Learn about electronics in a different and very effective way, and at the same time, have access to Mr Carlson's circuit designs! Go to Mr Carlson's Patreon page, click here: www.patreon.com/MrCarlsonsLab * (EDIT) UPDATE: New Curve Tracer video just launched on Patreon!*
Good video ! I remember building a V.U. meter in high school electronics. It too used the LM399 chip, but it used leds instead of a VFD. The front end used the LM324 chip to clean up the signal and provide the different frequency spectrums.
Mr Carson Sir . I am 62 years of age and a lifelong Electronics Enthusiast . I have learnt more in the Two years or so I have been following you than I did in all the preceding time. Thank you so much .
Watching these sessions has been such a blessing to my sanity. He's reminding me of so many things I have forgotten. I wrote him a nice long note telling him he was not only fixing equipment he's helping me as well.
I highly recomend Mr. Carlsons patreon class. You will in my opinion learn 10 times more then taking a formal class, at such a tiny price I can afford it .He does examples in point to point, surface and through all, sometimes making the same device those three different ways enabling you to better understand each process. He also shows you the pit falls and how to do it safely for you and the equipment your working or learning on. You also gain valuable experience learning the testing equipment he shares , building and explaining them in laymens terms . Thank you again for sharing your experience and knowledge Mr. Carlson. Cleveland P.
First of all, I admire the work you do. I've watched your content multiple times over. Matter of fact, your content often reminds me of my English teachers. I was famous, or possibly infamous, for adding extra words to my sentences. And here you are, one of the most intelligent people I have ever seen, and you do the exact same thing! You add "as well" to many of your sentences! It brings me much joy!! I'd like to go back to my English teachers and tell them that the smart people do what I do... "as well"!
i've studied electoincs in the past , and i was working on my home work at a gas station when a guy saw me doing it .. he took me under his wing and gave me my first job repairing monitors for compugraphic computers , but i wanted to brush up on stuff and mr carlson you are very very informative, taking me back to my electronic coarses and my teachers , but you sir are the best!!!!!!!!!!!!!!!!!!!!!!!!!! i did have a huntron 2000 curve tracer but had to sell it years ago when times where tough , but now im building a curve tracer and have renewed my passion for electronics
Thanks, Mr. Carlson! You keep showing me more uses for the Signature Analyzer (known as “Component Test” on my scope). I appreciate how you cut through the complexities to show us simple ways to troubleshoot.
Looking back as a young tech working on home stereo and TVs in the late 80's/ early 90's I can look at that Sansui schematic and really appreciate it. A work of art compared to today. Nice job finding the faults. Cheers, - Eddy
I've worked as a technician too, in this years, vintage hi-fi equipments where well and build for durability, not "buy, use and throw away" as nowdays ! The oldest hi-fi system i own, is 45 years old, it's a "compact studio" designed German device ( really current in the 70') , still works, but certainly needs à serious reconditionning ( recap, and readjustments..).
I recently had to diagnose a no start electric motor on a 1981 Singer furnace in one of my rental houses. I am not a hvac tech, or electrician by any means but have learned enough in my 43 years to get me into trouble. I was extremely impressed by the schematic neatly tucked inside the furnace that made it very easy to repair. I wish more companies did this today.
Hello, you have great and informative videos! I have been fixing electronic gear for over 35 years and still pickup some new tips and tricks. I have a very old Tenma analog oscilloscope that has a "Component Tester" built-in which runs the scope in a sort of "X Y" mode and looks and works just like your signal tracer. I get all the same readings when looking at Transistors, diodes, regular and zener. I thought I was going to get rid of the old analog after purchasing my Digital storage O-Scope but it is still very useful for a few reasons. Keep up the good videos!
Just found you. Don't understand anything you're saying. But I couldn't shut you off. I loved it. I can't imagine the experience and education for what you do.
HAHA, I was working on a project by myself today and caught myself saying "sodder" instead of "solder"...LOL, I corrected myself as I talked to myself reminiscing of the vid in which you explain why you are sure to pronounce the "L". Just something funny I found myself doing today. Thanks again for being one of those teachers that really stand out as being a great teacher. Cheers to you Mr. Carlson.
Hi Paul, great repair job and video. I love how the curve tracer works so well to find a faulty component(s). I notice that you have moved some gear around in the lab. :-P I see (and hear) you are using a different desoldering tool. It doesn't sound as robust as your revved up Hakko 470 does. That thing really growled. I also am impressed with the quality and attention to detail in the Sansui schematic. With modern electronics CAD programs, there is no reason that that level of detail (including illustrations of the components) could not be included in every schematic with the press of a button. It took designers countless hours of hand drawing to create those schematics in the 70's and 80's. So there is no reason to not make "good" schematics. Thanks again so very much for the videos and the graduate level education you provide the youtube community!
I'm so amazed this troubleshooting. Thank you Mr Carlson. And I'm seconded to Mr Cleveland for highly recommend everyone to take electronic course on patreon. If you have a few knowledge in electronics it will accelerated through this course, what are you waiting for? The magic revealed in there!
