I used to repair CRT TV's. On TV's with a weak tube but was too expensive to replace I would "band aid" the problem by running the filament voltage a volt higher. On a TV the filament was a 16 khz AC signal from a winding on the flyback. It was rather easy to cut the power to the filament and add in a self wound toroid transformer that had 5 turns for the primary and 6 turns for the secondary. This would wear out the CRT faster, but it was already dying. For the CRT's that had an internal short to the filament I would do the same thing but make a 1:1 (5 turns, 5 turns) toroid transformer.
Even when new those CRTs would bloom when turned up too high. Especially the longer persistence green ones.I wouldn't judge how tired the CRT is based on that alone.
@Egon Freeman personally I think Adrian is driving them top hard. Compared with modern displays those we're dim. For reference: my 14in VGA monochrome CRT is rated at max brightness for full resolution (in other words it will bloom if set higher) of 60 cd/m2. A Diamondtron XGA tube is rated at 90cd/m2 max. The minimal brightness on my desktop LCD is about 70. Max ca 350. So if one of those is as bright as your modern display at min setting... That's as bright as it's meant to be.
I think I might be one of the few people who like those mesh filters over the CRT's. Have them on my Vector 3's and used a Sirius 1 that had one fitted. I've found they can be cleaned quite easily with just warm water & left to dry. Did cringle a little when you cut the mesh on that Amdek. Mainly due to fear of scratching the CRT :)
@@rastislavzima I have to say that from my experience it is indeed possible to scratch the glass with a knive. I did this accidently while cutting off an anti-glare foil.
@@Dietzebacher than that had to be some knife made of hardened steel or the monitor glass could have some coating? As i've understood hardened steel is not very good for making knifes because it is not so flexible and can break more easily so knifes are made from softer steel, also because the softer steel is more easily sharpened. E.g. file is made of harder steel and that could scratch the glass.
@@rastislavzima Your kitchen knife may not be hardened, but razor blades certainly are! If you try to bend one, it will just snap as they are hardened.
#1 needs retrobright. Green is a much tougher phosphor than amber or white. Hard to burn, and stays bright longer as it's much more efficient. Green is the standard for oscilloscopes. When swapping tubes, it's also very important, that the two CRT's have the same socket, unless you want to get a replacement socket and rewire things.
I recently recapped my NEC JB-1201M(A) and I have the excel sheet of every capacitor thats inside if you require it. Even on the daughterboard. Great video!
I had great fun fitting a CRT to a Tandy model 4 case, the case came as a spare part from Tandy, that I used for a custom Model 1 rebuild. The CRT I ended up fitting was wrong in many ways, including the curvature of the front glass. It took many hours but I eventually succeded, including reshaping the Tandy bezel to suit. I also fitted a mesh filter, yes you lose brightness, but the improved blacks and anti glare well and make up.
Another interesting tidbit about the cover of Softporn Adventure is that the lady on the right is actually Roberta Williams, the co-founder of Sierra On-line and the creator of the King's Quest series of games.
@@shmehfleh3115 Heh, that's what I thought at first when I saw the mustache but according to Wikipedia he's actually an actual waiter from some local restaurant.
@@Nr7 there is a nice behind the scenes photograph in Ken's book 'Not all fairytales have happy endings' with him, the women and the waiter all in shot.
Fun fact about that Sierra game @04:32, the women on the cover were all Sierra employees. From left to right: Diane Siegel (Sierra's Production Manager), Susan Davis (Sierra's bookkeeper & wife to programmer Bob Davis) and finally Roberta Williams, co-founder of Sierra & creator/designer of the King's Quest series, Mystery House and Phantasmagoria! And the waiter was an actual waiter from a local restaurant, The Broken Bit. Which bit exactly, I wonder?
Adrian, thank you SO MUCH for this content. I'm a CRT fanatic, they're my fave part of retro consoles/retro computers. And to have a channel like yours, where they're often featured in depth, and also Steve's RetroTech channel, is just awesome for us CRT afficionnados in 2021. (not that I don't love your other content - I absolutely do - but I just thought I'd highlight this particularoty of your channel so that you know it's hugely appreciated by at least some of us.
Phosphor color will define the burn in risk. Most of the green phosphors are the most resistant to burn in. They chose the orange ones because it was closest to white without the glare of white phosphors. In the early 70s we bought monitors with ten different phosphors and one of the green ones has the most persistance. Another green was good for PPI radar displays. It had a white component that showed the radar sweep line, plus a slow green component that held the data for a full scan.
The monitor #2 is a Magnavox. That's the exact monitor I had on my first childhood computer, a Laser 128 Apple II clone. How fitting for you to be testing it with the Apple //c. It might even still be in my parents house.
@@Cherijo78 mine also had the expansion box with a mockingboard in it and perhaps another card. The 128 was a better Apple //c with that expansion box.. I typically watch them sell for $400 on ebay. Never have seen the expansion box on there. I learned BASIC on that thing and it really got me into computers. My laser 128 died eventually and got replaced with a //e. I miss my Laser 128. 😭
25:15 - I didn't realize this. Explains why I was able to buy replacement CRT's in different colors via mail order at very reasonable prices for my TRS-80 Model IV in the mid-80's. Langley-St. Clair, IIRC. I guess they were just surplus/repurposed from some other application.
