To everyone suggesting "turning the implosion band around", the problem is literally in the name. Adrian covers it in the video as well. A rectangular tube has an enormous amount of stress in the glass at the corners and edges with the (negative) pressure of the vacuum inside, the tube *wants* to equalize it by deforming back into a circle, but glass obviously isn't that pliant. So the band is there to provide tight positive pressure against the edges to equalize the stress. The moment that band comes off, you lose all of the protection it provides and you've basically made a glass bomb. You might be lucky and be able to swap it around before anything catastrophic happens, but without knowing the factory torque values they've used, there's a chance you've permanently compromised it. Shango066 has videos from friends that have tried to "de-cataract" larger rectangular tubes, where the pressures are even more intense when the band is taken off, and they have to cover their entire bodies and faces in thick material in precaution, and it still usually ends in failure. Stay safe friends
Seconded. Never EVER mess with the implosion band of a CRT tube. Go and watch some videos of a CRT tube imploding to see what I mean. I disposed of an old green screen tube that had no implosion protection in a skip (dumpster) at school once. I knew it was old enough to not have protection, so i threw it in the skip on it's edge for fun. The resultant bang was like a bomb going off, and people came out to see what the noise was as they were convinced it actually WAS a bomb (The IRA were constantly setting bombs off at the time). The skip thankfully protected me from the flying glass. It's not an experience I'd want to repeat.
@333Orobas 666 When I was kid, we had an old portable B&W TV set where the video had failed somehow. I had claimed it as a “TV radio” and decided to take it apart one day. I danced on the precipice of disaster that day. I had no clue that I hadn’t discharged the PSU caps, or the anode. I was just poking at things and tapping the bell of the CRT with a screwdriver trying to figure out what it was made of. Eventually I satisfied my curiosity and put it back together, plugged it back in, and listened to the TV station. Feeling kinda lucky to be alive and not full of glass shard scars at the moment.
this makes me think that the band must be fitted at the factory before the tube is vacuumed. therefore it would never be safe enough to remove the band from a crt.
Nice work Adrian! I love these old monitors. My main fun computer is a Raspberry Pi running in composite mode through an old 9" Javelin monochrome monitor. Makes me happy, don't know why.
My first memory of one of these was as a 5/6 year old... and my brother was watching TV on it! He got an 5155 from the local dump (he was forever getting old broken PCs from there to tinker with) and I think it was toast, but he wired up the screen to a VCR after realising it was standard composite. So yeah, we watched Father Ted on this thing in glorious amber vision! It accepts PAL 50Hz without any fuss.
I am an old man at that, my probe handles 50 kv dc, worked on many picture tube sets with an average 25-35 kv dc. A Zenith was a great TV nearly as good as a Sony during the 70’s and 80’s!!!
Polarized capacitors have to be "formed" when new. Under electrical bias (DC) an oxide layer forms on one side of the foil. This is part of their polarization. Aluminum oxide for example is a dielectric, and necessary for the capacitor to store a separated charge. When new (unformed), or stored for long periods, this oxide layer breaks down again into the electrolyte. Applying the right voltage at the right polarity over a period of time allows this oxide layer to reform. If the oxide layer is missing (new) or compromised (left idle) the resistance to incorrect bias (in AC or filter circuits) is reduced and shorts can form. They draw excess current and can overheat and explode. Gently applying a bias allows the oxide layer to either form or heal without overstressing the delicate foil inside. This is why restorers start old equipment on a Variac or with a bulb in series. As they form their ESR will drop and the overall current will go down. If shorts are too numerous or have perforated the doped paper, they won't reform and shorts will worsen over time as tracks form and electrolytes cook off.
Yep. I service equipment that have large electrolytes inside. And i preach the "keep the caps formed" doctrine everywhere i go. Because even people with electrical engineering degrees do not know this simple fact. I've seen so many spare parts installed, that have been sitting on a shelf for years, and then as soon as power is applied instantly explode. Due to the boiling of the electrolyte, as the capacitor is basically a dead short at that point.
I can attest to this in practice. I replaced the dangerous tantalum capacitors in my telescope mount with electrolyttics and to my horror the handbox took and extra 20 seconds to boot! But once it booted once it was fine.
@@ultrametric9317 for goodness sake, why "dangerous"??? At least with smaller tantalum capacitors, it's one and done when they die. Other electrolytics (because technically tantalums are also electrolytics) can leak slowly and ruin the board and traces and other components around it. Often Mac collectors start replacing aluminum electrolytic capacitors with tanatalums after seeing this damage. It's much easier to deal with one "exploded" capacitor and a little magic smoke. I find it hilarious that other electronic collectors do the opposite. In the end its mostly a matter of personal preference.
@@squirlmy Oh yes - dangerous. The electronics were made for 12v DC. The ratings on the tantalums was like 25v. Meade decided it was OK to run the system on 18v to get faster slews from the DC servo motors. They supplied a nasty 18v non-regulated power brick which had a tendency to surge and blow up the capacitors, which could, among other bad things, burn a fatal hole in a ribbon cable inside the handbox.
Fuses sometimes just blow. Especially if it is old (the fusing element can oxidize and blow at a lower current than it should). Replacing a blown fuse with a new one ONCE is not a bad idea. Especially on old equipment. If the new fuse blows, then you definitely have an issue. I have "fixed" a lot of equipment what had a blown fuse, and all that was wrong was the fuse was blown. Sometimes the fuse blows because of a power line disturbance, like a lightening strike or branch hitting the power line. Crap happens, in other words. But as Adrian said, NEVER just bypass a fuse. Unless you like electrical fires. If that is the case, and you don't care about your house, then bypass away!
I just love these small CRTs. Just got a VGA one, but a color one. Never saw an amber CRT that small. And the condition of this one ... amazing stuff! Keep these tubes coming! :-) Thanks as always and keep up the great work. Cheers!
I would guess the tube has amber phosphor, they just used an amber filter layer on the inside of the screen to increase contrast ratio. They made it similarly with modern colour CRTs, the inner ~0.5mm of the screen is a layer of "smoked" glass, so the black portion of the picture reflects back less of the ambient light, ei. producing higher contrast ratio. It might be possible though, that they were aware of the shorter life of the amber phosphor, and used white phosphor with a color filter inside the screen.
Great video Adrian. I remember when the 5155 came out in 1984, I was selling micro computers at a local department store. I thought that the amber screen on these was always dim compared to other amber displays. As I remember, the screens always did have an amber tint, even when they were off. These systems were portable compared to desktops. The 5155 IBM PC Portable was IBM's answer to Compaq. It never sold as well as the Compaq and was discontinued when the IBM Convertible came out in April 1986.
Compaq made $111 million its first year with the Portable. And the secret sauce was to have an MS-DOS almost completely compatible with PC-DOS. Microsoft kinda winked when it followed Compaq's desires to make such a compatible version. Every other company had been satisfied with incompatible DOS versions. Also, this all-in-one design inspired the first Macs.
There is a special high voltage varnish called Glyptal that may be good for the occasional touch up on yokes and older open flyback transformers. We also used that for years at work for sealing trimmer pots so the adjustment stays put (in the latter case, a toothpick works well as an applicator).
