At 20:33, I instinctively moved my arms up to catch the tube thinking it was going to fall off the table, haha. But I am enjoying your videos, there's something calming and yet compelling about them.
I had a similar problem with a Grundig TV. Here it wasn't a tube swap, but the tripler was bad. The replacement tripler had an anode cup that was a lot larger and interfered with the handle... And when I shoved a Vectrex motherboard into an IBM5151, I also had to flip the tube because the Vectrex' anode cable was way too short. I call it Wrectrex because the Vectrex had a broken case and CRT and the IBM5151 had a bad flyback.
When I repaired TV's in the 90's I had an CRT Analyzer/Rejuvenator that could burn of oxide on the cathodes and give a brighter image (or balance the RGB cathodes).
You were such a perfectionist! They all looked great, and I think I'd have just cleaned them all up and left them in their original cases! Those Amdeks definitely bring back good memories..
My family had a 13" Sampo TV. We had it at home for years, then my older brother took it to college for four years, then I took it to college for five years. That thing lasted forever with no problems.
Blooming when turning up brightness is the EHT dropping under load. With less voltage to accelerate the electron beam it suffers less deflection. They all look lovely...OF COURSE IT WAS WORTH IT..Geez😸
27:42 you could probably solve this by putting a glossy clear coat of varnish over it. The varnish fills the little holes and hills left by the etching. You can try out the effect by putting a tiny droplet of oil onto the screen. If that solves it, then the varnish will likely do the same. Clean away the oil first, of course.
The status bar on the Amdek looks to be an artifact of a TN3270 window. This, as the dirt tells, was probably in an auto or tire shope with direct access to the AS400.
And even those old mainframe / mid-frame terminals that had screen blanking ability after 5 minutes or so of inactivity would usually leave some indicators on the screen at the bottom as well, contributing slightly further to the burn-in.
When LCD's began to emerge and become mainstream, I was quick to jump ship as I recognized their technical superiorities like most of the rest of the world did. Only now after years of LCD being the norm can I look back and truly appreciate CRT's. It's insane that these sci-fi experiments worked at all, much less became ubiquitous for so many decades. A real thing of beauty
PS In the old days I worked with a chap who ran a repair shop. (I went on to go to college and run my own for twenty years) He ran the heater very hot (very bright but still orange, maybe up to 100% over)and started tapping the tube neck sharply with a big screwdriver..! Now I have done this a few times as a last resort knowing a tap too far will do it in...Results variable..But can be amazingThis is pretty much the same as a rejuvenator but that uses far less time, less voltage and no screwdriver action. A CRT tester that has a reservoir cap to blow out shorts can of course be done with a charged cap placed across the obvious shorts.
Well, @29:03 you could put the anode at the bottom, there is plenty of space, and then cut the yoke connector in the middel, flip hori and vert around, voila. Everything fits :)
When I used to work on CRTs I didn't use a high voltage probe to discharge the flyback lead. I merely attached a jumper wire to a flat blade screwdriver and grounded it to the chassis. I'd get a spark, but nothing dangerous.
I enjoyed this vid. It was quite nostalgic, working on CRTs etc. I like the methodical and careful approach here, and use of schematics for diag and tweaks.
Thank you for showing this process - its interesting to see how monitors were built and it seems like there were noticeable improvements in the three keepers. I love amber monitors - I remember working with them at work as the library catalog terminals used on old Unix system through the 1990s and they were so restful on the eyes vs. later CRTs.
@@MFKR696 Yet, UL is considered acceptable as an alternate certification, and becoming much more common with globalization. I'm not saying that's good, but it is what it is. Many manufacturers and importers are not going to invest the money for a certification that is not strictly required.
Brightness seems ok to me. Having used those amber monitors, i actually liked that they are reasonable dim yet have a great contrast, the color just perfect for monochrome, i personal like that much more over green or - the horror- BW. I don't recall maxing the brightness on the monitor i had, quite the contrary. Then again hard to judge on video i guess have to go with your judgement too.
This reminds me of something I did nearly 35 years ago - I'm 50 now so you do the math - to an Amdek 310, though not nearly as extensive as what Adrian has done here. The 310 I had used a proprietary 8-pin connector for the video cable. I swapped the connector out with a standard 9-pin video connector so it could be used in IBM PCs. It worked perfectly.
Very nice! A couple of years ago I was working on my Tek 465M scope. Taking it apart required removing the CRT and discharging the tube. After about the third troubleshooting, after there being no charge on the anode for those first three attempts, when I grounded it on the fourth attempt, ZAP!!! Lots of charge! I've now got a discharge tool / meter stick similar to yours. :)
@@darthrevan2063 the orientation of the yoke determines the picture :) you could even turn the tube 90° if you want (but you’d get a bunch cut off so you wouldn’t wanna keep it that way)
Sampo is part of an old legend from Finland. It’s a magical item that makes salt, grinds flour, and forges money. MST3K fans will recognize it from the movie “The Day The Earth Froze.”
I loved the MST3K ep where someone sent in a photo of a particularly goofy Sampo product. I'm pretty sure the Taiwanese company does not take its name from the Finnish legend though. xD
I remember when Nokia phones at their height and the company seemed to totally embody "Sampo", maybe even the phones themselves. I learned one more Finnish word; from the ski slopes: Perkele! 😝😉
Ah, you beat me to the punch! Ilmarinen: "Thats enough of that. You imagine we've come here to listen to an old woman raving!?" ~Well, thats why most people come...~ (Season 4 was the best!)
