Thanks for the video. I think I might still have one or 2 of those that are similar in my classroom storage. I never knew what they were for since I have several 60-70 vintage scopes that have the dual trace on them. I likely have one or 2 that have a single trace that I can use it on if I decide to restore it. My department wants me to throw them and buy new scopes and I do have 2 new DSOs but I still like the old units as they are simpler for students to use at first to gain an understanding of function before letting them play with the fancy DSO that does everything for them and has enough buttons to make their eyes gloss over. I need to go through all the working scopes and replace caps before they fail. I did replace a few bad caps already on 2 that were not working and they sprang back to life.
Those older scopes are your best learning tools, don't discard them, use them to teach! The newer scopes are fine for the end result (solving a service/repair issue) but very poor for the understanding of the scope itself. Sounds like you're on the right track kuhrd!
I was looking at the TBS1000B-EDU line of scopes if I do have to buy a few replacements in the future but I will try and keep the old stuff going strong for as long as I can. I have 2x Rigol DS1054Z that I have not firmware unlocked yet (waiting for the warranty to run out) I snuck them on my new class budget when I resurrected the electronics class 2 years ago. Electronics had not been taught since I was in high school at the very same school. Kinda felt it was my duty to get the class going again. The Rigol DSO scopes work well enough for showing students waveforms and troubleshooting circuits but I always let them play on the old ones first. It is nice to have access to a scope with 4 inputs when doing things with Arduino and stepper motors. Some days it is hard enough convincing the trouble makers that the lab power supplies are not arc welders. On those days when I am working on my own stuff I wish I had even 25% the experience you have with electronics.
Very much enjoyed watching your channel for the first time. Seeing that Heathkit oscilloscope brought back great old memories. Around 58 years ago I was a teenager working the summer as a dogsbody in my father's marine electronics shop on Fort Myers Beach, FL. It happened that he needed an additional oscilloscope on the work bench for the technicians. So he purchased a Heathkit and put me to assembling the unit. Well, I was over then moon being given such a challenge and responsibility. I completed the assemble and when the time came, it didn't work. One of the technicians took to troubleshooting the unit and found that I had failed to put a ground insulator between one of the can capacitors and the frame. Easy fix and I was relieved.
Hello a general question related to use and restoration of older test gear in your projects have you worked on Fluke 8600A DMM's? I have one I am interested in getting back into working condition. TX Theo
Your videos are not only stimulating for the brain, but they're a treat on the eyes too. That thing is ridiculously gorgeous. It really reminds me of the old equalisers they have in the Abbey Road studios.
Now all you need is a type 132 Sylvania oscilloscope to go with it. I think that is the model that was being made in the early 40's. It should make a great addition to your bench. It turned out really nice. Thanks for sharing.
Hi Mike. Would you be surprised if I told you...... I have a 132... LOL :^) And.... It's little brother, the 131 as well :^) They will both be future restoration video's. Thanks for stopping by Mike, always good to hear from you.
Mr Carlson's Lab LOL, your as bad as me. If it's old and electronic we probably have at least one in our collections. Now you have even more reason to restore one of them. I have been searching for years for one of the rare Sylvania VTVM's. They are supposed to be a beast.
I'd have to say this instructional on older tube technology is probably the best I've found on RUclips. Thanks for providing your knowledge and time to educate the rest of us. It's appreciated very much.
Wonderful work upgrading this fine old switcher. I liked your very clear demonstration and explanation of how it works. Reminds me of what we did in EE lab work during my college fun years.
Thank you for showing this. I have a project that i wanted to get started on and you gave me the motivation to work on it. One thing i need to get is a tube tester. for the past 2 years I have been obtaining tube radios from clean outs, most are in bad condition. I save the parts from them to one day build something crazy. I was thinking of a 7.1 surround system. something that i can be proud of. I had a teacher long ago that took his time to show me how tubes worked. Build my first radio for high school. Thank you again for taking your time to show us the projects you work on!
Hell,Paul! My name is Jim Ashton and I was born in Birmingham in England in 1943, so you can understand that this video took me back in time to my early days in valve (tube) electronics.I was most impressed by your very clear explanation of an instrument which I had never encountered. At no point did I become bored and I picked up a lot of useful tips. I shall be following your videos avidly from now on. As a matter of interest (or not!) I am now a qualified Egyptologist and travel each winter to that country. There is no danger and I encourage all my friends to go there and see the miracles that these people wrought! Jim.
This is so restful! I know just enough about the mechanical side of tube equipment restoration to feel like your apprentice. Watching your videos is like meditation to me. I wish I understood the electronics side of it better.
Thank you Mr Carlson! I am a motor head/electronic hobbyist from way back who has always had a fascination for old tubed devices. I understand enough about them to stay alive while servicing them but have had a few things puzzle me about their operation, one being “bias”. Your comparison of bias being like a stall converter on a starting line is one I understand well. Now I understand some of the mechanics behind bias as well! My shop is almost finished and I hope to put all the old collected equipment back to work here soon. Thank you for the awesome video's.
Great vid! My dad was an electronics tech for 60 years, graduating from Oaklands' Central Trade School, in 1937. Seeing these old units brings back countless memories. :-) It's great, knowing that there are young people keeping the old trade alive.
Always amazed at the knowledge on tap, in your brain. I have experimented a little with small projects in the past. But, I could never retain your level of knowledge. Fascinating to watch. You have convinced me to get another soldering station and get back into it. I'm retired now, so I have the time. Just not a lot of money or brain capacity to do much. But, I really enjoyed it, back in the day.
I’m drawing my own schematic of a Kenwood TS-120S just for the heck of it, and I’m really enjoying it. Mr. Carlson also has a few schematic drawing tips and tricks in his Patreon pages that are really helping me with the technique-gotta say thanks for that!
I would like to be you next-door neighbor! I have a great deal of test equipment (everything from decade boxes to microwave spectrum analyzers -- maybe more than you!) which I have collected -- and repaired/calibrated -- over, well, more decades than I want to recount; and I, too, really enjoy bringing old devices back to life. My current "stereo" has surround capabilities combined with Grommes 260A amplifiers for the main (front) left and right channels, most of the equipment for which I bought in less-than-perfect condition. Anyway, I really enjoy your videos (You da MAN!), and I hope they continue to be available for many years to come. Thanks, Paul.