I finally got one of these on eBay, the minute it was posted I snagged it. My 5155 will have a space CRT just in case something happens to it. Awesome find that there were NOS part for it! thanks
The luggable was the first PC I ever bought - I worked for IBM at the time and got employee discount for it - but it still cost a small fortune. Boy did that thing weigh some. I added a 30MB hard drive, ran Supercalc, the odd game or two and my favourite editor E3.......
This was a great video. I picked up half a dozen of these from Computer Reset also, along with a couple similar green monitors from Compaq portables. It's nice to see that you can swap out these tubes that easily, especially into a mac. I have a few projects planned including putting one in a case like you said.
I got a NOS B&W 9 inch CRT monitor from Philips made in 1987 a few weeks ago. It's a bit different, it wants a TTL video signal (although it can display shades of gray, but it needs at least 1V to display anything) and it has separate H- and V-sync inputs. That plus the specs say 15-18kHz horizontal means you could use it for MDA/Hercules too. I'm currently using it to test/repair arcade game boards. Had to replace a few caps, there was no vertical deflection. And just for kicks, the engineers used a 555 for horizontal oscillator (including sync/phase).
Very nice NOS CRT there. When you said what can we do to help the copper turns on the yoke, i was saying 'use nail polish!'.. haha. Its perfect for inductor windings. True also in RF work. Enjoyed that!
On the subject of fuses. Replace with the same current rating and *TYPE* of fuse. If the original calls for a slow blow, replace with a slow blow. If it calls for a quick blow, use a quick blow etc. Not all fuses with the same current rating are identical. The type is very important.
Really educational video, I wonder if you can adapt these to modern computers, given the composite to digital signal converters out there. Would love to see an amber gradient CRT used for modern tasks.
12,000+ volts in your boo-tay. Better to be safe than somebody feeling sorry for you. Excellent, informative video as usual. I actually saw a YT video not to long ago of a Commodore 1084 with a corroded yoke. I don’t think he was able to save it and ended up swapping it for another.
I had an amber Zenith monitor (the one that appeared to be designed for the Apple II) and it had genuine amber phosphor. I think this is an IBM thing. Their specs .. and it may have been to get a certain color balance, persistence or particular linearity in the brightness response.
With scan coils that use rubber wedges to hold them in place, it's worth checking to see if the rubber is still relatively soft and pliable, and hasn't turned to stone with time. If that happens, they will become hygroscopic and electrically-conductive, which will then eat through the enamelled coating of the scan coils. It was quite a common failure with some budget-brand TV's (Onwa, etc.). Preventative fix: Cover all the wedges with electrical tape and then re-seat the scan coil assembly.
Not sure it can actually be related but the amber display on Yamaha HI-Fi components it is actually a standard Vacuum Fluorescent Display emitting in the green/white range from which only the red/amber component is filtered. As such Yamaha displays are generally dimmer compared to other normal green display.
I remember seeing one of these about 30 years ago, they were never bright to begin with. The glass has a sort of brown color to it and makes the phosphor more of a darker yellow than orange.
You can touch up the enamel wire with cheap nail polish. It will arrest the oxidative processes and prolong the life. I saw evidence of discoloration due to heat in some shots. If the whole yoke is coated in enamel, that's about all you can do. If the windings can be separated gently with a soft plastic tool, you can separate the damaged ones and enamel them then pack it back together.
I remember taking our demo unit home for a few days when these first came out. I don’t remember the specifics, but I have the sense that I felt the screens on these didn’t look so hot. They were fuzzy, dim, or somehow else crappy.
Let's give Dave Plummer the full on respect he deserves. He coded into 'life' the Task Manager, he's part of a newly found MS Easter Egg, he helped write the coding for rebooting/resetting the Windows environment, oh, he ported PinBall into Windows, and a LOT more.
@@I_am_Allan So? You do the work your asked to do. I'm sure, in the decades he was at MS, he did a heck of a lot more too. The point is, Windows is a heap and Mr. Plummer is partially responsible for that. If you need a hero, please .. worship all you like. Unfortunately my life has taken me down a different road than yours. I have had to deal directly with the mess that has been Windows over the years.
@@uni-byte : Did you have a point in any of this? Windows is partly a mess because it didn't get a massive enough "clean up" phase to fix that, and partly because it's got so many parts that their number is enough to ensure it's never "clean". None of this can be credited to any one (or twenty) developer(s), it's a consequence of deadlines and scope. It's usefulness to the general public was enough to guarantee that it would be messy.
Im Currently watching this video on one of my Zenith data systems Amber monitors (model ZVM-122-e) and can confirm that it does not have an amber colour to the glass. What i will say though is when i got these monitors they had not been used in alot of years and they had a very low output (washed out image as adrian puts it), but after running them for about 40 mins to an hour, i had to turn the brightness and contrast down as they had come back to looking bright and vibrant and have stayed they way ever since.
IBM 5155, the first computer I've ever seen, my dad took it home from work sometimes when I was like 2-3 years old! I remember the machine having a very dark red, almost purplish, screen, and as a kid, I was very surprised to see the amber colored light coming off. And of course, the very noisy 5¼" floppy drives. I cannot tell if the phosphor is white or amber, could be both, having colored glass to increase the contrast.
I used an 12" Amber as my PCs primary screen for a long time...and even looked good with my VGA wonder card. Until I got my first multi-sync (VGA) monitor.
I still own a 9" amber monitor I bought in the early 80's for one of my Apple II computers. Bought it at Computerland, the long defunct chain of popular computer stores. It's nice to have an NTSC RS-170 monitor around for misc purposes, like displaying the video output on a digital camera.
I had a Mitsubishi amber monitor in the 80's and it was brownish too when off. But not as brown as the one you got there. I wouldn't bet on glass color...
@@cheater00 I do not deserve much credit as we gave the monitor and the 80286 computer to charity around 2005. It was interfacing a MIDI ISA card for our music studio. The amazing part is, everything on it was the original hardware including the 20mb hard-drive. In working condition...
33:37 those copper coils are not exposed; they can't be made out of the bare naked wire because it would short the winding losing the inductance; copper wire for winding has an enameled insulation, which you can only remove by sanding it (and it requires a heavy sanding) or by melting it with a flame (i.e. from a lighter); this is only done at the end tips to connect the coil to circuit.
Nice get! I've been looking for a PET 4032 composite out board but no one seems to sell them. Have several schematics but all seem for PET 2001 series only. Would like to add a second monitor to my PET for teaching. Thanks for sharing!
Sadly the PET 4032 uses 22khz so it's not NTSC compatible. I think a new editor ROM will fix that though -- you can get a patched one to output NTSC. Then you could use this board -- it's a bit low voltage for the 12" CRT but it should still work at 12.5kv.
When we bought our first home we opened the crawl space when having a home inspection and found someone had thrown a CRT Television down into the crawl space which had broken into pieces. We had to clean it out but it was the first time I had seen the inside of a CRT.
Another UA-camr, Joe of Joe's Computer Museum has already built an orange oriented classic Mac using an Amber CRT and a clear Mac Effects case. I've enjoyed this video, now off to watch Dave Plummer's Amber PET video mentioned in the description. I gotta have a dose of 8-bit content!