Pretty cool! My uncle used to work on crt tvs back in the 80's and 90's. Kids these days will never know what it's like using old style tv tuners that were worn out and you have to put a piece of paper behind the knob as a wedge to keep the contact in the tuner touching in order to keep the channel made. 😂
Adrian came across your Ch recently and LOVE IT !! I've made it a ritual to catch a vid of yours with my lunch cuppa daily , Got 14 years to catch up on ;) Keep up the amazing content !!
I got a commodore 1702 monitor off craigslist that was covered in mud and dirt and dripping wet when I brought it hpme After opening it, I was shocked at how little dust was on the crt, which is often a way of guessing runtime The green neon also wasn't blackened at all, and after a good cleaning, drying, and reassembly, the picture tube is astoundingly bright. Convergence was dead on the money too.
I have an Amdek Video 300, which is green monochrome. It came to me filthy as well. I also removed the anti-glare mesh, and was amazed by the difference.
Can’t argue with your comments on the looks of number 3. I had a 230V version of it connected to a BBC Model B. It was the cheapest one my parents could find at the time. The picture was way better than the 12” black and white tv I used before it.
Actually, sometimes you can dump a colour tube in a monochrome chassis. We did it a few times in the 90's when I worked at a TV repair place. It'll just fire all the guns so you get a B/W picture. You can also get something we called a "Tube Booster" that you can use to get more life out of those dim tubes, can't remember the proper name of it but might be worth tracking down to aid your salvage efforts.
If you see the movie The Phantoms. There's TV monitors inside the truck units. All the lights and visual stuff you see in there, I did. On some, I had to take apart the TVs to get them into the set. I shocked myself so many times. Yeah, it's not fun. CRTs pack a punch.
I think they all looked pretty good, apart from the one chassis, which I agree was rather awful. I don't see much reason to swap tubes, but would be interesting to see if any of them can be rejuvenated and improved.
I had the green version of that NEC monitor, it came from a school where it has been used with a BBC Micro. In 2005 I sold it on eBay and got a whole £1 for it - now I wish I'd never sold it. I also had a couple of Philips Computer Monitor 80s that had been used with RM Nimbus computers in a school, I kind-of wish I hadn't sold them but they had really bad screen burn. To make up for these I recently bought a Novex branded green monitor from eBay for £5, from somewhere close enough to me that I could pick it up in person. I've not even managed to plug it in once since I bought it.
Many years ago we used to have a B&W TV that looked like monitor number 3 (with the addition of some buttons to select the channels). My set had a kind of plastic transparent dark "mask" that fit there on the front (there is space for that if you look) and that made the set look much better... Of course it would have the same effect of that cloth in front of the crt, making it dimmer...
Those mesh screen covers were great in reducing reflection and glare from office lights or windows. I actually referred the green on black text based computer systems compared to the bright white windows based types of today when working with them for 8+ hours a day.
My favorite monochrome monitor of all time is the Apple Monitor III. It uses this gorgeous emerald green long persistence phosphor that gives a smeary, RADAR image quality to everything it displays. It also has a mesh anti-glare coating which definitely dims down the screen. But given that's it's green, it's generally bright enough to be visible in a bright room even with the mesh. It's only real downside is that, since it was meant to sit on top of an Apple III, its doesn't sit right on the top of an Apple II.
Same here. Have to recap the logic board. The rest will be recapped later. I was able to successfully twist horizontally the caps off very gently. None of the pads ripped off or came loose. Whew! Now, on to cleaning before signal tracing before recapping. 😁
@@richardbrobeck2384 I just did that to an SE/30 I bought on ebay. It was so satisfying I bought another one... then a 3rd. Eventually my house will be saturated with SE/30s!
You should get a crt emissions tester. Judging purely by looks isn't always the best. But seeing as you have multiple compatible tubes I understand the fun of said project.
Back in the days of B&W Television we used a tube tester/ regenerator to reverse the thermionic emission inside the tube. You could restore them to some degree
Hey Adrian, get yourself a proper brand new monitor like that guy at LGR and we, the community, will support you to buy it! Keep up the great content, you are such a good story teller in your videos!
I had one of those NEC monitors (it was featured in war games) the on eI had was a green screen model. I modified it to run from a 12 V supply and took it on holiday with me to run my Atari 2600 on. (Happy memorys).
That NEC monitor is basically the same as an HP 82913A -- only the HP version is a green-screen monitor. Kind of interesting to learn that that is, aside from the tube and bezel, the exact same hardware.
Those Philips monitors have been available in so many variants, rebranded under various names. Recently I usually also had to crank up the brightness to the max of the monochrome BM7502 / BM7522 and derivatives. I'm not sure it's always exclusively CRT related. A lot of these haven't been used that much, since they were usually paired with home computers. I have owned many of these and the last ones I had all had pretty dim screens. I don't sell them anymore for that reason. By the way: the Apple Monitor III also has a mat screen finish.
Adrian when my folks bought me the apple 2C they bought Apple's Color Monitor which was built by Hitachi and at that time it cost them $400. for the monitor alone . I will be restoring my Apple 2C this coming up year .
I've seen two models of the Philips Monitors (the version you have (EDIT: number 3) as well as one that mimics exactly the 1084) both in green and amber and yes - the color of the LED coincides with the phosphor on both models and the 1084-looking has either green or amber stripes printed on the lid, also depending on the color of the phosphor.
