Signal Tracer Troubleshooting Repair and Modification

More electronic troubleshooting adventures! Join Paul in the Lab as he explains "in great detail" the circuitry inside a Heathkit T-3 signal tracer. Then Paul will discover and fix some design flaws. See how the Watt meter (eye tube) and noise tracer functions work.

[@murdoch817]

Mr. Paul, what can I say except you produce the BEST videos I have ever encountered. Camera work A+, knowledge A+, explanations A+. You make other people's productions look like a pre-school finger painting. I have been doing what you do as a hobby for 20+ years and the first video I watched made me feel like I knew nothing. Please never stop, it has become Saturday ritual to watch 2-3 videos. I have learned SO MUCH,, keep up the awesome work. FYI I have been a chip head since age 10. Thank you so much cause I can imagine the gobs of time it takes to make just 1 production. Way to go, thanks again, Doug USA Philadelphia

[@MrCarlsonsLab]

Thanks for the kind words Doug! More video's on the way.

[@markweber1677]

Couldn't agree with you more mr. Carlson is amazing the genius so glad I found his channel also!

[@minkorrh]

Right on. The amount of innate knowledge that just pours out of this channel is second to none. I'm a 'know-nothing' compared to most of you but a 'know-everything' to my friends lol. I have loved electronics since I was a kid but never got the chance to stream through it in a formal education sense so my theory lacks substantially. It's great to learn from people like Mr. Carlson.......especially Mr. Carlson. Explanations, theory, 'hidden secrets' ....you get it all here. Thanks Mr. C!

[@lesliestone9166]

@@minkorrh a

[@SkyWire88]

I gotta know, Mr. Merlin--------exactly what is a "chip head"? Thanks!

[@dave-d]

Class act mate! Finds the spooky resistor and feeds it to the tester as desert. You crack me up sometimes. Love your work. Keep it coming.

[@paulh3846]

Long term technician here. Now 70. You do a great job of explaining as you troubleshoot. I grew up with vacuum tubes and still love them if one can love something like that. I've taught many troubleshooting classes over the years and am always amazed at the looks I've seen from students when I bring a vacuum tube device in for them to diagnose and repair. The "deer in the headlights" types of expressions. You do an excellent job in your presentations and video work. I especially like your thoroughness to make a device work as well as it can, even if some mods are required. Keep the videos coming.

[@iamhe999]

Excellent trouble shooting, and demonstration of noisey resister..... keep these videos coming, this is your great legacy..

[@bensolomon1872]

Paul - I've been continuously practicing electronic troubleshooting for 50+ years and I learn at least of a couple new tools and thoughtful insights - sometimes subtle, but always useful - with every video. And your even, unassuming demeanor and respect for the student are present throughout. Thanks and bravo!

[@geraldwellborn5047]

I learned electronics in the mid to late 60's from hanging around a radio & TV repair shop. It was a 1-man shop, so I became his helper. He was an old head at fixing radios and televisions. In fact, other shops would often call on him for help when they came across a tough old dog. I learned a lot from him, and I was very blessed to be his helper. He was much like you Mr. Carlson in his ability to troubleshoot and explain how things worked. I guess that is just one of several reason I enjoy your videos. You give great detail and are very methodical. No doubt the younger folks and even older folks like me learn a considerable amount from your videos. There are very few if any who teach how to troubleshoot vacuum tube circuits today. Thank you.

[@jameshicks6753]

Take my breath away?? This one of the most educational thing ever! 😮Thanks

[@JennyEverywhere]

Mr. Carlson, I continue to adore your videos. I'm understanding more about these circuits than I ever have before! Wonderful!

[@jimparr01Utube]

Thanks a bunch Mr. Carlson. Having been around at the dawn of the transistor age as a teenager but also doing lots of vacuum tube radio and TV repairs after school, I truly appreciate your rigorous and back-checking diagnostic procedures. Lots of relaxing fun watching you do your thing. Hoping to get my hands useful again shortly restoring about 10 ancient (pre- 1960's) radios and radiograms - all vacuum tube stuff. Can't wait! Something to do as retired, 71 year old, electronics design engineer.

[@BillyLapTop]

Wonderful episode. Could not tear myself away from it and watch the neighbors fire works display. Thank you for your great videos OM.

[@MrCarlsonsLab]

Thanks Billy!

[@towerman75]

Still amazed at your knowledge and expertise. Keep up the good work, and remember that I am a friend when your species takes over the world.

