Find Intermittent Electrical Noise - When Its Not Even There! Here's How.
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- Опубликовано: 20 мар 2023
- Here's an easy way to find a noise issue without it being present in a devices normal operation. Noises can hide, but can be found easily with this method.This is Part 7 of the RCA CR-88 Restoration, a part of the GRR Series. To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: / mrcarlsonslab
Part 1: here: • 1946 Secret Listening ...
Part 2 here: • 1946 Radio Receiver Te...
Part 3 here: • Capacitors And Electro...
Part 4 here: • Receiver Restoration S...
Part 5 here: • Electrical Troubleshoo...
Part 6 here: • Electronic Circuit Tro...
Part 8 here: • 1940's Radio Receiver ...
Part 9 here: • Restoration Adventure ...
Part 10 here: • RCA AR-88 And RCA CR-8...
Restoration finished: • Finished! Restored 194...
#restoration #electronics #repair 
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To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab
Hi I want to ask you do you have a Brother named Is lewis, I grew up in White Rock and I have been Trying to locate him as he was my Friend I have not seen him in years Highschool earl Marriott I think dad was comershal fisherman. It's been years his house is not there anymore.
If your brothers name is that can you let me know.
Thank you
Sean Brown
I wonder if scientist waved this past the human brain what it would pick up
Can you probe with a signal tracer for noise the way you did with the super-probe? That signal tracer is excellent for testing a suspect part, but can it find the suspect part?
I've been in electronics since I joined the USAF in 1980 and yet I'm still learning things in Mr. Carlson's Lab!
While I was in the USAF in 1976 I was allowed to recap my Hammarlund Sp200 in our avionics shop at Nellis AFB. That old Hammarlund is still soldiering on today.
1981 Keesler Comm/Nav grad here. I feel the same way!
Oh no another Mr Carlson's Lab has come out while I'm at work...... Looks like my Do not Disturb sign will be getting a workout again today ;) This has been a really great series to follow!
Thanks for your kind feedback!
Glad you finally decided to replace those 4700s. In the 1st episode when you found 2 bad mica caps, I was really surprised that you chose to leave the others. In any case, it made for a good lesson. Thank you for taking the time to share your experience with us.
I guess that's the idea, more to explain later. Or he's simply not wanting to replace things that seem to work, regarding caps I'm pretty much the other way around, I just replace all caps first and then troubleshoot. :)
@@VincentGroenewold the way i do it is if the caps test 95 - 100% good''and they are of modern design no matter what there age''' i leave them alone'''''unless they have sign's of leakage or bulging or any sign's that there going to fail'''''''then they get swapped out''''''but everybody has there own technic's'''''''thank you sir''''''just a passing thought.
surprised he didn't just replace all the caps and resistors, because 30 years ago, those "were" stable components, which have already lasted 30+ years by then. lol
they did last a very long time as they were known to do, but he'll be back into it again far sooner than later, as there's very likely out of spec resistors and other parts that change value with thermal cycling.
@throttle bottle I've never seen the point of swapping resistors in old radios, unless they are causing a measurable problem. "If it ain't broke don't fix it" - many old carbon resistors will have drifted, but not become unreliable nor forced the circuit out of spec. If I change a resistor, it's because I can nail a fault to it, or I've checked the schematic and the drift is enough to impair performance - a metering circuit is a good example. Many of these old resistors were 20% tolerance anyway. The other thing is that digging out an old resistor and replacing with new can risk doing more damage to the radio than you are trying to resolve, especially when it's tucked behind a wafer switch or some such. If it's got to come out fine, otherwise its best left in peace.
Great video. I'm troubleshooting a RBL-3 VLF receiver that is doing the same thing. I have found several leaky mica caps in the detector stage and rf stages. I'm changing them all out.
I sure wish I'd had your series of videos back in 1965 when I started working at a TV/radio repair shop.
One of the videos where Mr. Carlson is WRONG... kind of... I'm joking because your support for vintage Mica caps has been solid for a long time, and this radio gave your a batch of lousy ones. I fix guitar amps, and many times, I'll just freshen up the caps without testing them all... just as an insurance measure. Thank you for your service to the electronic tech world.
