1940's Radio Receiver Performance Check - RCA CR-88 With New Mica Capacitors!

[@MrCarlsonsLab]

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

[@josephsawicki9335]

God I love your show Please some day have a history of MR Carlson from kid till now like when you started being interested in electronics Thanks mr Carlson

[@JCWise-sf9ww]

I would like to hear that too, how Mr Carson got into electronics.

[@sascandave]

I third the motion

[@resipsaloquitur13]

Tetrad

[@DVINTHEHOUSEMAN]

Penta-motion

[@gervasiogurgel5231]

That would be great!

[@c185pilot3]

The restoration series is incredibly interesting and almost addictive...please continue with the restoration of these vintage receivers...the engineering is amazing for the times.

[@kennethdegruchy5503]

This video seems like a revelation to me especially since watching MCL's videos for years I became convinced the likelihood of finding bad classically color coded mica capacitors was highly unlikely and in most cases you did not have to consider replacing them with your refurbishing project. That thinking has now been dispelled and thank you to Mr. Carlson. Had to have been a faulty production run of these mica caps.

[@davidlovering6033]

Loved the Steely Dan “FM” reference… “No static at all”. Thanks for a great channel!

[@metalbill]

31:14 that was WWVH in Hawai. Female voice on that one and male voice on WWV in Colorado. They also don't talk at the same time in case they get received simultaneously. So yes, that thing is receiving quite well indeed!!!

[@michaelbishop3701]

One of the most amazing things to me is the ability of the human brain, not mine, to learn how to understand and control electrons. More amazing than that is, the mental ability necessary to understand all of the components and HOW they channel electricity to other components, to achieve a desired task. To me, it's magic. My 67 year-old brain just can't absorb that much information. I've been a residential electrician and a commercial electrician and have built a few power supplies and Fuzz Boxes for my guitar back in the 70's. But, Magic needs Wizards. And you, my friend, are the Grand Wizard. Always amazed. Hope your channel does well.

[@maryrafuse3851]

Mr. Carlson is one incredible engineer, cool when it comes to all the antics of bad caps & resisters. With all his abilities he has the smooth voice of an old time broadcaster. And to cap it off he is proudly Canadian and gracious to all.

[@SkyWire88]

Thank you for the introduction, Mary

[@fawazalfridy5940]

As usual, beautiful things from history, as Mr. Carlson's creativity increases the beauty of these masterpieces touched by the hand of a genius. Greetings to you from Saudi Arabia👍

[@littlebear5219]

You have opened my eye’s with to all the faults with. Capacitor’s.

[@KeritechElectronics]

Loveliness! I'll be on a lookout for bad mica caps, and the Heathkit signal tracer gave me an idea of hooking my regulated 100...300VDC supply through a resistor to the DUT, and using an amp/speaker for listening to what's happening there.

[@RestorationsbyKennyFidler]

Glad You’re Back!

[@terrym1065]

Another fantastic episode, thanks Mr C. Swapping the components totally enhanced the reception capability, just awesome. I can only imagine at this time just how good this receiver will operate when coils and alignment is final. Having the proper test equipment is obviously a necessity even if vintage, good stuff here. Well done sir, thanks again for a quality production.

[@gerardcorcoran-m4m]

Excellent Video Mr.Carlson, I enjoyed watching you today and can't wait for the next part.Thank you for sharing you knowledge with all of us.

[@Cyberplayer5]

Watching you work on this receiver is very Zen.

[@ПавелПопов-и1т]

I just admire your work on the restoration of old equipment. 40 years ago I had an AR88, just an amazing radio. best regards ra3apq from Мoscow!

[@CrispyCircuits]

Thank you. It was really neat to see some failed mica capacitors, especially since it was a big batch problem and how and what you used to test them. I'm 53 now and getting back into electronics again. I started by studying electronics when I was very young and my dad brought me a surplus shortwave receiver and transmitter that fit into a rack and was used by the military. All vacuum tube.😀

[@Go4Corvette]

Excellent work A+ Sr. Every time I watch these videos reminds me of my first class in Junior high and High school but your classes are at a much higher level. It wasn't till I went to GM advanced training schools that I learned more. I am trying to convince my son who is a computer science student graduating this year from Stanford University that he should subscribe to your classes and also learn how they work on the inside. Knowledge is power. Thank you, Mike

[@GeigerCounterVirtualMuseum]

Enjoying this series!

[@donl1846]

Way to go Professor Carlson, it is amazing with some tweaking how good a radio can sound. Look forward when you do the final tuning-up and see what happens. Thank you for sharing.

[@coldfinger459sub0]

I wish there was a KZbin with Mr. Carlson’s lab back in the 1970s. It would make my experiments with taking things apart as a child much more successful..

