving strategy with all of us. You are doing far more good than you realize. K

[@EngineeringVignettes]

You need another video on refurbishing your CRT tester... (Other CRT tester sources) Shango66 does a lot of CRT testing and some rejuvenating, in between yelling at the planes :) Bandersentv has a few CRT tester segments but he is more into the serious restoration of tube sets, getting into the guts. Looks like the patient will live a little longer, good work Doctor! Cheers,

[@ZombieRyushu]

Someone needs to tell Louis Rossman about this..

[@Laffs00]

I thought this exact thing

[@IlBiggo]

His comments section would explode with rants about the "impossible" Torx screws and "cramped" circuit design. Oh, and that you can't game on a Mac .-D Poor Louis is cursed with a terrible audience.

[@Margen67]

@@IlBiggo Modern macs are trash for gaming. macOS has an ancient version of OpenGL and doesn't even have Vulkan unless you count MoltenVK.

[@IlBiggo]

@@Margen67 Newsflash: gaming is not the main reason computers were invented. Cars are absolutely useless when cooking, but this doesn't make cars "trash".

[@Margen67]

@@IlBiggo They're not trash, but they're still not good for gaming.

[@TofuInc]

I used to work on arcade games around 10 years ago. We had a "tv guy" who would "shoot" the crts. The results were impressive what he could accomplish. If its the fist time on a crt it can last for years. He has since retired and close up his shop. I moved on from that job but learned a lot from it.

[@christianclark1354]

I remember seeing one of these things being used in the mid 90s on my parents tiny Toshiba CRT TV. Never knew what it was called until now. Thanks!

[@heathm]

I picked up a Sencore CR70 off ebay several years ago. It came in handy in testing and restoring monitors in a couple arcade machines. I guess it's suppose to burn off carbon build up within the CRT to clean off that buildup. But at the cost of shortening the life of the electron gun. But of course if it is looking bad and your going to junk the monitor. Might as well give it a go. As maybe a side note, The manual restore procedure on mine says to let the heater warm for 30 secs before hitting the restore/rejuvenate button and to never go over 15 seconds of holding the rejuve button. Not sure if that helps with the B/K operation. Any way, keep up the great work! I enjoy the videos that you have made available. Keep it going!

[@bobbybiggs4348]

Definitely a good idea to replace all those old caps. But 100% thumbs up for the video! I never knew equipment like that existed

[@apl175]

This was one of the most amusing, quirky, and interesting of the "Digital Basement" series.

[@johnsonlam]

Thanks Adrian, this is a very good experience of using that piece of old equipment, but I think you have to re-cap it with correct value, who know if a bigger capacitor will affect the meter's reading. And the good news is even the reading is not accurate the tester really work well. I do love the 60's and 70's equipment, they're build for durability and able to repair easily.

[@Jerkwad152]

Dang, I was hoping to see what Dyna Hi did. :D Glad it worked, at least for a while!

[@greendryerlint]

When you use Dyna Hi, all the lights dim, there's a bright flash, and when you regain consciousness, either the CRT has been obliterated, or it works better than new.

[@metalmusic1401]

I have to admit I'm really enjoying this video series I also enjoy your entire channel please keep up the great work and greetings from the land of Australia

[@ghettosteeve]

its generally reccomended you wait about 20 minutes for a tube to warm up before expecting an accurate picture in a mastering/color editing environment. you are supposed to run a white screen in that time for best results

[@DavidWatts]

Fascinating, ta for the video. I really enjoy seeing vintage test gear.

[@kiukku890]

That LCR meter is an excellent little tool, especially for the price. Bought mine last year, and only regret I didn't buy it earlier! btw. Great video, as usual.

[@lauram5905]

I wouldn't mind seeing a proper restoration on that tube tester if you have the time for it, rewiring it and having a standard base that you could plug all those sockets into would be neat. Maybe breaking out the sockets into a common (high voltage) connector (ATX molex?) might make it a bit friendlier to use

[@lauram5905]

Also you probably already know this, but Mr Carlson's Lab and Shango066 are both excellent resources on field equipment like that. Nice find!

[@Sheevlord]

@@lauram5905 Mr Carlson would also say that those old capacitors should go even if they seem to be fine. He always replaces old electrolytics.

[@benbaselet2026]

@@Sheevlord And I do think he's right. With the cost of those parts nowadays you'd be crazy to test them 6 different ways just to save $2 a piece to run them a little longer and possibly blow a bunch of other kit when they do go with a bang. Really easy to replace too with that old point to point wiring.

[@lauram5905]

@@Sheevlord Shango tends to make an important point depending on what he's working on that some pre-power on troubleshooting should be done before a wholesale recap in case that ends up masking an issue but yeah, checking voltages. physical inspection and calibration prior to connecting it to anything would have been my first thought. He definitely had the right idea making sure he knew what pinouts he'd be dealing with though. Wonder how many people have blown up tubes just socketing them without checking

[@theradiomechanic9625]

Adrian, go to e-bay and search for "picture tube booster" or "picture tube brightener". These are small transformers that go in line with the picture tube connector. ( it will be obvious when you see the photos of them ). They boost the filament voltage by about 2 volts. While there is a danger of the filament life being shortened, when all else fails they will give you some additional life from a "useless" tube. These were very popular "back in the day". There is presently a lot of 5 selling for $9.99 and one of them appears to have the correct socket/plug combination.