[@wesleymatthews137]

Brilliant timing. I was cleaning that pot last night AND my audio is crackling too! Where’s my soldering iron and parts bin!! Man, I love this channel…and this hobby! Thank you.

[@MrCarlsonsLab]

Thanks for your kind feedback Wesley!

[@johnfindley1188]

Excellent Job. I just purchased a Heathkit T-3 signal tracer. Thanks for your great explanation of how the unit works and your troubleshooting procedures. John

[@AnalogElectronicsGent]

Awesome Video: excellent circuit theory presented and I love the modifications and how you discovered the noisy component (resistor). The demonstration on how to use all of the functions of this signal tracer is admirable.

[@harrystevens3885]

I came on here 1hr 22 mins ago to watch a Meatloaf video but clicked on your channel and again just fantastic,never a wasted word is the way I describe your videos and you pass your knowledge on to other people better then anybody I have ever come across.Fantastic work.

[@MrCarlsonsLab]

Thanks for your kind comment Harry!

[@festinger3]

Meatloaf is not for listening to, it's for eating. Musical taste is a fickle thing I guess.

[@SkyWire88]

Wow! Guess I'm flabbergasted that a resister could cause an internal noise problem like you have found with the Heathkit T-3. But, there it is. Well done.

[@lavejim11]

These 1629 eye tubes intrigue me...need to do a little research on how they work. Love your vintage test equipment vids. Once upon a time, I put together a few Heathkit test equipment kits, but over the years I lost track of them. I want to put together another vintage bench like you are. Thanks for the videos!!

[@jwl9286]

Mr. Carlson, this is my second viewing of this video. It's even better the second time around. The biasing description is so clear. The 12av6 in the all American five also has the cathode grounded. I've been studying this grid bias phenomenon and this video explains it so clearly. Thanks, you do a fabulous job.

[@MrCarlsonsLab]

You're Welcome!

[@dufusk]

Your level of knowledge and the ease at which you explain your troubleshooting process boggles the mind. Keep up the excellent, excellent work.

[@MrCarlsonsLab]

Thank you!

[@VintageElectronicsGeek]

I second this statement! Looking forward to the signal tracer! Can you also do a function generator! Thanks!

[@JugSouthgate]

The reason Heathkit used unusual tubes in their 1950s kits (particularly test equipment) is because they were WW2 surplus and Heathkit got them for almost nothing. The 12C8, 12SH7, 12A6 and 1629 were common WW2 surplus that weren't used in "civilian" electronics so there was little demand for them, and Heathkit got amazing bargains on carloads of them. As they used up their supply of WW2 tubes, they gradually changed over to more-common types. The 1629 is a 6E5 with an octal base and 12.6 volt heater. It was used in the SCR-274N (ARC-5) transmitters. EXCELLENT video!

[@chriscunningham6362]

My bench looks as if it came out of the 1940's. I restore vintage tube radios and amps and other vintage electronics using all the test gear from the same era. When I sit down at my bench to work (play) it's as if I've been transported back in time to a 1940's radio repair shop. I find it very gratifying as well as escapist. It's a hobby I've done for nearly 40 years and still love it, as well as accumulating a collection of wonderful old radios. Nothing sounds like tubes, even in AM.

[@MrCarlsonsLab]

Thanks for taking the time to write Chris!

[@donaldj.mangold1342]

Hi Paul, Excellent. I would surely expect a bad volume control and either replaced it or doused it with contact cleaner. Your in depth kinowledge of troubleshooting has been very well presented and at my advanced age (81) I can still learn and appreciate the skills of others. Thank you for your excellent presentation and looking forward to more great learning videos. Don

[@MrCarlsonsLab]

Hi Don. Age is only a number, and at 81, using a computer and interested in electronics..... That's absolutely great!!!! I'm very glad your enjoying the video's, and thanks for your kind words too!

[@kdegru1080]

I basically was taught electronics as a child by building Heathkits, Eico kits and Knight kits, et al,. I always read over and over again the engineer's circuit description notes as to how the circuit worked until I could begin to comprehend them. This lead to a lifetime career of over 45 years and still continuing as a broadcast tv maintenance technician. Your educational videos are really top notch and so much better than the Jam Handy Organisation videos or those dry government instructional videos I was forced to endure in school. Your theory explanations are geared to practicality and would be most welcome to newbies trying to learn about electronics. To this day I always get a thrill from opening and restoring a piece of antique vacuum tube electronic gear to give it useful life again while at the same time I can relive a very happy childhood in that process.