Really enjoying watching this series. Thanks much for all the effort to teach in a clear manner. I know filming these can't be easy, but you do make it clear!
You're very welcome!
@@MrCarlsonsLab I would love to build a super probe and your cap checker even tho I have two Heathkit cap checkers and a Sencore LC-103. It's too bad you don't sell the boards in a kit along with the metal enclosure because making boards is quite a process. I love your channel and I learned several tricks.
@@edwardskoda2409 To be fair, getting boards made is literally easier than it has even been. I recently found out people get PCBs made soley for decorative purposes.
@@OnStageLighting I know it is and I can make one but I need a special printer and the solution and for one board I would just a soon buy one and populate it.
@@edwardskoda2409 There are PCB fabrication houses in china nowadays that deal with the public for exceptional prices
Mr Carlson is a complete Master !!! He makes all fails so easy to find and fix. This a probe of his experience and deep knowledge
First off, this is a wonderful video and you are doing a great job keeping this part of electronics alive.
Hey ARRL!! See this guy? There are alot of us out there just like him that work on stuff, fix stuff, like to use the old stuff, and have zero interest in hooking a computer to a radio in lieu of a mic or key, or exist only to be some kind of quasi first responder with a handie-talkie. CB operators and audiophiles are building some fantastic tube based designs, and you just consider it all ancient and worthless while others create. So wake up before your membership evaporates and the FCC just includes a free ham ticket with every foreign radio sold.
As a fellow ham, I feel like a kindergartner when I'm watching your vids. Keep up the great work! One day, I'm gonna tackle one of these sorts of restorations. thanks to you. I'll say a QSO and a card from you someday, will go to my MVP spot! Hope to catch you on the bands one day...
73's from K5MWA - Texas
Intermittent noise faults are the worst. Custom tools are king; that probe is a beautiful thing. I started repairing (mainly analogue) electronics in 1986 and find your videos amongst the best online. Thank you for your time and expertise.
I have been nothing but pleased with my Carlson Super Probe. I can't thank you enough for that design. What a gain monster. Love it.
brilliant... replacing that bad batch was such a good decision... although as you say Paul, that box is a difficult area to work in. I admire your very thorough approach...great series...
retired electronics service tech, always learning new tricks! Thanks, interesting video, Nice performance!
Each video I watch is a thumbs up.
Super debug with the SuperProbe! I also love the way that Heathkit analyzer verifies bad components.
Hi there, I've been fixing electronics for the last 50 years, 42 yrs at a major TV Network, and you are spot on with your analysis, and practices. A pleasure to watch you think! I however started screaming REPLACE THOSE CAPS about 2 episodes age! I tend to be a bit more proactive in that respect, but yeah, you got this! Looking forward to the alignment ! 73 de KK6PD
I'd love to see the testing results of the mica's you pull out that you haven't yet examined. Would be interesting to know how many of them are actually good, if any.
Amazing video. My solution to fixing intermittent faults is somewhat different. Hide the faulty unit in the loft, never allow myself to think about it again - and then hunt for another unit that works.
This was really interesting Professor Carlson, and your troubleshooting and analysis of the issues was great. Your 'homebrew' probe in conjunction with the good-old standby Heathkit tester sure made your job easier finding the culprit that was making you bananas. I learned a lot and thank you for sharing !!
Glad you enjoyed it!
I feel like a caveman watching Mr Carlson's genius at work.
Excellent! I will put your Super Probe back on top of my to-build list as soon as I get my new lab up and running. I thought you'd eventually replace all those 4700pf caps after you found two of them bad in your prior video. Always the prudent thing to do with complex restorations. I love these videos, Paul - please keep up the great work!
Using your Superprobe it sounded like a Geiger counter going off ! Just a different form of radiation in electromagnetic
waves which are supposed to be removed by those mica caps. Looks like those particular domino caps are just bad. It
does happen. Thanks Paul for another fascinating look into vintage electronics repairs.