[@Chris_at_Home]

That’s some old stuff. I worked in a TV repair shop in high school in 1969-1970. Then in the Navy on P-3s we had old and new electronics equipment. They taught us both tubes and transistors in A school. I think I have an old airplane radio around that I had in a small plane I had with all the discreet components. Circuit boards sure changed everything. It’s amazing how they put these together versus todays electronics. All those capacitors being bad makes me wonder if it didn’t take some kind of real high voltage hit. Something in the few thousand voltage range.

[@johnwaterman1579]

nice review... I have no idea how to do this... but I learn something every time.

[@mikefinn2101]

Amazing Engibeer love these videos learn so much Paul is the best of the best number 1 teacher on you tube

[@cfcreative1]

nice to shine a light on a historic piece of gear

[@faxcapper]

Those 2 RCAs are simply gorgeous!!!

[@ariedekker7350]

Nicely done. Nice video. The PE1KRX was QRV for VE7ZWZ and sends you the best of the seventy threes. Thank you and see you next time.

[@Greg-et2dp]

Mr Carlsons lab you are good at restoring vintage shortwave receivers and alignment of vintage shortwave receivers

[@nathkrupa3463]

Great engineer Mr Carlson sir you are awesome Thanks for the sharing this video sir ❤.

[@MrCarlsonsLab]

My pleasure!

[@Greg-et2dp]

Mr Carlsons lab your vintage RCA cr-88 communication receiver is awesome 👌 👏 👍 🎉😊

[@hugoromeyn4582]

That capacitor at 10:00m sounds like listening the HF bands during a thunderstorm!

[@MrDoneboy]

Great job as usual, Paul. 80 year old radio receiver, sounds great...will sound awesome after the tuning!

[@LarryDeSilva64]

I must say you do have an interesting way of testing for noise with those Mica capacitors. Really good to know when I am working on a noisy receiver I will look for that as well as dried out Electrolytic capacitors and checking tolerance on resistors as well as checking caps for leakage. Thanks for another informative video Paul.

[@leonardpeters3266]

Nice work. I know how hard it is to work in those areas. Brutal. Nice work there.

[@derlowe4590]

Nice to see you. Good wishes for Easter!

[@johnopalko5223]

31:15 That was WWVH. That's pretty impressive reception.

[@JohnShalamskas]

I noticed that too. Probably 10 or 15 MHz if it was daytime in Hawaii and Canada.

[@Greg-et2dp]

Mr Carlsons lab I love the RCA CR-88 communication receiver ❤🎉😊😊😊❤😊

[@Steve-GM0HUU]

👍Thank you for the video.

[@PeterMilanovski]

Is it just me, is there anyone else who loves doing something pointless like watching old capacitors being tested? I know well enough all the ways that capacitors fail and watching someone test old capacitors that I'm possibly never going to come across to test myself gives me so much satisfaction and yet I don't know why?

[@Davidjb37721]

Thanks for your time

[@johnparichuk8367]

I just brought a 1934 Silvertone Model 1806 back to life. The mica capacitors are original and in excellent condition. I usually buy radios that are in pretty bad shape that no one else will touch. I like the challenge.

[@PE1FWD]

I am waiting for the racal ra17, i have had one for a nummer of years and worked with it in my navytime as a radiotech.

[@rl2109]

A very interesting video!

[@JCWise-sf9ww]

Mr Carson is a very skilled electronics technician/engineer. I'm looking forward how well this receiver can pull in distant AM broadcast and shortwave stations after he gets all restoration done and completely aligned.

[@alamoaudio]

Really impressive knowledge, love this channel even though all this sounds like obscure sorcery to me

[@washerdryeradvicechannel8041]

Thanks for sharing Mr

[@jeffminnick5209]

Once again a great video Paul, hope your Easter went well and keep up the great work... looking forward to the Racal and the Collins as well !!! 73 WD8JM

[@josealfredoalcoviadebarcel4633]

The mica capacitors inside de FI cans were bad too, on my AR88. They were mica too, but had leakage. Noise I had not tested. I think that noise and leakage are “sisters”, or the same gost. After changing them and doing the right FI alignment, the receiver operates in a very great condition. Astonishing condition, to be more precise. Greetings from the south of Brazil. 0:08

[@Turbo-Drew]

Awesome as Always... As A Newbie,im really loving this series.Thank you

[@graemebrumfitt6668]

This is gonna be brutal when finished Paul! Stay safe n well. TFS, GB :)

[@alandrury9955]

Great job sir. Really enjoying this series

[@Greg-et2dp]

Mr Carlsons lab your utube videos are awesome 👌 👏 👍 🎉😊

[@craigmose5898]

Could explain in one of your videos what B+ is in the tube radios... Thank you and I really enjoy your videos...

[@MrDoneboy]

Wow..."Bath Tub Capacitors"..."Silver Mica Disease"...of course we've heard that one before, but...You go, Paul! Lol.

