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Electrical Troubleshooting Adventure! Let's Find The Issue Together!
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- Опубліковано 7 бер 2023
- Lot's of troubleshooting experience shared in this video! Let's find the intermittent issue, then solve it. More tube knowledge shared as well! This is Part 5 of the GRR Series involving the RCA CR-88 Receiver. 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: • 1946 Secret Listening ...
Part 2 here: • 1946 Radio Receiver Te...
Part 3 here: • Capacitors And Electro...
Part 4 here: • Receiver Restoration S...
Part 6 here: • Electronic Circuit Tro...
Part 7 here: • Find Intermittent Elec...
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
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
Years ago, I heard a story about a repair tech who died, but did not make it to heaven. While being shown around his eternal place of punishment, he was told that he would spend eternity in a state-of-the-art repair shop with every tool ever made, every part ever made, every piece of test gear available, and every service manual ever printed. He would also enjoy the assistance of beautiful women who would bring him units to fix and take away the repaired units. The tech was puzzled by this, and said, "I thought hell would be way worse than this!" It was then that he was told that every unit he would work on for the rest of eternity would be intermittent.
Yikes!
Nice joke, Scott! As an automotive diagnostician I often deal with intermittent issues. I can usually locate the issue via the ‘wiggle test’ (of the wire harness) or by applying heat to a component (an ECM, for example). I’d assume the wiggle test is probably useless on electronic components that don’t live in a vibrating environment.
@@djosbun In the vintage audio gear I work on most of the time, intermittent issues usually end up being (A) bad electrolytic caps, (B) transistors whose leads have oxidized ("black leg" transistors), or (C) dirty connectors. But it can also be thermally sensitive components, bad solder joints, hidden damage in wiring harnesses, etc. Intermittent problems are always a pain because you can never be sure you fixed them!
So the woman were there when he got off work. Sounds like he stole my life
MARVELLOUS BLOODEY MARVELLOUS. THAT MADE MY DAY .WITH A GOOD LAUGH.
I am 74 year old EE and have been involved in electronics since I was very young. In spite of my vast experience with both tube and solid state electronics, I still learn something new every time I watch one of Mr. Carlson's videos. His knowledge is truly amazing and I'm really thankful that he shares it so well.
Thank You for your kind feedback Greg!
I don't care how easy he makes it look. Only vast knowledge, experience and intuition can make this look easy, and in an age of disposable electronics this is becoming a lost art. Mr. Carlson is the last practitioner of a lost art and future generations will refer to him as a wizard.
In my 47 years as a dad, husband, and family repair guy. we all know the problem mysteriously goes away as soon as we show up or touch the thing.
Absolutely, it's called "Repairman syndrome."
Every single freeking time. Never fails. Never !
This is true. Sometimes I don't understand why the appliance works when I use it when it doesn't for others.
Hi Paul those micas look like the ones that are paper and foil inside
It's astounding how fast you narrowed down the intermittent crackle to those bad caps. Even though I learn a lot with each new video, I still wish I had .1% of your troubleshooting skill!
I wish I had .1 % of his test equipment 😉
@@gn1656 True but it's not the test equipment that allows him to chase and pinpoint such problems, it's experience and knowledge. The tracer is convenient but can easily be replaced by a signal gen and a scope (and today, even affordable Siglent scopes integrate both functions in a single box).
@@gn1656 If I had 0.1% of his test equipment, there wouldn't be enough space to walk through my house!
Never ceases to amaze me with the extent of your knowledge. Like I said, you should be 100 years old.
I'm born in1967 and star fix electronic a 8 year old , now I have 55 and love see you when repair the old school electronic.
My first thought when hearing the pops was silver mica disease. Now to finish the video.
Enjoyed your video. I am an electronic tech (not EE) and I gained most of my experience while in the USAF. My job was an analog flight simulator specialist. Tech school was 8 months long. Most large capacitors in the computer racks had a "bleeder resistor" across them. I made the mistake of assuming all capacitors had a bleeder resistor. While doing some work in one of the servo racks (power off), my hand brushed the back side of a capacitor...and WHAM. I got hit with about 400 VDC. It really rung my bell. I never made that mistake again.