Wow! What a cool device! Simple yet sophisticated. I think you are spot on for the estimated date of the device - Loctal sockets (trademarked as Loktal, and developed by Sylvania) were released to OEM about 1938. With all of the interesting gear you have restored for your circa 1950's test lab, I can't wait to see the setup and see your projects in the "old lab". Great work, Paul. And, thank you for keeping the lovers of the vacuum state (a.k.a "us old geezers who think that it only works when it glows orange") well informed and entertained. Your theory and practice of reverse engineering - or "forensic engineering" - was great. Would love to see more of it in vacuum state and solid state as well. Your process is very close to the techniques I teach in harmonic and melodic analysis in music theory.
Fantastic job as always. It's admirable to see you not only reverse engineering the device, but find and fix a problem that problably the very manufacturers themselves couldn't find and repair. I hope in the future i can afford joining your electronics course on patreon. Thank you for all your perfectly produced videos.
Big thumbs up for Mr Carl son's lab. I must get my patreon account sorted out. I just love the calm and logical but warm and engaging delivery. Thanks again.
This is awesome. As soon as the cover came off, the quality was evident. I sold my dad's O-11 scope before I saw your restoration video, and I hope the buyer enjoyed restoring it - his intention. He may have seen your video. Very enjoyable watching your restoration and explanation. Excellent work!
Aside from the education, I really love your passion for the history that the devices "tells" when you open it up. You show your anticipation and excitement of the preservation of history. That aspect is just as important as your videos.
Another wonderful piece of equipment restored. Thank you for another interesting presentation Paul. But for those of you interested in restoring old vacuum equipment there are five things to know. First, you need a circuit diagram. Never go fiddling in an equipment unless you have one, because you do not know what the heck you are connecting to. This can lead to causing more issues in the equipment by destroying valves and components, not to mention your test gear. Second, don't plug it in direct to the power source and destroy it. You need an isolation transformer, a variac, and current limit just like Paul's, so that you can see whether it is going to behave or not. Remember, you do not know where the equipment has been, or what condition it is in. It could be faulty, and old components invariably fail. Third, you need to understand how the circuit works. If you do not then it is like coming off the street, climbing into an F15 fighter jet and expecting to fly it! Well it is the same here too. If you do not understand how the circuit works, seek advice. Fourth, large capacitors charge up. Yes it is turned off and unplugged, but if you have had voltage on it they can charge up and still give you a very nasty surprise. Fifth, and VERY IMPORTANT you have to understand that this is not solid state devices like bipolar transistors and FET's that you fiddle around with with your bare hands, and that there are REAL voltages in there that can KILL YOU. My mentor always told me, ground on chassis, one hand in your pocket, and the other on the probe. It was valuable advice when working on valve gear. If you get connected to those voltages, and many have, you will definitely know! High voltage is pretty unforgiving of incompetence, and can put you in the hospital or the ground for good, so always take great care when in live valve equipment. Watch Paul's videos. You can learn a lot. He has mastered valve gear and electronics, knows the hazards, and understands the circuits in detail. You can have no better teacher. My mentor? Derek Colins, in television repair for over 20 years, and when I met him a bench radio transceiver repair technician. The best. Paul even uses some of the terms Derek did.......badly repaired electronics.......butchered boards! LOL
This is really long and very well done...... long is good..... Im going to add it to my watch it later since it is so late for me..... Im saying this to help you with your Analytic's so when you see someone clicking off the video early that its not a bad thing....... This video is awesome and I will be back to finish it. Thanks
Wonderful switch...I really love seeing this older equipment getting brought back to life! It is funny that the problem was an un-soldered capacitor that kept getting missed. That is one of those "DOH!" moments Homer Simpson keeps talking about :)
I always enjoy yr videos, grateful someone such as yourself still takes the time. Soon all of the analogue electronics knowledge will become mystery and rare if not already.
you polished up that front panel so well, it has a mirror finish. I also spend a lot of time polishing old stuff up. takes a lot of time but i enjoy it.
You find the neatest stuff! I especially liked the sleuth like detective work into the suspected low hours of use. Thanks for taking the time to draw up and explain the schematic.. I always learn something from your video's.. A++
As a retired EE, born in 1941, I can attest to the knowledge of Mr. Carlson. Other than a very minor pronunciation error (silent "l" in "solder,") this is a perfect video. Excellent in every respect.
I apologize, Paul, for the misunderstanding... I have since seen the outrageous lengths which you take to remain completely purist in every respect in all of your videos. In fact, I have to watch out that I don't start talking like a Brit and make people think I'm a transplant to the US! LOL You have set an extremely high bar for the rest of the electronics community. Bravo! de KQ2E
Excellent information, great detail. Many of us old timers learned about circuit design (and mechanical design) by disassembling military surplus items. Helps to develop a way of thinking that is invaluable today.
I used to go to sea as a Merchant Navy Radio Electronics officer, but it's been a while since I did any hardware work (got into computers when I came ashore.) Very pleasant and informative video to watch. I first went to sea with valve (tube) equipment which moved to solid state in the course of my sea-time. Definite thumbs up. :-)
My head is going to pop. You have an incredible amount of knowledge and understanding for this gear. Thank you for the great videos and narration. Absolutely enjoy all your shows Dr. Carlson.
Another excellent presentation, Mr Carlson. I am reading a 1956 book about oscilloscopes and there is a similar schematic of an electronic switch, but it only uses four pentodes, excluding the rectifier. And I must say, those big vintage Mallory capacitors are very pretty. If only the Czechoslovakian Tesla components I come across here in the Czech Republic were as colorful and with such nice writing as their American counterparts have. They would make for an interesting wall decor for the lab, framed in a flat glass box. Thank you for making this video.
My first job in 1982 was working with an older gentleman in a two way radio repair shop. He had a lot of equipment like this. Sorry to say it all went to the dump. Glad to see you save some of that kind of stuff.
