I ruined this Amdek 300A after fixing it

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We have a beautiful condition amber CRT in the basement and this time it turns on but there is no image. Let's figure out what has gone wrong with this to see that glorious amber image.
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Amdek 300A Composite Amber monitor
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1 окт 2024

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Комментарии : 310

@adriansdigitalbasement2 2 года назад

Thanks to viewer Todd, he pointed me to the SAMS schematic for the monitor, and indeed, that diode is just a bog standard 1N4138 part! I wasn't using my head there. Luckily, the 33v will just act as a normal diode in the circuit in this case since the voltages are under 33v. See Diode D101 on the schematic here: archive.org/details/cmt-3-2/page/n1/mode/1up

@dr_jaymz 2 года назад

You said you had another amdek300 so I was confused why you couldn't look at that one or connect it to the crt.

@JoeCdaYT 2 года назад

I was going to recommend that site when I did a quick search, good thing I looked in the comments. Too bad the monitor did not work out 100%. At least you got a good chassis to pit a decent tube into.

@adriansdigitalbasement2 2 года назад

@@dr_jaymz Heh yeah that one is away in storage at the moment -- sometimes stuff is really hard to get to :-)

@adriansdigitalbasement2 2 года назад

@@JoeCdaYT Yep exactly, CRTs wear out, it's just a fact. The other one has a pretty good CRT, so I'll swap the CRT and keep the electronics in case a hard to replace part on the one I keep dies, like the flyback.

@michaelterrell 2 года назад

@@adriansdigitalbasement2 I might be able to come up with a green 12" CRT for you. Do you have the tube number?

@vwestlife 2 года назад

Step away from the rejuvenation button, sir.

@mrnmrn1 2 года назад

No, I use the same tester with good rejuvenation results. The trick is you shouldn't allow it to go through the three automatic cycles. You should turn it off right after the spark show. Also the timing seems to be off on this tester, it feels like the cycles are too long. The timing is done by 555s and the longer timings use electrolytic caps, which are if leaky, can make the timing longer.

@martinda7446 2 года назад

@@mrnmrn1 I watched and thought NO! this was a do or die tester. Mike Tyson of testers

@mrnmrn1 2 года назад

@@martinda7446 Yes, it's do or die, with at least 70% chance to die if you let it go though it's automatic 3 passes. But if you use it with caution, and turn it off right after the sparking stopped, it gives you at least 70% chance that the tube will be better than before, and 90% chance that at least it won't be worse than it was. I even had a good success rate with a real brute-force 'Mike Tyson' rejunetaion method, before I had this tester: 9V transformer on the heaters, 230V mains across the cathode and G1 with a 1N4007 and a 60W bulb in series (40W bulb for smaller tubes). It woke up much more tubes than it killed, usually they lasted a few months or just a few weeks, but sometimes years.

@juliedunken1150 2 года назад

how DARE A GAY COMMENT in Adrians videos

@SFSWales 8 месяцев назад

@@juliedunken1150what are you waffling about, discrimination isn't cool

@FarnhamJ07 2 года назад

After working in a repair shop for a good long while back in the day, I really have to recommend not rejuvenating CRTs unless they're already truly unusable. It was just never intended to be anything more than a short-term temporary fix: the point was to get you through a couple weeks at most, until a new tube could be ordered and installed. Couldn't keep every CRT in stock, let alone cart all of them around in the van! Nowadays it's a not the best idea unless it's already pretty much dead; even when it 'works', it accelerates further degradation by literally vaporizing the emissive coatings.

@LaserFur 2 года назад

We saved some CRT boosters from old sets to use. we would tell the customer that they have months to plan for a new TV. Note: the CRT boosters were different from rejuvinators in that they just increased the filament voltage.

@adriansdigitalbasement2 2 года назад

Indeed -- I wouldn't ever do it on a CRT that's in decent shape, but this one was pretty dim and blooming. It's really hard to show in the camera because the HDR recording and automatic exposure compensation makes it look better than it is. (Plus my basement is pretty dark.) I was 99% sure it wouldn't turn out better anyway with a high likelihood of being worse. Perhaps some CRT testers do a better job but this B&K 490B is simply terrible at it! LOL!

@cheapasstech 2 года назад

You probably need a beltron- yet again those are for the 1960’s sets

@snagrul 2 года назад

What would it take to actually improve a CRT that has reached an almost unusable state? Is it possible to somehow take apart the tube and reapply emissive coatings inside (or otherwise fix things), re-vacuumize and seal it up again?