This video was great! It was almost as if you perfectly anticipated every question or comment I had while I was watching it.
For example, Me: Hmm, I can't remember ever seeing a mica cap go bad. You: These micas are leaking, which is uncommon for micas, but it does happen.
Also, Me: I so rarely handle micas, that I would need a refresher as to how to read the values. You: I've talked about reading these domino style capacitors in the past. I'll just quickly go over that.
Also, Me: Yes, but is the grid still glowing? You: Let's take a look at the 6K6 and see if we can see any glowing grids any more.
The only one that left me hanging, Me: I wonder if he replaced the missing snubber cap on the transformer?
Excellent video, Paul!
Looking forward to seeing the insides of the capacitors - more likely to be "mold" than mica!
With the abundance of AR88s on this side of the Atlantic, it has become accepted practice to replace the Micamold C118, 119 and 122 on sight. Often C119 is discarded altogether (as has been done with yours, I think) to save the output transformer from being burnt out when that cap fails, though it can be placed across the primary instead - if a mildly muffled tone is desired.
Troubleshooting periodic faults can be time consuming.. Mica caps can have "silver migration" due to moisture ingress, and the DC potential difference across them then cause this. In addition to the other differences between 6K6 and 6V6 you very correctly mentioned, the heater current is different. Would not be good in a series circuit
I would assume that the larger-value micas have more surface area, increasing the chance for failure.
It's always one of the biggest treats when you post a new video, thank you for all that you've brought to me during all kinds of different times.
You are so welcome!
Every place has that superstar that can fix anything. Mr. Carlson is who that guy goes to when stumped.
Let's Find The Issue Together!
In the 60's, we (RCA Service Co technician's) had VERY few testers in those days to use. Yes, we had a VTVM, Multi-Meter and an Oscilloscope. A Generator and a Sweep Generator. And that was about all.
Thus, I had never seen a capacitor tester etc, at all. So the only thing we could do; is to use the Ohm's part of out Volt-meters for testing capacitors. And when I saw this Video; I remembered having a hell of a time with a problem on a TV.
And I had never had a bad "flat" capacitor. But I tested it with my Multi-meter any way. And it seemed OK. So I kept trying other parts. With NO help. After several days, I said, "I'm going to change that flat capacitor"; with NO feeling it was going to fix it.
But it did! And I was as happy as a little boy; in an ice-cream shop. So I saved that dadgum "flat" capacitor for yrs. And thinking about it many times. So, I sad all this Paul; because you caused me to have "tears nostalgia". And thank you so much; for this old man that's 91 yrs old that STILL loves Ice-cream! Whoopee.
Yay day time new Mr Carlsons Lab!!!! Looks like I'll have to put up a Do not Disturb sign on my office door for the next hour ;)
I know almost nothing about electronics- or about electricity for that matter. I know enough to know I shouldnt be messing with it... But Mr. Carlson's videos are just so interesting and well put together. I honestly want to get into short wave radio now. I need a new hobby. Thx Mr. Carlson. Thanks for making such great content that is actually useful.
Glad to be that inspiration!
Mr. Carlson got me hooked and now I have 14 radios about half are repaired and the other half are in queue. Fun hobby. Just make sure that you learn about proper safety equipment (dim bulb tester, isolation transformer, variac) before you dive in. Also, don't cheap out on the soldering iron if you don't have to a good one makes a world of difference
This requires a lot of patience and knowledge but sooooo much more satisfying than fixing a line of code in software
Another pearl of wisdom from Paul, am I alone in thinking this guy is an electronics deity?
waving your hand past the antenna terminals brings back memories. dad had lost most of his hearing as a demolitions man in the army. he had taken a tv and electronics class via mail. since i had the best ears of us boys i would listen as he would tap on things. he also has a shielded trimmer screwdriver he would put electric tape over the end and explained capacitance and inductance to me as he would wander the circuitry to get an effect. we made a pretty good team but the days of tubes was waining and i had bigger apples to peel.