[@tomharris1457]

Nice ! Getting there.

[@hestheMaster]

The B+ Voltage on those old mica caps really wore them out. Seems they may have been from the same manufacturer. Guess we can call it Micamold disease. Great restoration series there with you as a teacher Paul. Time consuming repairs ( from unfortunate surprises) edited for sanity reasons no doubt and more repairs to come before aligning it. Can't wait!

[@nathanokun8801]

In following your channel, I find it interesting how many functions, sometimes simultaneously, capacitors are used for. Before IC components were introduced, capzcitors were the m9st versatile components in any electric, to say nothing about electronic, devices constructed.

[@analogaudiorules1724]

They still are.... Look up surface mount capacitors and also ic lithography

[@rsdandy]

Great video. Learning a lot.

[@JohnAlexanderBerry]

It's a big job to change all those capacitors (plus those resistors), but it's something that has to be done ! I'm going to do a similar thing to my 1947 AWA receiver, but it should be a lot easier to do compared to that receiver you have there !

[@jazbell7]

Those mica caps were probably quiet for the first 40 years of life. But now it's almost 80 years.

[@W1RMD]

I hope you and your family had a great Easter. Great video! I am curious how the mica's would test using your Carlson capacitor tester. I would also like to see you use the super probe the way you use the Heathkit signal tracer. I would assume that if you put high voltage on that mica it would make noise that the super probe or audio amplifier could pick up. Taking precautions with high voltage involved and using a .01 capacitor between the DUT and the amplifier if that is your weapon of choice. Although, no direct contact is need, even with most audio amplifiers. Also, Shango66 has some really cool night vision video of "silver mica disease" in action. Thanks again for doing the restoration video series on this beautiful receiver and piece of history!

[@toddsculley2710]

Love watching

[@xe1zlgg]

May be les overload on extreme large antennas.... congrats for your video...

[@migsvensurfing6310]

Noisy capacitor = perfect random generator.

[@mikesmithg0rfd356]

thank you

[@MrCarlsonsLab]

You're welcome!

[@mrb.5610]

I wonder if a thoughtful replacement of any old carbon composition resistors would help with the signal to noise ratio as well ? I replaced the resistors with metal film ones on an audio amplifier years ago and the background 'hiss' virtually disappeared !

[@MrCarlsonsLab]

Carbon composition resistors are quiet as well, there are just a lot of noisy ones out there to confuse. For example, My Fluke 5440B Calibrator has many carbon comp resistors in it. Your amplifier that had a hiss issue probably had a noisy resistor, replacing that resistor with a new carbon comp would have resulted in the same outcome that you have now.

[@JohnShalamskas]

The lower gain on the RF amps might have been chosen due to the receivers being used near high power transmitters. Lower gain in the front end would reduce gain compression in the presence of strong signals.

[@kellyblack4897]

"So not too bad on that one. But, of course I'd never trust it! Alright?" - Mr. Carlson

[@daveturner5305]

Sir, you mentioned that the 47k screen resistors were factory. If I've understood you correctly then you have another otherwise identical receiver with 33k standard factory resistors. Would it not have been more interesting to restore both as factory and then compare their performance, assuming all else is equal? Or have I missed a point?

[@MrCarlsonsLab]

It would just have lower front end gain.

[@tubbysailor]

What wears out inside and is it arcing that produces the noise? Thanks.

[@LitchfieldCountyComputer]

What's involved in re-manufacturing dials?

[@felixcosty]

Thanks for the video. Just wondering could the non standard resisters have been put in, because the caps where bad and that was there sort of fix?

[@ch2o2]

..love your noise sniffer. As far as I understand, the device basically only applies clean DC voltage to the component and at the same time sniffs out any minimal voltage drops (cracks) that may be present via a coupling capacitor. How high is the voltage that is applied to the components in this method? I already had transistors and OPs that caused similar cracking ...is it possible to test semiconductors with this device?

[@mikethompson2593]

How does RF noise and pulses affect your measurements?

[@no_more_free_nicks]

Those caps would make great components in random number generators.

[@analogaudiorules1724]

Assuming it lasts the initial power up lmao

[@kellyblack4897]

With all that noise I couldn't hear the caps! Maybe we should test them again? 😂

[@afnDavid]

Perhaps they wanted slightly less gain/sensitivity because the receiver was used with a multi-coupler which had gain of its own.

[@Graeme_Lastname]

I've not had a lot to do with mica caps and I would be interested to know how they generate noise. 🙂

[@josephcote6120]

Assuming this is the same problem that IF tuning caps get, it's called Silver Mica Disease. The plates of the caps are plated in silver. When it is in contact with the mica for many decades the silver migrates into the mica. This gives an intermittent conduction path between the plates. When B+ is applied it conducts through the silver in the mica. When it conducts it moves the silver around and changes the conduction paths, hence the crackling; it's tiny low-energy sparks in a way. Rarely seen because the mica is thicker than the mica in an IF can.