I actually really like that NEC's yellow colour. It's yellowed so thoroughly that it actually looks intentional, rather than looking like your average SNES does these days.
Yeah that's what I've been wondering. Monochrome CRTs are really easy to rejuvinate. It's possible to screw up and fry your tube, but if you're working with sacrificial components anyway, why not?
I’ve noticed that amber crts tended to be run on machines that displayed a constant picture or at least a border. There’s an old CNC machine at my job and the functions around the bottom and top are burned into it
Adrian is the kind of guy to drag his fingernails across a chalkboard while saying "I know some of you will hate me in the comments for this, but this is just what I do!", still one of my favorite TH-cam channels ❤
Do you check for x-ray emissions of some level? Exchange of tube to another flyback, added to the uncertainty protection from aged inner materials of the tube...at some exceeded kv the emissions can be harmful , you can check levels with a geiger for safety
Finished watching the video and it did not disappoint! Monitor 3 was a surprise. My first impression was that it was an older low-end model, but I think it was saved by the green phosphor CRT. From memory amber phosphors generally had a shorter persistence than the green ones, so they had to run them hotter to get the same brightness. You might find the brightness even lower on the amber tube once it's put into the chassis that the green one came from. And vice-versa for the green tube, it may be too bright in the other enclosure, but at least you can just turn it down. Anyway, this was a great way to start a lazy Sunday! Especially paired with my breakfast - a large mocha and (amber?) mango! 😁
it's more relevant for color CRTs since there's no convergence for monochromes... purity might suffer a bit, but most likely you won't even notice that by an eye
You might be able to get good results from all of those tubes after using a rejuvenator. I have a nice B&K model that has saved many dull tubes. They essentially use some controlled high voltage to blast the carbon off the electron gun. Mine have saved a lot of vintage arcade CRTs.
When there is burn-in there is not really any chance of making things better. I didn't show it but in the end I did try to rejuvenate the really dim CRTs but it actually made them worse. You win some you lose some. I have a Konig TR-850 tester/rejuvenator which is the same as the B&K Precision 490B.
Amber Phosphors degrade much quicker than White and Green due to the components used, On colour CRTs Red tends to be the first one to degrade, due to the rare earts losing their propreties with use
@@BavarianM I’m talking about TVs. Which are usually RGBW, not RGBG. You see ghost images on the red first, while the green, blue and white look clear.
The mesh coating on monitor #4 demonstrates how a shadow mask in color picure tubes reduces the amount of electrons hitting the phosphors on the screen.
I'm just awaiting capacitors and other parts to repair my 10" Torch RGB CRT monitor (actually a Sony somethingorother model "Trinitron Character Display" chassis in a hefty plastic case), any improvement on that would basically be it powering up... :P
Random trivia: that "ugly" monitor, aka, #3, was sold in a relabeled form by Leading Edge as the "Gorilla". (They also sold a printer called the "Banana".) That's the 80's for you.
I had an Amdek Video 310A on my first "real" computer (286-10 as I recall). I didn't like it because it wasn't color and I really wanted a color monitor. But looking back, man it was sharp for text display... much sharper than the Tandy CM-11 that I got later.
Hi Adrian. Interesting vid. Have I missed something though? You talk about not being able to swap CRT's due to differing mounting methods. Am I wrong in thinking they all at the bottom level are fitted into rubber gaskets around which the various type of mounting kits are fitted (which ARE case dependent)? That being so, as long as the glassware is of the same proportions, it's just a matter of removing the incorrectly fitting kit of the donor set & putting on the host monitor's own kit? Apologies if I'm being thick here. BTW, the ugly (sic) Phillips is the same as my original mono jobby. My old colour monitor waas much prettier.. bloody expensive too, due to long persistence phosphor!
The NEC monitor you tested first doesn't flicker at all, showing that it is an high persistence CRT, like all professional CRTs that time, which reduced flickering so peope could work longer and better in front. Of course high persistance CRTs (opposed to standard persistence) where way more prone to burn in. I don't think there was an actual great difference between amber and green, though. Also it depends on usage scenarios, which often related to using one or the other color. And with some software display where used bright on dark, but with others as dark on bright, making for a huge burn in difference as well. I think the first N.A.P monitor clearly matches the 1081 or 1st generation 1084, not the more rounded and less functional 2nd generation with less knobs. In general I don't think that rating the blooming is adequate for judging the CRT. Btw: Did you try an CRT refresh device before? They can do wonders and are really affordable no on EBay, while they where priceless in the 80s/90s. As an collector one should keep the monitors as authentic as possible, too bad you removed the fabric, instead of refreshing the CRT, it hurts :(
A lot of amber monochromes were used in installations for large companies where a single application would be always on the screen for the entire day. I don't remember seeing a lot of white or green monochromes for that use, but maybe I just am misremembering.
For a second I thought you had to get out the rabbit ears. :) “Stand over there. Raise your left arm high. Ok, stay like that.” “Ooh! Star Trek: The Next Generation is on! Can I watch?” “Hey! Get back there! We’re losing the picture!” lol
That's kind of funny, the video footage looks better than what your assessment of the CRT suggests, usually it's the opposite in other videos where people tells you the CRT looks better in real life. ^_^ Definitely works when you sync a digital camera to that of the CRT refresh rate, better than doing nothing at all that is heh. :) That is literally the case for most things, some will have higher quality parts than others. But I'd take any of those monochrome screens, my local prices for monochrome have been a little excessive for "vintage".