Awesome restoration! What Sylvania named at that time as an Electronic Switch, is actually a chopper circuit which, once integrated into future o-scopes got shortened to "CHOP" mode and eventually "ALTERNATE" or ALT mode. Even my late-80's dual-trace Tek scope has ALT mode on it :)
As others have said, a brilliant & detailed video, would it be worth mentioning that the replacement potentiometers musst have a linear track? So many are logarithmic for audio use these days. However nothing can beat silck smooth "sizzle" of a 1940s wire wound pot!
This is great. Had no idea what it is was for, until last part of video. But glad I stayed till end, as I just built an oscilloscope from a very old book written in 1979 by a chap named F.G Rayer. (one of the many brilliant Babani project books) Really simple circuit and covers 20hz to 20khz nicely. But of course its a single channel scope. So now you have shown me how I can turn it into a two channel scope. Brilliant!!!
my first oscilloscope was a sencore PS148 from the early 60's. I'm in the middle of restoring a vintage general radio audio frequency generator. love your vids!
What a reminder of my old years as a Radio & TV engineer !!! I loved those Continental Transmitters with a built quality as that Sylvania switch. Keep posting videos !! :)
I've been loving your videos Mr Carlson, they're all very informative, educational and very interesting. This was a great device, excellent restoration and great to see this old equipment come to life.
@@MrCarlsonsLab very much so, to the point where is renewed my interest in vintage tech. I recently received a General Radio Company impedance bridge. Note I just need to understand how it works and restore. Your videos are awesome, I'll be a patreon as soon as lockdown is over in my neighborhood.
Omg this channel is so useful but i could never watch it until i found 1.25 play speed. Now i can remember the beginning of the sentence by the time he reached the end of the sentence. Before i was falling off the concentration. Now it awesome.
That was super cool. Finding out why the unit was in such good shape was like solving a murder mystery from years past. Thanks for sharing another great piece of history with us. I need to sit down one day and put my unbuilt Eico switch together.
really love your vids , they take me back to when I was 12 years old and started playing with old electrical equipment , old radios mainly , back then stuff like you show in your vids sold for pennies in disposal stores , oh how I wish I had some of that old stuff now
I've been consuming your videos for the past while now and I went from 0 to absolutely stoked on vacuum tube electronics. Thank you, it's a great feeling. I've still only ever laid my hands on transistor equipment thus far, though. I'm looking to pick up an early 60's 4 watt EAF42-EL41 kit amplifier (with AZ41) as my first foray into vacuum tubes. I intend to give some fresh capacitors, if I do indeed get a word back from the current owner that he hasn't recently attempted to power it up. Judging by its casing alone, the caps are not going to be all of its issues. Bodgewires and questionably fitted afterthought connectors adorn most of the device's backside, and, I'm honestly still accommodating to the idea of electronics that aren't anchored to a PCB in the first place. Beyond being careful not zapping myself, and being gentle with the device and not zapping it , do you have any advice on the tubes it comes with, or European kit amplifiers in general? Are there more quirks to them than meets the eye? Should I just go for it, and, do you've any other words of wisdom for the very transistory man I am?
If your a transistor guy, just be careful around the high Voltage, it's all over vacuum equipment. Glad to read you're interested in the tube stuff now, I admit, it's much nicer to work on than the new stuff.
Great Video! A lot of good advice on how to approach a restore. A valuable take away for me was drawing the schematic, reverse engineering, since nothing was available. I am restoring a Hickok 209B VTVM, unlike other models in the series , no documentation appears to be available. I am going to stop searching and start drawing, a bit of work, but part of the restoration journey. Thank You!
On the EICO 488 Electronic Switch they labeled that "Balance" knob as Positioning, and there's a Heathkit model that calls it Separation (A up and B up)... So EICO and Heathkit agree with Mr. Carlson :)
This was very inspiring. Admiring your deep understanding of this technology and the way you bring it out to us. Thanx for bringing the zeitgeist of this era back to life.
Really enjoyed this. I started smiling when the trace started on the scope and didn't stop until it was over, heck I'm still smiling. That was so much fun and so interesting! Thank you!
Your attention to minute detail, like the up/down potentiometer facing, is so far above most electricians that it is like listening to Tesla himself compared to the Cable Guy. Wow.
I have not looked at your channel for a while and I am now wondering what I have missed. There is no doubt that whoever designed this unit took pride in what they did. It may look old fashioned but I think it looks bloody gorgeous. After 50 odd years I have gone back to electronics as a hobby so to me in a way it's not so old fashioned. I can remember 410 V across the end of my nose ( Mullard Amp). A small scar is still there after 50 years. Thank you so much for this video - it's perfect.
Mr. Carlson you forgot to measure the output voltage on the square wave on the output. Once again a great video that simplifies the explanation of circuit design theory.
Wow, what a great in detail explanation! I really like the reverse engineering part and I'm looking forward to see more like this in the future. Never thought, that reading schematics can be fun. You doing a great job, many thanks Paul!
Paul, its good to see another video on YT again, That electronic switch unit is a beautiful instrument !!!! I have heard of these being used with oscilloscopes but NEVER seen it actually done !! Thanks for the video restoration and demo, a real treat as always !!!!!! John A Bellas KC2UVN
That was great. What made it a joy to follow was everything is so clean and pristine. Are you sure you didn't go back in time and get this in a specialty shop? It's like brand new. Down to the leaves on the bakelite tube bases, and no tarnish on the goat shields. Please do more like this, what a great rebuild.
Very interesting and enjoyable video. Recently purchased a Tektronix 465 scope which works fairly well but is not displaying CH2 when ALT is selected. Works with CHOP. Might be the switches need cleaning. I have not investigated yet, but this video helps explain the operation clearly and should help with the thought processes needed to fix it. Thank you
Paul... Awesome job! This was just a really enjoyable video. And what a cool find... Now looking and working like new at almost 80 years old. Wow. Thanks for all the effort!
I also find point to point reverse engineering to be quite challenging. It is easier to reverse engineer circuit boards that are single or double layer, but multi layer boards are a mess. I used to design circuit boards for a living and some of them can have up to twenty layers on the modern circuit boards. Oh the days of laying out all those traces on vellum sheets. some of them were like 3 foot by 5 foot pieces because we scaled them up for easy layout. now everything can be done on PC which is much more practical. Always enjoy watching and learning from you. You remind me of my High School Electronics teacher. His logic was text books can teach you theory, but hands on is the only way to learn electronics. My first project was a Tesla coil using a 10,000 volt 30mA vacuum Tube Transformer as a power source. Was so cool to see it in action. I would love to see you do a restoration on one of those transformers in one of your videos.