Odd that an IBM PC with a built-in screen would use NTSC at all, instead of MDA. Maybe it had a built-in composite out for people who wanted to occasionally hook up a TV (similar to how laptops almost all still have a video port), and it was cheaper to include only the NTSC adapter circuitry?
Around '89 I had a client bring in a WYSE terminal that wouldn't work. Applying power produced an ominous hissing. When the back cover was taken off it was all revealed. When the unit was assembled the LV harness and EHT lead managed to press against each other. Over the years the plastic insulation of the LV harness had slowly pressed its way into the EHT lead to the point where both broke down. Let's just say that 13kV into 5 volt TTL circuits doesn't end well.
The brown monitor is basically a black and white monitor in brown color. This understands neither NTCS nor FBAS. Not even PAL or SECAM. But the common BAS S/W signal. With B/W SECAM, the color carrier was switched off and pure B/W was sent.
Al lot of talk on the wire enamel reminds me that I have a story to share. I somewhat recently wanted to do something with my CDi and I usually use it with a beat to hell Trinitron TV I have. When I turned the thing on, there was a ton of arcing. I figured it was at the anode cup, so I cleaned it up and regreased it before reseating it. After what I thought was a thorough visual inspection and cleaning, I turned it on. The was crackling accompanied with a burning smell. The enamel had degraded and caused a short, singeing the deflection coil. The tube still has a sharp and beautiful image, so I'm definitely going to keep it. I'm just no sure if I want to try and redo the enamel or rewind the yoke with fresh magnet wire. (When I say beat to hell, I mean it. As far as the case goes. It's scuffed, scratched, cracked and has a hole melted through it. The CRT is great and it's a crazy contrast.)
Arcing to/of the deflection yoke can be caused by the missing ground wire on the CRT that Adrian mentioned. The HV return has to go somewhere, and if it can't return through the CRT ground wire it will find the yoke winding instead, causing damage.
Regarding the corrosion on the wires I would assume that it is indeed a surface defect that happened during assembly. You know factory worker wedging on the thing on the tube. I am in my RL an engineering director at a company doing a lot of stuff with electroluminescent lights and had inverters manufactured that had outer windings really cruded (is that a word?) up in corrosion due to sea cargo shipping. After confronting the manufacturer they told us they used a “tool” to act as a spacer between a heatsink and the adjacent transformer. The tool turned out to be a screwdriver and it just chipped away the enamel of the wire. Only solution we had at hand was to desolder the transformers in Germany, completely vacuum pot them and then check for spec adherence in Q, R and L. Just a guess though on how this corrosion might have happened. But you know: there is always this one guy with a screwdriver
Old arcade video game machines used to have strips of coloured cellophane across a white phosphor screen to give the impression of a colour monitor, so it wouldn't surprise me that is just tinted amber. Love glowing green, hate dirty amber - lol -.
I have to chuckle at the HV warnings you give. In the early 1980s, I was in a factory training for a word processor A.B. Dick Magna SL. It was a full page display and required the anode voltage be adjusted to 25kv via a small trim pot. The instructor asked for one of us to adjust it. I volunteered and set it to the 25kv. He thanked me then told us from that point forward to ONLY use the 10 inch fiberglass adjustment tool as the solder trace almost touching the pot had the 25kv on it! I to this day am not sure but I think he was looking for a more dramatic demonstration 😅😅.
It's highly unlikely there would be 25kv on a trimpot, it's likely to be the bottom end of a long chain of resistors of much higher value, if it is in the feedback circuit at all.
I have a Zenith Z-160 PC compatible luggable from 1984. It has a 9" amber monitor. I actually pulled it off the shelf yesterday to do an upgrade to it in the next couple of days. When I open it up I'll have to see if the amber monitor uses the same Zenith CRT.
Opened it up this morning. The tube has a different part number, DJ9NK3. It is rated for 13v 1.4amp like the tube in the video. I have the SAMS Computerfacts for this machine and according to it just like the IBM 5155 the monitor is undervolted in the Z-160. In this case 11.8v are provided.
I don't know if you've ever watched implosion videos, but I would not go near a B&W CRT tube without eye safety goggles. Most implosions are caused by failing side walls, not the face plate. The band does not lessen the implosion, it contains it so that glass hunks don't go flying around outward. An uninhibited implosion is like a bomb going off!
I think you'll find that the blooming is due to insufficient EHT drive. Being a 12V to 12500 volt inverter, the impedance of the transformer's secondary is going to be substantial.
Blooming can be the video driver clipping, for example if its supply voltage is slightly low. It could also be that the beam current is lowish. Possible causes include al low +B (12V instead of 13V), electrolytics that need to be reformed or the CRT cathode that needs to be reactivated (leaving it switched on for some time will do the trick for the electrolytics and the CRT in most cases).
Phosphor wants to glow green. The only way to get white or amber is to add other chemicals to the phosphor. Which is why green phosphor monitors tend to be the brightest. Plus, even though CRT's are in a vacuum, there are still minute quantities of oxygen, and even vacuum tubes leak an extremely tiny amount. So a monitor that has sat for a very long time, may be super dim at the start, until you "burn off" the oxygen. And also the reason that the phosphor eventually burns out. CRT's are fascinating devices, and i like them very much. Even though they are much harder on the eyes than an LCD monitor. I grew up with good old CRT technology. Nostalgia is a thing... ^-^
There is a quicker, one handed way to remove the high voltage connection. Just grab the back of the connector and while pressing in, gently push it over to one side to release one of the clips. Then without pressing, gently move it to the other side, and the other clip will release.
I have a Brother Word Processor with one of those Datapoint style wide format "punch card ratio" CRTs. It produces an amber image, but the CRT is indeed a white phosphor CRT using an amber color filter. In this case, the filter is simply a plastic filter in front of the CRT, not integrated. Interestingly, the CPU is a 12 MHz enhanced Z80 clone, and it uses a PLA configured to manage an 820x240 bitmap stored in a 32K Video SRAM. The service manual covers the entire memory and I/O map. Would love to hack it into something else someday.
You mentioned the power supply it was attached before regulation on 12v as the analogue board of the monitor would pollute 12 rail with electrical noise if it was connected down stream.
Nice video! I learned a thing or 2 about crt's now! I have this iMac G3, which is working perfectly fine, the picture is nice and bright, no bleeding or distortion what so ever, but i can hear clicking sometimes, i don't know if it is the connection to the crt or if it is the flyback, but now at least i know i can try to mess with the anode cap to see if it goes away, i will try it later today even, sometimes it doesn't click at all, if it was the flyback, wouldn't it be clicking all the time? Anyhow, very enjoyable video to watch :)
I did take off the anode cap to clean it and there was some black gunk under there, i cleaned the prongs and the connector in the crt and the clicking stopped! The computer works perfectly fine now! I am stunned that this solved my problem!
Nice Monitor I would be fun to find one like that I used to see them forsale some surplus electronics places like old MCM Electronics which is nework sold a lot suplus stuff I once bought like bunch of Bose 6 1/2 nos woofers for like $5.00 each .
