1946 Radio Receiver Teardown - The RCA CR-88!
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- Опубліковано 2 жов 2024
- Let's see how they put this together, and what's been done to it over time. This is Part 2 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: • 1946 Secret Listening ...
Part 3: • Capacitors And Electro...
Part 4 here: • Receiver Restoration S...
Part 5 here: • Electrical Troubleshoo...
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
![1940's Forestry Radio Receiver And Transmitter [Teardown With Circuit Description]](http://i.ytimg.com/vi/H7RKEDPUy-8/mqdefault.jpg)
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
I legitimately thought you were going to do more hi-fi videos.
@@Poppinwheeeeellllllieeeeez Give the chap a chance...... Besides I have two RCA 88 one upstairs and one down...I have waiting for a instructional video like this for some time ( comment from England )
@@Poppinwheeeeellllllieeeeez This is much more interesting.
@@Poppinwheeeeellllllieeeeez There are lots of them on youtube. But not near the quality of production, camera shots and content.
Hello Watching this video as I write this, Just thought I would throw this out there, If in situations like this and Sliding heavy pieces out, Is it able to put a wooden/Plastic Dowel under it to help get it out, and Not Smashing your Fingers???
You always go out of your way to explain things, without time elapsing, but at a calm pace so that everyone can join in - it's just super professional - I love your fantastic videos.
I appreciate that!
This is what I like about your restoration videos, Paul! It's not all about Retrobrighting plastics. It's actually about electronics. 👍
You made one of the best decisions with your channel to keep your videos to about 1/2 hour and can pack a lot into that shorter time frame. A little bit at a time each week, I like it better this way. You cover every detail of what your working on, very nicely. 😀👍🥰
I am aware of 2 types of oil filled caps in the world. Ones that are leaking, and those who are about to start leaking.
I'm very much enjoying your work on this beauty. 73 de W5EN
What a splendid Special receiver that's in relatively great condition !! .....Radios that Large & heavy needs heav6 duty Side grip handles !!
Another exciting video. Personally im here for the replacement of near 100 yr old components and the expertise placement of 2023 components. Cheers!
you're a treasure to students of the craft like myself. I thank you for everything here and on Patreon. I've learned and put into practice so much from your teachings.
Thank You for your kind feedback.
@@MrCarlsonsLabit's more than appropriate. I look forward to every video!
The curse of making such a beautiful bench top Paul, a piece of Masonite also works well as a protective surface
Bizarre funny - went to pick up my tablet as you pulled up the tuning capacitor lid, swear my tablet felt the same 😂
I'm five seconds in, and I have to ask: New microphone? New audio processor? New studio? New larynx? The sound is much more "lively" than in the past, and that is obvious on my phone!
Foam Core: you can get black or white or "kraft brown" and also non-acidic for museum quality work: there is also some 1/2 inch stuff with various names one of which was "gaterboard"
That alignment is going to be amazing! Thank you for the videos, I love the new bench, love that you read my comment. Thank you for teaching me and showing me so much. Thank you
You are so welcome!
Nice as always, the capacitors are filled with polychlorinated biphenyl oil's, if I am right, I was see them in old motor run capacitors often, the smell is really unique
Awesome vid . If you lift the case a bit and slide your protection mat under the feet of the case you can then slide the inside component right out onto the matt without any concern of wrecking your table top . It will hold the mat in place . 👍
Just a minor note that the black paper-faced foam board is commonly referred to foamcore. It's typically used as rigid backing for photographs and picture framing, but it has other uses (as you've shown). Very interesting rebuild, looking forward to the next ones!
i currently place the black foam bds on my ( sun-facing ) windows to passively help keep my place a little warmer . . . i'll switch to white ones come summer!
Great series Paul!
Maybe you should hit Lowes and buy a sheet of plexiglass or aluminum to cover your benchtop so you don’t have to be distracted by that
NO!! Get the [non-rack-mount] trim pieces re-chromed, and spend the extra bucks for real, hexavalent chrome plating! You won't be sorry
What weighs more?
The radio or the alignment manual?
Paul, if you work on anything bigger you will need a jib crane!