In the true tradition of the Ham community, you share your hard-earned knowledge. Thank you. My dad and I made a curve tracer out of an old Heah Kit scope I think it was 65 or 66,, really foggy memory.
with all my respect I think is time for Carlson to have the camera pointed more at him than the equipment you have it is impressive that you have all that but equipment without a user is just a bunch of gizmos with no user just have a view of yourself, people might think that you are just showing off you know what I mean? you are the most important person and you are the one who deserved to be on the center of the screen than the equipment by the way I love your channel :)
Greetings from the UK! Love watching your videos! I had a Sansui A-60 Amplifier which was at times problematic but i drove my parents crazy blasting out my 'boom boom music' I miss those days!
I follow you from Istanbul. Everything is great. Thanks to your excellent English, I improve my English and improve my amateur electronic hobby every day. Thank you very much.
Mr. Calson's Lab has inspired me. He is a great person to learn from. I have inherited some old radios, a Philco 96 Highboy, and a Zenith 8A02. I have played the Zenith until the dial belt broke. Don't criticize yet, I didn't give a second thought to leaking wax caps until recently. I'm now starting the restoration process on the Philco, and hope to have it playing by Christmas. The Zenith will soon follow. Thank you, Mr. Carlson, for the inspiration. It will be nice to listen to BBC on short wave again.
Oh man. I loooove watching your videos Mr Carlson!! I know nothing about the stuff you do, but you sure make it very interesting with your excellent way of explaining and going through parts and telling about it's functions. Your knowledge is really impressing. And I also love the looks of the tech you restore and fix. Knobs, meters, buttons and all that sweet stuff! Greetings from Sweden Mr Carlson.
I know what you mean about quality. I have a AU-9500 Sansui from 1975. Still performs like it did back in the day. The cover has never been off, till last week. I sprayed the pots. Thanks for the video Paul.
Beautiful hand rendered artwork, with a gorgeous VFD up in front!! AWESOME! I put a new non-standard VFD in one of those 1980s Heathkit synthesized output ham radio transceivers. I remember getting a free tiny CRT television AM FM SW CB radio for attending a sales pitch for a time share in Nevada. The schematic for that is a thing of beauty! Wave forms galore, signal paths, diagrams of every component and even a quick guide to the most common problems. That RCA scope reminds me of "The Octopus" test circuit for an O Scope. OH HO! IT IS AN OCTOPUS & A Sine WAVE GEN ON AN OLD RCA Bread n Butter scope!
Have you seen how much equipment a real world every day production tech actually has on their bench? The lay person would be surprised how little there really is. Not knocking him but this is television with all that goes with it. 99% of that stuff is the set.
@@InsideOfMyOwnMind that said.... i don't do "television" but to tell you the truth, i would set my bench up this way if i had the option :) 'course, i always wanted to be an astronaut.....
@@InsideOfMyOwnMind You maybe forget that he's a collector, and also a working engineer - not *JUST* a "Yoo Toooba" - what do you think he does INBETWEEN videos? He works for $$ - a REAL, PHYSICAL WORLD JOB.
@@InsideOfMyOwnMind If you look through the videos almost all of that equipment has been used at some point. Mr. C Frequently remarks against creating shelf queens.
Amazing video. Love the way you have explained every single step and love the tools you are using. Signal tracer is great!! The curves looks like an scope working in XY mode.
I think this is a good basics and educational video. Lots of useful reminders even for the more experienced. Don’t know about the USA but even live chassis were common back in the day. Never used a signal trace. Very interesting.
Great, it's like school... but it's coooooool school! There is so much info you are so generously putting out in these videos, it's really quite something; and so, a gracious thank you is in order. Thanks dude!
What else would you expect from a world-class electromechanical video/audio enthusiast? I'd wager the equipment used to make this channel's upload content is likely in the best shape of any YT'er.
I had one of these. One of the cleanest sounding lower power amps Ive ever had. Wished I'd kept it. It was a gift to me from someone cleaning out there garage. I had 8 good heavy hard use of years out of it.
Loved the video. I haven't used a curve tracer since I was learning electronics back in high school. Thanks so much for reminding me what a powerful tool that can be in troubleshooting components.
Mr Carlson I've been watching your videos for some time now and while I only have a rudimentary understanding of electronics I find them fascinating and educational. Now how about tackling the most difficult electrical repair of the modern era. The scourge of pulling out last years perfectly working Christmas tree lights only to find half of the strand working! There must be an easier way to fix then the trial and error method of replacing every bulb one at a time. Thanks!! Merry Christmas/Happy Hanukkah!! :)
I love listening to your show always extremely informative and always spot-on thank you for the time that you spend and creating it and producing it for us greatly greatly appreciated again
Paul, as a teenage TV & VCR repair apprentice, in 1991, I remember being given LOTS of old VCRs, and smashing the fronts off the VFD displays and strumming those steel wires like a mini guitar - I still remember the sound and the smell of the "getters" :-) hah
Very cool trouble-finding method! Made me realise I should be doing more of this. I have a Hameg HM604 with a 'component tester' built into it - basically a rudimentary curve tracer. It's strange, I never thought to use this to find problems with in-circuit parts before. In my mind, it was just there to test desoldered parts and invdividual components of dubious history or origin. Turns out I was pretty much completely unaware of the very powerful circuit diagnostic tool I had been sitting on! I'm aware of the possibilities now, thanks! That old CRO is going to be warmed up more often at my bench now.
It's nice to see someone else using a tracer. I have the privilege to have a newer Huntron on my bench (Company purchased) and I really do use it at least once or twice a week. Keep up the great work!
