B-29 Aircraft Receiver Scrap Parts Unit, Will It Still Work?

hi everyone and welcome to another episode of mr. Carlson's lab on the bench today is a radio receiver out of a b-29 aircraft from way back when now when these radios were decommissioned and taken out of these aircraft they were sold to the surplus market and they were also sold to you know ham radio operators and the like now when these radios were in service they had a dynamo tur in him like this Pillsbury radio that I just did in the last video which I've had enough votes that yes it will get restored that's going to be a mighty lengthly restore lots of stuff to do and that thing but at any rate back to this receiver here these things had to die no motor in them that would make a lot of noise and they ran off of you know 14 volts or 28 volts or whatever in that area so that wasn't desirable for ham radio operators in the surplus market to really do anything with so the surplus market the surplus resale errs I should say they offered usually for about five or ten dollars they would convert the radio for you by installing a transformer and a rectifier and some filters and then of course ham radio operators just did this stuff themselves so this radio has had that conversion and it looks like it's probably been done in home I don't know maybe the 1950s or something like that so this radio was deemed as parts this is a parts radio that I purchased it's missing a whole bunch of just everything it's missing a lot of stuff but it would be really interesting to see if the thing actually starts will it actually run so what we're gonna do is we're gonna put power to this thing and see if it talks to us or if it lets out the magic smoke so let's find out here's the BC 348 that was deemed as a parts unit and it's missing lots of parts and pieces olla covers for the coil boxes here are all missing you can see all the dust that settled in there over the years usually these are spotless inside because they have little coverage that screw onto these little tabs and if you can see them you see this one here here and here in anyways they screw on to the top to keep everything nice and clean because there's a bunch of switches in the bottom here that all gets switched by this mechanism here when you change the so you see right over here is a big ratchet system here that holds the band switch in place and if I change the band you can see that ratchet move and it all goes into different notches and then that gear down here is changing the band switch so I'll see if I can get just a touch more light on that there we go alright and I'll move that around and you can see that so they're switches in each one of these boxes that are all ganged together by one shaft and that shaft sticks out right here so if I move that you can see that turn around turning in that little hole right down there so that changes everything and what happens is when the tops of these boxes are missing dust and garbage settles on down inside these things especially if the case is missing like it's been missing on this thing for who knows how long we'll get out dirty and disgusting this thing is so it's you know been missing I've noticed a tube is missing on this side we'll take a look at that in a moment the shield is still here thankfully they put the shield back as it looks like a pretty special shield it has a little shield that sticks off the shield so their shield goes between the two stages here so we'll take a look at that in a moment so we'll have to see what tube is missing out of here I have another two BC 348 that are going to be restored as well but they're different inside than this so actually quite a bit different in this area in this area over here so it's nice that this is here because I wouldn't have this piece at all it's also missing a regulator so a little regulator goes down inside here so you push it in and it's a Glo tube that just glows so for those of you that are into electronics and know this you can use neon bulbs as regulators and that's basically what that thing is so a little tube there so I'll have to find that I'll have to find this so far we're gonna have to leave the caps off because there aren't just no caps and what we'll do is we'll take a look at the underside what else can I show you on the top side here oh the Dynamo so the Dino motor the Dyna motor that normally sits in this area here like it sat in the Spilsbury in Tyndall radio has been removed and somebody has done a very nice job making a power supply now this was really commonly done way back in the day because people don't want to listen to that buzzing and whirring from the Dyna motor so somebody put this in here and you know they have an old directly heated vacuum tube here which dates the modification so this is probably done I would say probably in the 50s or maybe even in the 60s so they did a really nice job in almost from the top side looks like it's factory so normally the Dyna motor would sit on top of this and these would normally be powered by either 14 or 28 volts and as you can see this has a crusty line corn on it it's actually not in bad condition and it has a bunch of bare wires hanging out of the back so I'll have to locate where all the stuff goes make sure there's no AC on those bare wires I have a feeling it's probably for an external speaker so at any rate you know it's got the this standard you know butchered up face on it people have been drilling holes and putting extra switches in these things it's very hard to find a clean BC 348 because so many ham operators got their hands on these things and they thought oh I'm gonna modify it and make it better well they're a pretty fantastic receiver the way they are and you can see this is a bakelite knob here normally they're supposed to be sometimes there they're known as a toilet flush so there's a big handle it looks like a toilet handle and it goes click click click click and that's missing and somebody they put a variable control in here so this has been left alone this kind of looks like that what the same kind of switches that would normally be