[@MrCarlsonsLab]

Great! Thanks for taking the time to write!

[@randallculp2414]

I wish I had this exceptional man looking over my shoulder as a teacher and I’m in my 60s trying to work on old equipment. Amazing man. Thanks for your helpful and pleasant demeanour.

[@michaelj.mansell8235]

I am 65 as well, continuing to work on my hobby (hobby (#5) electronics,) now starting a more concentrated effort towads a major focus on Electronics & Amateur radio 📻. I have dabbled in electronics since approx 1966, I had parent's that were either too trustworthy or totally ignorant towards the dangers of "high voltage" in 📺 's! When I was approx 12 years of age I got to close to the high voltage transformer for the crt and was thrown clear across my bedroom. I didn't learn much, as all I did was get up, brushed out any lingering cob webs, walked back to my exploration adventure of a newly acquired TV set. Since that time l attempted to learn electronics on my own with mixed results! I have shocked myself a few times but never to the Olympic Games level of Manitoba puddle jumping adventures. There is a lot we can learn from this and so many more great teachers one can find on KZbin. Between all of my great books available, the internet and KZbin instructional videos, an individual can learn a lot, have fun and help the environment out.

[@waynecarlson3736]

Paul great to bring the older equipment back to life. I now have a Jackson model 106 rf signal generator to bring to life again The case is just pristine

[@MrCarlsonsLab]

Hey, that's a nice looking signal gen with the white "chicken head" knobs!

[@waynecarlson3736]

Yes it does have white chicken heads and looks brand new, not a scratch or mark at all. Bought on ebay and I now feel that I robbed the seller.

[@CharlesM-dp4xe]

OK, it's a little late for comments at this stage but here it goes anyway. I grew up with Heath kits in the boy scouts radio clubs in the 50s and 60s they were considered as fairly valid tools for learning and there certainly were some flaws in engineering. I always wondered if some of those flaws were intentional. Look at it this way ... If you were motivated not to accept everything at a complete and finite face value, you might want to find the seat of an issue and discover its remedy by simple experimental techniques. It would certainly teach you something in the process. Its been 50 to 60 years and I still love doing these things. These videos are very valuable and I am still learning new things every day. Thank you for all you do !

[@LordOuzin]

I'm not an engineer by trade, actually I'm a paramedic. I love these videos, as I've always had an interest in IC/EE/RF since a young age. My father is an EE by degree and trade. Keep up the great videos, I love them.

[@edmclaughlin4923]

Paul, I would have never caught that potentiometer problem. I would have been spraying deoxit in the original one until the cows came home. Excellent video Sir. Thank you!

[@stevefoudray487]

My shop looks forward to your videos, we all have different backgrounds and levels of experience. Electronic repair is part of what we do. Suddenly BK, HP, Agilent, Stanford, and even Heathkit is showing up on our benches for fun experiments and things we can do for our customers. Keep up the great videos!

[@MrCarlsonsLab]

Glad you guys are enjoying Steve.

[@SteveGunnfl]

I was brought up in the days of transistors and never really trained in tube technology, so they were somewhat mysterious hot fizzly dangerous high voltage thingies.. videos like this make them much less mysterious and I could understand the schematic - so thank you..

[@chriscunningham6362]

Paul, I've been restoring vintage electronics for nearly 40 years but I'm still stupefied at the level of electronics knowledge you possess. Thank you so much for sharing that knowledge with all of us. Watching every one of your videos is time well spent. You are an exceptional teacher and mentor.

[@beakytwitch7905]

Wow, today I learned the purpose of grid leak resistors, about noisy resistors and how to spot 'em, and about the signal tracers too. Much enjoyed watching. Thank you! :-)

[@rib180]

Amazing! I would have said the noise was caused by an old audio gain potentiometer and lived with it. Your design modification stopped the potentiometer crackling noise and stopped unnecessary plate current.

[@ibrahimkocaalioglu]

You are amazing. Fixing bad design is marvelous. Active elements should be always properly biased !!!