My father (age 67) watch this before me and after i mentioned loctal valve he then told me about the similar equipment he used to use. Because he has explained to me how these older valves work in detail i had figured out about half of it works but couldn't quite figure how it mixes the channels together so i just had a 10min explanation of the oscillator component.
Excellent video. I am from the UK, sadly no one in the UK produces Video's like you, Keith Rucker, etc. do from over the pond! I was an apprentice 1953/1959 at the D.S.I.R. Radio Research Station working for Dr Smith Rose, Wilkins, etc. making the all the type of equipment you are interested in! Your video,s are jogging my memories ,
Thank you for another greatly enjoyable video! The leaf - an oak leaf, actually - with the "S" letter inside was the earliest logo used by Sylvania after the brand was created by Nilco Lamp Works in 1924.
Very interesting. I have an EICO Model 488 Electronic Switch. It's shape is like yours, but shorter and wider, but the front panel components are laid out just about the same. This video makes me want to check it out and get it working. Will hooke it up to my old Devry tube Oscope. First I need to get my Eico 960B Cap tester going first. Thanks! My interests in electronics started out in the late 50's when I was about 9 years old so tube stuff is very familiar to me.
I actually have a radio built in 1944 that still works. Hand wired, original valves (tubes). I tested everything before I applied power. The set was bought by my grandparents, and still has the shop guarantee. They were supplied as kits of parts to local shops to assemble.
Steven Cook, Make sure you replace the caps as does Paul Carlson. That will keep your machine working for decades more. Add to the voltage rating as they are not the same as the caps were back then. Use a good brand (see his video on choosing components by brand).
Hi once more Paul, very interesting video again in the fixing of the Sylvainia Electronic Switch. The Heathkit oscilloscope you used there in the video. I picked one up years ago while on holiday at Filey on the UK East coast. It was outside a British Heart foundation charity shop. Could not resist going in to enquire regarding the scope. They wanted a fortune to get rid of it. £5.0. Whow, I could not believ it. Did not care about if it worked or not. £5.0 was worth it just for the case has far as I was concerned. When I got it home, it took a bit of sorting out but soon had it up and running. Not bad for the price. 73 de John _ G0WXU
Paul, My research on Wikipedia reveals that the Loctal tubes were introduced by Sylvania in 1939. So I would estimate the age of your switch is probably early to mid 1940s. It is also my understanding that the Loctal tube fell out of use in the 1950s. The octal tubes were still used (early "All American Five" radios) and most audio and test gear. To shrink the chassis real estate, miniature tubes (7 and 9-pin) were used in televisions, radios as well as test equipment. I have an old RCA Senior Voltohmist VTVM with a 12AU7 meter bridge and a 6AL5 AC rectifier to make AC voltage measurements. I also have a Hickok Model 6000A tube tester with a 5Y3 standard rectifier and a type 83 mercury vapor rectifier in it. I prefer tubes for audio as I like the "tube sound". I has a much warmer sound than the starkness of solid state. Thanks for the video and sharing your knowledge! Dave
Excellent restoration and presentation. I was surprised how good the channel switching square wave was with reasonably fast rise time and virtually no overshoot. Would like to have seen a DC offset control to allow DC measurement on both channels. Thank you
![FADA Radio Receiver From 1937 Electronic Restoration! [Repair]](/img/1.gif)
To go to the Mr Carlson's Lab Patreon Page, click here: www.patreon.com/MrCarlsonsLab
Thanks for the video. I think I might still have one or 2 of those that are similar in my classroom storage. I never knew what they were for since I have several 60-70 vintage scopes that have the dual trace on them. I likely have one or 2 that have a single trace that I can use it on if I decide to restore it. My department wants me to throw them and buy new scopes and I do have 2 new DSOs but I still like the old units as they are simpler for students to use at first to gain an understanding of function before letting them play with the fancy DSO that does everything for them and has enough buttons to make their eyes gloss over. I need to go through all the working scopes and replace caps before they fail. I did replace a few bad caps already on 2 that were not working and they sprang back to life.
Those older scopes are your best learning tools, don't discard them, use them to teach! The newer scopes are fine for the end result (solving a service/repair issue) but very poor for the understanding of the scope itself. Sounds like you're on the right track kuhrd!
I was looking at the TBS1000B-EDU line of scopes if I do have to buy a few replacements in the future but I will try and keep the old stuff going strong for as long as I can. I have 2x Rigol DS1054Z that I have not firmware unlocked yet (waiting for the warranty to run out) I snuck them on my new class budget when I resurrected the electronics class 2 years ago. Electronics had not been taught since I was in high school at the very same school. Kinda felt it was my duty to get the class going again.
The Rigol DSO scopes work well enough for showing students waveforms and troubleshooting circuits but I always let them play on the old ones first. It is nice to have access to a scope with 4 inputs when doing things with Arduino and stepper motors.
Some days it is hard enough convincing the trouble makers that the lab power supplies are not arc welders. On those days when I am working on my own stuff I wish I had even 25% the experience you have with electronics.
Mr Carlson's Lab Your mouth movements look animatronic
should show them king of random vids then. also show the troubler makers. the repair bills as well.
Very much enjoyed watching your channel for the first time. Seeing that Heathkit oscilloscope brought back great old memories. Around 58 years ago I was a teenager working the summer as a dogsbody in my father's marine electronics shop on Fort Myers Beach, FL. It happened that he needed an additional oscilloscope on the work bench for the technicians. So he purchased a Heathkit and put me to assembling the unit. Well, I was over then moon being given such a challenge and responsibility. I completed the assemble and when the time came, it didn't work. One of the technicians took to troubleshooting the unit and found that I had failed to put a ground insulator between one of the can capacitors and the frame. Easy fix and I was relieved.
Great story James, thanks for sharing that!
Hello a general question related to use and restoration of older test gear in your projects have you worked on Fluke 8600A DMM's? I have one I am interested in getting back into working condition. TX Theo
Your videos are not only stimulating for the brain, but they're a treat on the eyes too. That thing is ridiculously gorgeous. It really reminds me of the old equalisers they have in the Abbey Road studios.