in here does the same color to it but I have a feeling it's also been drilled and butchered in there what I see a lot of the time and these are the things you have to look for if you are going to purchase one of these things you know look for extra switches in extra knobs now some of the models had this knob which is a basically an antenna compensator knob so a pre tuning knob over here for the antenna section and some of them didn't I find a lot of people what they do is they remove the antenna jacks down here and they drill you know big holes and put you know big jacks on the front and do all that kind of stuff they I don't know I've seen these some of these things that are pretty bad so this one is deemed as parts it's not that bad yeah it's got some holes in the face and it's got this one silly looking a little bakelite knob here which you'll have to get replaced I may put the original automatic voltage control off and then manual voltage control I mean put that back in here again you know with a you know the proper toilet flush or handle on the front I'm usually down here there are two jacks four speakers it says tell so this here has got a switch in the top one what all of these switches are doing we'll have to find out so there's a lot of you know that's what you read going on in this thing let's take a look at the bottom here alright put this here and I'll adjust the camera and hopefully I can get most of this in the shot just about the tip of the microphone is right there I'll just move that out of the way and in the bottom here somebody's added an extra tube you know what this does I have no idea I imagine it does something let's get a little try out or something in the bottom just the end of the same old caps and stuff you know it's got a bunch of filters down in here and probably a bunch of things hiding under this platform and the existing power supply that's been added somebody's added an audio transformer looks to be and we don't even have to find out where these wires go now because they attach right to it so there you go it is it is attached that looks like it's just about touching that terminal you see how close that is look at that there's some there's some good designing right there look at that somebody's added this in here and this is like I'm sure it can touch the corner of that transformer it is actually so you know lots of things that would need to be cleaned up but it looks deemed as a parts unit I have to say it looks like it could be salvageable and any of you that you know I've watched this channel for a while know that I will not destroy something like this use it as parts if it can be saved you know if I purchase this thing and you know these boxes were missing here and maybe the gearing was all gone or something like that you know or it had been driven over by a truck or something you know of course they don't want to you know tend to use it as parts but when something is this incredibly complete I have a really hard time taking this thing down because this thing might work who knows right it's looking complete so on the top side you're going to see a data actually on the back we'll take a look here first so it's obviously some ham operator that's owned this I've just noticed this this is 40 meters 80 meters 10 20 so somebody has you know been in here and they've been marking this no chances are ham operator did this it's a nice clean job with the power supply I can't see the underside because there's kind of a space here and that's hidden but I'm imagining that the underside probably is looking okay we'll find out if we see any smoke now this has been added something to hold this right so whatever that is and yeah so just lots of lots of modifications that could have been that could have been done a little bit nicer just move the lens in here a little bit turn this thing around it's not very light that can tell you that you know they took these things out of those planes you'd probably get more altitude so anyways so this is how the band switch works here I don't want too much glare on that man get that out of the way what is glaring on that something is glaring on that pretty bad let's see if I can get that out of here and I'll see if I can get the focus on that there we go alright so you can see this here moves bands so this is from 200 to 500 km cycles okay and then you go up to this man and this is from 1.5 megahertz to 3.5 mega Hertz or megacycles if you prefer and it'll speak three point five to six mega cycles in that band six to nine point five mega cycles or mega Hertz if you prefer it's the same thing and then on the top band nine point five to thirteen point five and then I think there might be one more there is thirteen point five to 18 so now keep in mind as I'm turning this knob its tuning every one of these boxes here it's so it's changing a switch and it's selecting different coils in every one of these boxes and that's the reason there has to be caps on this there's gonna be a lot of you know crap that's gonna get in there is a big variable capacitor under here for the tuning so you can see this alright so it moves very slow I can very slowly turn this see if I can hold this steady you see how slow that's moving so before the capacitor was almost fully meshed so now it's opening up so the capacitance is going down right now so we're getting less and less capacitance right so there's if you want to look at it between going towards and microfarads or going towards pico farads this would be going towards pico farads right now okay right and there's a lot of different sections so each one of these sections are gained together by a common shaft and this is tuning each one of those separate sections at the same time and there's even a variable potentiometer on this side here as well so there's a lot of stuff going on in this at the same time you can see the you know the brilliance in the engineers when they put this stuff together lots of time and research went into this thing so you know a for gang's tuning section on a single conversion superheterodyne receiver is pretty fantastic