Of all your videos, I can't remember a time when so many mica capacitors were bad.
I was interested in electronics in the 50's. My brother-in-law gave me a WW2 issue of the ARRL handbook that I learned from. Joined the USAF in '62, then for a computer and banking machine co for 34 years, but I still pick up things here I didn't know before.
Knowledge is power!😊
Great method to locate the fault with your superprobe. Will build such a probe (head) for my existing signal tracer.
It demonstrates no matter how long you've been in this game there's always something to learn.Its unlikely your find someone more adept at this business than Mr Carlson.
You are the best. I need to build this probe... i’ve been lazy postponing this for the last few years and now I have a noisy preamp during warm up. Thanks so much for everything you do !
Appreciate watching these videos. Have no desire to work on these old things myself, having started out in the 90s and these days am happy to work on SMT with a microscope rather than heave lumps of fizzing metal about on the bench. Mr Carlson does this so I don't have to. Thanks again.
Another great blessing made my day love to watch the best trouble shooter on Earth Paul I Iove watching your videos so enjoyable.
Mr C👍👍 Awesome detective work, of course I'm not surprised you found the culprit. Using the Super Probe(which in and of itself is a marvel of a diagnostic tool)narrowed the fault down to component level, just amazing knowledge on display. Thanks for another fantastic video, well filmed and presented. Great series, loving it. Enjoy!
Intermittent faults were the bane of my life when I worked as an electronics engineer. I just wish I had had your skill and expertise when I was trying to find them. Not always successfully. Thank you, Paul for your videos. They are imparting knowledge to the new generation of engineers, which sadly I did not have.
Being confronted with a whole batch of (identical) bad components in a device is not that uncommon. I had a similar problem when restoring a B&O 901 amplifier on my channel, where several resistors of a specific value consistently turned out to be bad (the value was 30% off or more). That this happens now and then makes sense, I suppose, since manufactors often order large batches of components instead of frequent small batches, just to get a better pricing. Great video Paul, thanks for showing us fault tracing made easy ;)
Excellent as always, this one is finally getting me to build the super probe. Content like this is why I'm a supporter on patreon.
Mr C is great for insomniacs. Regards from over the pond
It is so satisfying to watch your videos. The attention to detail is awesome.
Your knowledge and approach to problem solving is breath of fresh air to me. So much so that I decide to become a patron. (first time I've done such a thing)
Thanks for passing on your knowledge and at such great value for money.
The level of detail and the depth of explanation in all of your uploads is outstanding. Thanks
I remember tweaking the 39A air search radar's rf section to get the maximum signal so that we could detect smaller targets. We swapped out a series of amplifier tubes to get them in the order that produced the best output. Also, we did a lot of troubleshooting using the o-scope to see the signals.
Lots of love to the Super Probe. Enjoyed as always, Thanks for sharing. 👍👍
Mr Carlsons lab you are good at restoring vintage shortwave receivers and alignment of vintage shortwave receivers 😊🎉🎉😊
My field has always been vehicle and mechanical repairs & restorations, but that often requires also dealing with some electric and electronic components. you are an expert-grade problem solver, and that attracts me to your channel, even if I may never use most of the knowledge you openly provide to us. I can't turn away from issues, I MUST know what causes an operational problem. so, thank you for sharing so much. fascinating.
This was a perfect example of exactly why older point to point wiring components were a MAJOR pain in the @$$ to work on, LOL!
Excellent video. I grew up in the vacuum tube days and loved to hang out at a local repair shop and watch repairs. My son has a 2016 Kia that intermittently wont start and will leave you stranded. It appears to me that the immobilizer module decides to have an attitude and won't signal the main CPU that we would like to use the car. If we give the car a time out for a couple of hours it will change it's mind and start. My son and I made a video of the situation and narrowed it down for the dealer to have a crack at it. It's a pain in the butt, one of the worse things to track down in a car....! It's pushbutton start and I fear they may have to shotgun the parts. Should be a nice repair bill....! Anyhow, I enjoy your videos...!
