RCA AM FM Table Radio Repair And Alignment 1968

[00:00:00]1969 RCA solidstate AMFM table radio repair and alignment.

[00:00:09]Actually, we got a lot going on in this.

[00:00:11]I KN&X is dropping their FM branding and their FM Simocast and going back to AM and they're going to make the 97.1 and FM sports station. So, we'll try and get some of the the PSAs they're running in this video. And also, I want to play with the FM alignment. I I saw something a better way to align the uh the FM ratio detector, and I want to sort of play with that and and test that out compared to what this thing, but we'll get into that later in the video.

[00:00:51]Let's first get this thing repaired or take a look at it.

[00:01:00]solid state.

[00:01:08]I believe this is Americanmade.

[00:01:17]Bob's TV.

[00:01:22]So, I guess it's been repaired. Imagine getting something like this repaired.

[00:01:28]The finest performance use only genuine RCA parts.

[00:01:33]Today, it would be disposable and you'd throw it in the trash. So, the the cabinet is screwed together. This is definitely a step above a General Electric product, isn't it?

[00:01:48]Looks like it's made out of real wood.

[00:01:49]We got real joints here.

[00:01:54]That one's not that good. But hey, you don't look at the back, right?

[00:02:01]I love how on some of these cords you get this green spooge leaking out. Is this the copper reacting with the plastic as the plastic deteriorates? Is that what that is?

[00:02:16]All right, here we go.

[00:02:30]So, we're again, we're looking at a lot of different outcomes right now, but we don't want >> extending [music] those cuts for the time being. 8:39.

[00:02:45]>> Hey, it's Ryan Douglas. In case you haven't heard, KN&X is leaving the FM.

[00:02:49]We're leaving 971 of them, but we're still going to be where we've been for decades. AM1070. Make a point to set your [music] preset now if you haven't already at AM1070. We'll see you there.

[00:03:00]Injured at work. Text injury.

[00:03:02]>> So, there it is. They're they're running the they're running those spots like constantly.

[00:03:09]And not that anyone ever really changed from the AM back to the FM because if you would just had it on in the car, you just kind of left it. Anyway, um, bad filter capacitors, right? What else?

[00:03:24]So, this should be an easy one. So, let me get it open. Let's check it out.

[00:03:31]So, yes, I would say this is very Americanmade. It's a little corroded.

[00:03:44]It's kind of cool.

[00:03:47]So the way these work is this is the audio output transistor and it's not pushpull. It's just singleended single transistor and it uses uh no power transformer. It just uses these these resistors dropping resistors and it runs about an 80 to 90 volt collector on this. So they get a bunch of gain out of that and then they use dropping resistors probably to supply 9 or 12 volts to the other semiconductors. It has a tuned RF on the FM. It does not on the AM. It's only got one and two AM and it's got three FMs.

[00:04:39]It's pretty small antenna.

[00:04:41]It's got the bigger a combination of the bigger ones. It's got some Japanese IF transformers. These little small ones.

[00:04:51]These are the electrolytics. This is probably the primary. This is the secondary. These that's a 250 at 25.

[00:04:59]You can see we got this resistor, then a diode, a silicon diode, then this capacitor, then a bunch of resistors, then this capacitor. So we want to change these two. We got two unconventional values here. We got 135 microfarads at uh 150 volt and we got 250 microfarads at 25 volts.

[00:05:27]220 and 330 are common values. Now I could just go with a 220 and a 330, no problem. And I might just do that or I might go with a 220 and a 220.

[00:05:43]It's not critical.

[00:05:45]Um, this this resistor is big enough to where it should be a good surge arresttor for any variance in capacitance. I mean, you can go up in value, just not ridiculously up in value. I'm going through here just my sort of spare capacitor box random stuff and I found a 330 at 25 volt which short with leads. I'll have to make that fit [snorts] for the secondary filter.

[00:06:15]Now I got to I I think I'm going to end up going with a 220 for the primary instead of a 150. I love these circuit boards with the lines on top so you can just follow it. So it comes directly from the line over to the resistor, from the resistor over to the diode, from the diode over to the switch, from the switch to the filter capacitor. And you can see that the other side is the return ground back to the line. Well, this one's gone up in value from 250 up to 478.