I'm going to recommend discharging the crt with a direct short and then perhaps checking it with the meter because you should not ever get any type of shock if it's been discharged properly. If the meter failed it could show 0 volts on an open circuit and you could receive a lethal shock
A direct short can result in the internal connection to the anode button being damaged. Also, through dielectric absorption, voltage up to a few kilovolts may reappear after having momentarily shorted out the tube. Best practice would be to discharge it through an HV probe, and then clip a shorting wire to it during further handling.
CRT is a tube - tubes have "heaters" that typically run on 12.6 VAC. Just a guess. I think we're spoiled by modern (bright) displays. Guessing the display is normal for its day.
Ibm was running the crt module with 12vAC, rectified, that actually ends up being about 15vDC, so that little board in the schematic must be doing more that advertised.
I think that amber monitors, like green monitors are using different phophor compounds. White monitors used on TV sets are using a mix of diferent chemicals and are a mix of blue and yellowish phophors.
I watched the videos Dave Murray put on the 8-bit Guy channel about his adventures with the Apple ][ monitors he got from Computer Reset's storage yard. The main problem he had is he couldn't find any circuit design or hardware manuals for the monitors. There was a specific diode that had mechanically broken down, and he couldn't identify the characteristics of the part. He eventually got a suitable replacement more or less by luck, although you can sometimes get some indication by looking at similar monitors. And that turned out to be all that was really wrong with the monitors that must have been at LEAST 20 years out in the weather, possibly between 30 and 40 years.
Most of these components are fairly generic. There is one high voltage power transistor that is somewhat critical and he high voltage diode stack that is mostly integrated into the flyback transformer. Anybody who can repair old tvs can repair these monitors easily.
Many years ago ,in the Mac plus days ..i had a working Mac plus board and i removed a tiny monitor from an IBM 5100 scientific computer .And i hooked up to the Mac Plus board..And i had the smallest Mac Plus computer on the planet ./.
Hi Adrian is was nice meeting you at VCFMW. By any chance do you still have this NOS 5155 Monitor. I am restoring a 5155 and am in need of this. Maybe you know where I can get one. Best, Jon
On the power connector , the purest in me is like "WHAT NO!!??" lol, but I get it. BUT you should get a set of those cylindrical pin extractor tools... you fit them over the pins in that connector and it forces the clips back into the pin, and it can be exracted. Not sure what diameter those are, amazon has a couple of molex pin extractor tools - I acually have a set of brass tubes, that I just aded an interior chamfered and use.
Analog phosphor is that a thing? I actually thought I heard wrong at first, so turned on closed captions and rewinded and yeah you said analog :P Also would not giving it the proper 13 volts also affect how much brightness it could handle? Would at least think so when a brightener does that to a tired CRT by just giving it more juice.. So maybe this is just a side effect of undervolting it.
Regarding your comment about not finding pickled chips in the USA, over here in Mississippi, we have golden flake pickled chips, fried dill pickle chips, and utz cajun dill tators.
I just recovered an IBM 3477 terminal from a recycling center, been left out at least the past week in a good few rain storms. I got it home, it was really dirty inside, I think it had a long running life. I stripped down every component, cleaned off the dirt, made sure there was no corrosion or anything obviously messed up... and.. it works!! (well as far as I can test it), I can't find a keyboard for it :( So I get a keyboard error on the status line. (If anyone knows if you can adapt a keyboard to that, that'd be great!!)
Ironically, the smaller the CRT, the higher the flyback output will be. 12KV sounds about right for a terminal monitor like that. Killer stuff too. You could have a 40" CRT that only takes 1,000volts to drive, but a rinky dink Sony Watchman pocket TV needed juice north of 10KV to operate.
get yourself a UV flashlight, you can check the monitors for use without powering them up, I can see all the burn in on my kaypro 2x I got, but the green phosphor is so strong in it it doesn't even actually show. also looks like might have to 3d print bezel adapters for these if the monitor will still fit length wise, its the only solution I can come up with. as for rectification, its not hard to do, a good example is the NES, it will take ac or dc power and rectify it, a simple way would be just drop in a 12v transformer in the pet off the mains switch, not a wall wart you can just get one for a 12v radio should be enough my kaypro2x has a very distinct green phosphor the 3 crt tv's I own one has a white grey, one has a darker grey and the other is a white grey, the darker grey actually has a better picture then the others
I have this ast monitor from 1993 where its pretty used and blew its fuze. I replaced the fuse and it works again, just the same as before so.. im not sure what could be wrong XD All i know is that ive been running it for about a year now with the new fuse and there has been no problems to report.
![Adrian's Digital Basement ][](http://yt3.ggpht.com/ytc/AIdro_k7CrQRe71qN6c0Ua7A1P_I8KkxjqLa70u0zYeCvdvnKw=s48-c-k-c0x00ffffff-no-rj)
To everyone suggesting "turning the implosion band around", the problem is literally in the name. Adrian covers it in the video as well.
A rectangular tube has an enormous amount of stress in the glass at the corners and edges with the (negative) pressure of the vacuum inside, the tube *wants* to equalize it by deforming back into a circle, but glass obviously isn't that pliant. So the band is there to provide tight positive pressure against the edges to equalize the stress.
The moment that band comes off, you lose all of the protection it provides and you've basically made a glass bomb. You might be lucky and be able to swap it around before anything catastrophic happens, but without knowing the factory torque values they've used, there's a chance you've permanently compromised it.
Shango066 has videos from friends that have tried to "de-cataract" larger rectangular tubes, where the pressures are even more intense when the band is taken off, and they have to cover their entire bodies and faces in thick material in precaution, and it still usually ends in failure.
Stay safe friends
Seconded. Never EVER mess with the implosion band of a CRT tube. Go and watch some videos of a CRT tube imploding to see what I mean.
I disposed of an old green screen tube that had no implosion protection in a skip (dumpster) at school once. I knew it was old enough to not have protection, so i threw it in the skip on it's edge for fun. The resultant bang was like a bomb going off, and people came out to see what the noise was as they were convinced it actually WAS a bomb (The IRA were constantly setting bombs off at the time). The skip thankfully protected me from the flying glass. It's not an experience I'd want to repeat.
OK, then do it in a vaccum chamber. ;-)
@333Orobas 666 When I was kid, we had an old portable B&W TV set where the video had failed somehow. I had claimed it as a “TV radio” and decided to take it apart one day. I danced on the precipice of disaster that day. I had no clue that I hadn’t discharged the PSU caps, or the anode. I was just poking at things and tapping the bell of the CRT with a screwdriver trying to figure out what it was made of. Eventually I satisfied my curiosity and put it back together, plugged it back in, and listened to the TV station.
Feeling kinda lucky to be alive and not full of glass shard scars at the moment.
this makes me think that the band must be fitted at the factory before the tube is vacuumed. therefore it would never be safe enough to remove the band from a crt.
I read that and wondered who Nairda is? I don't think my brain works properly.
Nice work Adrian! I love these old monitors. My main fun computer is a Raspberry Pi running in composite mode through an old 9" Javelin monochrome monitor. Makes me happy, don't know why.