@cheapasstech 2 года назад

@@snagrul would require some specialist equipment which is no longer made … making a CRT is sadly a one off thing like an incandescent lightbulb

@robinbrowne5419 2 года назад

Seeing that dim amber monitor reminds me of when I was working in an office back in the 80s and the secretary was complaining to the boss that her monitor was too dim. "Look" she was saying "I can hardly see the bold." After fiddling with the knobs for a few minutes the boss finally said "Ok. Order yourself a new monitor." Everybody else chimed in "My monitor is dim too." "And mine too." Supressing a look of exasperation, the boss said "Ok Ok. It's Christmas time. Order yourselves new monitors for Christmas. Get colour ones if you want. But make sure you run it by me before you order them." So we all gathered in the lunch room to choose our new monitors from a catalogue. Upon reviewing our order the boss said "No. You can't get those colour ones. They are way too expensive." Then, pointing at the catalogue, he said "I meant you can get colour green, amber or black and white." :-)

@tiporari 2 года назад

Maybe in the future show a CRT you think is fine next to the "dim" one so we can tell. They always look fine to us on camera.

@adriansdigitalbasement2 2 года назад

Yeah it's really tough to show on camera -- so a comparison is not a bad idea!

@ingmarm8858 2 года назад

Yeah this one looked pretty usable for a non-grayscale application as was typical for these beasts.

@laserhawk64 2 года назад

Tonight on Adrian's Digital Basement... Adrian learns the true meaning of the phrase "the perfect is the enemy of the good" -- and that he very likely has no shared heritage, after all, with Victor Frankenstein. Alternate title: "How to snatch defeat from the jaws of victory".

@minty_Joe 2 года назад

"Quiet, dignity and grace..." ~ I-gore (Young Frankenstein)

@kilwala2242 2 года назад

The brown gunk is likely an ethylene vinyl acetate (EVA) based glue gun adhesive that degraded and produced acetic acid (vinegar) as it decomposed.

@semifavorableuncircle6952 2 года назад

Usually some kind of chlorinated rubber based stuff. Guess what it breaks down into... Its really, really cheap and still used unfortunately because of that.

@mrnmrn1 2 года назад

I have the same CRT tester. You should check the timing components in its rejuv circuit. It's using 555 timers, and I think electrolytics for the timing. So I would say, not just test, replace all the elctrolytics in the timing circuits. It might just apply the rejuvenating current for too long because of a leaky timing cap. Based on my memory from last year, when I was using mine last time, I felt the cycles of yours are too long. Mine is working OK, BUT there's a trick: it goes through 3 cycles of rejuvenation every time you start the rejuventation process. If the first pass gives a nice sparky light show like this one did, I would turn off the tester right after the sparks disappear, and test the emissions. Especially with small CRTs like this. Probably the first pass was successfull, and the two remaining passes ruined the CRT. The bright orange glow after the sparks was the cathode, that was overheated by the 25mA of current the tester was pulling through it. You should have stopped within a second at that point to save the cathode. I have great luck with this rejuvenator saving tired CRTs, since I usually don't let it go through the three automatic cycles.

@cjh0751 2 года назад

This is exactly why i love you longer videos Adrian. Your just tenacious and won't give up and we learn so much from watching you. Great video.

@tarzankom 2 года назад

After nearly 40 years, it's tired and used up. Being in my 40s myself, I find that totally relatable. lol

@bulwinkle 2 года назад

Tarzan, you're just a kid. I'm into my 8th decade.

@bent-jl6rc 2 месяца назад

How are you feeling now ? 2 years younger? 😂

@rabidbigdog 2 года назад

Working with pure-amber or -green displays day-after-day was actually pretty easy on the eye compared to the colour displays that followed.

@russellhltn1396 2 года назад

The idea behind amber monitors was supposedly less eye strain. However the amber phosphor wasn't as efficient, so the drive had to be increased. That accelerated burn-in and shorted tube life. Call me old fashioned, but I like green screens better. I found the amber tended to be a bit fuzzy.

@BG101UK 2 года назад

I tend to agree on that. My eyes certainly respond better in terms of visual acuity with the shorter green and blue wavelengths. Have you ever tried to read stuff under low pressure sodium (SOX) lighting and also (separately) clear mercury vapour? You'll likely see what I mean if you have.

@KenjiUmino 2 года назад

@BG101UK 2 года назад

@@KenjiUmino Same here regarding appearance but since our eyes are less sensitive to those wavelengths it would mean driving the CRT much harder. I think cyan would work well in both respects though.

@gallgreg 2 года назад

Awesome troubleshooting! Sad that you didn't end up getting a good monitor out of it, but an excellent educational video anyway!

