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Time to drop everything I am doing! Carlson is in the house!

Had one of your mystery tubes when I was a kid - 70 years ago -- was mounted on a Bakelite chassis in an octal socket along with a vacuum tube of some kind and a relay. Mystery tube had a :"plastic": dome over it and a light tube. Shine a light on the tube, set the sensitivity control just right and the relay would close. Could use it when a parent was sneaking up on me and would break the light beam and a bell would ring warning me to put my comic book down and pretend to be sleeping. Thanks for the memory.

Early flux capacitor prototype. I had one in my Delorean.

J. Millen Co. mini oscilloscope, was made to fit in the place of an S-meter on a communications receiver. Millen was a legend in radio engineering, and designed some of the best equipment for National Radio Co. including the SW-3, SW-5, HRO, and NC-100 series

Millen 1 inch oscilloscope used one in my ham shack 50 yrs ago ,love your website, thanks

It’s a transtator, the basic building block for all federation technology.

I love, love, love the way you bring ancient electronics back to life, and into modern context. You sure find some interesting pieces! 😁

Watching your videos makes everyday life a bit more bearable! To me it's my "Bob Ross" moment, listening to your explanations of awesome stuff i've never seen before. Thanks for all those hours of fantastic video material, showing us the joy of electronics!

Many moons ago I used the same crt in a homebrew modulation meter, wish I still had it. Circuit came from an RSGB Handbook. Love the LIssajous trace.

No idea what that device is but I do know what the best electronics channel is! Just love your output and you always leaving us wanting more!!

When I worked in radio we had an old old old mixer desk. It had one of those on it, to show the sound (not the typical waves you see today, but stereo, with a center dot, showing sound from the center and out, depending on stereo/loudness/etc).

The moment I saw that little tube face sticking out it made me think of my portable Cossor 1039M that I’m currently restoring. And what did you do - pull out a Cossor tube. Made my afternoon that did!

You’re videos has such great audio Mr. Carlson. Very impressed by the quality of the sound and of course great lighting to really see what you’re working on , thumbs up!

I recently found this channel and have been blown away by the level of information you provide! Seeing how old electronics work has been a great experience!

Very cool! I love this channel, because I learn things I didn't even know I didn't know.

I used to see ads for this little device in 1950s QST magazine. I believe it was made by Millen. It's a tiny oscilloscope with a one-inch CRT and circuits for focus and brightness. It needs a power-supply and sweep, deflection circuits.

Always happy to see a new video from Carlson lab

Raise your hand if you ran around the house with a flashlight shining it at all your flickering power strip lamps! *raises hand*

Very nice little o'scope. Thanks for sharing, Mr Carlson :-) Years ago I built one from scratch as part of a homebrew tube-type 40 meter AM/CW transmitter/receiver rig and I connected the horizontal plates to the filament supply to get the horizontal sweep and connected a slug-tuned coil and capacitor tuned-circuit that would resonate in the 40 meter band (7-7.3 mHz) across the vertical plates and the thing worked nicely for adjusting the modulation on AM and monitoring the keying on CW. To couple the 7 meg RF into the coil I wrapped a couple turns of insulated hookup wire around the body of the coil-form in phase with the 7 meg coil and connected one side of that link to ground and the other side was placed nearby the transmitter section's output tank coil.

Must have been fun designing new tubes back then. I do remember a drawing of a similar looking photocell from a Philips book for automatic doors!

Gotta love 50's electronic test equipment, thanks for sharing Mr. Carlson.

You are the Carl Sagan of electronic repair, captivating absolutely love your videos please keep them coming

Your videos are so well done. The best on KZfaq.

Wonderful! Looking forward to the project to use that little CRT =D

You are an awesome teacher and you really know your stuff. Thank You, Mr. Carlson!

Interesting video, Yes I did learn something from you today. I will look forward to your next video. Thank you.

I like that little device. I think that's nice for display in your curve tracer project. Thanks

I do love the mini CRT what a treat. You have come up with some of neatest stuff. Your trivia question device looks like a high power arc lamp. So it will be fun to see what it actually is. Thanks as always. I love the videos...Vic

That's just bad-ass. I love the old tube stuff. NO idea what the device is for the trivia. Cheers! Chris - NI7I

Oh, that thing is adorable! Thanks for the video, Mr. Carlson!