The actual Sampo company here in Finland was first an isurance company, then they became a bank too, and then the Danish bought it and replaced the only thing going for it (its customer-facing software) with their own unreliable and feature-poor thing.
Cleaning on the inside is good practice as dust /dirt can cause tracking of HT voltages. This reminds me of working on these Philips monitors may still have service manuals Nice to see safety first as working on a 26inch back in the eighties knocked me out for three hours and numb hand with pins and needles for couple of days. As working on my own until my parents can home.
Nice work! Don't worry about this dimmed monitors, they are just survivors. Amdek problably got burned because of the high brightness needed by the clothe mask.
I have a close close cousin of that NAP that the greenscreen ended up in; it's my Apple IIe daily driver and I love it. NOS as of about 15 years ago when I got it.
I had a monitor like that Amdek for my apple iie.... green monochrome, sat on top of the black face disk drives.... when i eventually switched to a color monitor you're right... the fringing on the text was something to behold. Especially since my previous computer was a ti99/4a on a color tv....
Impressive! Extremely sad though that a lot of these monitors and CRT televisions are coming towards the end, and finding and replacing them are going to be a dreadfully difficult task. Thank God for things like the Retrotink 2x Pro, just won't be able to shoot ducks anymore, but its excellent for what it does!
You might be able to turn the CRT up side down so the HV connector is on the bottom. If it clears the circuit board, that will fix the problem with getting the rear cover on.
Incidentally, in regards to the need to ensure residual high voltage from a CRT is drained before handling it, it is because it is like a giant capacitor. One plate is the metallic lining you can see, the glass itself stores the charge, then the other plate is actually that dull black coating on the outside of the CRT. That coating is called ‘aquadag’ and I understand you can actually buy spray cans of the stuff to touch up CRTs where the coating has been damaged (making sure to mask off where it’s not needed; it’s just graphite and glue). Also, when mounting a CRT, for that reason, the grounding straps should be checked to make sure it is making good contact.
Actually the bloom on the green text at 26 minutes is from the cathode. Due to the very small pinhole for electrons, the current caries away the material in the center of the cathode so it no longer emits electrons, so when you turn up the brightness, the area around the dead center of the cathode produces the emission. This larger emission area through the grid results in that soft edge dot on the phosphor. If you ever trash an old worn out CRT, carefully disassemble the electron gun. Remove the grid off the cathode inside of it and look at the surface. You will see the center has been sputtered away by the emission current from the center of the cathode. In a prior career, I used to put new CRT's in televisions when color TV's were very expensive. Used to do the rejuvenation which blasts off some of the cathode material to remove the dead layer that blocks emissions. This is often a short lived fix as the now thinner layer of emission material is quickly burned through, and if the tube is old enough, the rejuvenation will remove the last of the active cathode material, rendering the tube useless. An alternative to rejuvenation of the cathode is to use an auto transformer on the filament to run the cathode hotter to increase the emissions. This too, increases the aging rate, but provides a temporary extension to the end of useful life of the CRT. The transformer often would raise a 6.3V filament to about 8 volts.
28:17 I love that footage. I wish a collection of CRTs turn off short footages, one after another. I might use it as a collection edit together with shango066's TV off takes of old tube CRT TVs. For future software emulation, they can be the models of reference. I think the deflection shrinks first as the power supply fall. Then, the emissions as the cathode cools. The high voltage might be the last thing to collapse, so it keeps the beam on good focus until the end of the emmisions. If I remember correctly, there is also a 'center dot' prevention circuitry to avoid the burn in on the screen center after repeated shutdown cycles.
I don't rush to toss out technology. Hense I still have most of my original equipment. Still have my families woodgrain console tv. The tube in it was excellent. We watched that TV for hours and I never noticed it dim. National brand.
Adrian if you want the picture to be sharper you should overhaul and possibly upgrade the power supply to lower noise on the voltage rails, as well as the amplifiers to make them less noisy and more linear
Not sure if it has been mention but grounding the high voltage to the monitor chassis does not discharge if the chassis itself is not currently grounded. Essentially its a floating ground at that point. Proceed with extreme caution if doing as Adrian has demonstrated.
I think it's the glass color. Cheaper glass as used in wine bottles (green) and beer bottles (amber) was used in CRTs as well, while the black and white ones (clear glass) went to TV sets and early Macintoshes.
@Adrian, if you watch shango066's channel, he does a process on some vintage CRT tubes where he removes and cleans off the cataract material between the front safety lens and the tube's viewing area, he uses a trash can and places the tube neck down inside the can while he does the cleaning. I was thinking you should do a similar thing when you go to clean the front of the tubes. This way, the neck won't accidentaly be broken.
I had that NAP monitor. Even brand new, it had that picture collapse at the top. I had a friend with the same monitor and same problem. That is the "personality" of the monitor. It was cheap and available at PriceClub (now CostCo). It didn't cost much. It was a tank though. It fell down and flight of stairs (carpeted) and survived without issue. I used it with my TS2068, and because that computer had a relatively large border in its display, the top weirdness was easy to ignore. I don't remember the price, but I am pretty sure it was dirt cheap (under $50).
That's interesting as it wasn't an entirely uncommon practice for budget-brand manufacturers to use 'factory seconds' i.e CRT's and components with known issues/ defects that could be bought cheap and repurposed.