My first memory of one of these was as a 5/6 year old... and my brother was watching TV on it! He got an 5155 from the local dump (he was forever getting old broken PCs from there to tinker with) and I think it was toast, but he wired up the screen to a VCR after realising it was standard composite. So yeah, we watched Father Ted on this thing in glorious amber vision! It accepts PAL 50Hz without any fuss.
Feck! Drink! Girls! Arse! I love Father Jack.
These monitors are small, those are far away
I don't believe it.
@@Okurka. Wrong show.
@@markphillips8019 Nope. Apparently you're not a big enough fan.
I am an old man at that, my probe handles 50 kv dc, worked on many picture tube sets with an average 25-35 kv dc. A Zenith was a great TV nearly as good as a Sony during the 70’s and 80’s!!!
Nice to see this follow up on this 9" amber CRT chase. Green Mac / White Mac / Amber Mac gota collect the set :)
Polarized capacitors have to be "formed" when new. Under electrical bias (DC) an oxide layer forms on one side of the foil. This is part of their polarization. Aluminum oxide for example is a dielectric, and necessary for the capacitor to store a separated charge. When new (unformed), or stored for long periods, this oxide layer breaks down again into the electrolyte. Applying the right voltage at the right polarity over a period of time allows this oxide layer to reform. If the oxide layer is missing (new) or compromised (left idle) the resistance to incorrect bias (in AC or filter circuits) is reduced and shorts can form. They draw excess current and can overheat and explode. Gently applying a bias allows the oxide layer to either form or heal without overstressing the delicate foil inside. This is why restorers start old equipment on a Variac or with a bulb in series. As they form their ESR will drop and the overall current will go down. If shorts are too numerous or have perforated the doped paper, they won't reform and shorts will worsen over time as tracks form and electrolytes cook off.
Yep. I service equipment that have large electrolytes inside. And i preach the "keep the caps formed" doctrine everywhere i go. Because even people with electrical engineering degrees do not know this simple fact.
I've seen so many spare parts installed, that have been sitting on a shelf for years, and then as soon as power is applied instantly explode. Due to the boiling of the electrolyte, as the capacitor is basically a dead short at that point.
I can attest to this in practice. I replaced the dangerous tantalum capacitors in my telescope mount with electrolyttics and to my horror the handbox took and extra 20 seconds to boot! But once it booted once it was fine.
@@ultrametric9317 for goodness sake, why "dangerous"??? At least with smaller tantalum capacitors, it's one and done when they die. Other electrolytics (because technically tantalums are also electrolytics) can leak slowly and ruin the board and traces and other components around it. Often Mac collectors start replacing aluminum electrolytic capacitors with tanatalums after seeing this damage. It's much easier to deal with one "exploded" capacitor and a little magic smoke. I find it hilarious that other electronic collectors do the opposite. In the end its mostly a matter of personal preference.
@@squirlmy Oh yes - dangerous. The electronics were made for 12v DC. The ratings on the tantalums was like 25v. Meade decided it was OK to run the system on 18v to get faster slews from the DC servo motors. They supplied a nasty 18v non-regulated power brick which had a tendency to surge and blow up the capacitors, which could, among other bad things, burn a fatal hole in a ribbon cable inside the handbox.
Best part about nos CRTs besides brightness is the lack of nicotine glaze.
Fuses sometimes just blow. Especially if it is old (the fusing element can oxidize and blow at a lower current than it should). Replacing a blown fuse with a new one ONCE is not a bad idea. Especially on old equipment. If the new fuse blows, then you definitely have an issue.
I have "fixed" a lot of equipment what had a blown fuse, and all that was wrong was the fuse was blown. Sometimes the fuse blows because of a power line disturbance, like a lightening strike or branch hitting the power line. Crap happens, in other words.
But as Adrian said, NEVER just bypass a fuse. Unless you like electrical fires. If that is the case, and you don't care about your house, then bypass away!
I just love these small CRTs. Just got a VGA one, but a color one. Never saw an amber CRT that small. And the condition of this one ... amazing stuff! Keep these tubes coming! :-) Thanks as always and keep up the great work. Cheers!
I would guess the tube has amber phosphor, they just used an amber filter layer on the inside of the screen to increase contrast ratio. They made it similarly with modern colour CRTs, the inner ~0.5mm of the screen is a layer of "smoked" glass, so the black portion of the picture reflects back less of the ambient light, ei. producing higher contrast ratio.
It might be possible though, that they were aware of the shorter life of the amber phosphor, and used white phosphor with a color filter inside the screen.
I have an amber CRT like this I need to test. Kinda strange looking.
Great video Adrian. I remember when the 5155 came out in 1984, I was selling micro computers at a local department store. I thought that the amber screen on these was always dim compared to other amber displays. As I remember, the screens always did have an amber tint, even when they were off.
These systems were portable compared to desktops. The 5155 IBM PC Portable was IBM's answer to Compaq. It never sold as well as the Compaq and was discontinued when the IBM Convertible came out in April 1986.
Compaq made $111 million its first year with the Portable. And the secret sauce was to have an MS-DOS almost completely compatible with PC-DOS. Microsoft kinda winked when it followed Compaq's desires to make such a compatible version. Every other company had been satisfied with incompatible DOS versions. Also, this all-in-one design inspired the first Macs.
There is a special high voltage varnish called Glyptal that may be good for the occasional touch up on yokes and older open flyback transformers. We also used that for years at work for sealing trimmer pots so the adjustment stays put (in the latter case, a toothpick works well as an applicator).
Glyptal is still around, but YEOW, they are proud of that stuff!
Glyptal is just a manufacturer, 1202 or 9620 are their clear insulating varnishes
A relaxing and interesting video after a long workday.
I finally got one of these on eBay, the minute it was posted I snagged it. My 5155 will have a space CRT just in case something happens to it. Awesome find that there were NOS part for it! thanks
It would be funny if someone snuck up behind you and yelled BANG!
Lots of great info and advice as usual. I would like to add, don't ever sit a CRT on it's neck, it's best to place it screen down on a thick towel.
It's so dinky and cute. It could go into a custom video game cabinet hooked up to a computer running Sapce Invaders. :)
The luggable was the first PC I ever bought - I worked for IBM at the time and got employee discount for it - but it still cost a small fortune. Boy did that thing weigh some. I added a 30MB hard drive, ran Supercalc, the odd game or two and my favourite editor E3.......
Have to laugh at the 30MB upgrade lol. Cool story though. I was a commodore kid, never used any of this older IBM stuff Windows 95 was my PC intro
This was a great video. I picked up half a dozen of these from Computer Reset also, along with a couple similar green monitors from Compaq portables. It's nice to see that you can swap out these tubes that easily, especially into a mac. I have a few projects planned including putting one in a case like you said.
I got a NOS B&W 9 inch CRT monitor from Philips made in 1987 a few weeks ago. It's a bit different, it wants a TTL video signal (although it can display shades of gray, but it needs at least 1V to display anything) and it has separate H- and V-sync inputs. That plus the specs say 15-18kHz horizontal means you could use it for MDA/Hercules too. I'm currently using it to test/repair arcade game boards.
Had to replace a few caps, there was no vertical deflection.
And just for kicks, the engineers used a 555 for horizontal oscillator (including sync/phase).