@david4368 2 года назад

If it isn't broken, fix it until it is. That's the way it goes sometimes.

@Darxide23 2 года назад

Steve? Is that you?

@treminaorugx 2 года назад

Wake-up period for a CRT can be tens of hours especially if it has cathode poisoning. Best to fully let it wake up before attempting rejuvination.

@titactaco 2 года назад

At about 38:50 you said "That looks like it's actually a zener diode, that's problematic" -- and I was just very curious about the 'why' - I know you can't explain literally everything in every episode, but I'd be curious to understand. Thanks!

@adriansdigitalbasement2 2 года назад

Zener diodes start to conduct at a particular voltage. That voltage can vary from a couple volts to 50, 60 or more. So you have to replace a zener diode with one of the same voltage usually -- but unless you know what that voltage is, you are going to have to guess or reverse engineer the design to figure out what the working voltage is.

@graealex 2 года назад

@@adriansdigitalbasement2 Technically, all diodes start to conduct at a particular (reverse) voltage.

@aziztcf 2 года назад

@@adriansdigitalbasement2 Not to mention the zener voltage, meaning it's not just the diode voltage which lets it pass current one way you have to worry about but the zeners have another voltage that cause them to let it pass the other way too.

@mashrien Год назад

You should've run it through the 50mv cycle as well, if it was already a lost cause then the only way to go is up.

@RealZomBiE8192 2 года назад

I've been working with CRT's sice 90's and my teacher told me that every time CRT sparks, it's 80% of its life gone away.

@Shmbler 2 года назад

That same brown gunk was still used in a 24" LCD monitor built around ~2012. It totally corroded several components on its LED driver board.

@erickvond6825 2 года назад

Something you might consider for future tubes is an inductive getter firing tool. It pulls impurities out of the gas from the tube. This is especially effective if a tube is slightly gassy. Of course of it's leaky it might work for a short time. The sure fire way to tell if a tube needs it is a discoloration of the silver patch that coats a small portion of the inside of the tube. If it's white the tube is usually gassed out. Other colors have other meanings but I'm sure you can look that up. The alternative is that I write the whole manual in the comments and while I'm sure a few people would like that, I don't think you really want a comment that long. Cheers for the great content mate.

@SenileOtaku 2 года назад

This was my first monitor for my Tandy 1000A (I had bought the whole setup used). I eventually ended up slicing the mesh off with a razor blade. Later on I acquired a Tandy CGA monitor to replace it. All of that has been gone for almost 30 years now.

@video99couk 2 года назад

My home-built CRT reactivator has never destroyed a tube, though I always quoted a 10% failure rate to people just so they were prepared for the worst. It's a slightly improved version of a design published in "Television" magazine in the 1980s. It looks like your Konig one may have a fault.

@mrnmrn1 2 года назад

Yes, the cycles seem to be too long. I have the same tester, I use it for rejuvenation with good results. The main problem with it is the three automatic cycles. If it sparks like crazy at the first pass, it should be switched off, otherwise it kills the cathode during the next two passes. Probably that's exactly what happened here. After the light show, the CRT was happy, but it got ruined by the remaining two and a half cycles.

@martinda7446 2 года назад

Re rejuvenation. Some are saying it's only temporary etc. Yes the idea was get some more life before replacement. But, the facts are this is a poorly understood science.Results will be variable is about all you can say. I've rejuvenated some tubes that continued to give superb results for years after and others that simply do not respond at all. That is a big range and the only useful thing that you can get from it is try and see. Some tubes are well known for being tricky and unsuitable for regen, but as I say try and see. Fingers crossed.

@valliantsteed 2 года назад

I did learn TV repair in the late 1990/ early 2000s. The way we did it with a similar König Tool was never use the auto rejuvination, give it short burst with the manual trigger and knock the crt's neck near the heating filament with the back of a screw driver (not to hard of course)

@aziztcf 2 года назад

I'm liking this idea. Guess the auto rejuv doesn't take it into account that it's working with decades old tubes!

@horusfalcon 2 года назад

Yeah... "brown gunk" was, in some cases, applied at the factory, and was used because it was expected to exceed the service lifetime of the equipment. Later equipment used either low acid RTV, epoxy, or something like Glyptal to dope down components. I'm wondering if the brown stuff is a form of hide glue? I've never seen any CRT rejuvenators that actually worked for more than a few weeks. I'm confirmed in the opinion that "rejuvenation" might be nice for a little while, but leads finally to equipment failure. I would love to see a "new" (or at least "newer") CRT put in this old classic.