I’m reminded of a recent BigClive video where he worked with a flashing light, that didn’t flash. It had writing in chinese on the box, which commenters noted, said “always on” or something like that ... Seems it would be a good idea to learn to read chinese, when debugging products built in China, Taiwan, Hong Kong, etc ... 😀
If you ever need to repair/replace aquadag. dry graphite lubricant works damn well. The aerosal works great but I ended up buying some loose graphite lubricant and mixing with elmer's glue, then diluted with water to paint on.
I'm seeing some optical illusion when the grid pattern is on the screen, particularly around 5:55. I'm basically seeing black diagonal lines that just aren't there, just found it interesting
Some where in the remote Scottish highlands next week I will be exploring the attic of a high school where I seen some monitors Macs and IBM typewriters when I had a quick peek 10 years ago... Kept meaning to go back up
The breathing expansion phenomenon is caused by the variation of the anode high voltage. Because the deflection sensitivity depends on the anode voltage, there are many ways to improve it. Separate the high-voltage circuit from the deflection circuit, and install a negative feedback for the high-voltage circuit to adjust the high-voltage power, which has the best effect. This method is used for high-end models. In some chassis, although a combined circuit is used, the Re-trace capacitor is divided into two parts. One part of the capacity is adjusted by the PWM switch, and the high voltage can also be adjusted. Generally, for CRTs produced in the 1990s, the ABL voltage is connected to the horizontal size modulation and the vertical size negative feedback for dynamic compensation, which can be partially improved. This is the most common method. However, the focus voltage is still affected. In addition, the pattern still produces multiple distortions. Some models use ultra-high voltage capacitors and resistor packs to remedy them. A lower cost method is to directly connect a resistor in the main power supply. When the beam current increases, the power supply of the deflection circuit also decreases, achieving self-compensation, but there are many side effects. Some FBT manufacturers will try to reduce the output impedance of high-voltage power, and even carefully design the resonance frequency to odd harmonics, so that the Re-trace parabola is closer to a flat-topped square wave and reduces voltage changes.
You know where as those cloth coverings are concerned I've always wondered why they didn't make them a snap-in attachment. It wouldn't have been hard to do and it would've made them a whole lot easier to clean. What a fail. On the one with the case that doesn't fit, you could safely flip the CRT over. It should still be safe enough for the PCB because there's more than 3" gap from the components in most of those old monitors. It's worth checking out.
@29:00 - can you not just mount the CRT upside down and invert the signal going to the deflection coils? (I have no experience fixing CRTs so this is probably a naive question)
I was going to say the same... But I guess Adrian doesn't really care about the monitor too much because of the burn-in - or there are other technical difficulties he didn't mention in the Video... . Anyways.. Adrian, maybe you can put it together again like that and give it away. Your basement must be cluttered anyways 😋
Look up VDC or Video Display Corporation. ive picked up so many NOS CRTs from them to fix various monitors, including IBM PS/2 monitors. my 8515 now has a NOS tube.
The blooming you see on #3 might also be secondary electrons. Not sure if you excluded that. It would come from an acceleration voltage that's too high. The electron beam smashes into the screen with so much force that it knocks other electrons out of it. They then fall back onto the screen in a circular pattern around the original electron, creating bloom.
First I love these videos. Second, I would like to ask. Do you like Simple Green? What is your opinion of it for classic electronics? Third, I noticed your floor dollies. Did you make those? Would you be willing to go over them and how you use them and if you did make them. Tell us about how you did that and give us a tour? Thank you, Keep up the great content.
Yeah these mono crts does earn a place. Only problem is they take so much space. Actualy.. all that stuff takes a lot of space😅 Nice job on these monitors, cool!
Hey you know a lot about crts I thought the technology had died for good by now. I am glad it’s not dead. Can you do a trinitron crt improvement someday?
And now I need one of those Sampo monitors 😅. Fun fact, Sampo is old finnish name, origin from folkstorie Kalevala. Sampo was a mill that produced richness.
19:24 - it used to be 220V but it's 230V here in Europe. 20:32 - I screamed internally, I was so afraid it would fall down of your table! :) 20:30 - did you cut out the mesh and put the frame back or you just threw it away? It seems like it's thick enough that the tube can be loose without it.
When yo turned the CRT around on #2 chassis (you also had to turn the neck board by 180 degrees). Wouldn't that make the picture appear upside down? How did you adjust that, by turning the yoke 180 degrees?
The tube is just a screen covered in phosphor and an electron gun pointing right to the center. It has no inherent orientation. The yoke affects the beam magnetically to point it at different spots. That’s why monitors have a scan that goes left to right and top to bottom. The electromagnet steers the beam around the screen according to the input signal. When you slide the yoke on the (upside down) tube, with the yoke still in its original orientation, the picture looks exactly the same because the force applied to the electrons IS the same (wrt your perspective.)
Not to be “that guy” as they say but get a flat tip for your HV probe. If you do find a CRT with a high stored charge then it will easily jump from to the screwdriver you were using which won’t be rated to kilovolts. I still work on CRTs for arcade enthusiasts so I’ve had a zap or two. Would you also mind telling me what the rode mic is you have clipped to your shirt?
I had a switchable Black and White / White Black which was interesting (Was it a 13in AST?). My first PC Clone (shop made) I got with an early Colour monitor at a cheap price
Well, my prediction on the previous video was right, the green tube was brighter when replacing the amber tube, hence the need to lower the sub-brightness control. And replacing the green tube with the amber tube resulted in a much dimmer picture. I'm guessing they'd use different component values around the brightness/contrast control circuits if they had different phosphor options on the same monitor. Also, it never occurred to me that you could flip the tube to put the anode connector on the other side. Anyway, good to see new life brought to some of these monitors. Just a shame that so many were so worn out or had such bad burn-in. At this point it's practically a lost art to repair the tubes themselves, since the equipment and skills required are so specialised. Especially manufacturing new tubes. I know there's a guy on YT that manufactures brand new Nixie tubes, but there's a huge gap in specialised technology between a Nixie and a CRT. So I guess tube swaps are the best we can do to try and save these old monitors.