[@Graeme_Lastname]

@@josephcote6120 Thanks for the info m8. It makes sense now but it had me buggered until you made it clear to me. Thanks again. 🙂

[@itsonlyme9938]

Have used .01uf caps instead of the 4700pf ?

[@MrCarlsonsLab]

In many spots, "Yes." The 1st detector (Mixer) cathode, and the AGC line got the factory values, (4700pF.) All the screen decoupling capacitors are now .01uF

[@itsonlyme9938]

@@MrCarlsonsLab thank you for the info I will change mine to .01uf. The ones in the RF amps I wired them direct to the earthing tag on the valve base to keep the leads short and the RF stage went into oscillation ? put them back as factory fitted them. I see the first RF amp has a ten ohm res in the anode.

[@DeadKoby]

Is this similar to "Silver Mica Disease" that one sees in vintage radios?

[@markanderson350]

I used to have a signal tracer with noise function, i never used. I think a Heath it 12. I never knew these could crap out like that, i am restoring an old hallicrafters sx-42 and did not. Change the micas. It is similar to your set. But has fm. I dont know about screen resistors, my radio has 56k

[@erikdenhouter]

It would be nice to see these mica caps under a microscope, to see if there are cracks in it where the atmosphere can get in, and compared with a good one.

[@davidsanderson625]

Thank you for a fabulous series of videos. Could it be that the radio was operated in a high humidity environment that caused the mica capacitors to fail?

[@McTroyd]

It wouldn't be as simple as removing the glue on the SWR meter with isopropyl alcohol, would it? Or is there paint on that glass that I missed?

[@MrCarlsonsLab]

Yes, they glued right to the paint, some of the glue even ran down in the meter face area :^/ I don't know why anyone would do that.

[@McTroyd]

@@MrCarlsonsLab UGH. That sucks. Know any artists who could repaint it? 😁 (j/k)

[@benrasmussen9878]

Hello I was wondering if large test tubes are available, like the ones you have shown inside large transmitters? Im looking for a tube that will work like a continuous doide. Thanks 0

[@christophermarshall5765]

Great job. I’ve never heard such noisy capacitors before.

[@JeffreyGroves]

I've never tried it, but I was wondering if a windshield repair kit might be able to hide the crack in the glass.

[@spudhead169]

You've just given me an idea. Those faulty caps might be a good way to produce entropy in things that usually have trouble generating it like servers.

[@analogaudiorules1724]

Not a good idea.... All it takes is for one up completely short and then take out something irreplaceable, if its more that25 to 30 years old and an oil filled electrolytic or more modern electrolytic, it's gotta go...

[@acestudioscouk-Ace-G0ACE]

Fine business, thanks! Your way of teaching and detailed shots are really helping me as I have 4 AR88s to check through. As you say, a bad batch of caps, I wonder if the one of a slightly different colour was a different batch or a replacement for a previous failure?

[@pglick123]

Do you know what's going on (physically) in those capacitors that is making them noisy?

[@utubejeffo]

Where do you source those Allen Bradley-style resistors?? All I can find are metal-film resistors from the "orient." I'm looking forward already to the next receiver renovation. Thanks! 73 Jeff

[@dougkathydavies3024]

I have an AR-88LF. What type of capacitor should I use to replace the old mica ones in this radio?

[@frankschultz4170]

I ALWAYS replace paper caps. Good luck on finding new bathtubs! Do you have a calibrated RF signal generator or service monitor so that you can make sensitivity measurements? It would have been interesting to make before and after measurements in the capacitor replacements.

[@DJW1959Aus]

Perhaps a very low viscosity UV cured bonding resin agent could seal and mend that dial cover crack to invisibility (as used to fill windscreen cracks).

[@frankowalker4662]

I don't think much of the Quality Control at the factory that made those caps. The lighter coloured cap that was fine might have already been a replacement.

[@davidstone1579]

This gain reduction is probably because it was a multi-receiver installation with a front end aerial amplifier / distribution driving the all. This was quite common with Government listening posts. G8FNR.

[@number6of1]

Enjoying the channel, makes me want to get back to restoring old radios (and by old, I mean around my age ;) or older) Where do you find these gems? Fleebay, swap meets?

[@richardmills5450]

What did you replace those mica caps with ?

[@drocles]

Is there any other possible cause like a really crappy power supply with surges damaging the radio over many years?

[@AlfDavidFjeld]

can you not take of the scaleglass and scan it in to your pc, in several parts if it is to long for one scan, and then fix up the image in software to remove any problems, and then make a new one yourself, or have someone else make it from the fixed up scans?