Great video as always Paul. What a wonderfully stereotypical (pun intended) piece of 80s gear. More circuitry dedicated to the blinkenlights than to the actual amplification. I have an '89ish Sony component system that has separate custom VFDs for everything from spectrum analyser and tuner frequency to a diagram showing the state of the CD changer. I don't use it, I just keep it as a reminder of when we felt we needed flashy lights and screens for absolutely everything.
Toujours aussi plaisant et instructif de suivre tes vidéos ! Merci pour le partage ! Always so fun and informative to follow your videos! Thank you for sharing !
The Eloquent Great One strikes again. Always flawlessly well done. I, as well, am off to invest in my future by joining Paul's patrion. I've learned more watching these videos than any other way I've tried. A job well done, many thanks for your ass kickin teaching style and kudos to your mind bogglingly vast command of knowledge and professionalism of the trade that you wrench from the guts of this dark art. As the gals in Tokyo used to tell me (at least one of them anyway if I recolect correctly) "please, don't stop!" ;) By the way, I have been playing an electric guitar through a non moded, totally original, RF input of an Eico 147A Signal Tracer, and it sounds bitchin. I call it the Eico Chimp. Thanks again and looking forward to more of your fantastic vids!
II learned about the repair of the spectrometer by using the siginture analyzer it is a good troubleshooting tool. Thank you for this video alan kellerhouse
You talked about displays and E.L. lamps. At one time, I worked for a co. that made trainers for NASA. One of the trainers was the LEM (lunar excursion module). All of the displays were back lit with E.L.'s. They were made on ceramics not plastic for very rough service. These types of units were eventually made into night lights that glowed green. BTW, I sat on one of the couches with all if the meters and gages lit. IT WAS AWLSOME!
Vacuum tube displays were currently used on hi-fi devices, videotape recorder, and kitchen appliances too ( programming displays on hight end microwave ovens.)
It's unfortunate (but understandable, as it's video focused on the repair) he didn't explain the VFD driver circuit, as in my opinion it's quite elegant. I figured I'd take a stab at it here. Schematic is shown a.o around 19:49. On the left of the schematic, there's the 10 opamps for the 10 frequency bands, each one surrounded by what I think must be a L and a C that together make a bandpass filter to filter out the frequency for that frequency band. The opamp is followed by a diode and a capacitor to do rectification; the output of that is more-or-less a voltage indicating the audio energy in that band. Now, the way the display works is that it's scanned: at every single time, there's only one of the grids active, allowing only the one column of indicators for one frequency band to light up; all the other frequency bands remain dark. This is done with the IC at the bottom of the schematic, which probably is a 4017-like decade counter: every time it gets a clock pulse it activates the next of its 10 outputs, looping back to the first one once it reaches its end. This counter is clocked by the free-running oscillator made out of a few discrete gates that's visible to the right of it. Every output of this decade counter does two things: first of all, it goes off to the right, to a comparator (that's being used as a voltage shifter here) that drives the grids of the VFD to actually activate the grid for the current frequency. Secondly, it goes off to the right, to the bank of bandpass filters, to let the signal of the filter for the selected frequency pass to one common line. (That's what the transistors next to the bandpass filter are for.) This line then goes over the VFD, all the way to the right side of the schematic, and gets passed into the bank of comparators there. That bank has a set of thresholds each a little higher than the other. so for every comparator that's above the next, it takes a little more power to activate. Each of these comparators drive all the segments (plates) that are in the same horizontal position, but as only one grid is active, only the segments under that activated grid actually light up. This way, you'll have a 'column' of activated segments which heights corresponds to the frequency in the selected band. All of that works together to effectively activate a VFD column for a frequency band, sample the filtered power in that frequency band and compare that to the threshold needed for each level segment to activate that, and drive the segments correspondingly. The electronics will let that sit for a short while before moving on and doing the same for the next frequency band and VFD column. This means at every single time, only one column is active, but because of persistence of vision, it looks like all segments are driven at the same time.
Thanks for taking the time to explain. I agree - Had he elaborated on VFD driver principals as you did, he could have immediately counted for row number coresponding to row that was stuck 'on', and home onto defective comparator directly. No need for curve tracer. Wait! may be he did that on purpose to spin this tracer and drum up donation.
@@jimwilliams8858 Eh, I think if it's more a case of 'when all you have is a hammer'... the curve tracer is very handy for when you have multiple signal paths that are more-or-less the same, and this is a prime example of that. Plus, for people who aren't that good at electronics, this is the easier route to take: with the curve tracer you can still find the error even if you can't make heads or tails of how the actual electronics work. Still, I think some explanation of the schematic would have been nice, as, as I said before, I think it's pretty elegant.
@@abc-ni9uw I'm not that familiar with degrading patterns of VFDs, but it can be some things. If the lower bars are dim but the upper ones are still bright, it's yer normal wear-and-tear: the phosphors will have a certain half life when lit and they will get naturally dimmer over time. If the entire display is dark, something may be going on with the supply voltages; obviously, if these are too low the VFD will also dim. I see the amp discussed here also has an automatic dimming circuit, perhaps the error is even as simple as whatever photosensitive is in there going off.
I enjoy watching your videos. As always, very informative in a great clear detailed explanation. By the way I have this same Sansui amp model. With the matching pre amp. As a trivia information, this same amp model along with the matching pre amp are here highlighted in the movie Aquaman. Even so that this Sansui model is from 1981 it still looks cool and modern .