[@bucyruserie1211]

Hi Paul, I really enjoyed watching you diagnose and repair this Signal Tracer.... You always explain your methodology so that even I understand what and why your doing it (very helpful for improving my own diagnosing skills) .. Great video as always!! Thanks for sharing, Tom

[@mrdouble]

My biggest bring home with this video was the noisy resistor. I have read about and performed calculations for resistor noise but nothing to bring it out of the theoretical. Mind blown. Thank you

[@helenbulmer5426]

Paul's unbelievably clever omg I have restored radios and hammond organs for years but know NOTHING compared to Mr carlson. Your videos sir are amazing in every way and I watch your productions day and night. You need a medal for your monumental work!!!

[@MrCarlsonsLab]

Thank You for your very kind comment Helen!

[@stephenmoore2754]

I should have sent this along earlier. The signal tracer looks like new. What a find! This is another great video. I grew up when tubes were at the end of their golden era, and my formal education was all solid state, but I keep gravitating back to the tube devices. You sure do them up right! Thanks for sharing your knowledge and I am looking forward to more in your series.

[@Joejoe-eo6yz]

Paul another great video. I really like the way you describe the problem, explain the theory of the circuit and then show how you find the defective component. I have learned a great deal watching your videos. I hope you have a video showing us how you use this signal tracer to repair and antique radio.Thanks again for another great video.

[@ZeedijkMike]

Probably the best troubleshooting / repair video I have seen for ages. You are so clear and and easy to understand. I like that even though you are doing - with my knowledge - a quite advanced repair, you still explain the simple steps too. I found the noisy resistor very interesting. I have heard that they exist, but never seen it demonstrate and with such a extreme result.

[@theonewease]

These videos on vintage test gear are awesome and always with the best presentation and quality! Please keep them coming Paul! Many Thanks!

[@hyperchannel4048]

Every single video is a large collection of knowledge for the practical application of electronics knowledge ! Still keep safety first and stay healthy in the New Year too ! Many thanks for so much tips and informations about electronics !

[@larrymccabe7888]

Paul... Another exc video.. Have watched all of yours multiple times. The diagnostic approach is especially valuable.. Love the tube gear as well as the solid state stuff. You hve given me the incentive to repair my Hamfest treasures sitting in the garage Pls keep them coming.. 73's Larry

[@brunofonseca9686]

It's just out of this world your approach on electronics videos. A lot of knowledge. Congrats Mr Carlson.

[@noelranasinghe3]

Gained lot of knowledge today never knew a resistor creates that kind of distortion to a circuit, thanks for sharing your knowledge with us

[@MrCarlsonsLab]

Glad to help Noel!

[@ActivateMission2ThisTimeline]

You should create some troubleshooting tips and tricks vids for tube, transistor, IC, power supplies and computers. You could pull the great parts of many videos together to create this. You should teach at the tech school or local college. You are the best I've seen in 50 years.

[@alecjahn]

I am so glad that you do these videos. I don't think there's anyone on the 'tube that does similar teardown+repair/mods on interesting equipment like this, let alone your truly impeccable teaching ability and delivery. Once again I thank you for another quality video! I learn so much on every single one, which is priceless to say the least.

[@MrCarlsonsLab]

Thanks for your kind comment alecjahn!

[@sniperneil53]

Ditto

[@BruceNitroxpro]

OK, OK... I'll admit I didn't believe that Heathkit would miss-design a bias level which would present a problem. I was DEAD wrong, as Paul pointed out. I could have fixed the problem, had I correctly spotted the plate voltage disparity. Geeze... it takes someone with a LITTLE more trouble shooting time than mine to spot something which was so obvious to him. Nice job. GREAT job, in fact. .

[@THOMMGB]

Thank you very much for very thoroughly showing how all the controls on a signal tracer work. I especially liked the troubleshooting and repair/modification as well. I'd love to see you showing how to actually use a signal tracer in a radio repair. A lot of these units seem to come without probes. If you'd show in a little more detail how to make up a probe, that would be great! Regards, Tom

[@MrCarlsonsLab]

Thanks for your input Tom!

[@ronfrost7587]

I really love watching your videos. They are very informative and the vocal commentary is not rushed but at the same time, the level of information is very deep. Keep up the good work.

[@dweishome]

Great course on general trouble shooting Mr Carlson. I just bought a Heathkit T4 tracer, so this should really help me out. Thanks much. I just stumbled on this set of videos. I will be back for more! Dave in Phoenix.

[@freddiemortos8519]

Hi Paul, You're really a very good not only in troubleshooting but teaching as well. You have a very deep understanding about all the circuit you're working on. I really enjoy watching all your videos coz I learned a lot from it. Keep it up. Gobless!!!