Adrian! 22:12 don't do that anymore!!! If you let the tube on the table like this it make a small sound like "crack" and then the Picturetube is total distroeyed. I was at Philips Videorecoder (IR3 Gutheilschodergasse 17, 1120 Vienna) Company her in Vinna from 1997 - 2000 and I work for 35 years as a Radio & TV service and this is a nogo. Sorry to tell this - but what you are doing if the tube make "crack"? You can hit the screen on the trash. Best Regards Volker from Vienna and Thumbs up Nr. 2522
What CRT tester are you getting? I recently bought a Sencore CR70 for my vintage/antique TVs that help feed my retro-gaming addiction. Funny thing is, the game consoles were not retro when I got them. Just couldn’t part with them and now they’re considered retro. Damn I’m getting old (recently turned 40).
One factor you could have weighed in is high-frequency noise emission. I'm past 40 so can't hear it, if there is any. But that could be important in case younger audiences are to be exposed to these things.
You can get a shock of an anode of the tube even if it has not been switched on for a while it is like a very big capacitor make sure it is discharged also remember your dealing with glass so I would wear glasses
11:13 Cleaning the inside (and the back of a CRT in particular) is not weird at all, older tubes can (due to static charge) have collected a lot of dust and if there was a smoker in the area also a lot of (sticky) tar. The high voltage can easily creep through and reduce the picture quality or even damage the electronics. Marvin says: Don't panic and wear your Mask. 🖖😷👍 ❗
Ah, the Philips again ^^ - yes, there was a version out there that had MDA/CGA input. The original one I had in the late 80s with my PC-I had a DIN socket that connected the the TTL CGA output. Can't remember the model number sadly.
Part of me puckered up when the board came out of the first Amdek monitor and the screen started tilting as though it was about to fall, that would have been messy..... :S I need to get the PSU for my Torch-branded Sony monitor re-capped, got the caps at long last for it, just need to work up the courage, scary 240 full-fat volts and all... :P
Adrian is the kind of guy who really knows where his towel is.
Never leave home without it
Definitely a hoopy frood.
I would have liked this post, but it currently has 42 thumbs up, I just couldn't do it!
@@DrummondsPoint Oh man! It did! Someone, NOT ME, took it to 43. Highpoint of my day! Besides getting my Covid vax.
@@AndrewTubbiolo Well now that it's done, I'll go and like it after all :)
At 20:33, I instinctively moved my arms up to catch the tube thinking it was going to fall off the table, haha.
But I am enjoying your videos, there's something calming and yet compelling about them.
You could reinstall the CRT upside down in the ugly monitor, and then the HV lead would be on the bottom and thus not interfere with the handle.
I did think that, but there didnt seem to be much space below so wasnt sure it would fit. I wonder if someone is doing NOS CRTs?
I had a similar problem with a Grundig TV. Here it wasn't a tube swap, but the tripler was bad. The replacement tripler had an anode cup that was a lot larger and interfered with the handle...
And when I shoved a Vectrex motherboard into an IBM5151, I also had to flip the tube because the Vectrex' anode cable was way too short. I call it Wrectrex because the Vectrex had a broken case and CRT and the IBM5151 had a bad flyback.
Came to the comments to say this indeed :-)
Ya, but then all the electrons would fall out!
I've lost 5 years of life when Adrian took the driver board off the filthy crt and the chassis began to fall face first off the table xD
Same here. This was bad for my poor heart!
haha yeah🤣
Me too !
It made my arm jump if I was going to push it back on!
I reached towards my screen to try to catch it as well! :0)
5:30 O.O new CRT rejuvinator? Can't wait! Please make a community post when it arrives!
When I repaired TV's in the 90's I had an CRT Analyzer/Rejuvenator that could burn of oxide on the cathodes and give a brighter image (or balance the RGB cathodes).
Thanks for the slow motion monitor power-off footage. That and the "de-gauss" functions were my favorite part of CRTs.
I also remember driving composite monitors with a VCR. I could watch TV and videotapes, if I didn't mind watching them in amber.
You were such a perfectionist! They all looked great, and I think I'd have just cleaned them all up and left them in their original cases! Those Amdeks definitely bring back good memories..
My family had a 13" Sampo TV. We had it at home for years, then my older brother took it to college for four years, then I took it to college for five years. That thing lasted forever with no problems.
Blooming when turning up brightness is the EHT dropping under load. With less voltage to accelerate the electron beam it suffers less deflection. They all look lovely...OF COURSE IT WAS WORTH IT..Geez😸
27:42 you could probably solve this by putting a glossy clear coat of varnish over it. The varnish fills the little holes and hills left by the etching.
You can try out the effect by putting a tiny droplet of oil onto the screen. If that solves it, then the varnish will likely do the same. Clean away the oil first, of course.
Glass polish is also a thing! Would not leave you with a coated monitor too!
The status bar on the Amdek looks to be an artifact of a TN3270 window. This, as the dirt tells, was probably in an auto or tire shope with direct access to the AS400.
Ya! I was thinking the burnt-in status line was from a 5250 terminal emulator if attached to System/3x or AS/400.