@garthhowe297 2 года назад

I really like all of your videos, but this one was exceptional. I have a number of CRT monitors, so I am very interesting in following your troubleshooting. Great video. I'm curious, are you able to lock your camera exposure to the normal room lighting, and then show the CRT you are working on?

@MyCrazyGarage 2 года назад

I think that crt tester is broken, the rejuvenation feels waaaay to long compared to others (less than 3 seconds).

@adriansdigitalbasement2 2 года назад

It's the BK Precision 490B and reading the manual, it is working "As designed." It's using 555 timers to run the process supposedly automatically .... I had an old B&K from the 60s (a 460 I think) and it was 100% manual but also almost always made CRTs worse in the same way.

@MyCrazyGarage 2 года назад

@@adriansdigitalbasement2 Oh interesting, didnt realize that it is a "smart" one. Just thought the internal timer broke and went from 2 seconds to 30 seconds non-stop rejuvination.

@kaitlyn__L 2 года назад

@@MyCrazyGarage it’s a pretty fascinating microcontrolled (IIRC) unit from the early 90s! I’d definitely recommend checking out Adrian’s video from about a year ago when he got it (though alas I don’t recall if the title specifically calls-out the new tester, or if he simply circumstantially shows the new unit in one of the CRT videos).

@graealex 2 года назад

@@kaitlyn__L Yes, it takes its sweet time and uses advanced micro-electronics to fuck up CRTs, instead of doing so in only a few seconds.

@kissingfrogs 2 года назад

watched it twice. Awesome tutorial on crt. Thank you so much for sharing. I have tinkered with these but you have well demystified so much for me

@randyab9go188 2 года назад

I have a Sencore 7000 and it is the absolute best at rejuvenation. It goes all the way from a gentle cleaning up to a full rejuvenation. I have had dead emission tubes restored to a very useable state and weak to like new and it held. If you can find one working for a reasonable price get it. p.s. the Sencore has a setting to draw 1 ma as a very light restore. Works wonders.

@TheSimTetuChannel 2 года назад

Great Scott! After all this time I finally realized your EEV Blog multimeter is the 1.21 GigaWatts model!

@NEEC1 2 года назад

I believe the camera showing the CRT as brighter than it is, is because of the reduced dynamic range of the camera, being less than the human eye. Dim things look brighter basically.. You'd have to be shooting in S-log or something to get a real representation of the dynamic range. Probably not worth it!. Seems like the 'rejuvenation' process is really hit and miss. More miss than hit!.

@NEEC1 2 года назад

PS. sometimes using a small rubber hammer or end of screwdriver lightly tapping the neck can help. Just enough to shake up the gun.

@NEEC1 2 года назад

PS number 2.. I once saw a technician take off the anode cap and with the CRT base disconnected, run the anode cap around the CRT pins. Causing some sparking.. It worked!. Picture got better. I've never tried this personally but thats what he did.

@radio-ged4626 2 года назад

I wouldn't feel bad about the rejuvinator fail. Even when it does work, many times the tube will start to look bad again a few days later. Most of the time those rejuvinators were used as a temporary fix while the engineer ordered in a replacement tube.

@TBMartin 2 года назад

I know you said in the video that we have probably seen this Amdek 300A before but honestly its the first time I have ever seen one and i was born in 1979 (UK). Great video as always and thank you.

@Potts1966 2 года назад

Nice video, enjoyed the process of trouble shooting, even if the outcome wasn't what you wanted.

@osgeld 2 года назад

dunno if I commented this in your other video's but whenever I saw one of the screens with a mesh glare filter they always seem to have a "pantyhosse run" like down the middle, guess it makes since since the fashion of the day was big hair, shoulder pads and wolverine nails

@kaitlyn__L 2 года назад

“Wolverine nails”, that’s hilarious. (And I say that as someone with just such nails….. no falsies here!)

@Choralone422 2 года назад

I would echo the other comments about not trying to rejuvenate a CRT unless it's already basically unusable. IMO that process has far to high of a failure rate to use on CRT that is still marginal. And the brown goop strikes again! I wonder how many devices that stuff has claimed the life of over the years! I'm sure it's an obscene number.

@fumthings 2 года назад

hi Adrian. when it is not sharp like that, is there a focus control? (possibly on the flyback). does it help?

@eDoc2020 2 года назад

When only bright parts of the image are unsharp it's not a focus problem.

@fumthings 2 года назад

@@eDoc2020 ok, good to know.