It looks like a fantastic car radio. It will make my center console look very impressive. I will try to keep my toes out of it.
i would bolt 2 vertical wooden blocks on the front of the rack ears. then you can tip it face down on the front.(with the blocks giving clearance. then pull the back up and off.
Theres probably PCB oil in those caps given the age. Nasty stuff!!
Simply amazing! The minds that created this absolutely incredible machine 80 yrs ago is nothing less than astonishing, using the available components at the time and engineering the mechanical processes is just magical. A lot of that was going on back then, Los Alamos, White Sands, Trinity Site... What's even more intriguing is how you know what these people were doing and thinking when building these things. I certainly hope that a bio is in the future sometime as you're pretty magical yourself Mr C.😉 73
Thanks for your kind words Terry!
I Dub, Mr. Carlson, The Master Wizard, Of Electronics.
The construction reminds me of the Vedolyzer
Hi Paul, I’ve found that using three or four dowels of appropriate size as rollers can be helpful to get a heavy chassis in and out of its cabinet.
Some years ago I purchased a number of new old stock parts for my RCA AR88 all in their original wax paper a power transformer the large capacitor block to name but a few. Upon opening the large transformer from its wax paper which had not been opened since 1943 I found a copy of an American News paper which was used as packing the front page give an update of the war. ( Comment from England )
In 1975 I went down to a surplus shop here in the UK and purchased a new output transformer for my AR88 and that came in USA news paper about the war effort making bombers.
You were indeed lucky,. I also have a new output transformer for the same 88 upon opening the wax wrapping a few months ago there was some 1943 America straw used as packing
Very nice receiver. Toodles!
Toodles ??!
Thanks so much for bringing back memories from 50 years ago. I had the AR88 version, spent hours in front of it spinning that wonderful geared tuning knob - such a stable and brilliant receiver. HF aviation reception presented no problem with just a 60 foot length of wire to the fence post!.
I did look inside and under the screening covers and wondered then about re-alignment but seeing all the twiddle points, and not having any test equipment, I resisted the temptation.
I had a hairbrained plan to find a motor and appropriate gear to add so I could tune it from my bed - fortunately I held off that master plan!
I regret selling it - but 8 years later I got more than I paid for it.
Thanks for sharing your story Barrie!
From what I have learned oil caps like the ones in you video could contain PCBs or polychlorinated biphenyls which are hazardous. As a side note PCBs are very hard to dispose of because they are resistant to acids, electricity and fire.
For reasons of safety it might be an idea to use the Low Voltage Vacuum tubes that were created in 1957 because the transistors were not ready for prime time and the manufacturer wanted to get rid of the vibrator as it was a source of interference which would mean that both the Heater voltage and B+ would be 12V and as it has no speaker just a headphone socket so why not.
I love how detailed your step-by-step explanations are. It's helpful for someone who doesn't work with analog electronics, and it's quite endearing, Paul :^)
Glad you enjoyed it!
I once had an AR-88. I got it from Ozona Bob, W5PYT (SK) about 30 years ago. Bob bought it sight unseen from the Yellow Sheets, and it arrived incomplete. It was missing an IF can, the phasing IF can, the mode switch, and the wiring harness was diked out! Bob gave it to me, and I promised I'd try to get it back in service. It took several years, but I did get it working quite well before Bob died in 1999. It actually HAD the alignment tool!!
Some comments as I remember them. The AR-88 and CR-88 had a different IF frequency, but the IF can coils inside were identical. The only difference was the internal fixed capacitors (Mica I believe). One thing that floored me was the HV DC power supply with dual chokes and several oil capacitors for the filter. Any attempt to add more bass to the audio was offset with the C-L-C-L-C filter being excited into resonance from audio as low as 200hz.
Jim
Wd5JKO
Thanks for sharing your story Jim.
I think that mrw stands for Montreal radio works, the original assembler of that radio.
Gunmetal gray is the color that you want.
This thing is going for $4000 on eBay and $1300 for shipping, from Australia.
Is Postr board they all that stuff maybe? IthinkI have heard it called that.
I know absolutely zero about radios, but I can see that this one is a work of art and was designed / built by people who had some pride in their work
Brief Specification for the RCA AR88 Radio Receiver: Weight 100 lbs (45.3 kg)
Instead of linking your "Part 1" video, you should just make a playlist for each subject's videos and link them to that when you upload, and then just link the playlist in the description. It's easier for viewers to see everything related by using playlists.