Great company Sansui, I bought a direct drive turntable in 1976 and it still works perfect. Cost me 2 weeks wages back then and well worth it. With a nice $90 cartridge and $400 needle it ended up perfect. ;) Anything early from Sansui is worth grabbing to replace the crap that came out in the last 25 years lol
I had a Sansui 9090DB Quad SQ amp/receiver back then when the Sarasota radio station (Quad 102.5) was broadcasting in SQ Matrix. I t was kinda cool with the 2 channel/4 track Sansui SD 5000 reel to reel that I used to record the new albums they broadcast every Friday night.
Probably right, I don't really remember exactly what Model it was. That was back in '74, but it was def QS which I had bought and used for the aforementioned radio station receiving..
Anyone subscribed with more than a simple passing interest should head over to Patreon and kick in a minimum at least. It only took me a few hours to move up from minimum to a "bit" more once I saw the quality that is there for any Patreon member. Mr Carlson, Kudos again! I have a small stack of projects I need to turn my attention to including a nice early 80s vintage Yamaha power amp that "let the magic smoke out" on me a few years ago, I could not bring myself to "recycle" it into parts or put it in a trash bin. I also have a Bogen tube PA amp that had the back panel get wet. NO idea how much damage was done, we have owned it since new and I was sick when I saw it wet in storage. I DID have a good outcome in repairing a Sony monitor that lost an IC. My first attempt at micro soldering and it worked! I now use that monitor along with a video camera to be a 20 power microscope. Another very handy tool to have on the bench!
I know many of these videos are troubleshooting/repair focused but I'd love to see more walkthrough of schematics even that are working correctly. I'd like to hear some of the design techniques that the engineers where using back when these devices were made.
I love your Channel. This Video had a lot of extra Breathing. It's a little off putting. Love watching you. You like a Hero of the electronic world. Thanks for all the info be well.
ive always wanted that b-77 i think its a very different power amp i like dual display leds and sptrm dislpay realy cool early to mid 80s man you realy went straight to the problem i learned alot of saftey info realy cool that box device you made and then the other one for checking those op amp ic s on the spectrum board displays and their circutry look so tedious and difficult to fix but no problem for u ! nice work .
Learn about electronics in a different and very effective way, and at the same time, have access to Mr Carlson's circuit designs! Go to Mr Carlson's Patreon page, click here: www.patreon.com/MrCarlsonsLab * (EDIT) UPDATE: New Curve Tracer video just launched on Patreon!*
Good video ! I remember building a V.U. meter in high school electronics. It too used the LM399 chip, but it used leds instead of a VFD. The front end used the LM324 chip to clean up the signal and provide the different frequency spectrums.
@Dave Micolichek I guess it was called a frequency spectrum meter. I guess I wrote the comment wrong. Thanks.
@hvacr tech you should see my work benches !
Mr Carlson's Lab pretian
Mr Carlson's Lab patron
Mr Carson Sir . I am 62 years of age and a lifelong Electronics Enthusiast . I have learnt more in the Two years or so I have been following you than I did in all the preceding time. Thank you so much .
Awesome job Paul. I’m 68 years old and I can still learn new tricks.
Watching these sessions has been such a blessing to my sanity. He's reminding me of so many things I have forgotten. I wrote him a nice long note telling him he was not only fixing equipment he's helping me as well.
Thank You for your kind feedback Jerry.
I highly recomend Mr. Carlsons patreon class. You will in my opinion learn 10 times more then taking a formal class, at such a tiny price I can afford it .He does examples in point to point, surface and through all, sometimes making the same device those three different ways enabling you to better understand each process. He also shows you the pit falls and how to do it safely for you and the equipment your working or learning on. You also gain valuable experience learning the testing equipment he shares , building and explaining them in laymens terms . Thank you again for sharing your experience and knowledge Mr. Carlson.
Cleveland P.
You're very welcome Cleveland!
First of all, I admire the work you do. I've watched your content multiple times over.
Matter of fact, your content often reminds me of my English teachers. I was famous, or possibly infamous, for adding extra words to my sentences. And here you are, one of the most intelligent people I have ever seen, and you do the exact same thing!
You add "as well" to many of your sentences! It brings me much joy!! I'd like to go back to my English teachers and tell them that the smart people do what I do... "as well"!
i've studied electoincs in the past , and i was working on my home work at a gas station when a guy saw me doing it .. he took me under his wing and gave me my first job repairing monitors for compugraphic computers , but i wanted to brush up on stuff and mr carlson you are very very informative, taking me back to my electronic coarses and my teachers , but you sir are the best!!!!!!!!!!!!!!!!!!!!!!!!!! i did have a huntron 2000 curve tracer but had to sell it years ago when times where tough , but now im building a curve tracer and have renewed my passion for electronics
Thanks, Mr. Carlson! You keep showing me more uses for the Signature Analyzer (known as “Component Test” on my scope). I appreciate how you cut through the complexities to show us simple ways to troubleshoot.
Every single video, no matter what year, the same volume! Outstanding!
I'm impressed you can say solder correctly. There's a lot of soddering going on south. The tracer is gold. Great video.
Soddering! Lol! Sounds funny! Is soddering carried out by sods or sodderers? Cotter keys instead of split pins!