@ThomasTalbotMD 2 года назад

I used to have an Amdek 300A as a secondary monitor - amber. Nice details, terrible grayscale contrast

@treminaorugx 2 года назад

Why waste the time and risk rigging up a bunch of alligator clips and a pot to the CRT cathode driver pin before just testing it for shorts, emissions and cutoff with a CRT tester? Risks like that with vintage electronics are not worth taking when you have the proper tools available. Since you got a raster by the end of this it demonstrates the pot setup wasn't even working properly. One of the repair rules is keep it simple stupid. Best to eliminate any chance of your test method being the reason for failure.

@twocvbloke 2 года назад

As for CRT rejuvination, it's possible the newer tool may have faults of its' own, causing it to over-do the process of "rejuvination" ending up with it wrecking the guns rather than cleaning them off, but that's just me purely clutching at straws, could be perfectly fine and the CRT was just on its' last legs anyway...

@8-bitbitsa821 2 года назад

Schematics and a Sam’s Service Manual is available for this monitor, no problem. I was excited to see at first as I thought you were doing the 310 version(I have a faulty one here). For the other Amdek 310 monitor version (with the 9pin input) nothing I can find ! The boards are completely different for the 300 and 310 models, sadly 🤷🏻‍♂️

@gabrielebiffi9018 2 года назад

I watched this video for 5 mins, wondering why he's talking about a monitor, before realizing the title said "Amdek 300A" instead of "Amiga 3000"...

@Ramdileo_sys 2 года назад

pity it was a nice looking monitor 😟.... "I spy.. I spy with my little eye"🧐... a future CRT swap? 🙂

@StevenSmyth 2 года назад

Amdek 300 is the first thing listed on a SAMS search. So schematic and parts list at least.

@Nas_Atlas 2 года назад

Amazing fix but we've had enough of the bug zapper. There's not a single 300a for sale on ebay. These things are getting rare!.

@BM-jy6cb 2 года назад

I hate to sound like a know-it-all RU-vid commenter, but jeez Adrian, you need to follow some basic safety techniques when messing around with a live CRT chassis - specifically not having one hand on a grounded strap while prodding around with the other! I enjoy your content - it would be shame to cut it short.

@KHzSineWave 2 года назад

Fix it 'till it's broken! jk, nice work, shame about the weak CRT, that brown glue is nasty stuff, it's called Sony bond, when it was new it would be a yellowish clear colour but over time it brakes down and becomes not only corrosive but conductive too, causes all kinds of issues, they used it a lot on stereo equipment from the 70s and 80s.

@enoz.j3506 2 года назад

As you say ,that brown goop goes conductive over time,also corrodes tracks and components.This goop was used on many,many electronic parts.As a retired engineer what we used to do in the 80's with soft tubes ( bad focus etc), was to increece the filiment voltage,this improoved the electron flow to the screen,you dont need much increece,millivolts infact,now obviously the filiment would have a reduced life,but we never had any come back with failure,many a 20"plus tube was done this way,and the results were positive.This wasnt an option on some tubes, just depends on the filiment voltage circuit,many were just a resistor reduction Good channel,Thank you Adrian.

@WinrichNaujoks 2 года назад

On balance, how many CRTs has the rejuvenator rejuvenated, and how many has it destroyed?🤣

@floooogy 2 месяца назад

Did you discharge the Kathode in 6:20 with that measurement of the high voltage? I may triy also to repair a CRT,but I 'm a beginner and afraid of the high voltage.

@tony359 2 года назад

Nice video, I enjoyed the troubleshooting journey! Looking at the title I was expecting a short or some sort of some physical damage but no, fireworks ruined it! :) (Nice to watch though!)

@martinda7446 2 года назад

..Also CRT testers vary in their performance with rejuvenation. I just watched it with my mouth open. This Konig I am not familiar with, but I was thinking WTF! as it set off. That is a fierce do or die setting with very little user control. I do not like it. As soon as it started I knew that gun would likely fail. Always start with a little coaxing and save the 'do or die' for just that when it's so far gone it's a last resort. Yeah, that is a last resort machine.

@eeveegamig Год назад

I have a Nintendo wii from 2009 that sometimes crashes during games. Boy I loved that thing.

@tenminutetokyo2643 2 года назад

The Sanyo cube monitors were all the rage for Apple II back in the day. The tiny security type monitors.

@markitzero12 2 года назад

As someone mention is that rejuvenating is Temporary and from what I learned from shango066 that there are some monitors you can't do rejuvenation on like for example Sony Trinitrons because it will just grenade it.

@Sobakin76 2 года назад

Looks like it's just freewheeling diode like 1n4148 and not a zener.