[@MrCarlsonsLab]

Thanks for your kind words!

[@rolfdieterklein]

excellent video, not only repair but also enhanced witg the modification

[@parsifal40002]

Mr. Carlson, I really enjoy watching your videos even though I don't understand much , just barely! LOL. I'm fascinated by electronics. But I was not good at mathematics and electrical theory. Still I enjoy watching!! Thank you!!

[@MrCarlsonsLab]

You're welcome Steven.

[@Discretesignals]

I love your videos! I'm a mechanic, but find electronics so exciting. Maybe i missed my calling. I been watching your videos for quite some time, so I subscribed to your channel finally. Thank you for sharing your love of electronics.

[@Alpha1545]

Outstanding! I forgot how a carbon resistor can get noisy. I heard the current flowing thru the speaker and knew the slight hum was acceptable the way you were demonstrating. My guess was going to be a unsoldered wiring point or cold solder joint. Great find with the resistor. Thanks for the video

[@rfburns5601]

I thought that the pot had a bad spot, tin whiskers, or leaky coupling cap on the wiper. I wasn't paying close attention when you went through the schematic; I didn't realize the pot was DC coupled. I can't believe the engineers at Heathkit did that! Cool video. Sometimes, I would parallel a suspect noisy resistor with an electrolytic cap to check for noise. That method is not always practical, and can cause damage if you're not careful. The outside techs would use a meter called a "Sidekick" that would put a couple of hundred volts on the cable to check it for noise. I hadn't seen a signal tracer with that function built in. Neat!

[@user-uv4xe3cq2y]

Doug of Philadelphia says it well. Thanks for all you make available for us to view and absorb.

[@MikePerigo]

Thanks for another excellent video and for bringing back the memories of Real Electronics with Real Voltages. As an old timer I found it to be the perfect level of detail and explanation of Real Faultfinding.

[@TheRadioShop]

Paul that was brilliant! I loved the way you explained the circuit and then did the mod to calm the voltage drop. But the noise troubleshooting was just out of this world. Big thumbs up my friend. You out did yourself on this one. I have an Heathkit IT-12. It quit on my last year. Man I miss it. Eye tube went bad. Will enjoy the next video on the SG and the series to follow. Working through a new series myself on the FT-101. I have 5 of them....Keep up the great work my friend.

[@MrCarlsonsLab]

Thanks Buddy! Have a great 4th. Our 1st went well up here.

[@JerryEricsson]

Very cool, I am still watching your old videos because they contain so much knowledge and deserve to be revisited from time to time. I too would have been beating that poor rheostat to death trying to get the crackle out of it! I never realized that a simple resistor could go noisy like that and emulate a bad control! Thanks a million, I am still paying to go for the good stuff, well worth the money, you are the only fellow I have used patreon with, there are others I have considered but their stuff is not up to the high quality and actual college level stuff.

[@MrCarlsonsLab]

Thanks for your kind feedback Jerry!

[@wildrootsfarm1975]

Thank you for taking the time to put this video together! The troubleshoot was most amazing. I enjoy troubleshooting, but never had seen it done at this depth. I have so much to learn. I look forward to watching more!

[@jerryuhte1284]

Great info and video , just so happened i finally needed to use the sig tracer , however didnt know it worked ! it and the matching Sig generator was purchased at Dayton Hamfest years ago ! Thanks for all the great work , good luck !

[@richardbrown9522]

Excellent! Really appreciate you showing the full troubleshooting process. More please when you have the time.

[@MrUbiquitousTech]

Great episode! Really nice job on that tracer! You outdid the factory with your mods. That's going to be a great series, fixing up other equipment using your restored vintage gear!

[@dnegrichjr]

Impressive! I love that you explained the equipment and it's operational theory and then proceded to troubleshoot while explaining logical steps to isolating each issue. Sir, the video is superior! Great job! Thank you for sharing you knowledge. I learned a lot.

[@MrCarlsonsLab]

Thanks!

[@netlogic1ify]

Wow.. You are really brilliant. You are the best electrician man I ever seen. The knowledge that you have is more like a professor on this branch. You are not only know what you are doing :) but you're also know what mistakes the designers make and know how to fix that. I'm really impressed. You are a good teacher and I'm really glad to be a part of your group. Bravo! You really deserve the positive feedback and the people that adore you :)

[@GrandsonofKong]

Awesome restoration video..again! Whenever my wife mentions that I might have too much electronic gear..I show her a clip of your lab!!