My AR88 has gradually lost performance and I was thinking of refreshing it this year... now I will wait for your hints to see all the things I might otherwise have missed! Many thanks.
Great Sir RAFIQUE MASTOI DG Khan Pakistan 🏝🇵🇰🇵🇰🇵🇰🇵🇰🇵🇰
I thought mine was clean but yours looks like it came off the factory floor. At 11:40 in the video you will see at the back of the shot on the side of the chassis there is a little spring clip. That is where there should be an Allen key (2mm I think) intended to remove the front panel knobs. As usual it is missing.
I was wondering what that little spring clip was for...
You often mention listening to AM radio in your videos. What kind of programming do you listen to up there? They've more or less stripped all the good stuff off the AM dial in my area.
A long time ago, I was a CB radio operator. Needed a licence at the time. A friend of mine showed me a book he had which covered repairing CB radios. One question was: " Your radio starts smoking. What is it you do next?" My friend wrote: " Turn it off, some b@#!%^&'s got a big linear amplifier!!" I had to chuckle. Have you seen Yaesu's FT-710 radio? They are good. I bought one a few days ago. Just waiting for conditions to improve.
Hi Paul.
Great series.
In downtown Copenhagen there is a museum known as the “post office museum “.
I understand it has been relocated since, but they had a great display of a listening station and a number of disguised receivers and transmitters.
The pride of the collection was an AR-88.
It took a minute, (10-15 years) but I finally snagged one.
It’s in decent condition, has the reverse reading meter, etc.
These were often used in embassies, as well as collins 51js and others.
Many thanks for all your efforts .
Greetings from Montreal.
The oil from the capacitors is not just unfriendly, it's a major carcinogen. It's considered a hazardous substance now.
Honestly, I feel like I'm in school every video. Thank you sir.
You are very welcome!
What would be some modern equivalents of this receiver?
I'm very interested in how you hook up the 50-ohm input of the spectrum analyzer. Thanks for doing these. I love your videos.
The input (one of them) of my spectrum analyzer is 1M Ohm. It's an HP 3585B. I use this input for these alignments.
Following along here, thank you for doing this. Tried my AR88LF and it works, but the top shield box over the RF section is missing. How much of a hit will that make to the performance when we're done?
For frequency stability reasons, I would find a replacement box.
The sound is better in the new lab. It’s less dead-we can hear just enough room echo to make it sound natural and lifelike.
Oil filled capacitors of that era may contain PBC's , a very toxic hazardous chemical used to preserve the oil .
Looks like you could use a gantry with a camera mount over the bench. Perhaps another Patreon invention? Really cool receiver. Love that gearing up front.
This is the kind of content that would benefit from 4K. Surely that camera you have can do 4K? I understand the issue of storage and computing power, but again, match the camera to the post hardware. It's nice to be able to zoom into these videos but at 1080 its still not great. Even looking at 100% there is a lot of detail missing on a 4K monitor or TV. I think if you did this at 4K it would look amazing.
Somebody needs perfection.....
20:17 ~ Hi Mr. Carlson. Can you please tell me what this goose neck lamp is called? I have been looking for one of these with this shape. Thank you.
Fantastically impressive piece of equipment Paul. From the front it looks much younger than it is. Nice work as usual.
Thank you so much Mr Carlson! I have a RCA AD88D which I bought in the early 1980's. I have not used it for a long time & I have been waiting for you to restore one so I could attempt to do mine. I was not sure on whether or not to replace the oil filled caps as I had heard they would be ok. I will definitely replace mine now. My AR88D has been modified at some point & a ECC83 has been added. Not sure why but hopefully I will be able to figure it out 😄 I look forward to your next videos. Thanks again 👍
Hi Mike. The ECC83 or 12AX7 is probably a product detector. A real common modification way back when.
Ok Paul.... let's see what part3 shows us. Thanks for all your efforts! Cheers
Paul, your lessons and knowledge helped me to get my 51-J4 working again. Thanks, keep it up! Glenn
Aha! the chromed strips hiding rack mounts. I assume the Rx is 19" wide?
Yes it is. There are three threaded holes at the bottom of each side where slide rails would be attached to pull the thing out for maintenance.