Thanks Amberoot!
Amberoot Audio You took the words right off my keyboard. Love this channel.
Absolutely agree Amber Root. That thing is handsome indeed, and I can't believe something I will never use or need is so fascinating.
@@indigogolf3051 I had the earlier model - used to put sound through it as a crude ring modulator thing - it was fun!
Now all you need is a type 132 Sylvania oscilloscope to go with it. I think that is the model that was being made in the early 40's.
It should make a great addition to your bench. It turned out really nice. Thanks for sharing.
Hi Mike. Would you be surprised if I told you...... I have a 132... LOL :^) And.... It's little brother, the 131 as well :^) They will both be future restoration video's. Thanks for stopping by Mike, always good to hear from you.
Mr Carlson's Lab
LOL, your as bad as me. If it's old and electronic we probably have at least one in our collections. Now you have even more reason to restore one of them.
I have been searching for years for one of the rare Sylvania VTVM's. They are supposed to be a beast.
Is there an oscilloscope you DON'T have hahaha
I'd have to say this instructional on older tube technology is probably the best I've found on RUclips.
Thanks for providing your knowledge and time to educate the rest of us.
It's appreciated very much.
Wonderful work upgrading this fine old switcher. I liked your very clear demonstration and explanation of how it works. Reminds me of what we did in EE lab work during my college fun years.
Thank you for showing this. I have a project that i wanted to get started on and you gave me the motivation to work on it. One thing i need to get is a tube tester. for the past 2 years I have been obtaining tube radios from clean outs, most are in bad condition. I save the parts from them to one day build something crazy. I was thinking of a 7.1 surround system. something that i can be proud of. I had a teacher long ago that took his time to show me how tubes worked. Build my first radio for high school. Thank you again for taking your time to show us the projects you work on!
Glad you enjoyed Taraku!
Hell,Paul! My name is Jim Ashton and I was born in Birmingham in England in 1943, so you can understand that this video took me back in time to my early days in valve (tube) electronics.I was most impressed by your very clear explanation of an instrument which I had never encountered. At no point did I become bored and I picked up a lot of useful tips. I shall be following your videos avidly from now on. As a matter of interest (or not!) I am now a qualified Egyptologist and travel each winter to that country. There is no danger and I encourage all my friends to go there and see the miracles that these people wrought!
Jim.
Thanks for taking the time to write Jim!
This is so restful! I know just enough about the mechanical side of tube equipment restoration to feel like your apprentice. Watching your videos is like meditation to me. I wish I understood the electronics side of it better.
I used to use one of those switches ages ago. I'm in my 70's now.
Thank you Mr Carlson! I am a motor head/electronic hobbyist from way back who has always had a fascination for old tubed devices. I understand enough about them to stay alive while servicing them but have had a few things puzzle me about their operation, one being “bias”. Your comparison of bias being like a stall converter on a starting line is one I understand well. Now I understand some of the mechanics behind bias as well! My shop is almost finished and I hope to put all the old collected equipment back to work here soon.
Thank you for the awesome video's.
Hey, that's great to read that the "stall converter" description resonated with you! I may be a bit of a motor head myself :^)
Great vid! My dad was an electronics tech for 60 years, graduating from Oaklands' Central Trade School, in 1937. Seeing these old units brings back countless memories. :-) It's great, knowing that there are young people keeping the old trade alive.
Always amazed at the knowledge on tap, in your brain. I have experimented a little with small projects in the past. But, I could never retain your level of knowledge. Fascinating to watch. You have convinced me to get another soldering station and get back into it. I'm retired now, so I have the time. Just not a lot of money or brain capacity to do much. But, I really enjoyed it, back in the day.
Hi Michael. The only thing that's limiting you..... is you. You can achieve what ever you set you mind too.... No matter what others say.
I’m drawing my own schematic of a Kenwood TS-120S just for the heck of it, and I’m really enjoying it. Mr. Carlson also has a few schematic drawing tips and tricks in his Patreon pages that are really helping me with the technique-gotta say thanks for that!
Glad to be there for you!
I would like to be you next-door neighbor! I have a great deal of test equipment (everything from decade boxes to microwave spectrum analyzers -- maybe more than you!) which I have collected -- and repaired/calibrated -- over, well, more decades than I want to recount; and I, too, really enjoy bringing old devices back to life. My current "stereo" has surround capabilities combined with Grommes 260A amplifiers for the main (front) left and right channels, most of the equipment for which I bought in less-than-perfect condition.
Anyway, I really enjoy your videos (You da MAN!), and I hope they continue to be available for many years to come.
Thanks, Paul.
hi ed enjoyed reading your comment do you have any interest in time travel machines
Easy to see Mr Carlson's passion for electronics in every video he makes. Always amazing to see work and skill of his caliber.
Wow! What a cool device! Simple yet sophisticated. I think you are spot on for the estimated date of the device - Loctal sockets (trademarked as Loktal, and developed by Sylvania) were released to OEM about 1938. With all of the interesting gear you have restored for your circa 1950's test lab, I can't wait to see the setup and see your projects in the "old lab". Great work, Paul. And, thank you for keeping the lovers of the vacuum state (a.k.a "us old geezers who think that it only works when it glows orange") well informed and entertained.
Your theory and practice of reverse engineering - or "forensic engineering" - was great. Would love to see more of it in vacuum state and solid state as well. Your process is very close to the techniques I teach in harmonic and melodic analysis in music theory.
Fantastic job as always. It's admirable to see you not only reverse engineering the device, but find and fix a problem that problably the very manufacturers themselves couldn't find and repair. I hope in the future i can afford joining your electronics course on patreon. Thank you for all your perfectly produced videos.
Big thumbs up for Mr Carl son's lab. I must get my patreon account sorted out. I just love the calm and logical but warm and engaging delivery. Thanks again.
This is awesome. As soon as the cover came off, the quality was evident. I sold my dad's O-11 scope before I saw your restoration video, and I hope the buyer enjoyed restoring it - his intention. He may have seen your video. Very enjoyable watching your restoration and explanation. Excellent work!
Aside from the education, I really love your passion for the history that the devices "tells" when you open it up. You show your anticipation and excitement of the preservation of history. That aspect is just as important as your videos.