Looking back as a young tech working on home stereo and TVs in the late 80's/ early 90's I can look at that Sansui schematic and really appreciate it. A work of art compared to today.
Nice job finding the faults.
Cheers,
- Eddy
I've worked as a technician too, in this years, vintage hi-fi equipments where well and build for durability, not "buy, use and throw away" as nowdays !
The oldest hi-fi system i own, is 45 years old, it's a "compact studio" designed German device ( really current in the 70') , still works, but certainly needs à serious reconditionning ( recap, and readjustments..).
Your videos typically make me feel stupid but I love watching them and seeing a genius at work!
I recently had to diagnose a no start electric motor on a 1981 Singer furnace in one of my rental houses. I am not a hvac tech, or electrician by any means but have learned enough in my 43 years to get me into trouble. I was extremely impressed by the schematic neatly tucked inside the furnace that made it very easy to repair. I wish more companies did this today.
Finally someone who knows this stuff and is willing to help us. Thank you Mr Carlson!
Our electric shop teacher in high school taught us to use a signal tracer. Never used one since, and your video shows me what I have missed.
Hello, you have great and informative videos! I have been fixing electronic gear for over 35 years and still pickup some new tips and tricks. I have a very old Tenma analog oscilloscope that has a "Component Tester" built-in which runs the scope in a sort of "X Y" mode and looks and works just like your signal tracer. I get all the same readings when looking at Transistors, diodes, regular and zener. I thought I was going to get rid of the old analog after purchasing my Digital storage O-Scope but it is still very useful for a few reasons. Keep up the good videos!
Mr. Carlson makes even the most complicated faults look so easy to fix. Thanks for this great and informative video.
40 years of electronic troubleshooting and you STILL teach me something new !
A new Mr. Carlson's Lab video!!!! Best day this week!!!!
IKR ! I already hit like even before watching knowing its going to be good regardless.
@@patprop74 Same here!!
patprop74 Same
Just found you. Don't understand anything you're saying. But I couldn't shut you off. I loved it. I can't imagine the experience and education for what you do.
Excellent video, nice clear shots. Very easy to follow. Best part, no music. Thanks.
HAHA, I was working on a project by myself today and caught myself saying "sodder" instead of "solder"...LOL, I corrected myself as I talked to myself reminiscing of the vid in which you explain why you are sure to pronounce the "L". Just something funny I found myself doing today. Thanks again for being one of those teachers that really stand out as being a great teacher.
Cheers to you Mr. Carlson.
Even though I don't understand much about electronics I find these videos fascinating and addicting.
That thing would have really made my eyes light up back in the 80s.
Probably one of the nicest schematics you’ve shown us.
“Enjoy” is a *massive* understatement!
Thank you, Mr. Carlson! 🍎
Hi Paul, great repair job and video. I love how the curve tracer works so well to find a faulty component(s). I notice that you have moved some gear around in the lab. :-P I see (and hear) you are using a different desoldering tool. It doesn't sound as robust as your revved up Hakko 470 does. That thing really growled. I also am impressed with the quality and attention to detail in the Sansui schematic. With modern electronics CAD programs, there is no reason that that level of detail (including illustrations of the components) could not be included in every schematic with the press of a button. It took designers countless hours of hand drawing to create those schematics in the 70's and 80's. So there is no reason to not make "good" schematics. Thanks again so very much for the videos and the graduate level education you provide the youtube community!
Thanks Gary!
I'm so amazed this troubleshooting. Thank you Mr Carlson. And I'm seconded to Mr Cleveland for highly recommend everyone to take electronic course on patreon. If you have a few knowledge in electronics it will accelerated through this course, what are you waiting for? The magic revealed in there!
In the true tradition of the Ham community, you share your hard-earned knowledge. Thank you. My dad and I made a curve tracer out of an old Heah Kit scope I think it was 65 or 66,, really foggy memory.
with all my respect I think is time for Carlson to have the camera pointed more at him than the equipment you have it is impressive that you have all that but equipment without a user is just a bunch of gizmos with no user just have a view of yourself, people might think that you are just showing off you know what I mean? you are the most important person and you are the one who deserved to be on the center of the screen than the equipment by the way I love your channel :)
Greetings from the UK! Love watching your videos! I had a Sansui A-60 Amplifier which was at times problematic but i drove my parents crazy blasting out my 'boom boom music' I miss those days!
I follow you from Istanbul. Everything is great. Thanks to your excellent English, I improve my English and improve my amateur electronic hobby every day. Thank you very much.
Excellent video Mr Carlson. Full credit to you for your patience and intuitive personality. I really enjoy your videos. Thank you.
Mr. Calson's Lab has inspired me. He is a great person to learn from. I have inherited some old radios, a Philco 96 Highboy, and a Zenith 8A02. I have played the Zenith until the dial belt broke. Don't criticize yet, I didn't give a second thought to leaking wax caps until recently. I'm now starting the restoration process on the Philco, and hope to have it playing by Christmas. The Zenith will soon follow. Thank you, Mr. Carlson, for the inspiration. It will be nice to listen to BBC on short wave again.
You're welcome Chad!
Oh man. I loooove watching your videos Mr Carlson!! I know nothing about the stuff you do, but you sure make it very interesting with your excellent way of explaining and going through parts and telling about it's functions.
Your knowledge is really impressing. And I also love the looks of the tech you restore and fix. Knobs, meters, buttons and all that sweet stuff! Greetings from Sweden Mr Carlson.