Would it be better to make a semi permanent padded area on the bench instead of wrestling around with those pads
I have an AR-88LF that spent it's entire life monitoring WWV on 10MHz at the Sandspit Airport on the Queen Charlotte Islands (Haida Gwaii). It had a number of tubes with metallized paint that were bad. I could never find replacements for them so had to substitute with metal ones with similar characteristics. The radio did work but never did perform like it should. Do you know of a source for these metallized tubes?
There are lots of old radio tubes still around, and many online stores that sell them for very reasonable prices.
@@MrCarlsonsLab I agree, there are still lots of old tubes still around but I couldn't find any with the metalized shield painted on. I notice your CR-88 has the metal shielded tubes. I will compare my schematic with yours and see if the nomenclature for the shielded ones is the same for both radios. If so, I will try and find the metal versions since they are probably easier to source. My AR-88LF must have been made prior to the actual metal shielded ones becoming available.
@@dougkathydavies3024 The only glass tubes in these receivers are the VR-150, the 5Y3GT and the 6K6GT, all the rest are metal. The glass tubes have the "GT" letters after the tube number. GT= Glass Tube. Do not use glass tubes anywhere else in this receiver.
@@MrCarlsonsLab Poor choice of words on my part. My apologies. I should have said "characteristics", not "nomenclature". I only have glass in the spots you mentioned. I have metal ones where the old painted ones were. I had to make up socket adaptors for some of the replacements which was a royal PITA. If I remember correctly, those painted shield ones were made by Rogers Majestic.
There is in the UK Langrex tubes and Colomor tubes might have new old stock.
I have a receiver very similar to this but different enough to be a previous model. I cannot locate a model number on it anywhere or a photo of one like it anywhere on the web. Where can I send you photo of it to see if you might recognize it.
We had these AR-88's when I worked as a CW op @ WPA/Port Arthur TX RCA coastal station....they were excellent on the 4/6/8MCs band but were so-so on t he upper HF frequencies.......we used 600Ω 'cans' but installed a step down xfmr 600:8 Ω so I could use a regular headset to keep the external noise to a minimum...it definitely was not a quiet room as we were monitoring 500KCs while at the operating position(s).
Thanks for sharing your story Tom!
enjoyed the video. Why were oil capacitators used in the first place? I view tube circuits as small oven, so, would that have an effect on to oil caps?
Absolutely Wonderful Radio. I like how you can "parallel" park it on your new bench.
foamcore
Great video! Although "boat anchor" radios are heavy and difficult to handle on the bench success is a matter of mastering leverage rather than physical strength. Yes, you are a vintage electronics bench ninja! I have a bench made of unfinished 3/4" fir plywood. I place the equipment on top of old terrycloth bath towels to drag them around the bench.
Wouldn't you like to have video of the production line as these were being built?
Great job! This is giving me incentive to get my Johnson Invader 2000 back on the air with the Heathkit SB 300 RX. I helped support the Ukraine and bought some 1N16 nixie tubes to build a cool frequency like the one you built back in 2016. I love seeing the old transmitters and receivers that you restore on here. Great to see you back in "full operation" again. Can't wait for the next Patreon project as well. Best regards!
Hello. Please make a tour explaning every equipment on the back.
Enjoying the new shop/format.
the board is called "Foam Core" perfect for what you are using it for.
I learned electronics at Ft Devens working on the R390
Wow It was so nice this morning to watch this long awaited next part of a very rare expensive radio restoration great to finally see the insides and see it restoration process begin, looking forward to the next video. great job too Paul. Be waiting for next videos Love watching makes my day 73s wb7qxu
Another common name for foam board is form core.
You need a power driver for those s.crews. Make your life a lot easier
with the wire looms and the way that is constructed it looks just as good as a piece of Collins Gear. Everything has a place and is separated from each stage to keep the radio from just taking off from RF. Very nice look inside the radio Paul. Thanks.
That radio does not have built in obsolescence, what a tank!
Look at the shine on the workbench! 👍
Thats a great name too! :^)
Maybe when you built the lab you should have put in a light bridge crane for handling all these boat anchors. :o)
I probably should have!