[@neillawlor7701]

Brings back lots of memories. ( Tubes ) You are a first class teacher the way you explain circuits etc.

[@redemptusrenatus5336]

Love these videos. Definitely looking forward to the whole series on troubleshooting and repairing devices using this equipment. Great work and glad that you put in the time not only to do it but to do it well. Thanks for sharing with everybody.

[@DennisMurphey]

yes, well its clear to me you are one smart cookie, the best part is you can explain what you find and why you are doing what you do to make it better. Sharing your gifts is the best part of the videos. Thank You again and again, Great effort and result. D

[@DennisMurphey]

If you can make the boards for us, i would love to make your Super Probe and Capacitor tester. I am getting an old Eico 147 you said the probe could be used with it, but had not changed to BNC connector.

[@DennisMurphey]

My Eico 147 arrived today but it has NO Tubes inside. Good price but now i need all 5 tubes, Green Eye Too. Are there upgrades to this i should consider too. D

[@EsotericArctos]

I am watching all your videos from start to finish and I have to sat you explain things better than anyone else on KZbin. I wonder how far we really have advanced since the 1930's though. Yes, computers are smaller and can run faster, but making things smaller and faster comes at the expense of accuracy and knowledge. More people knew how to handle things properly 90 years ago to what they do now.

[@cdrive5757]

Paul, thank you for yet another exceptional video. I'm 76 and my dad was building HeathKits in the 50's, while I was building them starting at about 1967. Back in those days HeathKit offered their products both as Kits and "Factory Wired & Assembled". My memory of those days remember a higher resale value of the factory wired versions. Not surprising because many kit builders had awful wiring and soldering skills. I have a friend and old coworker who's motto is "The bigger the glob, the better the job"! I would tell him I've seen rookie welders with better joints! 😂 Wakodahatchee Chris

[@jwl9286]

Great Video, I just had stop and appaud your statement about the problem not only giving a chance to continue troubleshooting but have fun as well. This is wonderful.

[@MrCarlsonsLab]

Thanks!

[@coffdrops69]

Another fascinating video and a joy to watch. Your thought processes and logical approach to troubleshooting make it easy to understand and follow along, as well as learning a few things along the way. Thank you for devoting the time to these videos and I'm already looking forward to the next one.

[@toddanonymous5295]

Mr Carlson, Another brilliant presentation. We expect nothing less out of your lab . Imagine after one day over 2500 views. Guess you know how we all anxiously await your next video. The analysis and mod of the second stage was the best part. BTW I like the way you heat the lab on those cold Canadian nights.

[@MrCarlsonsLab]

Thanks Todd! I already have the next video in mind.

[@johncunningham5435]

Excellent Paul; a great demonstration in the modification of the unit and tracking down the noisy resistor that can be difficult to locate in some situations. "Well Done"

[@northstarforest]

Best. Channel. Ever.

[@MrCarlsonsLab]

Thanks!

[@robertjacko1718]

Enjoyed the signal tracer video and in particular your comments such as athe transformer location and the "why" of its orientation and what effect might result were it mounted differently.Bob

[@RevelationNowatHand]

I've now watched most of your videos here and I think out of all of them I've enjoyed watching this one most. Of course they've all been really very good and I can honestly say I would have loved to have had this kind of access to your knowledge and instruction back in the days when I worked in electronics repair. Thank you, Paul, for sharing! David

[@mikesradiorepair]

Great job on tracking down the noise. That can be a bugger some times. Nice to see I'm not the only person that installs modern X1 Y2 safety caps. In a lot of gear especially radios I work on they used standard ceramic caps and I don't have enough fingers and toes to count how many of them I have seen exploded. I always replace them no matter what they look like. Especially across the line caps. Their on 24/7 as long as the equipment is plugged in, hardest working part there is. If you ever run across a Paco Z80 cheap grab it. I love mine. In addition to the variable gain pot it has a switch for multiplier of X1-X10-X100-X1000. The scope/VTVM output is also very handy.

[@abeleballestri612]

Very interesting how you trouble shouted an old very precious signal tracer with tubes. I wish I could find a piece like that in working order,but it is only a wish I suppose..! Thank you very much for your easy and excellent explanations how to proceed in order and how you have made a very cute change in the diagram. I think a case like that with the disturbing noise is rather frequent in old radios. Abele. Suisse.