Another wonderful piece of equipment restored. Thank you for another interesting presentation Paul. But for those of you interested in restoring old vacuum equipment there are five things to know. First, you need a circuit diagram. Never go fiddling in an equipment unless you have one, because you do not know what the heck you are connecting to. This can lead to causing more issues in the equipment by destroying valves and components, not to mention your test gear. Second, don't plug it in direct to the power source and destroy it. You need an isolation transformer, a variac, and current limit just like Paul's, so that you can see whether it is going to behave or not. Remember, you do not know where the equipment has been, or what condition it is in. It could be faulty, and old components invariably fail. Third, you need to understand how the circuit works. If you do not then it is like coming off the street, climbing into an F15 fighter jet and expecting to fly it! Well it is the same here too. If you do not understand how the circuit works, seek advice. Fourth, large capacitors charge up. Yes it is turned off and unplugged, but if you have had voltage on it they can charge up and still give you a very nasty surprise. Fifth, and VERY IMPORTANT you have to understand that this is not solid state devices like bipolar transistors and FET's that you fiddle around with with your bare hands, and that there are REAL voltages in there that can KILL YOU. My mentor always told me, ground on chassis, one hand in your pocket, and the other on the probe. It was valuable advice when working on valve gear. If you get connected to those voltages, and many have, you will definitely know! High voltage is pretty unforgiving of incompetence, and can put you in the hospital or the ground for good, so always take great care when in live valve equipment. Watch Paul's videos. You can learn a lot. He has mastered valve gear and electronics, knows the hazards, and understands the circuits in detail. You can have no better teacher. My mentor? Derek Colins, in television repair for over 20 years, and when I met him a bench radio transceiver repair technician. The best. Paul even uses some of the terms Derek did.......badly repaired electronics.......butchered boards! LOL
I'm glad to hear you tell people to beware going off willy nilly and plugging old crap in before looking inwide.
This is really long and very well done...... long is good..... Im going to add it to my watch it later since it is so late for me..... Im saying this to help you with your Analytic's so when you see someone clicking off the video early that its not a bad thing....... This video is awesome and I will be back to finish it. Thanks
Wonderful switch...I really love seeing this older equipment getting brought back to life!
It is funny that the problem was an un-soldered capacitor that kept getting missed.
That is one of those "DOH!" moments Homer Simpson keeps talking about :)
I always enjoy yr videos, grateful someone such as yourself still takes the time. Soon all of the analogue electronics knowledge will become mystery and rare if not already.
Hi Paul, I want to thank you for sharing your knowledge and your love for these vintage devices.
You're Welcome Bobby! I'm glad you're enjoying the video's.
you polished up that front panel so well, it has a mirror finish. I also spend a lot of time polishing old stuff up. takes a lot of time but i enjoy it.
You find the neatest stuff! I especially liked the sleuth like detective work into the suspected low hours of use. Thanks for taking the time to draw up and explain the schematic.. I always learn something from your video's.. A++
As a retired EE, born in 1941, I can attest to the knowledge of Mr. Carlson. Other than a very minor pronunciation error (silent "l" in "solder,") this is a perfect video. Excellent in every respect.
Thanks Bruce! I pronounce solder like this, click the link, then click "UK" dictionary.cambridge.org/pronunciation/english/solder
I apologize, Paul, for the misunderstanding... I have since seen the outrageous lengths which you take to remain completely purist in every respect in all of your videos. In fact, I have to watch out that I don't start talking like a Brit and make people think I'm a transplant to the US! LOL You have set an extremely high bar for the rest of the electronics community. Bravo! de KQ2E
Excellent information, great detail. Many of us old timers learned about circuit design (and mechanical design) by disassembling military surplus items. Helps to develop a way of thinking that is invaluable today.
Glad you're enjoying Dall!
I used to go to sea as a Merchant Navy Radio Electronics officer, but it's been a while since I did any hardware work (got into computers when I came ashore.) Very pleasant and informative video to watch. I first went to sea with valve (tube) equipment which moved to solid state in the course of my sea-time.
Definite thumbs up. :-)
Thanks Bob!
That's why we don't "sea: tubes any more!
Fascinating and great to see the old equipment brought back to life and to see how well it works when in good condition.
Thanks for sharing!
What an amazing device, I love the fact that you are reviving this old equipment!!! Keep up the good work.
My head is going to pop. You have an incredible amount of knowledge and understanding for this gear. Thank you for the great videos and narration. Absolutely enjoy all your shows Dr. Carlson.
Another excellent presentation, Mr Carlson. I am reading a 1956 book about oscilloscopes and there is a similar schematic of an electronic switch, but it only uses four pentodes, excluding the rectifier.
And I must say, those big vintage Mallory capacitors are very pretty. If only the Czechoslovakian Tesla components I come across here in the Czech Republic were as colorful and with such nice writing as their American counterparts have. They would make for an interesting wall decor for the lab, framed in a flat glass box. Thank you for making this video.
My first job in 1982 was working with an older gentleman in a two way radio repair shop. He had a lot of equipment like this. Sorry to say it all went to the dump. Glad to see you save some of that kind of stuff.
Paul....you never cease to amaze, your knowledge is 2nd to none...cool find for sure....kudos and 2 big thumbs up
I have used that type of device in the past with older single trace scopes. Very interesting that you found one still around. Thanks for the share.
Thanks Gary, glad you enjoyed!
Awesome restoration! What Sylvania named at that time as an Electronic Switch, is actually a chopper circuit which, once integrated into future o-scopes got shortened to "CHOP" mode and eventually "ALTERNATE" or ALT mode. Even my late-80's dual-trace Tek scope has ALT mode on it :)
brilliant video with exceptional detailed explanations as always. Thank you Mr Carlson!
As others have said, a brilliant & detailed video, would it be worth mentioning that the replacement potentiometers musst have a linear track? So many are logarithmic for audio use these days. However nothing can beat silck smooth "sizzle" of a 1940s wire wound pot!
This is great. Had no idea what it is was for, until last part of video.
But glad I stayed till end, as I just built an oscilloscope from a very old book
written in 1979 by a chap named F.G Rayer. (one of the many brilliant Babani project books) Really simple circuit and
covers 20hz to 20khz nicely. But of course its a single channel scope. So
now you have shown me how I can turn it into a two channel scope.