Prolly can see "F1=Help F3=Exit"... burnt-in.
And even those old mainframe / mid-frame terminals that had screen blanking ability after 5 minutes or so of inactivity would usually leave some indicators on the screen at the bottom as well, contributing slightly further to the burn-in.
When LCD's began to emerge and become mainstream, I was quick to jump ship as I recognized their technical superiorities like most of the rest of the world did. Only now after years of LCD being the norm can I look back and truly appreciate CRT's. It's insane that these sci-fi experiments worked at all, much less became ubiquitous for so many decades. A real thing of beauty
People rushed to dump their Crts then years later wished they had kept them.
PS In the old days I worked with a chap who ran a repair shop. (I went on to go to college and run my own for twenty years) He ran the heater very hot (very bright but still orange, maybe up to 100% over)and started tapping the tube neck sharply with a big screwdriver..! Now I have done this a few times as a last resort knowing a tap too far will do it in...Results variable..But can be amazingThis is pretty much the same as a rejuvenator but that uses far less time, less voltage and no screwdriver action. A CRT tester that has a reservoir cap to blow out shorts can of course be done with a charged cap placed across the obvious shorts.
Well, @29:03 you could put the anode at the bottom, there is plenty of space, and then cut the yoke connector in the middel, flip hori and vert around, voila. Everything fits :)
When I used to work on CRTs I didn't use a high voltage probe to discharge the flyback lead. I merely attached a jumper wire to a flat blade screwdriver and grounded it to the chassis. I'd get a spark, but nothing dangerous.
I enjoyed this vid. It was quite nostalgic, working on CRTs etc.
I like the methodical and careful approach here, and use of schematics for diag and tweaks.
Thank you for showing this process - its interesting to see how monitors were built and it seems like there were noticeable improvements in the three keepers. I love amber monitors - I remember working with them at work as the library catalog terminals used on old Unix system through the 1990s and they were so restful on the eyes vs. later CRTs.
Think we had Newbury Terminals that were orange
The CSA sticker at 19:00 stands for "Canadian Standards Association". CSA approval is meaningful up here
@@MFKR696 Yet, UL is considered acceptable as an alternate certification, and becoming much more common with globalization. I'm not saying that's good, but it is what it is. Many manufacturers and importers are not going to invest the money for a certification that is not strictly required.
This brings back memories of me and my uncle buying scrap crt tv and monitors and mix and matching parts to make a usable tv or monitor to sell
Brightness seems ok to me. Having used those amber monitors, i actually liked that they are reasonable dim yet have a great contrast, the color just perfect for monochrome, i personal like that much more over green or - the horror- BW. I don't recall maxing the brightness on the monitor i had, quite the contrary. Then again hard to judge on video i guess have to go with your judgement too.
This reminds me of something I did nearly 35 years ago - I'm 50 now so you do the math - to an Amdek 310, though not nearly as extensive as what Adrian has done here. The 310 I had used a proprietary 8-pin connector for the video cable. I swapped the connector out with a standard 9-pin video connector so it could be used in IBM PCs. It worked perfectly.
Very nice! A couple of years ago I was working on my Tek 465M scope. Taking it apart required removing the CRT and discharging the tube. After about the third troubleshooting, after there being no charge on the anode for those first three attempts, when I grounded it on the fourth attempt, ZAP!!! Lots of charge! I've now got a discharge tool / meter stick similar to yours. :)
29:41 although not worth the effort, you might be able to mount the CRT upside down.. ?
Yeah, I thought the same. I also don´t think that this case is THAT ugly.
I had wondered if that was possible, or if there would be something else preventing that.
Wouldn’t the picture be upside down then? Or is the ordination or the crt it’s self not important.
@@darthrevan2063 the orientation of the yoke determines the picture :) you could even turn the tube 90° if you want (but you’d get a bunch cut off so you wouldn’t wanna keep it that way)
@@darthrevan2063 you know, I just thought the yolk would determine the beam deflection, maybe the emitters would be reversed?
Sampo is part of an old legend from Finland. It’s a magical item that makes salt, grinds flour, and forges money. MST3K fans will recognize it from the movie “The Day The Earth Froze.”
I loved the MST3K ep where someone sent in a photo of a particularly goofy Sampo product. I'm pretty sure the Taiwanese company does not take its name from the Finnish legend though. xD
I remember when Nokia phones at their height and the company seemed to totally embody "Sampo", maybe even the phones themselves. I learned one more Finnish word; from the ski slopes: Perkele! 😝😉
Ah, you beat me to the punch!
Ilmarinen: "Thats enough of that. You imagine we've come here to listen to an old woman raving!?" ~Well, thats why most people come...~ (Season 4 was the best!)
The actual Sampo company here in Finland was first an isurance company, then they became a bank too, and then the Danish bought it and replaced the only thing going for it (its customer-facing software) with their own unreliable and feature-poor thing.
Lol... MST3k was the first thing I thought of when I got to that part of the video. I just posted a link to the a clip.
6:20 - Maybe the video amps on the neck PCB need re-capping?
Nice, this was a helpful start to an Amdek 300A I just picked up. Thanks for the hard work!
Cleaning on the inside is good practice as dust /dirt can cause tracking of HT voltages.
This reminds me of working on these Philips monitors may still have service manuals
Nice to see safety first as working on a 26inch back in the eighties knocked me out for three hours and numb hand with pins and needles for couple of days. As working on my own until my parents can home.