I have some philips BM7502 monochrome (green/amber) monitors they are really nice and sharp for use with the BBC micro...much better than using a modern LCD via RGB scart input..the only downside being they are mono
I've got a monochrome CRT from a CNC control and the CRT is shorted. Sometime when it's safe, I'd like to visit and see if your gizmo can fix the short.
The Amdek Monitor was produced July 1 1985 You take the last series of 4 numbers 7 = Month 1 = Day 85 = Year Hope that helps for future reference.!😉😉🤗🤓🤓
If you ever want to check burn-in on a CRT without being able to turn the unit on, use an inexpensive hand-held UV flashlight. It will activate the phosphors from the FRONT of the glass, and will clearly show if there are "weaker" sections where burn-in has occurred... and you don't have to go through the trouble of powering it on or supplying a pure white video source.
In case you end up in dire need of a spare tube, could you harvest one from that Samsung TV you posted a while back? It might be tired but at least isn't burnt.
i used to have a philips black n white tv very like that NAP one, had very poor frame sync, sudden changes in average picture brightness would make the picture 'shake' a few times vertically, and no there was no fault, as i had a couple of other models in different case but with the same innards do the same thing, looks like a known 'issue' with them!
The simple reason that amber CRT's are more susceptible to burn-in is because the phosphor used is more reactive to the electron beam, which is why they are also more susceptible to blooming.
Green phosphor CRT would tend to be used at a lower brightness, because the human eye is more sensitive to green, thus the users would keep the brightness down on them. The amber would be on the lower sensitivity, so would tend to have the brightness turned up to compensate, so the burn in is more likely. You CRT would, even for a mono CRT, have a dot pitch for the coating applied, as the powder used was ground to be a specific mesh, and thus your best resolution is the size of a grain of the phosphor, plus the electrode gun resolution plays a big part in making the spot small. Most common reasons for blooming, aside from a totally flat CRT, are the drive board having failing electrolytic capacitors, and the high value resistors drifting up in value. Repaired plenty of them by replacing all electrolytic capacitors, from large to small, and checking all resistors in circuit, to see if the printed value is within spec, or is high. Also you need to set the B+ voltage to the correct spec, as all the voltages are derived from it. In most small CRT units that have a mains transformer and rectifier with a linear regulator, that voltage is around 11.6V, and is critical for correct operation. Heaters are either provided from the LOPT, or the heater has a resistor that supplies it from the regulated rail, dropping 6V.
Adrian's analog basement!
cls used to have a couple of good drives made by Eastern Analog
I used to repair CRT TV's. On TV's with a weak tube but was too expensive to replace I would "band aid" the problem by running the filament voltage a volt higher. On a TV the filament was a 16 khz AC signal from a winding on the flyback. It was rather easy to cut the power to the filament and add in a self wound toroid transformer that had 5 turns for the primary and 6 turns for the secondary. This would wear out the CRT faster, but it was already dying. For the CRT's that had an internal short to the filament I would do the same thing but make a 1:1 (5 turns, 5 turns) toroid transformer.
Even when new those CRTs would bloom when turned up too high. Especially the longer persistence green ones.I wouldn't judge how tired the CRT is based on that alone.
Yeah, the high voltage regulation on non-high-end 80s TVs and monitors wasn't always great, and that can cause blooming when the CRT is fine.
@Egon Freeman personally I think Adrian is driving them top hard. Compared with modern displays those we're dim. For reference: my 14in VGA monochrome CRT is rated at max brightness for full resolution (in other words it will bloom if set higher) of 60 cd/m2. A Diamondtron XGA tube is rated at 90cd/m2 max. The minimal brightness on my desktop LCD is about 70. Max ca 350. So if one of those is as bright as your modern display at min setting... That's as bright as it's meant to be.
Hes been watching shango066 too much lol
Your schedule is a reliable constant in unpredictable times. Thanks :-)
I used to know a couple called Phillip & Amber. They suited each other and got along very well.
I think I might be one of the few people who like those mesh filters over the CRT's. Have them on my Vector 3's and used a Sirius 1 that had one fitted. I've found they can be cleaned quite easily with just warm water & left to dry. Did cringle a little when you cut the mesh on that Amdek. Mainly due to fear of scratching the CRT :)
The glass is very hard cant be scratched with the steel knife, thats why diamonds are used for cutting glass plates.
@@rastislavzima I have to say that from my experience it is indeed possible to scratch the glass with a knive. I did this accidently while cutting off an anti-glare foil.
@@Dietzebacher than that had to be some knife made of hardened steel or the monitor glass could have some coating? As i've understood hardened steel is not very good for making knifes because it is not so flexible and can break more easily so knifes are made from softer steel, also because the softer steel is more easily sharpened. E.g. file is made of harder steel and that could scratch the glass.
@@rastislavzima Your kitchen knife may not be hardened, but razor blades certainly are! If you try to bend one, it will just snap as they are hardened.
@@AerFixus ok understand, but makes me want to test this :-D
#1 needs retrobright.
Green is a much tougher phosphor than amber or white. Hard to burn, and stays bright longer as it's much more efficient. Green is the standard for oscilloscopes.