One of your best Mr. C. Thanks a bunch for sharing the project and passing along your insights. This is much appreciated. I always look forward to you videos. I'd be interested in your advice on sourcing components for things like your Super Probe; what to look for and where to look. Thanks again....
Another great class. I think I'm going to build the super probe. The time and trouble it saved you in this one was wonderful. I also picked up 2 old EICO signal tracers with noise abilities, The circuit is very close to the heathkit. Taking notes and looking forward to putting this all to work in my radio room. Thank you for a great class.
Awesome as Always...Great Vid...Really impressed with the Super Probe
Mr (Sherlock) Carlson and Dr Super probe (Watson) strike again! Great work as always Paul, Stay safe n well Dude. TFS, GB :)
Mr Carson,
Love your work, been watching for years. I’m really glad we have a place for geeky content like this.
I had made a comment earlier, but I think it was removed because I made a reference to another large website. Anywho.. I’ll retype most of it…
You could consider adding a 2nd probe to your box with a tip that picks up on magnetic fields. If you search for “HP current tracer” you’ll find an example, and schematics are out there as well..
Current tracers work a bit different than your super probe, in that it picks up on changes in current, and not changes in voltage. Most commercial current tracers have a small wire wound inductor at the tip as a sensor, and then circuitry to amplify and filter out unwanted frequencies. The inductor is typically shielded with a copper foil to reduce electrostatic interference.
In my experience, a current tracer is typically faster (for tracing circuits) because you can follow the actual current path, and not a broadcasted electrostatic signal. It works just like a clamp on ammeter, but no need to encircle the conductor. It would be interesting to see if it would work for this type of application?
Nicely done! I've also used freeze mist to trigger noise sources. Intermittents, especially when they only cause noise, are always challenging!
"Absolutely top-notch"! Thumbs up!
@ 26:50 Not directly related, but I found a silicone spray lube that contains acetone, and the directions say to not use it on plastic. Thought this might be useful; I always thought silicone sprays were safe for plastics.
Great info sir, Signal tracing "outside the box"! I really thought it would be the OD3. Thank you sir.
23:23 "...in-circuit tester..."
In-Circuit Tester usually refers to equipment that can perform components tests while the component is installed (as opposed to lifting one leg as you're done in this case).
Once upon a time, we worked with a huge Factron 770 (?) In-Circuit Tester (ICT) and it could test 99% of the components on an assembled CCA in-situ (no lifting legs).
Another marvelous video by Carlson ❤❤❤❤❤
wonderful troubleshooting. 🥳 Also. sometimes you can use a small heat gun to excite bad capacitors. 😎 Thank you.
I’ve never run on to a bad Mica so I will be more vigilant
Thanks
Another reason to keep my Heathkit tracer. Thanks, Mr.C.
I agree, 3 strikes for one brand and value, they're out. I have an old precision electronics signal tracer that has a tube (6av6 iirc) in the probe and it works similar for listening to noise. Probes like that are neat to play with. Probing a phone to hear the screen refresh or the auto focus mechanism. I couldn't find any information on the model, so I traced it out and made a schematic. I even sent it to bama, but I don't think he published it.
Fantastic learning experience. Thanks !
Hello Paul I have had a very similar problem with those same type capacitors within a Collins HF band radio receiver the noise would occur when switching the BFO in to circuit and upon replacing the capacitors all was good. I was told that the problem is due to silver migration within the capacitor it's self which causes them to become noisy. Please keep up the good work, kind regards, Ian Birmingham UK.
Good analysis indeed. I used to find these devils by freeze spray on a q-tip and apply to component and or using pinpoint heat. Almost always id'ed the noisy component. This way is easier.
Back when I first started working on RF circuitry, an elderly man who was teaching me, gave me an RF probe he built. It was nothing more than a probe, diode, cap, potentiometer and meter in a metal case.
It allowed me to trace the RF of a transmitter from the oscillator to the output stages, and when the signal was too high, you could turn the potentiometer up and decrease the sensitivity.
While it was a useful tool, I found the oscilloscope was as handy to use, and it worked on many frequencies and levels, the simple probe couldn't handle, so I transitioned away from the probe to the o'scope, and never looked back!