I appreciate that!
I know what you mean about quality. I have a AU-9500 Sansui from 1975. Still performs like it did back in the day.
The cover has never been off, till last week. I sprayed the pots. Thanks for the video Paul.
I'll never be able to use all this knowledge from you but so informative and easy to grasp how you explain things, thanks
Beautiful hand rendered artwork, with a gorgeous VFD up in front!! AWESOME! I put a new non-standard VFD in one of those 1980s Heathkit synthesized output ham radio transceivers. I remember getting a free tiny CRT television AM FM SW CB radio for attending a sales pitch for a time share in Nevada. The schematic for that is a thing of beauty! Wave forms galore, signal paths, diagrams of every component and even a quick guide to the most common problems. That RCA scope reminds me of "The Octopus" test circuit for an O Scope. OH HO! IT IS AN OCTOPUS & A Sine WAVE GEN ON AN OLD RCA Bread n Butter scope!
Amazing... your lab looks like the international space station.
Greetings from France
Have you seen how much equipment a real world every day production tech actually has on their bench? The lay person would be surprised how little there really is. Not knocking him but this is television with all that goes with it. 99% of that stuff is the set.
@@InsideOfMyOwnMind that said.... i don't do "television" but to tell you the truth, i would set my bench up this way if i had the option :)
'course, i always wanted to be an astronaut.....
@@InsideOfMyOwnMind You maybe forget that he's a collector, and also a working engineer - not *JUST* a "Yoo Toooba" - what do you think he does INBETWEEN videos? He works for $$ - a REAL, PHYSICAL WORLD JOB.
@@unlokia Thank you. I wondered about that. In general a person is only seen as deep as what you've seen them do which is always understated in video.
@@InsideOfMyOwnMind If you look through the videos almost all of that equipment has been used at some point. Mr. C Frequently remarks against creating shelf queens.
Amazing video. Love the way you have explained every single step and love the tools you are using. Signal tracer is great!! The curves looks like an scope working in XY mode.
I am impressed. Quick and easy, after seeing that! You're very competent and professional. Kudos!
I think this is a good basics and educational video. Lots of useful reminders even for the more experienced. Don’t know about the USA but even live chassis were common back in the day. Never used a signal trace. Very interesting.
Hey man! Nice seeing you here. This weekend I'm going to catch up on your great videos. Been busy with work. Cheers!
@@fullwaverecked Not been doing anything interresting recently but your always very welcom to drop in
How I love your silent intros! They really make me look forward to the show.
Great, it's like school... but it's coooooool school! There is so much info you are so generously putting out in these videos, it's really quite something; and so, a gracious thank you is in order. Thanks dude!
You are very welcome Mike! Thanks for your kind comment too.
Thank you so much for sharing your knowledge with us. Always a treat to see one of your videos. Very interesting to see the curve tracer at work.
Your audio quality is stunning! There are many channels that could learn from you when it comes to audio and video quality. Keep up the great work.
What else would you expect from a world-class electromechanical video/audio enthusiast?
I'd wager the equipment used to make this channel's upload content is likely in the best shape of any YT'er.
Yeah he's using a $2k microphone & probly a $2k valve preamp mate! I'd expect no less!
I've got one of these amps. Still sounds great! Have never had this issue with it.
Hmm i like your channel
I had one of these. One of the cleanest sounding lower power amps Ive ever had. Wished I'd kept it. It was a gift to me from someone cleaning out there garage. I had 8 good heavy hard use of years out of it.
I'm a proud owner of Yamaha CX-1000/EQ-1100/MX-600 combo...but this machine IS BEAUTIFUL. I want one already.
And another top notch video Paul ♥ And yes, THAT'S what I call a schematic!!! SO NEAT, amazing job indeed by the tech at Sansui, hats off to them !
Thank you Mr Carlson. Very nice neat little video. Just goes to show the 70's rocked....lol... even the schematics were better.
Loved the video. I haven't used a curve tracer since I was learning electronics back in high school. Thanks so much for reminding me what a powerful tool that can be in troubleshooting components.
Awesome watching how simple and straightforward you work. Thanks for the great vid.
Mr Carlson's Patreon class is hard to beat! Bar none.
Mr Carlson I've been watching your videos for some time now and while I only have a rudimentary understanding of electronics I find them fascinating and educational. Now how about tackling the most difficult electrical repair of the modern era. The scourge of pulling out last years perfectly working Christmas tree lights only to find half of the strand working! There must be an easier way to fix then the trial and error method of replacing every bulb one at a time. Thanks!! Merry Christmas/Happy Hanukkah!! :)
I loved the new picture in picture, it's a fantastic addition.
I love listening to your show always extremely informative and always spot-on thank you for the time that you spend and creating it and producing it for us greatly greatly appreciated again
Thanks for you're kind words Glenn!
This is just up my street.
As usual no matter what content Paul provides for us I love it all.
Good to see you your looking very well
Paul, as a teenage TV & VCR repair apprentice, in 1991, I remember being given LOTS of old VCRs, and smashing the fronts off the VFD displays and strumming those steel wires like a mini guitar - I still remember the sound and the smell of the "getters" :-) hah
Those poor tubes.. LOL.