[00:06:49]And the ESR is quite low, too. That's that's pretty good. That thing's almost doubled in value.

[00:06:57]Anyway, I've got a 200 at 220 microfarad as the primary now. And I've got a 330 at 35 volts as the secondary. I want to test the rest of these little blue ones.

[00:07:10]These three check. Okay, they've gone up in value quite a bit, but the ESR is low, so I'm not going to worry about those. All right, let's see how it works.

[00:07:21]in Washington. I'm Natalie Devidian News 1070 a.m.

[00:07:25]>> Some residents are getting really fed up with the behavior of a neighbor who's been disrupting their lives for years and they're angry that police haven't taken any action against him yet. People living near the man tell CBS LA that he's repeatedly exposed himself while standing in an upstairs window and also often goes on long and loud yelling sprees when he says a lot of awful things.

[00:07:44]>> I've heard him screaming the n-word.

[00:07:46]We've heard terrible like, you know, uh, kind of like sexual assault type phrases coming from the house. I've even stopped walking the dogs over here. My mom's afraid to come over.

[00:07:55]>> He's getting a response, isn't he? Okay, FM works.

[00:08:03]>> I disconnected the antenna.

[00:08:08]>> Healthy boundaries. How about just life lessons?

[00:08:21]We're hearing from all over the country on the telephone top five at 8448.

[00:08:26]Now at number three, this call from Mississippi >> woman.

[00:08:36]>> Scratchy uh banana slicer.

[00:08:42]>> Oh yeah. Splatoon.

[00:08:58]>> So what what usually works on these is you can put a little cleaner, contact cleaner on the thing, the banana slicer.

[00:09:07]You could just do this.

[00:09:23]And you just see how the scratchy goes away.

[00:09:26]>> Magician to Africa.

[00:09:28]>> Just needs to be used.

[00:09:39]There it goes.

[00:09:52]All right, let's play with the alignment.

[00:09:56]Well, side diversion. This is a Wavete Tech 3000 signal generator, and I really kind of like this. And it was working, and then it just went dark. And this came with my recent lot of te television acquisitions from Al. And Al is okay. I don't know why people thought that he died in that last video. He's fine. he he put this deal together for me. But anyway, this is a really neat piece of Americanmade uh kit and it was working and then it just went dark. So, I started measuring the power supply rails and I got a a short on one of them here. So, I'm trying to find it. Uh this one here is just a dead short that's on diode mode.

[00:10:48]probably a tanelum capacitor. Those things. So, I got to just start disconnecting stuff and try and find the short, but this is really uh really threw me for a loop in this radio video. Well, the short is right here. I've just been disconnecting these power supply rails from these modules, and it's in this module down here all the way at the bottom. That one.

[00:11:17]Well, it's kind of working again, but the frequency is way off. I got it on one megahertz there, and it's at uh 9 megahertz.

[00:11:29]Do I dare take that module off there and take it apart?

[00:11:34]My dumb ass just did something completely I didn't realize this was socketed, so I desoldered all the wires off of it.

[00:11:46][sighs] Ah. All right. Yeah, that one there is a little bit blobby, but for the most part, I got my mess, my stupid mess cleaned up.

[00:11:57]And I got this open. And I'm pretty sure it's exactly what I expected. It seems like it's always the problem with vintage Americanmade test equipment. And I want to show how beautiful this thing looks on the inside.

[00:12:18]See those capacitors right there? Let me see if I can light it up.

[00:12:22][clears throat] Let's see here. They are right there on the pins. See those black capacitors?

[00:12:33]10 microfarads? I bet one of those is shorted. But look at this. Look at how beautiful this is.

[00:12:46]Had I just known that these things were socketed.

[00:12:52]Oh boy, there's more of them there.

[00:12:56]Those black little bullet looking things are tanelum capacitors and they like to short. And look at the little filter chokes.

[00:13:11]So, I bet it's that one right there.

[00:13:14]There's actually three of them. This one, that one, and that one up there.

[00:13:18]And they're all measuring. So, I'm going to just start disconnecting these first cuz they're a lot easier to get to. Wow.