A brand new cereal from Mr. Carlson's Lab, Crack, Pop and Hiss!
Great information! Thank you!
Great tool. Damn, i needed that piece in the '80s. 😊
Thank you sir, for another fantastic video, and for another diagnostic method for me to use.
Bub You are awesome...keep up the good work.
Knew it would be a capacitor problem even before looking at the video. That tool you designed is very good for this kind of problem solving. Thank you for another great video. Heard stories about old caps that changed depending on the wheater so those old ones can be a bit cranky.
Ok, I'm convinced, I need to build a superprobe. I restored a radio for my wife, it worked great, except for the occasional CRACK.... I pretty sure it's silver mica disease, but is a real challenge to find.
Very informative. Thank you.
You are welcome!
Mr Carlsons lab your vintage rca cr-88 shortwave desktop receiver with ssb is awesome 🎉🎉🎉😊
Had a SS stereo receiver in the shop that had a bad component like this on one side. It would go off like a finale to a fireworks show for a couple seconds then be great for an hour or two. Freeze spray did allow us to narrow it to a group of components and eventually found the Class A VAS was to blame. I have no doubt your probe would have saved us hours of listening time.
I really enjoyed watching this video on how you narrowed down the noise issue to another bad 4700 mica capacitor. I would do the same thing then, replace all the 4700's.
Excellent! I'm going to build one of those probes.
Huh! I have one of those Signal Tracers, never knew how to use it. Might have to pull it out of the garage.
vibrate it, heat it, freeze it, beat it. lol that usually works out, but there's always some sneaky outliers. an engraver with rubber tip(pencil eraser) or even a bristle brush gently grazed over components tend to make rotten apples sing.
listening to and seeing the electrical noises with a probe/scope would sure work great as well, so long as you know what to listen or look for and that is where experience comes in.
I like this series of communication receivers very much and learn a lot of your videos and thinking of buying a Collins (expensive in Europe) or a Racal .
Greetings from the Netherlands
Hans
I was in a building this morning and saw the exact same speaker you have on the left, in that building! lol
it's a pretty crazy building, made in the 1950s of low-background materials because of the sensitive equipment inside it
Mr Carlsons lab your utube videos are awesome 👌 👏 👍 🎉🎉
Great video! I appreciate you taking the time to break this down for us.
I need to revisit your video from way back on that Heathkit tester. It seems to have it's own use that it can test things that the Super Probe can't. Can you do a video, if you haven't already, on comparing the advantages and disadvantages of both. Also, if it's possible to make a modern equivalent of the Heathkit tester. If I remember correctly, there is not much to the Heathkit tester.
Its very satisfying to watch and detecting the bad cap.
At first I was hedging my bet on the dropper 2.7 k resistor to VR150 my failed due to the heat it weakened the lead wires where it enters the body of the resistor and snaped when I moved it in side my AR88D and also the solder joint became crusty because of heat and age.
Thanks for this video!, l'll be sure to check out your video on the super checker test box, and make one, have an upcoming repair of a guitar amp that's described as making this kind of noise!! Thanks again, Mr. Carlson
You're very welcome!
Great video!
Glad you enjoyed it!
I wonder if there's a maker's name on these caps - we certainly don't consider similar ones reliable in AR88s. I might just dig one out myself to compare. I suppose there may be some component of the filler in the plastic/phenolic case decomposing. On the "melted" coil formers - The AR88 series was one of the pioneers of polystyrene in high Q circuits, but at the time, "trike" was liberally sloshed around as a cleaner. In the days when we all were expected to be pushing up daisies by 70 of course...
Jay the Florida pool pump motor repair guy. When Service Calls Longwood approved ! that was good info 2 see & know👨🔧good tool !! Mr Carlsons Lab
Awesome stuff, thanks mate!
My pleasure!
Your testing mathed are essay to understand nice presentation Mr Carlson sir you are awesome Thanks for the sharing this video sir ❤❤.
You are very welcome!
That was amazing!
That was great, thanks.