Awesome to see the previously restored Heathkit make a cameo appearance alongside the Superprobe. Seeing stars of episodes past reappear really underscores the continuity of their utility in the lab.
Mr. Carlson troubleshooting an intermittent problem? WHAT A BONUS!
Wow! Fascinating! Great video. I had a similar bias problem on a Drake R4C receiver that was moving a 6BA6 control grid to positive 4V (!) ONLY after the unit was on for about 10 minutes. Normal voltage was around negative 2 or 3V. This problem only happened when the tube got good and warm. When I pulled the tube, proper negative bias instantly returned. I had a tube with a contaminated grid, where some cathode material had migrated onto the control grid wires. When the wires get hot enough, they give off electrons (DC Current flow from the grid) pulling the grid positive.
One of my newer tube testers checks for this, calling it "grid leakage". This 6BA6 in question failed grid leakage after it heated up a while, when tested.
This problem caused AGC drift on my R-4C, the S-meter would not stay "zeroed".
That 0D3 tube looks awesome with the purple glow!
Excellent tube knowledge!
I completely agree that there is a visible and significant structural difference between beam tetrodes and power pentodes, but I was unaware there had been illicit swaps and intentional mislabeling passing one off as the other! I know a thing or two about tube circuits, and use refurbished ones from the 1950s every day, but your knowledge of the tribal world out there and your snooping technique has impressed me immensly! Thanks for sharing that great acquired knowledge!
I really enjoy how you go about fault finding. I'm 78 Years and I learn from you all the time. Thank you Mr Carlson.
Another very thorough fault tracing exercise. It’s good to see that you make the effort to prove the cause of the problem and not just ‘get rid of it’.
Thanks for the wonderful tips on finding bad caps in old radios your a good teacher 👍
It would be interesting to see the eye tube on your Heathkit IT-11 capacitor checker in leakage mode for these crackling capacitors at various leakage test voltages.
Wow - you are one clever bloke to find that so quickly. When I was an apprentice (Mechanical engineering), when intermittent faults were reported, our foreman in the maintenance workshop had the mantra "let it develop", I guess his theory was to speed up diagnosis when the fault finally was no longer intermittent. Caught him out a couple of times with catastrophic failures and extended production machinery downtime as a result..
Thanks for taking us along Paul!
Your experience in electronics is nothing less than MIT proffesorism. I picture you as a child growing up at home, driving your parents crazy tearing apart radios and appliances giving them more power. "LOL". Excellent trouble shoot Paul. Thank you for taking the time to show troubleshooting tips!
Mr. Carlson your a bad ass on vintage electronics, Fantastic job.
pretty cool!
yea the mica chicklet caps are an issue.
heat and time gets them.
i was trained back in the 1960's and in the 1980's
we replaced them with upgraded caps.
and smart to just fire the parts cannon at the radio!
I learn at least one thing every time I watch one of your videos. I love how you go the extra mile and a half when doing these wonderful and very thorough restoration series. Museum quality. Awaiting the next video with much anticipation.
A "Tip of the Hat" to Mr Carlson for isolating the failing capacitors. Very well done!
Nothing but black plate 6K6's here at Mr. Carlson's Lab!
Really appreciate your time and effort. Having a blast w/this restoration.
I really do appreciate your videos on this project, Paul. They are so enlightening and interesting.
Excellent tutorial, Paul! In 1965 I purchased a realistic reel to reel tape recorder. It developed an intermittent crackling noise, which was bearable on playback, but on record it would land up in the recording! I brought it to a local tv shop and an old technician tied it up for a week and found a bad cap and resistor. The charge? Around 10 dollars. I wish I could find one of these recorders for nostalgia reasons.
One of the first recordings I made with it was "My Girl" by the Temptations.........
Thanks for sharing your story John!
Neat to see the older test gear in use.
BTW, Thanks so much for sharing your expertise, especially on the older tube equipment!
I've been doing electronics for almost 50 years and yet I learnt something here today.
Great Job Paul on the diagnostics. I am fascinated with the vacuum tube labeling issue.