When swapping tubes, it's also very important, that the two CRT's have the same socket, unless you want to get a replacement socket and rewire things.
some may have the same socket/base but different pinout, you have to watch out for this! also may need different a1 and focus voltage
I recently recapped my NEC JB-1201M(A) and I have the excel sheet of every capacitor thats inside if you require it. Even on the daughterboard. Great video!
Philips made very nice monitors. I used to have an EGA one which could be switched to green or amber with a push of a switch.
I had great fun fitting a CRT to a Tandy model 4 case, the case came as a spare part from Tandy, that I used for a custom Model 1 rebuild. The CRT I ended up fitting was wrong in many ways, including the curvature of the front glass.
It took many hours but I eventually succeded, including reshaping the Tandy bezel to suit.
I also fitted a mesh filter, yes you lose brightness, but the improved blacks and anti glare well and make up.
Another interesting tidbit about the cover of Softporn Adventure is that the lady on the right is actually Roberta Williams, the co-founder of Sierra On-line and the creator of the King's Quest series of games.
Ken Williams is the dude with the mighty moustache, too.
@@shmehfleh3115 Heh, that's what I thought at first when I saw the mustache but according to Wikipedia he's actually an actual waiter from some local restaurant.
@@Nr7 there is a nice behind the scenes photograph in Ken's book 'Not all fairytales have happy endings' with him, the women and the waiter all in shot.
Fun fact about that Sierra game @04:32, the women on the cover were all Sierra employees. From left to right: Diane Siegel (Sierra's Production Manager), Susan Davis (Sierra's bookkeeper & wife to programmer Bob Davis) and finally Roberta Williams, co-founder of Sierra & creator/designer of the King's Quest series, Mystery House and Phantasmagoria! And the waiter was an actual waiter from a local restaurant, The Broken Bit. Which bit exactly, I wonder?
Adrian, thank you SO MUCH for this content. I'm a CRT fanatic, they're my fave part of retro consoles/retro computers. And to have a channel like yours, where they're often featured in depth, and also Steve's RetroTech channel, is just awesome for us CRT afficionnados in 2021. (not that I don't love your other content - I absolutely do - but I just thought I'd highlight this particularoty of your channel so that you know it's hugely appreciated by at least some of us.
Phosphor color will define the burn in risk. Most of the green phosphors are the most resistant to burn in. They chose the orange ones because it was closest to white without the glare of white phosphors. In the early 70s we bought monitors with ten different phosphors and one of the green ones has the most persistance. Another green was good for PPI radar displays. It had a white component that showed the radar sweep line, plus a slow green component that held the data for a full scan.
The monitor #2 is a Magnavox. That's the exact monitor I had on my first childhood computer, a Laser 128 Apple II clone. How fitting for you to be testing it with the Apple //c. It might even still be in my parents house.
I also had a Laser 128, with the sidecar! I miss it! Now they're like gold.
@@Cherijo78 mine also had the expansion box with a mockingboard in it and perhaps another card. The 128 was a better Apple //c with that expansion box.. I typically watch them sell for $400 on ebay. Never have seen the expansion box on there. I learned BASIC on that thing and it really got me into computers. My laser 128 died eventually and got replaced with a //e. I miss my Laser 128. 😭
25:15 - I didn't realize this. Explains why I was able to buy replacement CRT's in different colors via mail order at very reasonable prices for my TRS-80 Model IV in the mid-80's. Langley-St. Clair, IIRC. I guess they were just surplus/repurposed from some other application.
Videos like this one are turning out to be far better and more interesting than what's on Freeview TV here at the UK.
Pretty cool! My uncle used to work on crt tvs back in the 80's and 90's. Kids these days will never know what it's like using old style tv tuners that were worn out and you have to put a piece of paper behind the knob as a wedge to keep the contact in the tuner touching in order to keep the channel made. 😂
Adrian came across your Ch recently and LOVE IT !! I've made it a ritual to catch a vid of yours with my lunch cuppa daily , Got 14 years to catch up on ;) Keep up the amazing content !!
I got a commodore 1702 monitor off craigslist that was covered in mud and dirt and dripping wet when I brought it hpme
After opening it, I was shocked at how little dust was on the crt, which is often a way of guessing runtime
The green neon also wasn't blackened at all, and after a good cleaning, drying, and reassembly, the picture tube is astoundingly bright. Convergence was dead on the money too.
I have an Amdek Video 300, which is green monochrome. It came to me filthy as well. I also removed the anti-glare mesh, and was amazed by the difference.
Can’t argue with your comments on the looks of number 3. I had a 230V version of it connected to a BBC Model B. It was the cheapest one my parents could find at the time. The picture was way better than the 12” black and white tv I used before it.
Actually, sometimes you can dump a colour tube in a monochrome chassis. We did it a few times in the 90's when I worked at a TV repair place. It'll just fire all the guns so you get a B/W picture. You can also get something we called a "Tube Booster" that you can use to get more life out of those dim tubes, can't remember the proper name of it but might be worth tracking down to aid your salvage efforts.
If you see the movie The Phantoms. There's TV monitors inside the truck units. All the lights and visual stuff you see in there, I did. On some, I had to take apart the TVs to get them into the set. I shocked myself so many times. Yeah, it's not fun. CRTs pack a punch.
Great Video!! I love old CRTs. I also recently changed the CRT of my 9“ color VGA monitor. Was lucky to score a new replacement tube. 😃
I would just love to get my hands on a small 9" VGA monitor -- perfect for quick testing without taking up too much room!