Woo hoo! Millen 90901 mini oscilloscope unit! Saw it in the radio amateur's handbook when I was 11. Nerd porn at its finest! I've got one of those now too!! Highly collectible. Hooked mine to a scope clock board. Thought I posted a video?? Guess not. The center of the screen is dim because of sine wave scanning. It is causing a form of velocity modulation.

First thing I thought was the tuning scope for RTTY demodulator.

Wow, I haven't seen a setup like that since I was a kid in the '60s. I had 2 friends who's fathers had shops like yours, but they were never interested in any of it. They became my foster-fathers due to my own dad shunning me from birth. They were both kind and patient with me and got a kick out of my enthusiasm and I learn a lot. One gave me a military emergency 2-way radio that was the size of 2/3 carton of cigarettes with rabbit-ear collapsible antenna that formed 2 "Ts". I managed to hook it up and when I hit the transmit button the TV went berserk. I called a friend 1/4 mile away and he said his was doing the same. I subbed your channel and look forward to more

Photocell tube was the first thought on the mystery gizmo. Great to see a young feller so well versed in the old craft.

You had me guessing! Thanks Carlson for an always interesting vid!

Very nice video! I haven't seen your channel before.

damn I expected a hologram of princess Lea to appear.. asking Mr Carlson to save her...

Done with work...straight to Mr. C’s lab!

When I saw it, I knew what it was. Smallest oscilloscope I have ever seen. 1950's pocket version. I'm impressed that it fired up. You find the most interesting electronic equipment, I never find the cool stuff here in AZ.

Thanks Paul! Cool little CRT! I guessed wrong the last time and would guess wrong on this one.

And again a very interesting video. Beautiful old device! Thanks, greetings from the Netherlands 🇳🇱! 🤗🤗🤗

Best trivia quote ever. "If this is too easy,, they can get a lot harder. I have some very strange devices"

I think the 1-52 RCA is a phototube/ gas photocell, used in old proyectors to make the soundtrack for proyected films. Works like a IR encoder today.

Just tried the neon indicator + flashlight thing and yup, it works! Cool stuff!

this "trivia" was all new for me. again, best thanks!!!!

That little Millen scope looked familiar. They used to show that device in their ads in QST in the 50’s. As for the challenge question, I think it’s some type of phototube, possibly infrared. It would conduct if it was receiving light waves. They were used for door alarms etc before photocells.

It reminds me of a device I saw in a "quad" receiver that thought was really neat. It displayed merely a dot, but as you adjusted the volume of each speaker, the dot moved to roughly demonstrate where the audio "center" of the room would be.

That 1cp1 brought back memories. It was used in a Technical Materials Corporation 10kw Navy shore transmitter for syncing the oscillator.

My college roommate found a pair of similar devices in flee market. A way cool device you set on top of your left and right stereo speakers, connected to each speaker you could "watch" the music... Had setting on in my speakers for several years in the early 1980s...way cool and fun.

Must be a a phototube and if it's from RCA it must be a a 9xx series. I've seen tubes like that in movie cinema projectors for audio and projector switch mark circuits. Nice greets from Germany🙂👋

I wouldn't guess without the others' comments :) Interesting trivia question! Thanks a ton! 👍

I built one of those small displays into my 500 watt WRL transmitter as a modulation monitor. It worked very well. I really enjoyed seeing one of them again.

That is an old side viewing argon gas photo tube. It's used in a circuit for a relay type application. 2 of the pins are connected to both caps. Great video.

I say its a photo tube and I've seen them used in assembly line sensors, (as part of a counter) "magic beam" sensors (used in alarms and door beams) and supermarket scanners.

i have an old alarm clock from the 70s that used to have that problem with the neon bulb light for the clock and that photoelectric effect thing is really cool to see

That was very interesting, I had no idea that this kind of displays was made.

Nice. I love that little scope. It would make for a small handy little modulation monitor for a ham radio station, particularly if you're running on AM and need to check for\ overmodulation, clipping, asymmetrical peak limiting, etc.

Thanx, i was going to say crt and even modulation display. That's one thing that I'm good at is guessing what high tech stuff is. It was a newly posted video but then you went ahead and spilled the beans.

very good video thank you from Gary in the UK.