Brilliant!!!
my first oscilloscope was a sencore PS148 from the early 60's.
I'm in the middle of restoring a vintage general radio audio frequency generator. love your vids!
Thanks Scott!
What a reminder of my old years as a Radio & TV engineer !!! I loved those Continental Transmitters with a built quality as that Sylvania switch. Keep posting videos !! :)
Thanks Pedro!
Thanks to you for the memories !!
Another excellent video made entertaining and educational as always. I really enjoy when you have great vintage gear on your bench. Thank you.
Mel
Your instruction is very thorough and easy to follow...the best!!!
Your knowledge of electronics is astonishing, I am sure it comes with many years of experience. Great video as always, keep up the good work.
Thank you Mr Carlson.....that is what I want to learn....you are so blessed man....
I wish my teachers were this good! Mr Carlson has taught me so much. i hope to buy him a beer someday.
Always a good audio description, knowledgeable and articulate.
the comments are the best , mr carlson i am ready to bust open a old tv or radio. thanks for sharing
Bravo with that restoration. Your videos take me back to my young working years. Thank You.
Thank you Mr Carlson for another wonderful reverse engineering video. I am really learning a lot from watching you work.
I've been loving your videos Mr Carlson, they're all very informative, educational and very interesting. This was a great device, excellent restoration and great to see this old equipment come to life.
Glad you like them!
@@MrCarlsonsLab very much so, to the point where is renewed my interest in vintage tech. I recently received a General Radio Company impedance bridge. Note I just need to understand how it works and restore. Your videos are awesome, I'll be a patreon as soon as lockdown is over in my neighborhood.
i love how detailed you are in your explanations !!
Omg this channel is so useful but i could never watch it until i found 1.25 play speed. Now i can remember the beginning of the sentence by the time he reached the end of the sentence. Before i was falling off the concentration. Now it awesome.
That was super cool. Finding out why the unit was in such good shape was like solving a murder mystery from years past. Thanks for sharing another great piece of history with us. I need to sit down one day and put my unbuilt Eico switch together.
Hi Buddy! Thanks for stopping by. Building that kit (with new caps of course :^) would make a great video.
really love your vids , they take me back to when I was 12 years old and started playing with old electrical equipment , old radios mainly , back then stuff like you show in your vids sold for pennies in disposal stores , oh how I wish I had some of that old stuff now
I've been consuming your videos for the past while now and I went from 0 to absolutely stoked on vacuum tube electronics. Thank you, it's a great feeling. I've still only ever laid my hands on transistor equipment thus far, though.
I'm looking to pick up an early 60's 4 watt EAF42-EL41 kit amplifier (with AZ41) as my first foray into vacuum tubes. I intend to give some fresh capacitors, if I do indeed get a word back from the current owner that he hasn't recently attempted to power it up. Judging by its casing alone, the caps are not going to be all of its issues. Bodgewires and questionably fitted afterthought connectors adorn most of the device's backside, and, I'm honestly still accommodating to the idea of electronics that aren't anchored to a PCB in the first place.
Beyond being careful not zapping myself, and being gentle with the device and not zapping it , do you have any advice on the tubes it comes with, or European kit amplifiers in general? Are there more quirks to them than meets the eye? Should I just go for it, and, do you've any other words of wisdom for the very transistory man I am?
If your a transistor guy, just be careful around the high Voltage, it's all over vacuum equipment. Glad to read you're interested in the tube stuff now, I admit, it's much nicer to work on than the new stuff.
Great Video! A lot of good advice on how to approach a restore. A valuable take away for me was drawing the schematic, reverse engineering, since nothing was available.
I am restoring a Hickok 209B VTVM, unlike other models in the series , no documentation appears to be available. I am going to stop searching and start drawing, a bit of work, but part of the restoration journey. Thank You!
Great Bill! Thats a nice VTVM you have!
On the EICO 488 Electronic Switch they labeled that "Balance" knob as Positioning, and there's a Heathkit model that calls it Separation (A up and B up)... So EICO and Heathkit agree with Mr. Carlson :)
This was very inspiring. Admiring your deep understanding of this technology and the way you bring it out to us. Thanx for bringing the zeitgeist of this era back to life.
Very nice Paul. Not only the electronics details but the cleaning / restoration process shows your attention to detail. Thanks Jim
Thanks Jim!
Thank you Paul: your explanation about the mechanics of this switch device made perfect sense.
Phil.
Really enjoyed this. I started smiling when the trace started on the scope and didn't stop until it was over, heck I'm still smiling. That was so much fun and so interesting! Thank you!
Thanks Buddy, glad you enjoyed!
Your attention to minute detail, like the up/down potentiometer facing, is so far above most electricians that it is like listening to Tesla himself compared to the Cable Guy. Wow.
"Chicken Head Knobs"! So that's what they've called. Thanks.
Mr Carlson Great troubleshooting as always. Always good to learn something new Thank You
I have not looked at your channel for a while and I am now wondering what I have missed. There is no doubt that whoever designed this unit took pride in what they did. It may look old fashioned but I think it looks bloody gorgeous. After 50 odd years I have gone back to electronics as a hobby so to me in a way it's not so old fashioned. I can remember 410 V across the end of my nose ( Mullard Amp). A small scar is still there after 50 years. Thank you so much for this video - it's perfect.
Thanks jp! I'm glad you stopped by.
Mr. Carlson does it again! Great job Sir.
Thanks Sam!
i enjoyed every second of this vid. the fqct you took over an hour of your time to go into detail shows that you have a passion keep it up my friend
Mr. Carlson you forgot to measure the output voltage on the square wave on the output. Once again a great video that simplifies the explanation of circuit design theory.
Wow, what a great in detail explanation! I really like the reverse engineering part and I'm looking forward to see more like this in the future. Never thought, that reading schematics can be fun. You doing a great job, many thanks Paul!
Thanks Reb!
Fascinating! I have some crusty gear from 1970, but had no idea it went back another 30 years.
That may just be the coolest thing I've ever seen. Who would of thought dual traces on an O-11!
Keep it up! Looking forward for more videos from you, don't stop!