so I can tell you that these receivers are pretty good receivers I'll just show you this here moving you can watch little band up here moving as I'm turning this down here so what I'm going to do is need to reposition the camera we'll take a look down at the missing tube here and over in this section here and I'll go grab a bunch of parts at least what I think we'll get this thing going we'll plug it in and see if we can listen to it or maybe we'll see something like smoke okay I found a tube and a glow discharge bulb right here alright so I'll put this one in you didn't fool around when they made sure they made contact so there it is it's in there so now this has a regulator so this requires regulation for stability so that this thing doesn't drift all over the place with a voltage variation so yeah remove this brime our tubes is brime our radial valve I remove it it says you know brime our radial valve on it look at that this be VA so let's see what is it the British valve Association ranked British radio valve that's what it stands for now if I be VA was British valve Association but okay so British radio valve it says right here you know I hear the British they package these tubes like this I'm just kidding so obviously somebody's used this in something and taking it out of the box okay so see you down in here that hopefully if his tube works it looks like it's a pole maybe another tube something like that that was a maybe it got replaced and the old one got put in this pucks let's troubleshoot more things than the radio let's put a bad tube in there and make our job even worse okay so here we go cap is on the top and that's in there so what I'll do now is I'll turn this on slowly so I'll put this into my current limited isolation transformer and variac supply make sure that this is right down at the bottom and I'll turn some lights off here so maybe we can actually see if this glow discharge tube does come on that's a good indication of the power supply works so and actually come on I'll just move that over okay so I'll turn this on there we go okay so I'm bring it up to about thirty volts and it's not pulling a whole lot of current and fact it's pulling no current so that means that this thing might be turned off let's see what would be an on switch maybe that's on let's find out is this on No oh there it is it's ah there it is so it's not clicking on right away so I'll see if I can make it do that you know just wiggle it hear that it clicked on and I see the current being drawn now okay so we're getting places well there it is so the power supply is working so I could turn it down turn the voltage back up again here alright so I'm up to about 70 volts right now so it's lighting up that's a good sign so that means that the power supply is working that is a really good sign er you see that nice looking a little tube now you'll notice only one half of it is lighting up why is that that's because they're putting DC into the bulb you'll notice a neon bulbs usually have two little poles inside them and both the poles are lit up when it's plugged into AC when you're running on DC because it's direct current only one side will light so depending which way you have the bulb put in it'll light up either side so that is normal so only one half of that is lit it's looking good okay so I don't see smoke so far I'm gonna shut that off we're doing good what I'm gonna do is get a speaker and attach an antenna to this thing and let's see if it lives not having a whole lot of faith with this one but the tube in the bottom and everything like that and wires poking over to the back that back over here okay I'll go get a speaker I'll be right back I have two Allen wrenches or allen keys hex keys whatever you want to call them on the bench here and I'll just use these as connections for the antenna and the ground so these are spring-loaded antenna connections so I can just push this in there's a hole on the side and can just push that little connection through there so now this little allen key or allen wrench in there and I'll put this one in the ground and just leave them like that this is running to my antenna so I'll just clip this on to the antenna hot lead right here I'll leave the common unhooked at this point because depending on the band that I'm on sometimes this is beneficial and sometimes it isn't I'll grab a speaker from the other side here so it's just an old portable speaker and I'll plug it in here and see what happens so hopefully it makes some form of noise and we'll just go from there how does that sound okay I'll turn this thing on and it's still at 70 volts so I'll just let it sit here for just a moment the Glo tube on the other side just started glowing it's a nice nice color orange in there kind of a creamsicle colored orange okay so I'll turn this up to about 100 volts and I'll see what's happening here it's making it's making noise it's supposed to be a parts radio so that is an RF game and at the end it seems open [Applause] see if this BFO works sounds like it's trying to we need a signaler to get a tone the things working this thing is supposed to be parts and it's even been partially stripped in the things still working this thing definitely wants to get restored the spills marine Tyndall was complete you know aside from the crystals were missing other than that which doesn't mean a whole lot because that's just you know for the old Marine bands at any rate and it worked and this thing here missing parts and it's working it really goes to show you how resilient these old things really are even with that you know that tube here that was kind of you know sketchy okay so we're on the highest band here so it was a turn the volume down cuz usually these older receivers make a lot of noise when you move the band switch around you can hear it's trying to pop already let's go right down to the bottom or just about the bottom this one here would be beacons so we'll just go here and see if we can hear any maybe anything in the AM broadcast so I'll move in and 10 a compensator here and see if it Peaks things up it is so you