The best laid plans of mice and Adrian... Really good job(s). Shocked (pun) that the linearity is so close after the swaps. Cheers
Nice work! Don't worry about this dimmed monitors, they are just survivors.
Amdek problably got burned because of the high brightness needed by the clothe mask.
I have a close close cousin of that NAP that the greenscreen ended up in; it's my Apple IIe daily driver and I love it. NOS as of about 15 years ago when I got it.
Your channel is my favorite on You Tube! You are almost at 100,000 subs. Keep up the great work!! 👍
I had a monitor like that Amdek for my apple iie.... green monochrome, sat on top of the black face disk drives.... when i eventually switched to a color monitor you're right... the fringing on the text was something to behold.
Especially since my previous computer was a ti99/4a on a color tv....
Impressive! Extremely sad though that a lot of these monitors and CRT televisions are coming towards the end, and finding and replacing them are going to be a dreadfully difficult task. Thank God for things like the Retrotink 2x Pro, just won't be able to shoot ducks anymore, but its excellent for what it does!
You might be able to turn the CRT up side down so the HV connector is on the bottom. If it clears the circuit board, that will fix the problem with getting the rear cover on.
Incidentally, in regards to the need to ensure residual high voltage from a CRT is drained before handling it, it is because it is like a giant capacitor. One plate is the metallic lining you can see, the glass itself stores the charge, then the other plate is actually that dull black coating on the outside of the CRT. That coating is called ‘aquadag’ and I understand you can actually buy spray cans of the stuff to touch up CRTs where the coating has been damaged (making sure to mask off where it’s not needed; it’s just graphite and glue). Also, when mounting a CRT, for that reason, the grounding straps should be checked to make sure it is making good contact.
Actually the bloom on the green text at 26 minutes is from the cathode. Due to the very small pinhole for electrons, the current caries away the material in the center of the cathode so it no longer emits electrons, so when you turn up the brightness, the area around the dead center of the cathode produces the emission. This larger emission area through the grid results in that soft edge dot on the phosphor.
If you ever trash an old worn out CRT, carefully disassemble the electron gun. Remove the grid off the cathode inside of it and look at the surface. You will see the center has been sputtered away by the emission current from the center of the cathode.
In a prior career, I used to put new CRT's in televisions when color TV's were very expensive. Used to do the rejuvenation which blasts off some of the cathode material to remove the dead layer that blocks emissions. This is often a short lived fix as the now thinner layer of emission material is quickly burned through, and if the tube is old enough, the rejuvenation will remove the last of the active cathode material, rendering the tube useless. An alternative to rejuvenation of the cathode is to use an auto transformer on the filament to run the cathode hotter to increase the emissions. This too, increases the aging rate, but provides a temporary extension to the end of useful life of the CRT. The transformer often would raise a 6.3V filament to about 8 volts.
28:17 I love that footage. I wish a collection of CRTs turn off short footages, one after another.
I might use it as a collection edit together with shango066's TV off takes of old tube CRT TVs.
For future software emulation, they can be the models of reference.
I think the deflection shrinks first as the power supply fall.
Then, the emissions as the cathode cools.
The high voltage might be the last thing to collapse, so it keeps the beam on good focus until the end of the emmisions.
If I remember correctly, there is also a 'center dot' prevention circuitry to avoid the burn in on the screen center after repeated shutdown cycles.
I am really good at dropping CRTs, I have two now with chipped glass
I don't rush to toss out technology. Hense I still have most of my original equipment. Still have my families woodgrain console tv. The tube in it was excellent. We watched that TV for hours and I never noticed it dim. National brand.
I've been waiting for this one since part 1
Adrian if you want the picture to be sharper you should overhaul and possibly upgrade the power supply to lower noise on the voltage rails, as well as the amplifiers to make them less noisy and more linear
4:11 - That connector doesn't look to tight! I would think this type of ground-wiring would be against code!
Not sure if it has been mention but grounding the high voltage to the monitor chassis does not discharge if the chassis itself is not currently grounded. Essentially its a floating ground at that point. Proceed with extreme caution if doing as Adrian has demonstrated.
Have you considered replacing some of those capacitors to try to fix geometry and brightness issues? Thanks for the video! Lots of good info!
The color depends on the chemistry of the phosphor. Higher-end CRT’s had rare earth phosphors, with richer colors.
I think it's the glass color. Cheaper glass as used in wine bottles (green) and beer bottles (amber) was used in CRTs as well, while the black and white ones (clear glass) went to TV sets and early Macintoshes.
@Adrian, if you watch shango066's channel, he does a process on some vintage CRT tubes where he removes and cleans off the cataract material between the front safety lens and the tube's viewing area, he uses a trash can and places the tube neck down inside the can while he does the cleaning. I was thinking you should do a similar thing when you go to clean the front of the tubes. This way, the neck won't accidentaly be broken.
I had that NAP monitor. Even brand new, it had that picture collapse at the top. I had a friend with the same monitor and same problem. That is the "personality" of the monitor. It was cheap and available at PriceClub (now CostCo). It didn't cost much. It was a tank though. It fell down and flight of stairs (carpeted) and survived without issue.
I used it with my TS2068, and because that computer had a relatively large border in its display, the top weirdness was easy to ignore. I don't remember the price, but I am pretty sure it was dirt cheap (under $50).
I would like to see the results of a recap and a CRT rejuvenation.
Yes, what are on the units board issues and what CRT ones ? I think there is a link in the description to a CRT rejuvenator I have not followed it
(09:38) That sticky stuff is a dielectric grease that keeps moisture from entering the anode and the HV candlestick cabling.