Anything Prof. Carlson does is sheer joy and extremely educational. I wish I had teachers like him in college learning even basic electricity and then electronics. All the "Da*&%%$mm" math and complicated equations etc to get through exams just by regurgitation🤢🤢. Most of what I retained was due to some tinkering with electronics and repairing old tube radios before I graduated. Unlike some academically gifted students, most of us learn better by doing than just from theory alone and I am one who grew up learning more by doing. The joy of learning by doing grew into a passion that has stayed with me and has saved me a ton by being able to troubleshoot and fix most household gadgets including washing machines and even auto ECG's
Thank you so much from my heart you are really a treasure for a bigger like me and I love your language because many youtubers speak fast I cannot trace them because English is not my mother taunted, thank you so much again
It's my pleasure!
Tip: you can run a video in 0.75x speed under the settings.
It's like going back to A-school! Yeah!
Pretty cool that sucker worked awesome!
Hey Paul, please consider uploading in 1440p (even if it's only 1080 source). I know you're big on image/sound quality and the issue is that 1080p on RUclips is heavily compressed and low bitrate - 1440p will still display in native res but the playback quality is MUCH clearer. I've only realized this recently and the difference is pretty dramatic despite me not caring about vid quality generally.
Noisy component test jig. Brilliant. Stealing that.
I promise ill be contributing to your patreon soon. Rent is high, work is slow.
As far as old big micas going bad. Mica is quite a brittle polymer. And i imagine the old resins probably expand and contract a little differently then modern ones. And after being warmed up and cooled off countless times over a long period of time they become faulty. These are my thoughts on it. That receiver may have just seen far heaver more frequent use over it's life or something. I've seen/experienced reasons to have this suspicion with old mica caps as well and it's probably part of why people suspect they are paper caps.
I don't blame you for replacing all those Mica's. :)
Hey, love your channel! This is such a good video idea.
On another note (please accept my constructive criticism), the ducking of the audio (the gate) and the amount of compression / eQ is a little strong. Every time you pause, I can hear the room noise completely go away in the intro and then you talk again. This doesn't make for a good audio experience. Try some room noise in the background to blend in or just let the mic go without a gate or don't go so hard with the threshold on the gate, please. Again, I'm here to watch to the end, like and subscribe! only wish you the best.
@@TD75 You're listening through your phone and not headphones. this is just basics of good production. I'm not kidding. I'm fine with him continuing to do it as he does, but its just a very normal feedback when it comes to production - people listen in all different ways. I know it sounds super pretentious but I'd like this guy to be super successful. This is a minor tweak that will elevate his quality. He's already made a lot of upgrades so if you don't like what I'm saying, I don't care. It'll probably happen anyway.
In my distant past I was superficially involved (meaning I was observing and discussing) something called Partial Discharge in a high voltage AC power cable. I got advised about the phenomenon where tiny buried bubbles charged up, forming an Insulator - Bubble - Insulator series connection. At some voltage the charge in the bubble became excessive and it "settled" as the partial discharge. Because it was internal in the cable insulation, it was called partial discharge. Also, it was repeating on the slopes, positive and negative, of the AC voltage. The discharge energy was a few picocoulombs per shot. Well, I don't know how much ripple voltage in the B+ line may have been, but here is my speculation: Mica structure tends to be formed of multiple layers that may start separating on long time repeating temperature variations. With that, tiny air gaps are formed either internally, or under the silver contact. From there on, you may see the tiny sparking going on and actually eating up the insulation by spark erosion. I consider it possible that the mica treatment in one brand or batch left more possibility for layer separation. Only a speculation on my part, but plausible, until a better explanation is presented.
fire the parts cannon at the caps for sure.
i would replace them all.
cool to see the individual parts traced.'
after 2 are bad that is when i make the call to replace them all.
on some of the old radios they work better than back in the day with late model 2023 parts.
that is if you can find better spec parts.
on the coils make your own forms and wind your own.
just make sure to spec the exact wire and dia as well as the slug.
do you have a 3d printer yet?
hooray for the super probe!!!,I will have make one.