Another splendid video Paul I can’t wait for the next stage 😀
You say you intend to use a spectrum analyser to do the alignment of this receiver, but, how was it originally done, back in the 1940’s, before, spectrum analysers were available..?? 🧐
They used an oscilloscope and a sweep generator. This performs the same function that the spectrum analyzer does. The device (way back when) was also known as a "Wobbulator."
@@MrCarlsonsLab Ok. Way back in the 1940’s I thought that it would have been even a bit too early, for the use of Oscilloscopes. 🧐
I thought it may have been more like a matter of them having to use a Sweeper, with a VTVM, and a whole lot, of, patient, ‘tuning tool twiddling’ along with, a whole lot more, of, muttering, and quietly spoken, ‘cursing’ mixed in, for good measure. 😉
Time to slow down and enjoy some time at the bench with Mr Carlson…
Well said, i usually save these videos to watch on sunday mornings, that thing does look heavy, and with the components getting removed that case probobly gets really flexible, he is a real artist
That is a beautiful example, great to see it being massaged by someone of your abilities & experience.
Hi Paul, The timing of this video is good for me. Although I’m not working on a CR-88, I just started on a Hallicrafters SX-42. As you likely know, these are very similar beasts but different. Like yours, mine looks all original.
I’ve been meaning to ask you for some time: have you considered making a camera gantry? I’ll bet that moving that tripod gets old and if you had a roll-away, overhead gantry that be remotely controlled by a simple stepper motor arrangement (could be manual too, but what fun is that?) and you’d have an optimal platform for lighting. You do such a good job producing your work but I’ve often though that your setup efforts are sometimes difficult. Anyway, with all the room you now have, I thought I’ve make the suggestion.
Cheers, Scott
Thanks great video! Definately a finger pincher this one, its model number is almost its weight in pounds.
Oo.... I'd be very happy to wear one of those Mr. Carlson's Lab sweatshirts - are they available? (sorry to go massively off the point of this excellent video!)
For heavy equipment like this I have a large Lazy Susan, makes moving it around a lot easier.
just wanna say thank you for sharing these incredible videos showing deep knowledge and tricks to repair
My Ar88D came with as rare as hens teeth special tools for adjusting the plunger trimer caps which are clipped to the tuning capacitor box.
You are very lucky!
@@MrCarlsonsLab My AR88D is date stamped on the tuning gear drive mech 1943 by the navy and those trim tools must have been supplied with the set from the factory all those years ago.
Foam core board
Nice video, very interesting. The only thing missing is the sound of your old tube mike :)
Only the 1st scratch on a new bench hurts. After that, it's Oh well.
You cannot stress enough the value of shielding in these old receivers with all that dangling point-to-point wiring going on, and all those zillions of screws giving the whole thing not just bonding but physical integrity. This is a cold-war treasure and it's in great, good hands. Thank you!!
Speaking of ‘physical integrity’ of construction of electronic devices, just reminded me, that back in the early 1970’s as a then young and pimply faced Government ABC radio tech, I had the opportunity, to peer, into the innards, of a Wandel & Golterman Spectrum Analyser, that was being used for sweeping the response of some NEC low power, TV ‘Translator’ Transmitters, and their tower-mounted Antenna Arrays, that we were installing at that time, throughout remote and regional areas of Australia, and comparing the ‘physical’ construction of that device, to the construction of this 1940’s era RCA receiver, are a bit like comparing chalk, and cheese.
The build quality, of the engineering in the W&G Analyser was, eye-opening, with every individual section of the circuit, being separately, fully compartmentalised, and with the entire, chassis, of the whole thing, being made from 1/3” (8mm) thick, Die-Cast, Aluminium, and with Teflon standoffs, and insulators, and gold-plated RF-coils, and contacts, used throughout it, everywhere.
Needless to say, it weighed ‘a Ton’ (figuratively speaking) and was valued , at more, than my own, then, entire, annual salary.
Needless to say, we treated it, ..reverently. 😉
I'll be honest. Something made me expect some sort of carnage when the back was shown in the previous episode... but this ain't bad. It's actually quite a bit cleaner than other examples i've seen online, cleaner than other other-than-civilian equipment i've seen. What a great little capsule.
Paul have you got any hifi or tv repairs lined up? Cheers.
I do!