Very cool trouble-finding method! Made me realise I should be doing more of this. I have a Hameg HM604 with a 'component tester' built into it - basically a rudimentary curve tracer. It's strange, I never thought to use this to find problems with in-circuit parts before. In my mind, it was just there to test desoldered parts and invdividual components of dubious history or origin. Turns out I was pretty much completely unaware of the very powerful circuit diagnostic tool I had been sitting on! I'm aware of the possibilities now, thanks! That old CRO is going to be warmed up more often at my bench now.
It's nice to see someone else using a tracer. I have the privilege to have a newer Huntron on my bench (Company purchased) and I really do use it at least once or twice a week. Keep up the great work!
A couple of General Motors cars had vacuum tube displays as such and I used to repair the dashboards in the same manner very nice tutorial
Great video as always Paul. What a wonderfully stereotypical (pun intended) piece of 80s gear. More circuitry dedicated to the blinkenlights than to the actual amplification. I have an '89ish Sony component system that has separate custom VFDs for everything from spectrum analyser and tuner frequency to a diagram showing the state of the CD changer. I don't use it, I just keep it as a reminder of when we felt we needed flashy lights and screens for absolutely everything.
I found this amp on the road. Hooked up to my desktop speakers. sounds good but intermittent channel issue. Great video.
The best never rests....Looking forward to this.
That schematic is a thing of beauty.
Golden! Can't wait to have the time to check out the projects on the patreon!
I am fascinated with your videos. Absolutely brilliant, and professional. Thank you. 👍
The VFD displays are just nostalgic!
Their tone, dullness and the colours just can't be replaced by 32 segments LED displays.
Aloha Paul! Another fantastic video you never cease to amaze me with your vast knowledge. I learn something every time.
Toujours aussi plaisant et instructif de suivre tes vidéos !
Merci pour le partage !
Always so fun and informative to follow your videos!
Thank you for sharing !
Thanks George!
The Eloquent Great One strikes again. Always flawlessly well done. I, as well, am off to invest in my future by joining Paul's patrion. I've learned more watching these videos than any other way I've tried. A job well done, many thanks for your ass kickin teaching style and kudos to your mind bogglingly vast command of knowledge and professionalism of the trade that you wrench from the guts of this dark art. As the gals in Tokyo used to tell me (at least one of them anyway if I recolect correctly) "please, don't stop!" ;) By the way, I have been playing an electric guitar through a non moded, totally original, RF input of an Eico 147A Signal Tracer, and it sounds bitchin. I call it the Eico Chimp. Thanks again and looking forward to more of your fantastic vids!
Awesome video Paul!!! you are a genius in electronics, I'm also looking forward for the vedolizer video.
II learned about the repair of the spectrometer by using the siginture analyzer it is a good troubleshooting tool. Thank you for this video
alan kellerhouse
Still have Sansui speakers from when I was i was in high school in the 70,s and they still sound awesome !
I love these videos thank you sharing your knowledge and experience
Once again, excellent trouble-shooting and procedure. Outstanding... 10/10
What better than a good old power amp to take a break from a rabbit hole
I agree!
You talked about displays and E.L. lamps. At one time, I worked for a co. that made trainers for NASA. One of the trainers was the LEM (lunar excursion module). All of the displays were back lit with E.L.'s. They were made on ceramics not plastic for very rough service. These types of units were eventually made into night lights that glowed green. BTW, I sat on one of the couches with all if the meters and gages lit. IT WAS AWLSOME!
Always eagerly awaiting your tubes! *So professional Well laid out and informative*
Vacuum tube displays were currently used on hi-fi devices, videotape recorder, and kitchen appliances too ( programming displays on hight end microwave ovens.)
It's unfortunate (but understandable, as it's video focused on the repair) he didn't explain the VFD driver circuit, as in my opinion it's quite elegant. I figured I'd take a stab at it here. Schematic is shown a.o around 19:49. On the left of the schematic, there's the 10 opamps for the 10 frequency bands, each one surrounded by what I think must be a L and a C that together make a bandpass filter to filter out the frequency for that frequency band. The opamp is followed by a diode and a capacitor to do rectification; the output of that is more-or-less a voltage indicating the audio energy in that band.
Now, the way the display works is that it's scanned: at every single time, there's only one of the grids active, allowing only the one column of indicators for one frequency band to light up; all the other frequency bands remain dark. This is done with the IC at the bottom of the schematic, which probably is a 4017-like decade counter: every time it gets a clock pulse it activates the next of its 10 outputs, looping back to the first one once it reaches its end. This counter is clocked by the free-running oscillator made out of a few discrete gates that's visible to the right of it.
Every output of this decade counter does two things: first of all, it goes off to the right, to a comparator (that's being used as a voltage shifter here) that drives the grids of the VFD to actually activate the grid for the current frequency. Secondly, it goes off to the right, to the bank of bandpass filters, to let the signal of the filter for the selected frequency pass to one common line. (That's what the transistors next to the bandpass filter are for.) This line then goes over the VFD, all the way to the right side of the schematic, and gets passed into the bank of comparators there. That bank has a set of thresholds each a little higher than the other. so for every comparator that's above the next, it takes a little more power to activate. Each of these comparators drive all the segments (plates) that are in the same horizontal position, but as only one grid is active, only the segments under that activated grid actually light up. This way, you'll have a 'column' of activated segments which heights corresponds to the frequency in the selected band.