I have one of those tubes + the magnetic shield. It was for a mini-oscilloscope project that was featured once upon a time in Radio Electronics (I think) from the '60s. The other tubes used, were 12AX7's. It was a great project, although the CRT display is only 1 inch! I may still have the actual article.

Very interesting, great video. Thanks for sharing Paul!

At about 17 minutes, the description of the photoelectric effect being used to initiate conduction in a tube... yeah, it blew my mind. I've seen a neon lamp that would only work when externally illuminated by light of sufficient energy, and have lost most of my hair trying to figure out how to make proper use of the effect. Thanks to your discourse, I still have enough hair to comb over. Thanks for all the great videos.

Excellent vid once again Paul... 10/10

Oh! I have one of those as well I found in a dumpster. Thanks for the info!

How does Mr. Carlson's lab not have a million subscribers yet?

When you got that Lissajous pattern on the CRT I was reminded of an old TV show where they control the vertical and they control the horizontal. Aah, flashbacks!

Yup what WB3BJU said below, I had one around here in my tube junk boxes. They were used in sound projectors with a focused beam of light on it for the sound track of 16 mm or other film sizes and code tape machines for teaching Morse code and I am sure other things that used modulated light. Happy Spring Paul, KØOJ

Although often larger, that little CRT could be used as a goniometer, an audio phase meter scope, essentially just an X-Y mode oscilloscope. They would display a Lissajous pattern showing stereo (or multi-channel) content and could alert one to unwanted phase errors. They generally reduce brightness to zero when input is below a low threshold to save display life and prevent burn in. These are commonplace in the recording and audio production industries and were used well in to the 1990s. Today it's done in software. SAE included a scope about this small on their Mk6 FM tuner.

I have a 1936 Stromberg Carlson console radio I inherited from my Great-Grandfather. It needs a full-on restoration. Would love to send it to you and have the pleasure of watching a KZfaq video of it's restoration and modernization to make it even more practical and safe to use today!

I never owned one, but I saw many trapezoidal patterns on these in ham radio publications in the 1960s. If I had one today, I might tend to use it for displaying stereo audio, a great tool for determining channel correlation, or lack thereof.

Love your videos man so much knowledge to share thank you!

one of the first things that came to my mind when you described it was it could be used as a tool to determine unknown frequencies and phase shifts if used to view lissajous patterns. I'm surprised you didn't mention that when you up the first pattern.

Another note about loctal based tubes. Many times you'll find them squeezed in fairly tight spaces and you can't get your fingers on them to pull them out. The correct way is look for the little dimple on the side of the metal base and push the tube at the top in the direction of the bump. This releases the lock and when you quit pushing the tube will basically just fall out. Of course with this little scope you can't do that but I noticed the base of the tube does have the little bump. I learned this the hard way on the radio in my 1948 Dodge...

The mystery device is a flux capacitor used in time travel. Thanks Paul. Thanks for taking us way back when.

Still have a tiny crt from a viewfinder lying around, sadly it uses magnetic instead of electrostatic deflection. I still plan on turning it into a tiny analog scope just as a project. Fun things to play around with!! This'll be interesting, thanks for the great content!

I learned all of this material in the 50's and 60's. I spent 40 years in the electronics business. I'm retired now and miss it all so much.

Photomultiplier tube? Fascinating video as always.

Not sure where you're located, but if I ever find myself traveling through your neck of the woods, I would love to get a tour of some of your devices and machines. I'm loving these videos.

Terrific video as always. thanks!!

Great video of reanimating that old scope unit, thank you @ Mr Carlson! Answer to trivia question: I concur with all who say it is a phototube, its the cartridge type either 921, 922 or 926, often found in cinema projectors to scan the soundtrack, also fitted in some door opener light beam switches. What never ceased to baffle me since I first saw one in the early 1970s is how they managed to keep the areawise large metal to glass frit airtight at the ends. I would have guessed there would be a reliability issue at some time due to the tube drawing gas there. Could you test this one on a video please? Best regards from Germany

This is so cool. I have a small crt based viewfinder from an old camcorder that's basically the same as what you have here. The only difference is it accepts a composite video signal. It needs new capacitors (only 2 or three). But will make for a really neat project sometime. Can't wait to see what you decide to do with yours. It's so much easier to work with than my little 1cm crt.