[@CharlieTechie]

Well Paul, you did it again. Fantastic video. Learned a lot, picked up more tube theory I had forgotten over the years, and learned more troubleshoot tips. Can't wait for the new series. I know it takes time to put the videos together, and I thank you so much for taking that time and sharing with us.

[@jflimbach]

I have the later iterations, the IT-12, and looking at the schematic I see they incorporated the essential elements of your modification to the grid leak circuit. Since that was 50+ years ago they must have come up with it on their own. Love your videos and have learned tons. Been a ham and hobbyist since the late 1950's, so needless to say, I am a tube guy through and through.

[@MrCarlsonsLab]

Glad your enjoying the video's! I'm pretty fond of tubes myself.

[@injoelsgarage3934]

Mr. Carlson, Thank you for another awesome video, your attention to detail and explanation of trouble shooting steps in this project are outstanding. You have helped me out tremendously, the light has gone on for me, as I now see how useful and import to have a properly working signal tracer is. Noise is bad, and that's why we can test for it. So cool. Thanks again for your time and sharing with us all. Happy holidays to you and yours! Joel

[@MrCarlsonsLab]

Thanks Joel! You will really like my next video. It should be up in a day or so. Have a Merry Christmas!

[@coilsmoke2286]

Wow And THANX...! That 'Microphonic' and noisy resistor is a first for me. (Shades of the old carbon microphones) Got problems, hit it, bang on it, wiggle it. I love dumb luck testing when it works. That often does help find faults in things like pinball machines and appliances.This makes me appreciate the value of all low noise passive components too.

[@DonDegidio]

Paul That Heathkit sure brings back some old memories. Very good video. You and the family have a safe 4th. WB3BJU

[@stargazer7644]

Lol, not much worry about a safe 4th in Canada.

[@MrCarlsonsLab]

Thanks Donald! I did have a safe 1st!

[@MrShobar]

Many thanks for another enjoyable video. How I mourn the demise of Heathkit.

[@jeepman1244]

I feel same way nothing close to them today,just sad!

[@TRXLab]

super cool restoration, troubleshooting and repair Paul!. Love this old lab gear. Take care 73

[@MrCarlsonsLab]

Thanks Peter!

[@bignastytrees]

Excellent job Paul. I've had my eye on one of these signal tracers for quite some time.

[@MrCarlsonsLab]

Hi Joe. After they are re-capped, they are pretty nice to use.

[@Tony770jr]

Very educational. Nice troubleshooting tips for noisy components, etc. Thanks, a bunch!

[@jajames65]

Another Great and well put together presentation. Thank you Paul.

[@MrCarlsonsLab]

Your welcome James!

[@robertcalkjr.8325]

Nice job. Thanks Paul. It's nice to see old equipment still working.

[@derekbailey2429]

Really cool video Paul. What a neat little piece gear too. I never would have suspected a resistor over a VR as the cause of some of that noise. One always assumes a dirty or bad VR. Thanks again for a very informative and interesting repair. All The Best! Derek

[@andrewchurchley5705]

Truly excellent. I love Heathkit gear. The logic and careful testing, re-testing and deduction around the valves was impressive. With the noise gone, the silence was really golden. Thank you for this brilliant lesson.

[@jimadams2473]

Another excellent video. Very detailed and sequenced. I am humbled at how well you know electronics repair. My success rate is around 50/50 and i won't tackle anything with surface mount components. Keep up the great work!!!! Thanks

[@sebokaz]

Thanks for the great video! Amazed with how few subscribers you have, your channel deserves times and times more!

[@bergarteric5713]

Hello Mr I love your pedagogy and you are a very good teacher for me !!! Thanks for all , your time and your knowlege ... please don't stop never !!! long life for you and your wonderful lab Eric from France .

[@ianbutler1983]

Paul, I just got the EICO 147 tracer. Different tubes, but amazing how much the circuits are the same. It does not seem to have the switch to ground the grid of the first amp tube though. The manual for the 143 states that the current sent to the probes on the noise function is "about 130 vdc" but that there is no danger of damaging components since the short circuit current is "about 1ma." It also states "some care" should be used in handling the probes, though the shock that can result is "relatively harmless."

[@dell177]

I built the EICO 147 version of that back in the 60's and it still works as good as it did when I built it. The eye tube is expensive if it has to be replaced but they are still available.