Gotta love that 555! Unsung hero of how many things :-)
Very nice NOS CRT there. When you said what can we do to help the copper turns on the yoke, i was saying 'use nail polish!'.. haha. Its perfect for inductor windings. True also in RF work. Enjoyed that!
On the subject of fuses. Replace with the same current rating and *TYPE* of fuse. If the original calls for a slow blow, replace with a slow blow. If it calls for a quick blow, use a quick blow etc. Not all fuses with the same current rating are identical. The type is very important.
Really educational video, I wonder if you can adapt these to modern computers, given the composite to digital signal converters out there. Would love to see an amber gradient CRT used for modern tasks.
12,000+ volts in your boo-tay. Better to be safe than somebody feeling sorry for you. Excellent, informative video as usual. I actually saw a YT video not to long ago of a Commodore 1084 with a corroded yoke. I don’t think he was able to save it and ended up swapping it for another.
I had an amber Zenith monitor (the one that appeared to be designed for the Apple II) and it had genuine amber phosphor. I think this is an IBM thing. Their specs .. and it may have been to get a certain color balance, persistence or particular linearity in the brightness response.
Indeed, quite possible!
With scan coils that use rubber wedges to hold them in place, it's worth checking to see if the rubber is still relatively soft and pliable, and hasn't turned to stone with time. If that happens, they will become hygroscopic and electrically-conductive, which will then eat through the enamelled coating of the scan coils. It was quite a common failure with some budget-brand TV's (Onwa, etc.).
Preventative fix: Cover all the wedges with electrical tape and then re-seat the scan coil assembly.
Not sure it can actually be related but the amber display on Yamaha HI-Fi components it is actually a standard Vacuum Fluorescent Display emitting in the green/white range from which only the red/amber component is filtered. As such Yamaha displays are generally dimmer compared to other normal green display.
Not a surprise that the green lasts longer than the other types of phosphor. It's all about the chemistry.
I remember seeing one of these about 30 years ago, they were never bright to begin with. The glass has a sort of brown color to it and makes the phosphor more of a darker yellow than orange.
You can touch up the enamel wire with cheap nail polish. It will arrest the oxidative processes and prolong the life. I saw evidence of discoloration due to heat in some shots. If the whole yoke is coated in enamel, that's about all you can do. If the windings can be separated gently with a soft plastic tool, you can separate the damaged ones and enamel them then pack it back together.
I remember taking our demo unit home for a few days when these first came out. I don’t remember the specifics, but I have the sense that I felt the screens on these didn’t look so hot. They were fuzzy, dim, or somehow else crappy.
Let's give Dave Plummer the full on respect he deserves.
He coded into 'life' the Task Manager, he's part of a newly found MS Easter Egg, he helped write the coding for rebooting/resetting the Windows environment, oh, he ported PinBall into Windows, and a LOT more.
He's also partially responsible for the mess that Windows is.
and he actually made the mod with this crt
@@uni-byte he wrote the Windows Zip program, and ported Win 95 UI into NT/MIPS/RISC, and ported the original PinBall game into Windows.
@@I_am_Allan So? You do the work your asked to do. I'm sure, in the decades he was at MS, he did a heck of a lot more too. The point is, Windows is a heap and Mr. Plummer is partially responsible for that. If you need a hero, please .. worship all you like. Unfortunately my life has taken me down a different road than yours. I have had to deal directly with the mess that has been Windows over the years.
@@uni-byte : Did you have a point in any of this? Windows is partly a mess because it didn't get a massive enough "clean up" phase to fix that, and partly because it's got so many parts that their number is enough to ensure it's never "clean". None of this can be credited to any one (or twenty) developer(s), it's a consequence of deadlines and scope. It's usefulness to the general public was enough to guarantee that it would be messy.
You [are] really becoming the "Electron Whisperer"... I really get a charge out of watching these videos (CRT or LCD). Cheers!
Im Currently watching this video on one of my Zenith data systems Amber monitors (model ZVM-122-e) and can confirm that it does not have an amber colour to the glass. What i will say though is when i got these monitors they had not been used in alot of years and they had a very low output (washed out image as adrian puts it), but after running them for about 40 mins to an hour, i had to turn the brightness and contrast down as they had come back to looking bright and vibrant and have stayed they way ever since.
my family's first PC was the Heath Zenith luggable that had the same tube in it. i played king's quest on that thing
IBM 5155, the first computer I've ever seen, my dad took it home from work sometimes when I was like 2-3 years old!
I remember the machine having a very dark red, almost purplish, screen, and as a kid, I was very surprised to see the amber colored light coming off. And of course, the very noisy 5¼" floppy drives. I cannot tell if the phosphor is white or amber, could be both, having colored glass to increase the contrast.
I think the idea to do an amber Mac with that new old stock CRT would be a lot of fun to see
I used an 12" Amber as my PCs primary screen for a long time...and even looked good with my VGA wonder card. Until I got my first multi-sync (VGA) monitor.
I only had a terminal with a amber CRT. Some kind norwegian tandberg data terminal if I recall correctly.
I still own a 9" amber monitor I bought in the early 80's for one of my Apple II computers. Bought it at Computerland, the long defunct chain of popular computer stores. It's nice to have an NTSC RS-170 monitor around for misc purposes, like displaying the video output on a digital camera.
What a beautiful monitor.
I had a Mitsubishi amber monitor in the 80's and it was brownish too when off. But not as brown as the one you got there. I wouldn't bet on glass color...
amazing you can remember the grade of the color 40 years later
@@cheater00 I do not deserve much credit as we gave the monitor and the 80286 computer to charity around 2005. It was interfacing a MIDI ISA card for our music studio. The amazing part is, everything on it was the original hardware including the 20mb hard-drive. In working condition...
33:37 those copper coils are not exposed; they can't be made out of the bare naked wire because it would short the winding losing the inductance; copper wire for winding has an enameled insulation, which you can only remove by sanding it (and it requires a heavy sanding) or by melting it with a flame (i.e. from a lighter); this is only done at the end tips to connect the coil to circuit.
33:58
Nice get! I've been looking for a PET 4032 composite out board but no one seems to sell them. Have several schematics but all seem for PET 2001 series only. Would like to add a second monitor to my PET for teaching. Thanks for sharing!
In Dave's video he shows how he made one to convert the signal
Sadly the PET 4032 uses 22khz so it's not NTSC compatible. I think a new editor ROM will fix that though -- you can get a patched one to output NTSC. Then you could use this board -- it's a bit low voltage for the 12" CRT but it should still work at 12.5kv.
@@ReinaldoRauch Dave's video is for a PET 200 and doesn't work on the 4000 series PET
When we bought our first home we opened the crawl space when having a home inspection and found someone had thrown a CRT Television down into the crawl space which had broken into pieces. We had to clean it out but it was the first time I had seen the inside of a CRT.
totally love amber screens
As always Sir, excellent video!
Another UA-camr, Joe of Joe's Computer Museum has already built an orange oriented classic Mac using an Amber CRT and a clear Mac Effects case. I've enjoyed this video, now off to watch Dave Plummer's Amber PET video mentioned in the description. I gotta have a dose of 8-bit content!