@gordonwelcher9598 2 года назад

The rejuvination cycle ran for too long. I used to zap them for a second or two on manual cycle. The flash was all the cathode material burning away. Next time just give it a bit on manual cycle.

@dosdoktor 2 месяца назад

The problem is that you welded the filament to the cathode's case. This kind of tube wants to be held top-down while rejuvenating so the filament can hang free.

@jk180 2 года назад

Adrian, go check out the TV Museum youtube channel. It may be worth a visit to see what they could do with a rare old CRT. It could be a cool crossover video.

@asherael 2 года назад

the spectrum analizer is just showing you the audio spectrum of the monitor running?

@EyeOfAllah Год назад

Do you ever use decontamination methods after working on Cathode Tube Monitors?

@BG101UK 2 года назад

I don't know if you watch shango066's videos but he does say that rejuvination attempts are usually a waste of effort on really worn-out CRTs and even if it does work, it usually doesn't for long. It might work on CRTs which have just "gone to sleep" after a long period of storage, I think.

@michaelterrell 2 года назад

The CRTs last longer when powered by AC. A school system bought about 100 Channel Master TVs that had series filaments. Within two years, the CRTS all started to fail. The so called engineer had a total of 85 volts in the series string, so he used a 'Diode Dropper' to only apply one half of each cycle to the filaments, cutting their dissipation in half. (120 VAC x .707 = 84.84 effective voltage) I added filament transformers and let them burn in for a few hours with a CRT brighter, then removed the brighter., then returned them to the schools. This effect is known as Cathode poisoning..You can have the same effect from keeping the filaments hot, with no B+ for a long time. I changed my first CRT in the mid '60s at 13, and I was a Broadcast Engineer less than 10 years later. Most younger techs haven't worked enough with tubes to understand them properly.

@eDoc2020 2 года назад

@@michaelterrell I'm not saying it isn't true but I don't see how running the filament on AC vs DC would have any effect on the cathode emissions. On normal CRTs the two are electrically isolated. It might have an effect on directly heated cathodes like transmitter tubes though.

@michaelterrell 2 года назад

@@eDoc2020 Believe what you want. I've seen it first hand in hundreds of poorly designed TVs. Many monitors use a winding on the flyback to power the CRT, instead of readily available 12VDC.

@BG101UK 2 года назад

@@michaelterrell "Most younger techs haven't worked enough with tubes to understand them properly." Unfortunately this is also true of me, All my formal "education" was about solid state stuff and so was my time in the TV service trade; my only experience with valves (tubes) is with my hobby at home restoring and using vintage tellies.

@michaelterrell 2 года назад

@@BG101UK It was definitely a different mindset. Tube circuits were simple, compared to today's electronics. Early radios used 50% tolerance resistors, and 20% tolerance on wound paper capacitors. Resistors were made, then test before having the color bands hand painted on them. I often hear complaints, 'Every resistor was out of tolerance' from people who insist that 20% was the lowest grade ever produced.. They were the E3 class, and we are up to E192 for some resistors. Gain in tubes varied quite a bit, as well. The old Radiotron handbooks were an in depth reference on early electronics. The third and fourth editions are available online as free scans. ere is a detailed description of the various resistor E series: en.wikipedia.org/wiki/E_series_of_preferred_numbers

@danielk2112 2 года назад

With those Konig rejuvenators only 1-2 seconds of needle deflection on rejuvenate on a mono CRT then turn it off else you will strip the gun bare

@paveljelinek772 2 года назад

Do not worry about zener voltage.. no matter at all because it is reverse voltage, meaning if reverse voltage goes higher than it's rate, POP! If lower, good, it has to be lower

@terryraymond7984 2 года назад

Adrian we all make mistakes. :-) Reguarding installing the diode backwards

@weazeldark3983 2 года назад

I think you need to learn how crts work in depth and how the tube is built U can't just use a rejuvenation unit to fix have to know how it works and what to do Don't scrap the tube u can cut off the neck and rebuild the gun and reseal it If future out exactly how works and wat causes failure u might be able to fix it externally like using induction cook to redo the ray gun and use getter leftover and maybe use laser to clean etc But isn't as hard as would seem cut gun off neck rebuild it and reseal Use to be done back in heyday

@organiccold 2 года назад

Ou well, you win some and you lose some. Looks like you took the advice and started using a mirror.

@terryraymond7984 2 года назад

Hey this is very interesting Adrian you really know youre stuff with monitors

@garyjohnson4608 2 года назад

Looks like this poor old monitor is just about dead. Maybe you should just scrap it for parts ?