Grimy Bezel would be a good name for like a sludge rock band.
The Chinese characters literally says "Not Bright", or simply dim......
Yeah its either not bright, or not lit up (I.e. not working). Its entirely possible this crt had a fault before too
That's interesting as it wasn't an entirely uncommon practice for budget-brand manufacturers to use 'factory seconds' i.e CRT's and components with known issues/ defects that could be bought cheap and repurposed.
I’m reminded of a recent BigClive video where he worked with a flashing light, that didn’t flash. It had writing in chinese on the box, which commenters noted, said “always on” or something like that ...
Seems it would be a good idea to learn to read chinese, when debugging products built in China, Taiwan, Hong Kong, etc ... 😀
Some times that word could also mean "doesn't emit light", so when it comes to monitor, "doesn't work at all".
If you ever need to repair/replace aquadag. dry graphite lubricant works damn well. The aerosal works great but I ended up buying some loose graphite lubricant and mixing with elmer's glue, then diluted with water to paint on.
I'm seeing some optical illusion when the grid pattern is on the screen, particularly around 5:55. I'm basically seeing black diagonal lines that just aren't there, just found it interesting
Some where in the remote Scottish highlands next week I will be exploring the attic of a high school where I seen some monitors Macs and IBM typewriters when I had a quick peek 10 years ago... Kept meaning to go back up
The breathing expansion phenomenon is caused by the variation of the anode high voltage. Because the deflection sensitivity depends on the anode voltage, there are many ways to improve it.
Separate the high-voltage circuit from the deflection circuit, and install a negative feedback for the high-voltage circuit to adjust the high-voltage power, which has the best effect. This method is used for high-end models.
In some chassis, although a combined circuit is used, the Re-trace capacitor is divided into two parts. One part of the capacity is adjusted by the PWM switch, and the high voltage can also be adjusted.
Generally, for CRTs produced in the 1990s, the ABL voltage is connected to the horizontal size modulation and the vertical size negative feedback for dynamic compensation, which can be partially improved. This is the most common method.
However, the focus voltage is still affected. In addition, the pattern still produces multiple distortions. Some models use ultra-high voltage capacitors and resistor packs to remedy them.
A lower cost method is to directly connect a resistor in the main power supply. When the beam current increases, the power supply of the deflection circuit also decreases, achieving self-compensation, but there are many side effects.
Some FBT manufacturers will try to reduce the output impedance of high-voltage power, and even carefully design the resonance frequency to odd harmonics, so that the Re-trace parabola is closer to a flat-topped square wave and reduces voltage changes.
You know where as those cloth coverings are concerned I've always wondered why they didn't make them a snap-in attachment. It wouldn't have been hard to do and it would've made them a whole lot easier to clean. What a fail. On the one with the case that doesn't fit, you could safely flip the CRT over. It should still be safe enough for the PCB because there's more than 3" gap from the components in most of those old monitors. It's worth checking out.
Most of the blooming and geometry issues were due to the age/state of electrolytic capacitors. They have exceeded the manufactures rated lifespan x 4.
@29:00 - can you not just mount the CRT upside down and invert the signal going to the deflection coils? (I have no experience fixing CRTs so this is probably a naive question)
I was going to say the same... But I guess Adrian doesn't really care about the monitor too much because of the burn-in - or there are other technical difficulties he didn't mention in the Video... . Anyways.. Adrian, maybe you can put it together again like that and give it away. Your basement must be cluttered anyways 😋
i have to say that that green and amber screens really have their charm.
29:40 if you used a heat gun i bet you could deform the inside of the handle a bit so that it would fit over the anode cap.
Look up VDC or Video Display Corporation. ive picked up so many NOS CRTs from them to fix various monitors, including IBM PS/2 monitors. my 8515 now has a NOS tube.
The blooming you see on #3 might also be secondary electrons. Not sure if you excluded that. It would come from an acceleration voltage that's too high. The electron beam smashes into the screen with so much force that it knocks other electrons out of it. They then fall back onto the screen in a circular pattern around the original electron, creating bloom.
This might be definitelly interesting for Vectrex owners, will share link on Vectrex user group. 👍
First I love these videos. Second, I would like to ask. Do you like Simple Green?
What is your opinion of it for classic electronics? Third, I noticed your floor dollies.
Did you make those? Would you be willing to go over them and how you use them and
if you did make them. Tell us about how you did that and give us a tour? Thank you, Keep up the great content.
Yeah these mono crts does earn a place. Only problem is they take so much space. Actualy.. all that stuff takes a lot of space😅 Nice job on these monitors, cool!
Hey you know a lot about crts I thought the technology had died for good by now. I am glad it’s not dead. Can you do a trinitron crt improvement someday?
And now I need one of those Sampo monitors 😅. Fun fact, Sampo is old finnish name, origin from folkstorie Kalevala. Sampo was a mill that produced richness.
19:24 - it used to be 220V but it's 230V here in Europe.
20:32 - I screamed internally, I was so afraid it would fall down of your table! :)
20:30 - did you cut out the mesh and put the frame back or you just threw it away? It seems like it's thick enough that the tube can be loose without it.
As I understand it's 240V in the UK, 220V in the rest of Europe, so they standardized on 230±10V
Yeah, that @20:32 struck me and made me move my hand to try to catch it. :-D
When yo turned the CRT around on #2 chassis (you also had to turn the neck board by 180 degrees). Wouldn't that make the picture appear upside down? How did you adjust that, by turning the yoke 180 degrees?