@@adriansdigitalbasement yeah, they are damn hard to find and very handy
D’oh! I detest being left on a cliffhanger episode!
Nice video and well edited to make the comparisons concise. Looking forward to the next part!
I think they all looked pretty good, apart from the one chassis, which I agree was rather awful. I don't see much reason to swap tubes, but would be interesting to see if any of them can be rejuvenated and improved.
Excelent, I always love some CRT action!! Can't wait to view it
I had the green version of that NEC monitor, it came from a school where it has been used with a BBC Micro. In 2005 I sold it on eBay and got a whole £1 for it - now I wish I'd never sold it. I also had a couple of Philips Computer Monitor 80s that had been used with RM Nimbus computers in a school, I kind-of wish I hadn't sold them but they had really bad screen burn.
To make up for these I recently bought a Novex branded green monitor from eBay for £5, from somewhere close enough to me that I could pick it up in person. I've not even managed to plug it in once since I bought it.
Many years ago we used to have a B&W TV that looked like monitor number 3 (with the addition of some buttons to select the channels). My set had a kind of plastic transparent dark "mask" that fit there on the front (there is space for that if you look) and that made the set look much better... Of course it would have the same effect of that cloth in front of the crt, making it dimmer...
Those mesh screen covers were great in reducing reflection and glare from office lights or windows. I actually referred the green on black text based computer systems compared to the bright white windows based types of today when working with them for 8+ hours a day.
I like that you're willing to get creative and swap parts, not a lot of people do that on TH-cam.
oh man you are capturing those screens so nicely through the camera
I love the case designs. They match the computers of that era nicely! I had a NEC for my II albeit a different model.
The Amdek was made in Elk Grove Village, Il. My old home town. Very cool!
My favorite monochrome monitor of all time is the Apple Monitor III. It uses this gorgeous emerald green long persistence phosphor that gives a smeary, RADAR image quality to everything it displays. It also has a mesh anti-glare coating which definitely dims down the screen. But given that's it's green, it's generally bright enough to be visible in a bright room even with the mesh. It's only real downside is that, since it was meant to sit on top of an Apple III, its doesn't sit right on the top of an Apple II.
Came across my feed just as I was adjusting the pots on a Mac SE/30 analog board. Convergence!
I feel a great convergence in the Force, as if millions of CRTs were suddenly adjusted
Nice I am getting ready to completely replace all the capacitors in my Apple SE/30
Same here. Have to recap the logic board. The rest will be recapped later. I was able to successfully twist horizontally the caps off very gently. None of the pads ripped off or came loose. Whew! Now, on to cleaning before signal tracing before recapping. 😁
@@richardbrobeck2384 I just did that to an SE/30 I bought on ebay. It was so satisfying I bought another one... then a 3rd. Eventually my house will be saturated with SE/30s!
@@BestSpatula sweet I want to get another too my Se/30 has 8MB RAM, 80MB Hard disk
You should get a crt emissions tester. Judging purely by looks isn't always the best. But seeing as you have multiple compatible tubes I understand the fun of said project.
Back in the days of B&W Television we used a tube tester/ regenerator to reverse the thermionic emission inside the tube.
You could restore them to some degree
Hey Adrian, get yourself a proper brand new monitor like that guy at LGR and we, the community, will support you to buy it! Keep up the great content, you are such a good story teller in your videos!
I had one of those NEC monitors (it was featured in war games) the on eI had was a green screen model. I modified it to run from a 12 V supply and took it on holiday with me to run my Atari 2600 on. (Happy memorys).
Keep coming with the next parts as quickly as possible
That NEC monitor is basically the same as an HP 82913A -- only the HP version is a green-screen monitor. Kind of interesting to learn that that is, aside from the tube and bezel, the exact same hardware.
Softporn adventure, for those who don't know, was the text adventure whose plot became the first Leisure Suit Larry.
Thanks Adrian for the content in the weekend!
Those Philips monitors have been available in so many variants, rebranded under various names.
Recently I usually also had to crank up the brightness to the max of the monochrome BM7502 / BM7522 and derivatives. I'm not sure it's always exclusively CRT related. A lot of these haven't been used that much, since they were usually paired with home computers. I have owned many of these and the last ones I had all had pretty dim screens. I don't sell them anymore for that reason.
By the way: the Apple Monitor III also has a mat screen finish.
Adrian when my folks bought me the apple 2C they bought Apple's Color Monitor which was built by Hitachi and at that time it cost them $400. for the monitor alone . I will be restoring my Apple 2C this coming up year .
I've seen two models of the Philips Monitors (the version you have (EDIT: number 3) as well as one that mimics exactly the 1084) both in green and amber and yes - the color of the LED coincides with the phosphor on both models and the 1084-looking has either green or amber stripes printed on the lid, also depending on the color of the phosphor.
I love the TRS-80 ZONE poster! I loved my TRS-80's I kept them for years until they died..:-)
I saw your t-slim Adrian 😃
I have one also. They are great insulin pumps. Good video I enjoy them all
I actually really like that NEC's yellow colour. It's yellowed so thoroughly that it actually looks intentional, rather than looking like your average SNES does these days.
Hopefully Adrian busts out that TV repairman suitcase kit in the next video. I don't know why, but I really dig that thing! Love the channel!!
CRT Rejuvinator time?