[@flemmingchristiansen2462]

Great work bringing the screen back life. There are probably many people who envy you. You probably might want to replace the capacitors in your CRT Tester. I think i saw an old "roundy" resistor, they dont handle moisture so well I'm no expert but even though the capacitance and ESR measure right, the can be leaking badly. "Mr Carlson's Lab" have some good tutorials on old components. Great piece of equipment you found there.

[@finkelmana]

Have you checked out Mr Carlson's Lab on KZbin? He repairs and used vintage tube test equipment to repair other vintage tube test equipment. If you had any questions about testers or anything tube related, he is the guy to talk to.

[@root42]

awesome. I didn't know you could rejuvenate CRTs. Would be nice if some decent replacement tubes could be manufactured though. :)

[@ovalwingnut]

I liked "and" approved of this video! Very COoL. Enjoyed it immensely 👍😎

[@simonstergaard]

shango066 will hate you for rejuvenating that gun

[@Ra-zor]

Remember using one of those back in the 90's to bring back to life hundreds (probably over a thousand thinking about it) poorly customer crt's over the years, and must have had about 30 different base plates in a big drawer in our lab. Most heaters ran at 6.3v. They worked quite well for about a year or so but then the crt would fade fast, but you could kick a tube several times before it was scrap. If you gave it a good blast you could see the rubbish being blown off the gun, see the needle kick and usually worked quite well.. The good old days! Oh and ALWAYS make user you fully discharge the tube or you will blow a hole in the phosphor on the tube lol

[@casperknudsen7086]

That really is amazing. I did not know of this until now :D Good job and fun little project :D

[@tekvax01]

This was a fun video to watch and remember the good ole days! :P Thanks!

[@Sloxx701]

Great video Adrian. Damn nice piece of gear to find at a thrift shop, I love vintage test gear like that and especially old vacuum tube based oscilloscopes. But yeah as a bunch of people already said in the comments, them old electrolytic caps gotta go. All it would take is one of those caps to short out and potentially damage that power transformer, and that thing probably has a dozen taps for all the different heater test voltages. Finding a replacement would be difficult to say the least.

[@mjl4423474]

You're a brave man using that Tube repair kit! haha, I would have been too frightened to plug it in in case it blew something up

[@QuaaludeCharlie]

I have 3 TV testers , I have never used them yet , but I am happy I found them in my city . I hope to get a chance to use the rejuvenator functions and well any result as good as this will be a Win :) QC

[@unaphiliated5090]

I had some luck with these back in the day, but those old monochrome tubes could be replaced with new ones fairly cheaply. Unless you bought from Apple of course, their prices were way higher. The trick was to find the right replacement based on specifications. Most picture tubes came from 2 or 3 manufacturers, and they had very detailed catalogues (this was pre-Internet). Got to be careful to discharge them before you work on them, the tube itself is a large capacitor that can store it’s 20 kilovolts for a couple of weeks.

[@video99couk]

I built my own CRT rejuvinator from plans in the UK publication Television magazine. It brought back many a TV and old computer monitor to get some more life out of them for their owners. Not used it in years now but it's still in one piece, maybe I'll get a tired CRT in one day and get to do a KZbin video like this. Nice find to get one of these in the thrift store, though it's not very pretty inside.

[@mikehansell7156]

I'd like to make a couple of points: 1) A heater is not a filament. A heater is used to indirectly heat the cathode. A filament is a directly heated cathode 2) The raster is the grey (in this case) area displayed on the tube. The lines that are visible with extreme brightness are called retrace lines. 3) I think you'll find that the 6.3V heater supply is AC, not the 12V DC that is probably feeding the Mac tube. I the old days when tubes (or valves as we call them in Australia) were popular, there were devices that were basically a small transformer that could supply higher heater voltages to brighten picture tubes. These picture tubes lasted some number of years with the increased voltage. Many years ago

[@valdisblack1541]

this is great video to watch, I don't have a bit of experience in CRTs and this is just WOW

[@infinitecanadian]

Thank you for saving it! Hope you can put that power supply to good use.

[@TheTarrMan]

I remember RetroChad or drh4683 doing this years ago. It's nice to see that someone else doing this too.

[@gkcnalaka]

Im still using my own DIY rejubivanation kit .... it work really nice

[@greendryerlint]

Cool video. You should zero the analog meter with the screw on its face--it might be a little more accurate. I've always wanted to see one of these used, and love it when ancient test gear can still be relevant. I'm not nearly old enough to know this, but I remember there were also kits you could install for ailing CRTs that would boost the heater voltage on a weak tube to get a bit more emission.

[@StefanoNerozzi]

Great video, but I second other people suggestion of *replacing all caps*. Even if they test fine in a meter, they are most likely electrically leaky, which may also explain why some readings are off. Mr. Carlson's lab has several restoration videos showing how old caps that look perfectly fine both aesthetically and on sensitive meters are completely gone from an electrical standpoint. I would also check all the other components to be sure, and try to find a service manual to see if the device needs any alignment.