If you have it, it will work. You da man!

Oscilloscope tubes like this were sometimes used to tune a receiver for RTTY (radio teletype) reception of FSK (frequency shift keying). Since the RF carrier itself was shifted between two frequencies separated by the same interval as the audio frequencies to be fed to the demodulator (850 Hz difference), the receiver’s BFO (beat frequency oscillator), also used to demodulate CW (code) and SSB (single sideband), had to be adjusted so that one RF carrier frequency, when combined with the BFO, would produce the audio tone for Mark (resting state between characters, or logic 1), and the other RF carrier frequency would produce the tone for Space (start of a character or logic 0). A tube like this would help tune in the signal. The audio from the receiver was fed to the AFSK (audio FSK detector), which had two narrow band tuned audio amplifiers, one for Mark and one for Space, to flip the relay controlling the DC signal to the printer. These signals were also fed to the horizontal and vertical inputs of the scope. When the signal was tuned in properly and the BFO was adjusted correctly, the scope would show a vertical line alternating with a horizontal line at teletype speed, or with persistence of vision, a cross with equal length arms. The appearance of both frequencies at the same time would produce a fast changing Lissajou pattern, which would smear into a rectangle or square.

You are one consummate professional. My hat off to you, sir.

Taking a guess at the 1 minute intro. Committed now.. CRT electrostatic vector display. Show phase relationships such as RF Carrier and modulation level for an AM transmitter. RF vertical and audio Horizontal would show if modulation exceeds 100% with carrier cut off. Now back to the video.

The mystery item looks like a vacuum photocell, with photo sensitive cathode. If I remember correctly, these tubes used a cesium metal additive to activate the tube released inside in much the same way as other tubes are `gettered` using induction heating. Not sure of the part number, maybe a RCA921. Great channel by the way!

one of THE first takeaways was that you powered up an unknown unit where usually you say that bad caps can cause major issues. and also that as soon as you removed the high voltage you seemed to have your fingers all over it seemingly unconcerned about any possible "charged" caps. still, was cool to watch the process, thanks

Another outstanding video!

Thumbs up always, and a bow, sir!

Very interesting the animation @ 15:48 seems as if you've got a 3 dimensional circle of sine waves rotating around the center origin in the horizontal direction.

I remember using one of those little guys, perhaps it was a bit larger, built into a Radio Teletype Rig in the US Army back in 1971-73. We used it when tuning up the rig, there was a switch NSK and some other SK, can't recall any more, but I always thought they were cool. You could watch as the teletype transmitted the letters at 60 WMP.

That looks like a RCA 926 or 921 gas phototube. What did you rescue that from? Nice little photo detector if you add an amplification stage after it.

Great video as usual! My guess is some sort of light pickup device possibly used for audio in film projectors ?

The tube looks sort of like the one I have. Mine was made in the 50's or 60's. It was part of an electric eye for some kind of alarm system. The common name now days is a photo cell. The striking or absence of light would turn on or off relays etc. The one I had used a regular tube socket. It kind of works on the same principal as the last example you gave us. The light would excite the gasses in the tube and allow electrons to flow. On the little scope tube, I use the eye piece out of the older type video cameras. If you take the eye piece apart, it looks just like a picture tube from a old TV set, but only about an inch square. They run on only 6 to 12 volts, depending on the camera type, then on the composite input, you can do all kinds of things with them. If you mess with the deflection coils, you can make a very portable pocket O' scope.

Your knowledge is exceptional

A), izzat a photo tube from a movie projector? B) I have a freezer in my basement that used to drive me wonky bcuz th power lamp (neon) flickered in th dark & was on full when I turned th lights on.... I actually did ur recommended experiment years ago to make sure I wasn't going loopy! GREAT videos! Keep it up!

Great video Mr Carlson

I vote for photo-electric tube. Predecessor to CdS cells. Love the trivia!

Speaking of radioactive tubes some used Radium 223 inside and are quite hot to this day (still reasonably safe to handle when intact though). Some however had either a dot of paint or a little foil on the outside so those can be a little more problematic regarding contamination. I have some on my collection of radioactive stuff