Yeah that's what I've been wondering. Monochrome CRTs are really easy to rejuvinate. It's possible to screw up and fry your tube, but if you're working with sacrificial components anyway, why not?
Yes please I came her to add this comment. Zap those toobs!
I’ve noticed that amber crts tended to be run on machines that displayed a constant picture or at least a border. There’s an old CNC machine at my job and the functions around the bottom and top are burned into it
Still taking a box cutter to a glass screen makes my spine shiver
Well, any screen for that matter
Went to say the exact same thing. Leaded glass is soft and far easier to mar up than you'd expect.
Adrian is the kind of guy to drag his fingernails across a chalkboard while saying "I know some of you will hate me in the comments for this, but this is just what I do!", still one of my favorite TH-cam channels ❤
I could see Fran from Fran’s Lab having a field day with these CRTs! :)
Do you check for x-ray emissions of some level? Exchange of tube to another flyback, added to the uncertainty protection from aged inner materials of the tube...at some exceeded kv the emissions can be harmful , you can check levels with a geiger for safety
I must say that you have quite an impressive collection of free software stickers
Ooh! Adrian playing with CRTs? Seems like the perfect way to start a lazy Sunday!
Finished watching the video and it did not disappoint! Monitor 3 was a surprise. My first impression was that it was an older low-end model, but I think it was saved by the green phosphor CRT.
From memory amber phosphors generally had a shorter persistence than the green ones, so they had to run them hotter to get the same brightness. You might find the brightness even lower on the amber tube once it's put into the chassis that the green one came from. And vice-versa for the green tube, it may be too bright in the other enclosure, but at least you can just turn it down.
Anyway, this was a great way to start a lazy Sunday! Especially paired with my breakfast - a large mocha and (amber?) mango! 😁
When swapping the CRT's I recomend swapping the yokes with them, makes tuneing less painful.
it's more relevant for color CRTs since there's no convergence for monochromes... purity might suffer a bit, but most likely you won't even notice that by an eye
@@sawarineko4491 True, but it does save having to re cal the whole tube
You might be able to get good results from all of those tubes after using a rejuvenator. I have a nice B&K model that has saved many dull tubes.
They essentially use some controlled high voltage to blast the carbon off the electron gun.
Mine have saved a lot of vintage arcade CRTs.
When there is burn-in there is not really any chance of making things better. I didn't show it but in the end I did try to rejuvenate the really dim CRTs but it actually made them worse. You win some you lose some. I have a Konig TR-850 tester/rejuvenator which is the same as the B&K Precision 490B.
@@adriansdigitalbasement it's always a last resort gamble. I've been lucky with the arcade stuff, and the burn in is somewhat expected.
There used to be a program you could run to display patterns that would remove the burn.
Seeing that Syntax error message brings back lots of memories.
Amber Phosphors degrade much quicker than White and Green due to the components used, On colour CRTs Red tends to be the first one to degrade, due to the rare earts losing their propreties with use
Also happens with OLEDs, red is where pixels begin to noticeably dim first
@@kaitlyn__L On OLED Blue pixels die first
They counteract this with doubling the blue subpixels
@@BavarianM I’m talking about TVs. Which are usually RGBW, not RGBG. You see ghost images on the red first, while the green, blue and white look clear.
The mesh coating on monitor #4 demonstrates how a shadow mask in color picure tubes reduces the amount of electrons hitting the phosphors on the screen.
I'm just awaiting capacitors and other parts to repair my 10" Torch RGB CRT monitor (actually a Sony somethingorother model "Trinitron Character Display" chassis in a hefty plastic case), any improvement on that would basically be it powering up... :P
Random trivia: that "ugly" monitor, aka, #3, was sold in a relabeled form by Leading Edge as the "Gorilla". (They also sold a printer called the "Banana".) That's the 80's for you.
Monochrome monitors worked today in factories EU . People see how this see . Thanks him . I like. And woman
I had an Amdek Video 310A on my first "real" computer (286-10 as I recall). I didn't like it because it wasn't color and I really wanted a color monitor. But looking back, man it was sharp for text display... much sharper than the Tandy CM-11 that I got later.
Wow. That AMDEK monitor looks familiar. I'm sure I used to have one, or used one at a place of work, many years ago.
Will the CRT rejuvenator kit see some use in the next episode?
I may not be a crt expert but i feel like amber might be left on more often because of it's less harsh color.
That'd be my guess as well. Combined with the fact that amber and green crts often displayed non-moving images (like text on wordprocessors)
Maybe amber CRTs were used more in businesses and just happened to be left on longer?
Hi Adrian. Interesting vid. Have I missed something though? You talk about not being able to swap CRT's due to differing mounting methods. Am I wrong in thinking they all at the bottom level are fitted into rubber gaskets around which the various type of mounting kits are fitted (which ARE case dependent)? That being so, as long as the glassware is of the same proportions, it's just a matter of removing the incorrectly fitting kit of the donor set & putting on the host monitor's own kit? Apologies if I'm being thick here. BTW, the ugly (sic) Phillips is the same as my original mono jobby. My old colour monitor waas much prettier.. bloody expensive too, due to long persistence phosphor!