All of that works together to effectively activate a VFD column for a frequency band, sample the filtered power in that frequency band and compare that to the threshold needed for each level segment to activate that, and drive the segments correspondingly. The electronics will let that sit for a short while before moving on and doing the same for the next frequency band and VFD column. This means at every single time, only one column is active, but because of persistence of vision, it looks like all segments are driven at the same time.
Thanks for taking the time to explain. I agree - Had he elaborated on VFD driver principals as you did, he could have immediately counted for row number coresponding to row that was stuck 'on', and home onto defective comparator directly. No need for curve tracer. Wait! may be he did that on purpose to spin this tracer and drum up donation.
@@jimwilliams8858 Eh, I think if it's more a case of 'when all you have is a hammer'... the curve tracer is very handy for when you have multiple signal paths that are more-or-less the same, and this is a prime example of that. Plus, for people who aren't that good at electronics, this is the easier route to take: with the curve tracer you can still find the error even if you can't make heads or tails of how the actual electronics work. Still, I think some explanation of the schematic would have been nice, as, as I said before, I think it's pretty elegant.
@@jimwilliams8858 Nothing stopping you setting up your own TH-cam channel may also be a better use of your time then leaving sneering comments.....
I have a pioneer sa9800 if your familier with it.
I have a lovely bright display but I'm lucky as many of these are dim.
What causes this
@@abc-ni9uw I'm not that familiar with degrading patterns of VFDs, but it can be some things. If the lower bars are dim but the upper ones are still bright, it's yer normal wear-and-tear: the phosphors will have a certain half life when lit and they will get naturally dimmer over time. If the entire display is dark, something may be going on with the supply voltages; obviously, if these are too low the VFD will also dim. I see the amp discussed here also has an automatic dimming circuit, perhaps the error is even as simple as whatever photosensitive is in there going off.
More mysteries explained, I love it. Thanks Paul.
I enjoy watching your videos. As always, very informative in a great clear detailed explanation. By the way I have this same Sansui amp model. With the matching pre amp. As a trivia information, this same amp model along with the matching pre amp are here highlighted in the movie Aquaman. Even so that this Sansui model is from 1981 it still looks cool and modern .
Cant' wait for part 2 of the Supreme Vedolyzer !!
I'm learning so much from this guy, love these videos :)
The LM series ic’s are brilliant, just built a 2x10 vu peak meter using a pair of lm3916 chips
We love you Mr Carlson... so methodical.
Hello! My father still have this same Sansui device back home, a lot of memories :D
Great company Sansui, I bought a direct drive turntable in 1976 and it still works perfect. Cost me 2 weeks wages back then and well worth it. With a nice $90 cartridge and $400 needle it ended up perfect. ;) Anything early from Sansui is worth grabbing to replace the crap that came out in the last 25 years lol
Excellent Paul , as always
Thanks Paul!
Nice piece of testing equipment, Very easy to understand how it works. Thanks for all of the knowledge,love your work.
I've built hundreds of Heathkits of all kinds, especially audio. Their designs were superb for safety.
What a fantastic marvellous video. I have zero repair skill, But love audio
Glad you enjoyed it Joe!
Back when Sansui was a name to be reckoned with.
They're still a name to be reckoned with but for different reasons lol
I had a Sansui 9090DB Quad SQ amp/receiver back then when the Sarasota radio station (Quad 102.5) was broadcasting in SQ Matrix. I t was kinda cool with the 2 channel/4 track Sansui SD 5000 reel to reel that I used to record the new albums they broadcast every Friday night.
The 9090DB had Dolby FM but not SQ. All 4 channel models were QRX-xxxx.
Probably right, I don't really remember exactly what Model it was. That was back in '74, but it was def QS which I had bought and used for the aforementioned radio station receiving..
@@nfergus11 QRX-5500 maybe ? I just restored one of those for a customer a few months back, amazing piece of equipment.
I always learn a lot from you. Outstanding. Thank you sir!
Is that a silkscreen pattern of the copper side? Neat!
Anyone subscribed with more than a simple passing interest should head over to Patreon and kick in a minimum at least. It only took me a few hours to move up from minimum to a "bit" more once I saw the quality that is there for any Patreon member. Mr Carlson, Kudos again! I have a small stack of projects I need to turn my attention to including a nice early 80s vintage Yamaha power amp that "let the magic smoke out" on me a few years ago, I could not bring myself to "recycle" it into parts or put it in a trash bin. I also have a Bogen tube PA amp that had the back panel get wet. NO idea how much damage was done, we have owned it since new and I was sick when I saw it wet in storage. I DID have a good outcome in repairing a Sony monitor that lost an IC. My first attempt at micro soldering and it worked! I now use that monitor along with a video camera to be a 20 power microscope. Another very handy tool to have on the bench!
I know many of these videos are troubleshooting/repair focused but I'd love to see more walkthrough of schematics even that are working correctly. I'd like to hear some of the design techniques that the engineers where using back when these devices were made.
I love your Channel. This Video had a lot of extra Breathing. It's a little off putting. Love watching you. You like a Hero of the electronic world. Thanks for all the info be well.
ive always wanted that b-77 i think its a very different power amp i like dual display leds and sptrm dislpay realy cool early to mid 80s man you realy went straight to the problem i learned alot of saftey info realy cool that box device you made and then the other one for checking those op amp ic s on the spectrum board displays and their circutry look so tedious and difficult to fix but no problem for u ! nice work .