The tube is just a screen covered in phosphor and an electron gun pointing right to the center. It has no inherent orientation.
The yoke affects the beam magnetically to point it at different spots. That’s why monitors have a scan that goes left to right and top to bottom. The electromagnet steers the beam around the screen according to the input signal.
When you slide the yoke on the (upside down) tube, with the yoke still in its original orientation, the picture looks exactly the same because the force applied to the electrons IS the same (wrt your perspective.)
Not to be “that guy” as they say but get a flat tip for your HV probe. If you do find a CRT with a high stored charge then it will easily jump from to the screwdriver you were using which won’t be rated to kilovolts. I still work on CRTs for arcade enthusiasts so I’ve had a zap or two.
Would you also mind telling me what the rode mic is you have clipped to your shirt?
I miss that warm glow of an amber monitor. I’m looking for stuff in my area now but there are slim pickings.
I had a switchable Black and White / White Black which was interesting (Was it a 13in AST?). My first PC Clone (shop made) I got with an early Colour monitor at a cheap price
Love the look of the amdek monitor's
I'm really interested in that rejuvenator..
18:17 i have a sampo computer monitor, never thought i would see this brand anywhere else
The rear cover on the NAP would fit if you install the CRT upside down.
Well, my prediction on the previous video was right, the green tube was brighter when replacing the amber tube, hence the need to lower the sub-brightness control. And replacing the green tube with the amber tube resulted in a much dimmer picture. I'm guessing they'd use different component values around the brightness/contrast control circuits if they had different phosphor options on the same monitor.
Also, it never occurred to me that you could flip the tube to put the anode connector on the other side.
Anyway, good to see new life brought to some of these monitors. Just a shame that so many were so worn out or had such bad burn-in. At this point it's practically a lost art to repair the tubes themselves, since the equipment and skills required are so specialised. Especially manufacturing new tubes. I know there's a guy on YT that manufactures brand new Nixie tubes, but there's a huge gap in specialised technology between a Nixie and a CRT. So I guess tube swaps are the best we can do to try and save these old monitors.
The older Philips monitor on the left was originally developed for use with the P2000T home computer.
Turn the philips tube upside down so you can get the cover back on, might fit. What are you doing with all these old monitors?
I wonder if de gausing the screen would help with reducing the burn in.
I simply love amber monochrome monitors.
We control the horizontal and the vertical. We can deluge you with a thousand channels or expand one single image to crystal clarity and beyond.
I remember using a Pericom VT100 amber screen terminal, and it had crazy burn in, amber just seems to be worse for getting burn in
Every time I hear "Sampo" I still get visions of The Day the Earth Froze from MST3K.
On my console linux boxes I configure my XTerms to be amber, and on my laptops my XTerms are green. I loved amber monitors.
And I loved the greens. xD
Adrian! 22:12 don't do that anymore!!! If you let the tube on the table like this it make a small sound like "crack" and then the Picturetube is total distroeyed. I was at Philips Videorecoder (IR3 Gutheilschodergasse 17, 1120 Vienna) Company her in Vinna from 1997 - 2000 and I work for 35 years as a Radio & TV service and this is a nogo. Sorry to tell this - but what you are doing if the tube make "crack"? You can hit the screen on the trash. Best Regards Volker from Vienna and Thumbs up Nr. 2522
That Amdek reminds me of the Apple III monitor they had.
When that CRT started to fall forward I definitely reached out instinctively to grab it then remembered I was watching a video and felt like an idiot.
I've reacted exactly the same. :-D
Thanks for the effort, guys. Good looking out. :-)
What CRT tester are you getting? I recently bought a Sencore CR70 for my vintage/antique TVs that help feed my retro-gaming addiction. Funny thing is, the game consoles were not retro when I got them. Just couldn’t part with them and now they’re considered retro. Damn I’m getting old (recently turned 40).
I got a Konig TR850 which is the same as the B&K 490B. I'll be showing it on the channel soon as it's a neat tester.
One factor you could have weighed in is high-frequency noise emission. I'm past 40 so can't hear it, if there is any. But that could be important in case younger audiences are to be exposed to these things.
Something weird is going on with the audio around 10:00 and the next few minutes. Like a periodic static noise.
That NAP monitor is even cooler with the amber phosphor
You could cut away the interference area of the handle for #5 and 3D print a part to cover it up
or just turn the crt upside down, as long as the deflection coil is right side up it should still work.
keep up the great work Adrian 🕹 ♥
You can get a shock of an anode of the tube even if it has not been switched on for a while it is like a very big capacitor make sure it is discharged also remember your dealing with glass so I would wear glasses
11:13 Cleaning the inside (and the back of a CRT in particular) is not weird at all, older tubes can (due to
static charge) have collected a lot of dust and if there was a smoker in the area also a lot of (sticky) tar.
The high voltage can easily creep through and reduce the picture quality or even damage the electronics.
Marvin says: Don't panic and wear your Mask. 🖖😷👍 ❗
another great video! Thank you!
I love that holodeck simulator :D
Ah, the Philips again ^^ - yes, there was a version out there that had MDA/CGA input. The original one I had in the late 80s with my PC-I had a DIN socket that connected the the TTL CGA output. Can't remember the model number sadly.
Part of me puckered up when the board came out of the first Amdek monitor and the screen started tilting as though it was about to fall, that would have been messy..... :S
I need to get the PSU for my Torch-branded Sony monitor re-capped, got the caps at long last for it, just need to work up the courage, scary 240 full-fat volts and all... :P