[00:13:25]Well, that was lucky. I disconnected this one. And this is the one that shorted.

[00:13:34]So, let's replace that one.

[00:13:37]And yes, the whole thing needs to be recapped.

[00:13:42]Um, and I would have to order these.

[00:13:44]They're 10 microfarads, but not right now. I'm I'm uh trying to finish this radio video. It's It really sucks when you're in the middle of a radio video and your test equipment fails. But yeah, these these these ones and the teardrop capacitors, they short all the time in this era of Americanmade uh test equipment. Didn't have any 10 microfarad 25V tanelum capacitors. So I used a one of these poly capacitors.

[00:14:17]These are very low ESR. I use these when I redo automotive ECUs.

[00:14:24]Um, the tanelums are very low ESR. That's and they're small. That's why they're used in this stuff, but they can be extremely low ESR when they short.

[00:14:37]So, the whole thing needs to be recapped. That's going to be a pain in the ass to redo all these modules. But for now, hopefully this gets the thing up and running so I can finish the radio video. Yeah, poly. It's not a not an electrolytic. It's a solid polymer capacitor. And they're they're low ESR.

[00:14:59]You got to just admire this thing. Look at the coax.

[00:15:05]Look at the little wire inside the copper tube.

[00:15:13]And then all the little chokes.

[00:15:19]What a beautiful piece of test equipment.

[00:15:22]All right. Well, we are up and running again. One megahertz here, one megahertz there.

[00:15:32]And we should just take a look at how this is built.

[00:15:36]Isn't that cool?

[00:15:43]I didn't even see this. This is on the bottom of the top cover. So that was the DAC that had the PLLL DAC.

[00:15:54]Now I guess it's the PLLL that had the shorted capacitor.

[00:16:03]Very cool.

[00:16:05]Wave 3000 signal generator with nicotine glaze stains.

[00:16:11]back to where I was an hour and a half ago, two hours ago before I had this thing go off with shorted capacitors. So about a week ago, Mr. Carlson introduced an FM alignment method that I found extremely fascinating and I want to play with it a little bit because I've never seen the method that he used listed in any service data. And the method he used for aligning the FM detector, ratio detector, discriminator, whatever you want to call it, is he fed 10.7 megahertz AM into the radio and he minimized he adjust he adjusted did the FM detector. I'm going to call it an FM detector for minimum sound. So, maximum AM rejection. The only way I've ever seen it written was to put 10.7 MHz into the radio and adjust that transformer for 0 volts or center the scurve on the marker if you're doing visual marker alignment. So, I want to play with that a little bit on this radio. Um, if if if that's the same, then that's an amazing uh thing to learn and makes it so much easier to align than trying to deal with connections. I mean, if you just put it on AM and just adjust it for minimum sound, then that's totally awesome. But why have I never seen that documented anywhere? You know, feed 10.7 MHz AM modulated into the radio and adjust for minimum. I've never seen that. So, let's look at the alignment the way that Sam's wants you to do it and compare it. So RCA actually has a specified test point right there for the alignment.

[00:18:35]So right now I'm at 10.7 megahertz. I'm going to show you the voltage here. So I'm at 1.1.

[00:18:45]That's 10.8.

[00:18:48]That's 10.9.

[00:18:50]So I start to go I start to go positive.

[00:18:54]So it's out of alignment.

[00:18:56]10.93 10.91 91 92 93 94 95 So let's try this 10.8 10.81 81.

[00:19:26]So there it's going. It does it. It wants to go more wants to go more uh negative than it does positive, but unfortunately I can't turn the damn core. All right. I got a metal Allen key in there and I can actually get it, which is not ideal. But okay, I'm going to rotate it here.

[00:19:51]Now the question is there's going negative zero's going positive. Now the question is if I give it am modulation. So am so the question is is the lowest point here is closest to zero here also the quietest. So, here we go.

[00:20:42]Okay, there's the quietest.

[00:20:50]There's the closest to zero.

[00:20:56]Now, I will admit I haven't done the rest of the the rest of the alignment.

[00:21:01]It looks like it's close, but it's not exact.

[00:21:27]Looks like it's real close.