@Arcadenut1 2 года назад

I really like my B&K 467 Rejuvenator. It has a "Clean" option which is less aggressive than the "Rejuvenate" option. I've seen some stubborn tubes that after a rejuve weren't any better (or worse), but after they were transported somewhere they started working. I'm guessing that the tube was vibrated and possibly shook something loose that was causing a problem with the guns in the CRT. An excellent resource for tube information is also here: tubular.atomized.org/

@jk180 2 года назад

Hit it with more voltage ;) Let's see if we can kill it further

@maxtornogood 2 года назад

Ouch, that so called rejuvenation was just the death knell! 😕

@paulschmidt7473 2 года назад

I think the real fix for these, is to have the actual CRT refurbished. Might be expensive though......

@Knaeckebrotsaege 2 года назад

No one rebuilds CRTs anymore. Another channel I used to watch (bandersentv) used to send off CRTs from 40s TVs to be rebuilt with a new gun, but the company doing that stopped doing so in 2013 or so and they were the last one around in the US

@RixtronixLAB 2 года назад

Nice video, thanks for sharing, like it :)

@ceasecommed 2 года назад

Used to hook vcrs to composite monitors back in the 80s in middle school

@Darxide23 2 года назад

It might not necessarily be the rejuvenator's fault. The way those things work is by providing a very powerful positive charge to the cathode of the CRT to literally blast away any oxidation. Applying these kinds of charges is risky and can cause catastrophic damage. And even when they do work, they cause some amount of damage anyway and shorten the life of something that's already one foot in the grave. They're not meant for anything but a short term fix. In the best case scenarios you'll get a few more months of regular use out of a CRT that would otherwise be too tired to be usable. It's really a last ditch effort. It's like giving dying grandpa a shot of morphine and adrenaline so he can have another nice day at the park before kicking the bucket.

@mrnmrn1 2 года назад

It really depends on the tube. Before I had a CRT tester, I rejuvenated tubes with a 1N4007 diode, a 9V mains transformer, and a 60W bulb in series with the 230V mains, and that across the cathode and G1. It produced the same light show as Adrian's tester at the beginning. Not many tubes died, almost all of them was improved for at least a short time (weeks or a few months), and some of them lasted really long. Like our 22" Chechoslovakian TESLA color tube (Toshiba licence), the emissions were OK-ish (by eye, it wasn't very dim), but the convergence and focus was horrible in the corners. I hit it with the 60W bulb method, and it was used for about 2 more years with great picture, about 12 hours a day! The flyback died before the rejuvenated tube. I still have that tube, last time it was used in an other set for testing it still had good picture (that was around 2006-2008...). Now I have the same tester as Adrian's, and it can be used for rejuvenation with great success, as long as you don't allow it to go through all three passes. I always turn it off after the sparking tamed down, and test for emissions. Sometimes it needs a second pass, but almost never a third one like it would do automatically. If you let it go through two more passes after the tube sparked, it kills the tube. That was happened here almost surely, the tube was good after it sparked, than the two remaining cycles killed it. Also it seems to me that Adrian's has some timing issues, the cycles feel to long. It uses 555 timers with electrolytics for the longer timings, so it's entirely possible that some timing capacitor gone leaky and made the corresponding timing longer.

@RealZomBiE8192 2 года назад

Actually, you can get 100's to 1000's of hours life out of those tubes if you learn how those do actually age. What you have should done: Put it in an oven and put a negative charge over grids and anode tied less than 8kV below ground.

@RealZomBiE8192 2 года назад

Aka migrate crap from cathodes SLOWLY to anode, which doesn't hurt that much. Oven about 270 Celsius "anodes" including filaments -350V.

@gotj Год назад

Tuen off the lights and (in the dark) look at the filament.

@aeboni 2 года назад

Honestly, it sucks that CRTs aren't being made anymore. All CRTs will die eventually, we need some company to start producing CRTs again.

@aeboni 2 года назад

Companies could also definitely try to see if higher resolutions and quality are possible using CRT technology

@thomasandrews9355 2 года назад

@@aeboni never going to happen. too much environmental concerns and cost of shipping, they'd cost thousands. This has been discussed to death

@daylightanimation 2 года назад

@@thomasandrews9355 what's funny , modern tech production is much worse for environment because of its atrociously growing numbers, but everybody is "nah, that's okay"

@Breakfast_of_Champions 2 года назад

@@thomasandrews9355 I can't imagine eg. Sony taking up production of current tech, quality CRTs would be a failure. Not mass market, but as a niche product with definite demand.

@Quickened1 2 года назад

@@daylightanimation just imagine if they still made the old tech in the numbers they're making the new tech in!