The NEC monitor you tested first doesn't flicker at all, showing that it is an high persistence CRT, like all professional CRTs that time, which reduced flickering so peope could work longer and better in front. Of course high persistance CRTs (opposed to standard persistence) where way more prone to burn in. I don't think there was an actual great difference between amber and green, though. Also it depends on usage scenarios, which often related to using one or the other color. And with some software display where used bright on dark, but with others as dark on bright, making for a huge burn in difference as well.
I think the first N.A.P monitor clearly matches the 1081 or 1st generation 1084, not the more rounded and less functional 2nd generation with less knobs.
In general I don't think that rating the blooming is adequate for judging the CRT. Btw: Did you try an CRT refresh device before? They can do wonders and are really affordable no on EBay, while they where priceless in the 80s/90s. As an collector one should keep the monitors as authentic as possible, too bad you removed the fabric, instead of refreshing the CRT, it hurts :(
A lot of amber monochromes were used in installations for large companies where a single application would be always on the screen for the entire day. I don't remember seeing a lot of white or green monochromes for that use, but maybe I just am misremembering.
For a second I thought you had to get out the rabbit ears. :)
“Stand over there. Raise your left arm high. Ok, stay like that.”
“Ooh! Star Trek: The Next Generation is on! Can I watch?”
“Hey! Get back there! We’re losing the picture!”
lol
That's kind of funny, the video footage looks better than what your assessment of the CRT suggests, usually it's the opposite in other videos where people tells you the CRT looks better in real life. ^_^ Definitely works when you sync a digital camera to that of the CRT refresh rate, better than doing nothing at all that is heh. :)
That is literally the case for most things, some will have higher quality parts than others. But I'd take any of those monochrome screens, my local prices for monochrome have been a little excessive for "vintage".
I have some philips BM7502 monochrome (green/amber) monitors
they are really nice and sharp for use with the BBC micro...much better than using a modern LCD via RGB scart input..the only downside being they are mono
I still have that Amdek monitor down my basement in storage but I don't think I've plugged it in for thirty years.
I've got a monochrome CRT from a CNC control and the CRT is shorted. Sometime when it's safe, I'd like to visit and see if your gizmo can fix the short.
The Amdek Monitor was produced July 1 1985
You take the last series of 4 numbers
7 = Month
1 = Day
85 = Year
Hope that helps for future reference.!😉😉🤗🤓🤓
If you ever want to check burn-in on a CRT without being able to turn the unit on, use an inexpensive hand-held UV flashlight. It will activate the phosphors from the FRONT of the glass, and will clearly show if there are "weaker" sections where burn-in has occurred... and you don't have to go through the trouble of powering it on or supplying a pure white video source.
Focus looked great -- I would liked to have seen a close up of the 80 column text though!
Love your videos Adrian.
Laughing as the one Adrian doesn't like is the one I own #3
It would be neat (if possible?) to see a classic Mac with a 9" amber or green CRT swapped in.. Could that be done?
I think that would look weird without also inverting the display since the mac used black text on bright background.
In case you end up in dire need of a spare tube, could you harvest one from that Samsung TV you posted a while back? It might be tired but at least isn't burnt.
Amber monitors seemed to be left on on in commercial or library applications. We still have some running 24/7 at work
Funny, I really like the design of that #3 monitor.
I had the Amdek 300A on my first PC (Tandy 1000a), and I ended up cutting the screen mesh off eventually.
i used to have a philips black n white tv very like that NAP one, had very poor frame sync, sudden changes in average picture brightness would make the picture 'shake' a few times vertically, and no there was no fault, as i had a couple of other models in different case but with the same innards do the same thing, looks like a known 'issue' with them!
the innards look very similar to the tv except left/right reversed! weird!
Thank You for making those videos!
The simple reason that amber CRT's are more susceptible to burn-in is because the phosphor used is more reactive to the electron beam, which is why they are also more susceptible to blooming.
keep up the great work Adrian 🕹
I am surprised you did not use your monitor exerciser/ regenerator first before swapping to get a brighter picture
Green phosphor CRT would tend to be used at a lower brightness, because the human eye is more sensitive to green, thus the users would keep the brightness down on them. The amber would be on the lower sensitivity, so would tend to have the brightness turned up to compensate, so the burn in is more likely.
You CRT would, even for a mono CRT, have a dot pitch for the coating applied, as the powder used was ground to be a specific mesh, and thus your best resolution is the size of a grain of the phosphor, plus the electrode gun resolution plays a big part in making the spot small. Most common reasons for blooming, aside from a totally flat CRT, are the drive board having failing electrolytic capacitors, and the high value resistors drifting up in value. Repaired plenty of them by replacing all electrolytic capacitors, from large to small, and checking all resistors in circuit, to see if the printed value is within spec, or is high. Also you need to set the B+ voltage to the correct spec, as all the voltages are derived from it. In most small CRT units that have a mains transformer and rectifier with a linear regulator, that voltage is around 11.6V, and is critical for correct operation. Heaters are either provided from the LOPT, or the heater has a resistor that supplies it from the regulated rail, dropping 6V.
I used to have the NAP. It's a tough little performer.
Some of the size changes that accompanied the blooming is probably due to weak caps. You should consider recapping that monitors.
It is the lack of voltage regulation for CRT high voltage: If you pull more current, the voltage drops.
I could watch Adrian rate CRT's all weekend long :)
you need a tube rejuvenator for dim crt's we used to use one back in the day.
sounds like you may have one. we will see!
i love amber monitors, easy to see and easy on the eyes