I look forward to seeing the "Golden Delicious" amber Mac Classic. :D
Odd that an IBM PC with a built-in screen would use NTSC at all, instead of MDA. Maybe it had a built-in composite out for people who wanted to occasionally hook up a TV (similar to how laptops almost all still have a video port), and it was cheaper to include only the NTSC adapter circuitry?
Amazing how many channels I watch have some hardware from Computer Reset In Dallas.
Around '89 I had a client bring in a WYSE terminal that wouldn't work. Applying power produced an ominous hissing. When the back cover was taken off it was all revealed. When the unit was assembled the LV harness and EHT lead managed to press against each other. Over the years the plastic insulation of the LV harness had slowly pressed its way into the EHT lead to the point where both broke down. Let's just say that 13kV into 5 volt TTL circuits doesn't end well.
Oh dear -- I feel like all of these things are on some borrowed time
The brown monitor is basically a black and white monitor in brown color.
This understands neither NTCS nor FBAS. Not even PAL or SECAM.
But the common BAS S/W signal.
With B/W SECAM, the color carrier was switched off and pure B/W was sent.
Al lot of talk on the wire enamel reminds me that I have a story to share. I somewhat recently wanted to do something with my CDi and I usually use it with a beat to hell Trinitron TV I have. When I turned the thing on, there was a ton of arcing. I figured it was at the anode cup, so I cleaned it up and regreased it before reseating it. After what I thought was a thorough visual inspection and cleaning, I turned it on. The was crackling accompanied with a burning smell. The enamel had degraded and caused a short, singeing the deflection coil. The tube still has a sharp and beautiful image, so I'm definitely going to keep it. I'm just no sure if I want to try and redo the enamel or rewind the yoke with fresh magnet wire.
(When I say beat to hell, I mean it. As far as the case goes. It's scuffed, scratched, cracked and has a hole melted through it. The CRT is great and it's a crazy contrast.)
Arcing to/of the deflection yoke can be caused by the missing ground wire on the CRT that Adrian mentioned. The HV return has to go somewhere, and if it can't return through the CRT ground wire it will find the yoke winding instead, causing damage.
maybe it's a contrast-increasing filter like the red filter on 7 segment led modules
Regarding the corrosion on the wires I would assume that it is indeed a surface defect that happened during assembly. You know factory worker wedging on the thing on the tube. I am in my RL an engineering director at a company doing a lot of stuff with electroluminescent lights and had inverters manufactured that had outer windings really cruded (is that a word?) up in corrosion due to sea cargo shipping. After confronting the manufacturer they told us they used a “tool” to act as a spacer between a heatsink and the adjacent transformer. The tool turned out to be a screwdriver and it just chipped away the enamel of the wire. Only solution we had at hand was to desolder the transformers in Germany, completely vacuum pot them and then check for spec adherence in Q, R and L. Just a guess though on how this corrosion might have happened. But you know: there is always this one guy with a screwdriver
Old arcade video game machines used to have strips of coloured cellophane across a white phosphor screen to give the impression of a colour monitor, so it wouldn't surprise me that is just tinted amber. Love glowing green, hate dirty amber - lol -.
I have to chuckle at the HV warnings you give. In the early 1980s, I was in a factory training for a word processor A.B. Dick Magna SL. It was a full page display and required the anode voltage be adjusted to 25kv via a small trim pot. The instructor asked for one of us to adjust it. I volunteered and set it to the 25kv. He thanked me then told us from that point forward to ONLY use the 10 inch fiberglass adjustment tool as the solder trace almost touching the pot had the 25kv on it! I to this day am not sure but I think he was looking for a more dramatic demonstration 😅😅.
It's highly unlikely there would be 25kv on a trimpot, it's likely to be the bottom end of a long chain of resistors of much higher value, if it is in the feedback circuit at all.
PLEASE put this in a classic mac, an SE/30 or something, to contrast the green one you did. I've always wanted to do that.
I have a Zenith Z-160 PC compatible luggable from 1984. It has a 9" amber monitor. I actually pulled it off the shelf yesterday to do an upgrade to it in the next couple of days. When I open it up I'll have to see if the amber monitor uses the same Zenith CRT.
Opened it up this morning. The tube has a different part number, DJ9NK3. It is rated for 13v 1.4amp like the tube in the video. I have the SAMS Computerfacts for this machine and according to it just like the IBM 5155 the monitor is undervolted in the Z-160. In this case 11.8v are provided.
I don't know if you've ever watched implosion videos, but I would not go near a B&W CRT tube without eye safety goggles. Most implosions are caused by failing side walls, not the face plate. The band does not lessen the implosion, it contains it so that glass hunks don't go flying around outward. An uninhibited implosion is like a bomb going off!
lovely display
i need one of these. it would make the perfect fallout monitor for my club
cut safety - touchy touchy = ouchy ouchy 🙂 Excellent Adrian safety warning.
I think you'll find that the blooming is due to insufficient EHT drive. Being a 12V to 12500 volt inverter, the impedance of the transformer's secondary is going to be substantial.
It may also be a Polaroid filter which reduces output, but eliminates reflection of impinging light.
Yeah it's just really curious -- maybe it's just to make it look more amber than it would on its own?
Green is pretty cool. But amber is the nicest in my opinion.
Blooming can be the video driver clipping, for example if its supply voltage is slightly low. It could also be that the beam current is lowish. Possible causes include al low +B (12V instead of 13V), electrolytics that need to be reformed or the CRT cathode that needs to be reactivated (leaving it switched on for some time will do the trick for the electrolytics and the CRT in most cases).
If you were worried about a dead short across the power leads, then test for that first. You have the DMM already out in diode mode, ready to go.
Haha! I was going to recommend re-enameling the wire, but you were ahead of me.
I had an amber CRT by Zenith at my Apple ][, and well, your CRT seems fine regarding brightness.
Phosphor wants to glow green. The only way to get white or amber is to add other chemicals to the phosphor. Which is why green phosphor monitors tend to be the brightest. Plus, even though CRT's are in a vacuum, there are still minute quantities of oxygen, and even vacuum tubes leak an extremely tiny amount.
So a monitor that has sat for a very long time, may be super dim at the start, until you "burn off" the oxygen. And also the reason that the phosphor eventually burns out.
CRT's are fascinating devices, and i like them very much. Even though they are much harder on the eyes than an LCD monitor. I grew up with good old CRT technology. Nostalgia is a thing... ^-^
Yeah the green ones by far seem to have the best longevity and resistance to burn-in, at least from my experience.... and amber is, by far, the worst.
There is a quicker, one handed way to remove the high voltage connection. Just grab the back of the connector and while pressing in, gently push it over to one side to release one of the clips. Then without pressing, gently move it to the other side, and the other clip will release.
I have a Brother Word Processor with one of those Datapoint style wide format "punch card ratio" CRTs. It produces an amber image, but the CRT is indeed a white phosphor CRT using an amber color filter. In this case, the filter is simply a plastic filter in front of the CRT, not integrated. Interestingly, the CPU is a 12 MHz enhanced Z80 clone, and it uses a PLA configured to manage an 820x240 bitmap stored in a 32K Video SRAM. The service manual covers the entire memory and I/O map. Would love to hack it into something else someday.