@andic6676 2 года назад

Rejuvenation of CRTs is the very last resort.

@gotj Год назад

That's a really beautiful monitor.

@FightingForceSoulless 2 года назад

It's a shame, it was an interesting journey, looking for the problem, and everything looking good, and one simple seemingly insignificant diode being the problem, and you nearly had it. But I think there really needs to be a change, this rejuvenation, while it is entertaining, it looks like it's doing more harm than good. Maybe it's not all rejuvenators, but with this one, you seem to be having no luck at all. Also, it really isn't a permanent fix, not even like retrobrite, you do this, and 3 weeks later, you're back to square one, except the tube is even more worn out and will wear faster, so, it's probably time to put this concept to rest. OR, use it specifically for completely dead tubes like this one was AFTER the rejuvenation, for fun and experiments and such.

@tigheklory 2 года назад

I have a Heathkit rejuvenator and it works great. I always do a clean before doing a rejuvenation. Usually a clean will do the job.

@quayzar1 2 года назад

Great diagnostic work here but too bad about the tube. Incidentally when I've rejuvenated crts successfully I didn't get that sparking but more of a brighter glow. I suspect that KONG while perhaps okay at testing shouldn't be used for rejuvenation. Also it looks a lot like a B&K Precision 490B. Is it a knock off?

@maxheadrom3088 2 года назад

SIr, that yellow stick is too short. I remember my dad showing us high voltage sparks by just getting a long screwdriver near it. It was an old tube Philips very large (for the time) and faulty TV but, well, high voltage is a killer beast. Thanks for the troubleshooting! I have two color Apple IIgs monitors and one is not working while the other has issues and your troubleshooting will be helpful! I got info from a guy called Mr.Joooooohny (nor sure how many letters - really nice channel that I'm not sure still exists) who told me "if the filament is lighting, your tube is ok or fixable". Very nice guy from Eastern Europe, btw!

@terryraymond7984 2 года назад

The heater tube is not litup though looks dead on there

@channelsixtysix066 2 года назад

The CRT ended up being a dejuvination.

@Dorff_Meister 2 года назад

Some time into it, do you PREFER the Hantek $60 PC scope or the $125 stand-alone?

@aziztcf 2 года назад

Could the diode be there for back emf? Now I'm wondering if the 30 odd ohms I see on my laptop mb could be a failed diode instead of a cap. Hmmh, gotta build that kelvin probe for my DE5K

@stephenoflaherty5656 2 года назад

Brown gunk ate away inductor leg on quite recent LCD TV. Didn't have replacement so unwound inductor to extent leg so could solder back in🤔. Worked 👍

@twocvbloke 2 года назад

The brown gunk is just evil stuff, causes annoying faults at best, ruins everything at worst, nasty nasty goo... :S

@evileyeball 2 года назад

Hey Adrian, Where do you commonly get your supplies of Deoxit? I have never bought any before but have some very scratchy pots on my stereo I want to clean with it. I'm in Canada if that makes a difference.

@evensgrey 2 года назад

Always seems to be the blood diodes in these old monitors. You're lucky you've got any readable markings on it. The 8-Bit Guy fixed some monitors that had been stored outdoors for a few decades a while back (fortunately this was in Dallas, TX, so they didn't spend all that time wet) and his monitors didn't work properly because each had a critical diode that had disintegrated and was completely unreadable before it fell apart.

@jabbawok944 2 года назад

I just repaired my set of active speakers, where the fault was a bad zener. It got hot and eventually went short. It was part of a circuit that split 24V in to +12V 0V and -12V.

@pawspaws101 2 года назад

Worked as Electronics Tech back in the day, and the CRT Tube Rejuvenation was over in the factory. Not sure why I didn't go over there more to see what they did. But it all look like Voodo Magic to me back then! I stuck to TTL and Digital from that time on! Glad I did!

@rickhunt3183 2 года назад

I was rocking an amdek ttl amber screen

@jimsteele9261 2 года назад

I had an Amdek Color 300 on my Atari 800. It replaced the surplus Magnavox monitor I pulled out of a scrapped terminal.

@EngineeringVignettes 2 года назад

I got the inside scoop that you are going to be a special guest star this Friday on a show hosted by a guy with a very special history. :D Looking forward to watching that! I hope it goes well. Cheers,

@RaleighLittles Год назад

Who else is here from Se7en?

@Nabraska49 2 года назад

That was awesome that you could find that one little component that stopped the whole show and yeah after watching your rejuvenation doo hicky thing bust up all your tubes .. I get nervous every time you bust it out ..