I want to share about a Russian 12AX7 that is maybe a 12AX6.5 at best. I have a Martel/Roland FAX-200C receiver from the mid 60's. It had a red plating issue NOT caused by the grid coupling caps. The filaments of 2 12AX7's in the preamp are used as the cathode resistor for the 6BM8 outputs. I had ordered 10 12AX7's from ~12AX7 ~ ECC83 SILVER GRID TUBE VOSKHOD NOS TESTED OTK USSR.
It turns out that The normal pin-out for the filaments is pin 4 to 5 with pin 9 a centertap. Well this Russian tube omits the center tap and the filaments seem to be for 8.5V or so not 12 volts. Using this "almost 12AX7" still caused red plating in the outputs.
Moral of the story.. Be very, very careful when you purchase tubes. These tubes worked ok for "Normal" circuit configurations. The devil is in the details.
Lots of good information here, Mr Carlson...thanks for sharing.
Fantastic troubleshooting and analysis Professor Carlson. I can't get over how clean the inside looks for the age of the receiver. Thank you for sharing.....
I learned something today about how tubes can be "re-labeled", never knew that, started working on tube gear in 1976, thanks
Glad to help!
The new shop is looking great and it's nice to see everything flowing smoothly as you make further videos. I really enjoy this series a lot and REALLY enjoy your teaching style! Thanks for sharing and best regards.
Another success of a video! Thanks, Paul! I can't wait for the next one.
Thanks for sharing another troubleshooting adventure!
Believe it or not... over my career as both tech and engineer, I was often tasked with diagnosing intermittent issues for which they're often laying for years within a bonepile. Whenever getting assigned, I usually cleared them out within less than a few months (if not days). I approach almost all intermittent issues similar to what this video demonstrates. And yes, anywhere from "tube/valve" and discrete components over point-to-point circuitry all the way up to densely populated multilayer PCB's with large integrated IC's, it's important to examine and be familiar with how each component in the fault line is expected to perform and observe the behavior. Great job with the video Mr. Carlson. 😇
Oh my gosh, this solved my problem! I have been tinkering with a GE-C600 for longer than I care to admit, and I had assumed this whole time that I wouldn't have a bad mica cap in my first attempt at a radio restoration. Well it turns out that C21 was functioning more like a resistor than a capacitor. Thank you so much!!
Wow that brought back memories working on color TV's in tech school!
I'm loving following this project!
I remember that Heathkit T-3 signal tracer. The gain control was a weak design using a 12SH7 tube. Your modification was
simple and replacing a noisy resistor made the gain control of the tracer far less noisy. Here you found leaky old domino
mica type capacitors with it. I always learn something new (to me) from your videos . Another excellent video on the CR-88 receiver project Paul.
Paul “Rapid fire” Carlson! 😃
Well done. Thank you. ❤
I am enjoying these series immensely. I think I have an old radio receiver at my cottage. Thinking future project maybe.
Just another very helpful video from Mr. Carlson. Yes, we want more of this kind of troubleshooting videos. Definitively.
Love the video keep them coming great work
Great video as always Paul!
The cap from the anode of the 6K6 to deck have known to short out and take out the very hard to find output transformer. it was the first thing I did was to change the cap, 3000pf.
Impressive troubleshooting 👍👍👍
Thanks, Paul. Another wonderful lesson!
My pleasure Robert!
Thanks Paul, very interesting. Actually I had just finished watching all of UA-cam and was waiting for a new video to be uploaded. Good timing!
Your depth of knowledge is amazing. A true master of the craft.
Hey Paul. Fascinating detective work in this one! You really know this stuff. Many thanks again for all your work. Cheers
Mr. Carlson is pure genius.
Sir, you are truly brilliant. Thank you for the detailed descriptions and explanations.
Mr Carlsons lab you are good at restoring vintage shortwave receivers with ssb and alignment of vintage shortwave receivers
Thank you for all the knowledge you share.
Absolutely fantastic video and a real eye opener. Many thanks!!
Mr C👍👍 Another fantastic learning experience, thank you. Really enjoying this restoration, will not miss an opportunity to see it through. Great video, well filmed and presented as always. See you next time, enjoy.