[00:21:43]We can certainly leave it. We can certainly adjust it like that. Okay. I went through and aligned the rest of the radio and it it is it really is very close [bell] right There is about maximum AM rejection.

[00:22:31]Well, that is a touchy adjustment.

[00:22:38]So, it it's really close. And you can hear that if we go from 10.7 to 10.6 to 10.7 to 10.8.

[00:22:59]So it it's really close. Um is it exact?

[00:23:05]I don't know. That's to be debated. But I will say this, on some of these handheld transistor radios where you don't really have the alignment instructions or know where the test points are, this is probably a good method to use the AM modulation.

[00:23:25]And I'm just I'm just loosely coupling that into the front end.

[00:23:33]I'm just I just have that cuz this is a hot chassis set. So I don't want any connection between this and the signal generator.

[00:23:41]It actually appears that that's 10 kHz away from the the dip.

[00:23:55]So and I'm sure there's a specific reason for that.

[00:23:59]The zero voltage point here is 10 kHz away from the minimum volume or maximum AM signal rejection. So, let's do the AM, which is doing this all [music] backwards cuz you're supposed to do the AM first.

[00:24:41]Wow.

[00:24:45]Well, the AM was off, so now I got to go back and do the FM.

[00:24:51][music] Yes. Despite all my rage, I'm still just a rat in a cage.

[00:25:04]>> And keep your drone till I close the door and I'm jumping bones. 312s, 313s, 215s, 803. Read your horoscope and eat.

[00:25:18]>> Lifetime warranty and installation time frames subject to terms and conditions.

[00:25:21]results maybe [music] and simple things just left me needing to sit down right away. I tried different shoes. I tried all >> every deserves a moment just for her. I need a break. This Mother's Day Caleb is giving >> it. It has that sort of 60s muffled, you know, radio sound that the sort of I like the the crisper highs that the newer stuff has, but these seem to have some DM emphasis where they roll off the high end and they just sort of have that warmer that sort of warm, you know, midbase tone to them.

[00:26:06]>> Prize is provided by Caleb.

[00:26:11]>> [music] >> The oscillator's way off cuz Kale should be up a lot higher. [music] >> Not at Morocco Travel Center.

[00:26:29]>> Mexican plantain le That's DX. That's from out in the valley.

[00:26:57][music] The a the AFC seems pretty snappy. So, I think it's working. Okay. I think the alignment's pretty good cuz the AFC will try and hold that at zero volts.

[00:27:18]>> Chase has used tools and expert BANKERS [screaming] [music] next week.

[00:27:36]>> [clears throat] >> vacations different.

[00:27:42]>> Nothing special here. This is a 2if uh AM set. So, this is like a a pocket radio.

[00:28:14]Yeah, we're not going to get the old school station on this. This is channel.

[00:28:24][music] Well, I think I think we're good here.

[00:28:32]So, that's uh it might have been 1967.

[00:28:36]Let me see what the the the cap said on it.

[00:28:41]I thought I said I thought I saw 1967 here somewhere.

[00:28:53]6707.

[00:29:02]So six. Yeah, this could have been a little bit older than the radio. So 6768 late60s uh RCA Victor AMFM table radio solid state. I really wanted to try that alignment trick out that um Mr. Carlson introduced and um it seems seems pretty legit.

[00:29:30]Seems pretty legit. I think I would probably still try and couple that method with [snorts] um a meter of some type. Probably a VTVM would be a lot better than this. I did I did try flipping the the positive and negative to see if that affected it like it would swing it the other way like this thing was causing a weird load. I don't know. We'd have to try it on more radios, but it seems like a a really good basic alignment technique.

[00:30:04]Uh but I would just suggest uh back it up with a meter the way the SAMs does.

[00:30:12]That way you can actually visually see and make sure you're swinging positive and negative because I've seen where the dodes go bad and you only get one side of it. There's two diodes down here.

[00:30:27]Uh let's see.

[00:30:31]Yeah, they're hard to see, but there's one right here and one right here.

[00:30:45]So, and I've seen where those dodes go bad and you only get one side of it and it sounds like crap.

[00:30:53]So, there you go.