can hear that [Applause] [Music] so the stages are working so I'll give it a bit more volume put this down here just in case it gets loud and let's see so that's two megacycles they're trying to receive something [Applause] it's receiving [Applause] [Applause] [Applause] Wow the thing is actually receiving hard to believe so see if it's gonna receive on a higher band let's say the time signal so up here just turn this down I'll go to it should be around five megacycles I throw the time signal sits it's always a good way to test the receiving on this band it's always a good way to test these things see how close it is if it is so I should be rated around five so I'm gonna zoom in on that a little bit so should be right around five sounds like it's there [Applause] something read at five I'll attach the ground here gets rid of some of the noise there it is Wow this thing is supposed to be parts and how could anybody want to use this thing as parts when it works like this you know taking something like this and you know using it for parts is crazy well let's see if any of the other bands are noisy let's goes to sex so I'll just turn this down because usually they pop when you change the band switches I mean popping noises haven't seen any smoke or anything this is all good and I can also bring it up to the actual line voltage we're just at 100 volts right now so bring it right up to 120 might pick up the sensitivity as well the filaments will light up a little brighter so let's just move it around in this band and see what happens put the speaker up here snow can hear it [Applause] [Applause] some computer-generated stuff there really not optical Wow nice and strong some shortwave stations in there let's move this out of the way first SEC turn this down its next band I don't know if this bands working I think the oscillator isn't working in this band maybe it's trying yeah it is there's a shortwave frequency in there not very sensitive so it's probably detuned or miss tune somebody's been in there and tried to tune this for something so since they were using this for you know ham radio use you know who knows how many screwdrivers and hands have been inherited I'll see if the time signals at ten should be around Tanner as well so move this all the way down to ten take about an hour to get there here we go turn this out it doesn't sound very sensitive down here might be off see if it has more sensitivity without it its maximum gain down here so obviously this band is very quiet so there should be this should be very loud with static right now so this band is obviously down let's try another one thirteen point five to 18 so that's how it should be should be that loud it's a higher band and it's late at night so it's probably not a whole lot will go down to the bottom and here so there should be a time signal at 15 as well so let's see if there's again of you time signal here yeah attach my antennae common to make things quiet there's lots of volume there it is [Laughter] there it is let's see if the BFO works it's working [Applause] so the vfo does work so all in all this thing is mostly working one of the bands is very very quiet on this so probably you know obviously dirt and you know garbage and the switches and you know if the tubes are all checked and the whole thing was retuned and you don't replace the needed components this thing would just come right back to life again so you know why this thing is deemed as parts I have absolutely no idea so you know I'd have to fabricate some covers for the top boxes you know for the coil boxes and stuff here and this would make a great restoration and yeah that's amazing you know so I'll just one plug this back hum so why this was deemed as parts I have really no idea yeah everything is just it's dirty and disgusting inside but it's working not bad for something that was supposed to be in the scrap pile so just like this bills bury and Tindall this will have to get restored because this is so nice you know it's working without anything done to it and with all the old components and it is well just like this Spilsbury absolutely amazing you know this is a total testament to the dependability of this stuff created in this era you know this is you know 1945 maybe 1943 1945 in that era is when this radio was made so we're talking on 75 plus years of you know and it's still going absolutely amazing absolutely amazing definite restoration coming soon thanks for stopping by the lab today I hope you've enjoyed this video if you are enjoying my videos you can let me know by giving me a big thumbs up and hang around there'll be many more videos like this coming in the near future we'll be taking a look at solid-state electronic devices and vacuum tube electronic devices so there's a lot of really interesting things coming I also have a lot of very interesting electronic things that you may not have seen before a lot of very interesting technologies I've got that I'm gonna slowly bring out and we're going to through together so if you haven't subscribed now would be a good time to do that as well if you want to be notified as soon as I post a new video don't forget to tap that Bell symbol if you're interested in taking your electronics knowledge to the next level and learning electronics in a very different and effective way you're definitely going to want to check out my ongoing electronics course on patreon I've also released many of my personal inventions and designs there I've designed a lot of different pieces of test equipment that many people have built and are benefiting from at this time I'll put the link just below the show more tab just below this video's description so if you click on the show more tab it will expose the link and I'll also pin the link at the top of the comment section so if you click on the link it'll take you right there alright until next time take care bye for now you

Channel: Mr Carlson's Lab

Views: 264,403

Rating: 4.9471016 out of 5

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Id: 74ZynoXL1xA

Length: 31min 34sec (1894 seconds)

Published: Tue Jul 07 2020