Glad you enjoyed it Terry!
It was fun again. Your knowledge of tubes is amazing. Greetings from pe1krx.
Experience as well as logical method. Not just a hunt from end to end for the fault. This is how to do it folks! Love this channel more each time I watch a video. Thanks Paul.
Great troubleshooting video, thanks! The basis of my troubleshooting skills stem frommy military training in the early 70's, both electrical and mechanical, as a generator mechanic/ technician in the 82nd Airborne. Those skills have been useful throughout the last 50+ years. Lately I've been relearning basic electronics, your videos are fun to watch and help rekindle some of what I learned in those early years as I also learn that so many of the same principals apply to much of today's electronics.Thanks Mr Carlson!
You're very welcome Dave!
great video and Heath-KIt made some neat test equipment. 🥳 Another bunch of interesting radio and making very old vacuum tube videos is glasslinger... 😎 Thanks a lot.
Great video Mr. Carlson! Thank you for sharing live advanced troubleshooting with test equipment.
You're very welcome!
Thanks for the information about vacuum tubes and the hints for troubleshooting. The more I read and hear about vacuum tubes, the more curious I am about them. Again, your experiences with the components and what you share is truly remarkable and appreciated. I also enjoy seeing the testing devices that you've created and your words about wanting to fix things the right way. The tools you've created help you do just that. Perfect.
Mr. Carlson, I am really enjoying this restore series. Your teaching style is one of the best. Even though through out your "lesson" I can not interact with you, you really cover everything I need to know. Thank you very much for all your efforts.
You're very welcome!
I loved the troubleshooting of the noisy components, especially the tube construction details and explanations. I, for one, would love to see more tube construction details and troubleshooting videos.
Thank you.
Thanks I am glad I picked up the same heathkit signal tracer you used....thanks for the lesson!
good job explaining... I'm new to all this and could actually follow.
Always so informative
Excellent, again. Those "mica" caps sure resemble the paper/foil caps they used to "hide" in a mica looking case. I assume not ,due to Mil spec construction, but they sure look like it.
That they're all the same value by the look of it (typical of areas where value/tolerance is non critical), of a fairly high value for a mica, and in an audio stage makes me think they are molded paper and foil. Either way I'd replace every big "mica" of that value.
This was a good one. I used to be a repair tech for a medical equipment company. Thanks for your continued content!
Thanks for another great video.
I learned something new on the 6V6, 6K6 thank you. As many years as I have on electronics, I can still learn something new about what I thought I knew,. Thanks again.
Glad to help Gerald!
Excellent video! I've been on-and-off troubleshooting a Hallicrafters S-38. When I get back to it, I'll be sure to check, or even just replace the mica capacitors.
Great episode.
Fantastic Mr C. Interesting and informative. Surprised by how much I am learning :)
That video was amazing! I also love your Patreon videos.
I have a Marantz 2226b. In 1980 approximately, it began making a quiet static sound in one of the channels. I took it to my local electronics repair shop for repair. A week later they called to tell me they fixed it, so I paid up and brought it home, but the quiet static was still there, so I had them listen again. Their work was guaranteed so the tried again. After about a month they had found the leaky capacitor. No additional charge. I still have that Marantz. Some day I will replace the caps and give it another spin.
nice tracer. My signal tracer doesn't have that, but I've used my cap tester to put some voltage on the cap and used my signal tracer to find those.
Thanks again Dr. Carlson!! Outstanding information sir.
My pleasure!
Excellent. Learned about 6K6's and my Heath signal tracer. Tnx!
Your knowledge is amazing.
Very interesting, Paul! So much info I didn't know is packed into this video! I've seen you trace intermittent mica caps before but not three at once in the same receiver. The rebranding issue is disappointing but not too surprising given the competition in the marketplace. I'm just surprised it is still a problem today as I'd have thought those problems would have weeded themselves out by now. Thanks for the tips on what to look out for.
Glad it was helpful!
Excellent presentation
Thank you so much for the tip regarding vacuum tube branding, I learned something new about that. Then again, I am always learning from your expertise and great explanations.