You really had passion with electronics. Your really make simple what is really complex. Congratulations.
Paul, its good to see another video on YT again, That electronic switch unit is a beautiful instrument !!!! I have heard of these being used with oscilloscopes but NEVER seen it actually done !! Thanks for the video restoration and demo, a real treat as always !!!!!! John A Bellas KC2UVN
That was great. What made it a joy to follow was everything is so clean and pristine. Are you sure you didn't go back in time and get this in a specialty shop? It's like brand new. Down to the leaves on the bakelite tube bases, and no tarnish on the goat shields. Please do more like this, what a great rebuild.
Very Well Explained.
Easy to follow!!!
Enjoyed this very much!!!
Looking forward for more!!!
Thank You!!!!!
Thanks Michael, glad you enjoyed!
Very interesting and enjoyable video. Recently purchased a Tektronix 465 scope which works fairly well but is not displaying CH2 when ALT is selected. Works with CHOP. Might be the switches need cleaning. I have not investigated yet, but this video helps explain the operation clearly and should help with the thought processes needed to fix it. Thank you
Paul... Awesome job! This was just a really enjoyable video. And what a cool find... Now looking and working like new at almost 80 years old. Wow. Thanks for all the effort!
Thanks Phil!
Fascinating ,such attention to detail in the old equipment. Very documented , you really know your stuff ! Cheers
I also find point to point reverse engineering to be quite challenging. It is easier to reverse engineer circuit boards that are single or double layer, but multi layer boards are a mess. I used to design circuit boards for a living and some of them can have up to twenty layers on the modern circuit boards. Oh the days of laying out all those traces on vellum sheets. some of them were like 3 foot by 5 foot pieces because we scaled them up for easy layout. now everything can be done on PC which is much more practical.
Always enjoy watching and learning from you. You remind me of my High School Electronics teacher. His logic was text books can teach you theory, but hands on is the only way to learn electronics. My first project was a Tesla coil using a 10,000 volt 30mA vacuum Tube Transformer as a power source. Was so cool to see it in action. I would love to see you do a restoration on one of those transformers in one of your videos.
My father (age 67) watch this before me and after i mentioned loctal valve he then told me about the similar equipment he used to use.
Because he has explained to me how these older valves work in detail i had figured out about half of it works but couldn't quite figure how it mixes the channels together so i just had a 10min explanation of the oscillator component.
Wonderful, I have been watching one of you videos every day this last week, can’t leave the alone , thank you
Excellent video. I am from the UK, sadly no one in the UK produces Video's like you, Keith Rucker, etc. do from over the pond! I was an apprentice 1953/1959 at the D.S.I.R. Radio Research Station working for Dr Smith Rose, Wilkins, etc. making the all the type of equipment you are interested in! Your video,s are jogging my memories ,
interesting video , your a true electronics engineer. i used to work on valve amps may years ago but your in a totally different league :)
Thank you for another greatly enjoyable video! The leaf - an oak leaf, actually - with the "S" letter inside was the earliest logo used by Sylvania after the brand was created by Nilco Lamp Works in 1924.
Thanks for your input Norman!
I have no idea of what are you doing or how this thing works but I found this fascinating
THOROUGHLY enjoyed this. Thank you for posting it, and PLEASE do more!!
Thanks!
Ohh yeah, a new video from Mr Calson.
Sheffield Lane I think he's already there!
Cathode ray porn star?
Excellent presentation.. I had one of these Oscilloscope switchers about 45 years ago..
Lots of good tips in this video. Thanks Paul.
Very interesting. I have an EICO Model 488 Electronic Switch. It's shape is like yours, but shorter and wider, but the front panel components are laid out just about the same. This video makes me want to check it out and get it working. Will hooke it up to my old Devry tube Oscope. First I need to get my Eico 960B Cap tester going first. Thanks!
My interests in electronics started out in the late 50's when I was about 9 years old so tube stuff is very familiar to me.
Made back in the day when construction was a work of art, when people really cared about what they built.
I actually have a radio built in 1944 that still works. Hand wired, original valves (tubes). I tested everything before I applied power. The set was bought by my grandparents, and still has the shop guarantee. They were supplied as kits of parts to local shops to assemble.
Boat anchor art to fill the shelves.
You have to understand all this hand built stuff is extremely expensive.
Steven Cook, Make sure you replace the caps as does Paul Carlson. That will keep your machine working for decades more. Add to the voltage rating as they are not the same as the caps were back then. Use a good brand (see his video on choosing components by brand).
Fantastic work, both electronic and video production. i learned something new about dust in pots, makes sense to mount them hole down.
Hi once more Paul, very interesting video again in the fixing of the Sylvainia Electronic Switch. The Heathkit oscilloscope you used there in the video. I picked one up years ago while on holiday at Filey on the UK East coast. It was outside a British Heart foundation charity shop. Could not resist going in to enquire regarding the scope. They wanted a fortune to get rid of it. £5.0. Whow, I could not believ it. Did not care about if it worked or not. £5.0 was worth it just for the case has far as I was concerned. When I got it home, it took a bit of sorting out but soon had it up and running. Not bad for the price. 73 de John _ G0WXU
Thanks for sharing your story John!
Paul,
My research on Wikipedia reveals that the Loctal tubes were introduced by Sylvania in 1939. So I would estimate the age of your switch is probably early to mid 1940s. It is also my understanding that the Loctal tube fell out of use in the 1950s. The octal tubes were still used (early "All American Five" radios) and most audio and test gear. To shrink the chassis real estate, miniature tubes (7 and 9-pin) were used in televisions, radios as well as test equipment. I have an old RCA Senior Voltohmist VTVM with a 12AU7 meter bridge and a 6AL5 AC rectifier to make AC voltage measurements. I also have a Hickok Model 6000A tube tester with a 5Y3 standard rectifier and a type 83 mercury vapor rectifier in it. I prefer tubes for audio as I like the "tube sound". I has a much warmer sound than the starkness of solid state.
Thanks for the video and sharing your knowledge!
Dave
Excellent restoration and presentation. I was surprised how good the channel switching square wave was with reasonably fast rise time and virtually no overshoot.
Would like to have seen a DC offset control to allow DC measurement on both channels.
Thank you
Thanks for your comment Peter!