I'd love to get my hands on one of these I'm building a new dumb terminal and an amber CRT would look amazing as compared to a flat LCD panel.
You mentioned the power supply it was attached before regulation on 12v as the analogue board of the monitor would pollute 12 rail with electrical noise if it was connected down stream.
Nice video! I learned a thing or 2 about crt's now! I have this iMac G3, which is working perfectly fine, the picture is nice and bright, no bleeding or distortion what so ever, but i can hear clicking sometimes, i don't know if it is the connection to the crt or if it is the flyback, but now at least i know i can try to mess with the anode cap to see if it goes away, i will try it later today even, sometimes it doesn't click at all, if it was the flyback, wouldn't it be clicking all the time? Anyhow, very enjoyable video to watch :)
I did take off the anode cap to clean it and there was some black gunk under there, i cleaned the prongs and the connector in the crt and the clicking stopped! The computer works perfectly fine now! I am stunned that this solved my problem!
Nice Monitor I would be fun to find one like that I used to see them forsale some surplus electronics places like old MCM Electronics which is nework sold a lot suplus stuff I once bought like bunch of Bose 6 1/2 nos woofers for like $5.00 each .
I'm going to recommend discharging the crt with a direct short and then perhaps checking it with the meter because you should not ever get any type of shock if it's been discharged properly. If the meter failed it could show 0 volts on an open circuit and you could receive a lethal shock
A direct short can result in the internal connection to the anode button being damaged. Also, through dielectric absorption, voltage up to a few kilovolts may reappear after having momentarily shorted out the tube. Best practice would be to discharge it through an HV probe, and then clip a shorting wire to it during further handling.
@@mjouwbuis fair enough. But I would make sure you do a direct short after discharging before handling as a safety precaution
well that was awesome :) best lunchbreak ever
CRT is a tube - tubes have "heaters" that typically run on 12.6 VAC. Just a guess.
I think we're spoiled by modern (bright) displays. Guessing the display is normal for its day.
Ibm was running the crt module with 12vAC, rectified, that actually ends up being about 15vDC, so that little board in the schematic must be doing more that advertised.
I think that amber monitors, like green monitors are using different phophor compounds. White monitors used on TV sets are using a mix of diferent chemicals and are a mix of blue and yellowish phophors.
Would be pretty awesome to mount something like that right into your bench for testing/running systems. Great vid!
I was at Computer Reset, and there were A LOT of CRTs there. They REALLY wanted people to take them.
Yeah seems that happened in the end, but it look a long time. I think if people realized what they were maybe more would have snapped them up?
@@adriansdigitalbasement2 Possibly. I didn't take any CRTs because they would've been difficult to transport and store. Though, maybe I should've...
I watched the videos Dave Murray put on the 8-bit Guy channel about his adventures with the Apple ][ monitors he got from Computer Reset's storage yard. The main problem he had is he couldn't find any circuit design or hardware manuals for the monitors. There was a specific diode that had mechanically broken down, and he couldn't identify the characteristics of the part. He eventually got a suitable replacement more or less by luck, although you can sometimes get some indication by looking at similar monitors. And that turned out to be all that was really wrong with the monitors that must have been at LEAST 20 years out in the weather, possibly between 30 and 40 years.
Most of these components are fairly generic. There is one high voltage power transistor that is somewhat critical and he high voltage diode stack that is mostly integrated into the flyback transformer. Anybody who can repair old tvs can repair these monitors easily.
Many years ago ,in the Mac plus days ..i had a working Mac plus board and i removed a tiny monitor from an IBM 5100 scientific computer .And i hooked up to the Mac Plus board..And i had the smallest Mac Plus computer on the planet ./.
"Shades of gold displayed naturally"
If you still have this amber Zenith try the UV light trick you showed us-if it’s not purple-maybe it IS some kind of amber coating….
Hi Adrian is was nice meeting you at VCFMW. By any chance do you still have this NOS 5155 Monitor. I am restoring a 5155 and am in need of this. Maybe you know where I can get one. Best, Jon
On the power connector , the purest in me is like "WHAT NO!!??" lol, but I get it. BUT you should get a set of those cylindrical pin extractor tools... you fit them over the pins in that connector and it forces the clips back into the pin, and it can be exracted.
Not sure what diameter those are, amazon has a couple of molex pin extractor tools - I acually have a set of brass tubes, that I just aded an interior chamfered and use.
So good!
Analog phosphor is that a thing?
I actually thought I heard wrong at first, so turned on closed captions and rewinded and yeah you said analog :P
Also would not giving it the proper 13 volts also affect how much brightness it could handle? Would at least think so when a brightener does that to a tired CRT by just giving it more juice.. So maybe this is just a side effect of undervolting it.
Regarding your comment about not finding pickled chips in the USA, over here in Mississippi, we have golden flake pickled chips, fried dill pickle chips, and utz cajun dill tators.
The amber CRT is not bright because the glass faceplate is amber which reduces the light of the P4 phosphor.
I just recovered an IBM 3477 terminal from a recycling center, been left out at least the past week in a good few rain storms. I got it home, it was really dirty inside, I think it had a long running life. I stripped down every component, cleaned off the dirt, made sure there was no corrosion or anything obviously messed up... and.. it works!! (well as far as I can test it), I can't find a keyboard for it :( So I get a keyboard error on the status line.
(If anyone knows if you can adapt a keyboard to that, that'd be great!!)
Ironically, the smaller the CRT, the higher the flyback output will be. 12KV sounds about right for a terminal monitor like that. Killer stuff too. You could have a 40" CRT that only takes 1,000volts to drive, but a rinky dink Sony Watchman pocket TV needed juice north of 10KV to operate.
get yourself a UV flashlight, you can check the monitors for use without powering them up, I can see all the burn in on my kaypro 2x I got, but the green phosphor is so strong in it it doesn't even actually show.
also looks like might have to 3d print bezel adapters for these if the monitor will still fit length wise, its the only solution I can come up with. as for rectification, its not hard to do, a good example is the NES, it will take ac or dc power and rectify it, a simple way would be just drop in a 12v transformer in the pet off the mains switch, not a wall wart you can just get one for a 12v radio should be enough
my kaypro2x has a very distinct green phosphor the 3 crt tv's I own one has a white grey, one has a darker grey and the other is a white grey, the darker grey actually has a better picture then the others
Split the wire carefully then treat the wire then use some uv mask to seal the wires push back into place
The windings were very strongly glued together it seemed, so did not want to move at all
Was there ever a blue monochrome?
amber is cool..so is green and white
but I always wonder 'bout blue!!!...
thats funny. I thought of you when dave did his video..
Yeah I actually recorded this before Dave put out his video, but I was too slow at editing so it came out after LOL
I have this ast monitor from 1993 where its pretty used and blew its fuze.
I replaced the fuse and it works again, just the same as before so.. im not sure what could be wrong XD
All i know is that ive been running it for about a year now with the new fuse and there has been no problems to report.
Could have been extra load from capacitors reforming if it happened after being turned off for a long time. Otherwise fuses can fail too
Heh if you used the same rating, there is no danger really ..... or shouldn't be at least.
so the capasitors "unformed" overnight?