An elderly gentleman who owned a Motorola dealership taught me the in's and out's of car radio repair during the mid-70's. He explained that they were forced to limit standard inductors to output circuits, RF (ignition interference) chokes, and tuning slugs. AM Auto radio IF circuits demanded "minimal length windings" because multi-frequency shielding was very difficult to incorporate into the transformer design, and that IF transformers almost always processed ignition noise better than the RF Oscillator/Detector feeds. Grounding of the IF can was a critical aspect of signal noise rejection, especially before resistive ignition wiring became available in the very late 1960's. I also remember antenna trimming as being extremely critical way back when... Hope this helps.
Thing was, for some reason FORD engines in the early days put out one hell of a lot of ignition signal, you could see them on the television when they drove into our farm yard, but only the FORDS other vehicles seemed to have solved that problem. I thought perhaps the same was involved in the build of radios to put inside such a static producing rig. I can still remember the lines and the pop pop pop on the speaker when FORDS pulled in to visit. When they just drove by some would be strong enough to interfere but not strong enough to be that annoying. Since there were only 3 farms on our old country road there was not a lot of through traffic to be had.
The reason for car radios having an RF stage and the 262khz IF is simple. A car radio must be able to operate in between cities where it may be subject to interference from stations close to each other on the dial. Normally the FCC assigns stations so that in an urban area no two strong stations are next to each other on the dial. However in fringe areas all bets are off. A car radio MUST be sensitive as well as selective, it must be able to operate far from any cities and strong stations. That's why the RF stage, to pull in the distant stations. And that's why the 262khz IF, greater selectivity due to the higher Q possible with LF IF coils. Actually, I'd have expected them to have TWO IF stages at 262khz as well, but that might have made them TOO selective unless the IF coils were critically coupled and you'd need a TV like sweep generator to align them.
+shango066 Forgot to mention that with that 262khz IF they NEEDED an RF stage to have sufficient image rejection on the high end of the dial. Early BCB superhets ALL had an RF stage and an IF of around 175Khz. During the depression they eliminated the RF stage to lower the cost, and raised the IF to 455Khz (about as high as it could go) to keep image rejection good. But auto radio design called for a different compromise in design.
Hi Shango. It Amazes me how people from other countries who have came here to live, care more about the goings on of our messed up government then most Americans do. You asked me once if I were a patriot, if loving this Country and hoping for something better than the lairs we call politicians these days makes me one than yes I am one. Great job on the radio repair.
shango066 Hi Shango. No Nothing special about me. I am a nobody like 99% of the population .Never been rich,and I am not naive enough to think I can change the past or future. Things are the way they are and it's our own fault for not standing up for whats right. I have a Daughter and grand children, It's them I worry about. Though I know I can't do a damn thing about it. Not alone at any rate. You have no Ideal how many times I wished I didn't care like most. But yes you said you looked at my channel and wondered if I were a patriot, I guess due to my uploads and shares plus the many favorites I had.. I would like to see what this and other countries Could be. A fool yes, but no not a patriot if thats what one is as you stated.. Thank you for the reply. Take care.
shango066 Hi Shango. I would never take it that way. I have came to respect you and your style over the years I've watched your videos. I've learned alot and appreciate you taking the time to do these videos. Take care.
***** America is *much* bigger than any politician, and will survive, the elected-and-appointed kooks who control its government. Things in America today aren't perfect by a long shot, that's for sure. But I will say that life in general is *a lot* better today than when it was, say, in 1967. This is from someone commenting here who was alive back then, perhaps others on this thread were around back then and remember those days, also. Think about all the advances in medicine, food production, automobile safety. Longer life expectancies, too! At the supermarket, adjusted for inflation, food in general, and produce in particular, is considerably cheaper now than it was then.
I live in Mexico my 1964 beetle has a saphire radio it works with 6 vcd and a wire resistor to convert 12vcd to 6vcd, I made a complete restore and cleaning all the circuit plate and lubricate the tuning parts, the radio works and looks great.
YEAH... So there it is!😁👍 The radio that brought to my ears FOR THE VERY FIRST TIME (Different Drum - The Stone Poneys). 1967 (on Linda G's) Volkswagen Beetle radio. (Her last name is "a color" that you get when you mix "Black" and "White" together. She was washing it in her driveway with the windows DOWN of course). I heard the Radio Station Jingle, THEN they "SEGGED" straight into it (with no talking over it) Excellent! ... WKNR... "Keener 13- Detroit"! I was 7 years old then. And, that song's been my constant companion ever since! (I looked in the Beetle, and YEP that was the radio)! I KNOW.. I BORED YOU, SORRY! :36
There’s still a few Music stations on AM in Reno. When I drove all the way down California the other day I was wholly disappointed there was no AM music!
I once read a manual for an 80's ford laser that used push button tuning, and it explained how to set them, turns out that procedure applies to most push button tuned car radios. I was in my late teens at the time (several years ago)
The RF stage was ahead of the converter stage to maximize the radio's sensitivity so it could pull in stations in the most fringe conditions. Bendix was a major supplier of radios to Ford (prior to their acquisition of Philco) and Chrysler as well as Volkwagen. GM made their own radios at their Delco division in Kokomo, IN. If you think AM music stations are bad in your area, here in Central CT, in the daytime, there isn't a single AM that can be picked up that has music.All boring talk; conservative, liberal, news, foreign language . The only stations that have music are the Canadians that come in at night.
If I'm not mistaken prior to 1967 the beetles I had were 6 volt? I was lucky because I found a 6 volt am/fm radio for my 1961 Bug. Wasn't stereo though. I miss my old bug.
Dunno if you guys cares but if you are stoned like me during the covid times you can watch all of the new movies on instaflixxer. Been binge watching with my girlfriend for the last couple of days xD
I used to ride out to Ft. AP Hill with a buddy in his VW Bug, they were quite the car. I went to buy one used once, but there seemed to be a lot of oil leaking from the engine after our little test drive, so I bought an Opel instead. Loved my Opel Manta, she was a great car, but not the same as a bug. As far as AM Radio, I grew up listening to it, as we still have no FM here although before the pandemic there was talk of a new FM station starting here, that would be our first FM station ever. I have simply converted to Internet radio using a little ESP32 hooked to a converter, then through an amp to a couple small stereo speakers. I can program in about 70 stations before I screw up the preferences file and have to start over. Sounds great, and I have it all running off 4 slab batteries I recovered from my old Macbook Pro after spilling coffee into the unit while camping in the Mohave Deseret outside Oatman Arizona.
Nice Job on that. VW's are simple yet weird. I remember having to diagnose a no headlight problem on a '70s VW. Took me forever to figure out that they were on a fuse, not a breaker. Of course I had to order the fuse because nobody stocked those pointy ceramic things. I had to laugh out loud at AM 1230 👍 Sounded EXACTLY like the radio I remember... I hated it so much then, but miss it now. Brought back memories. Heck, even the DJ reminded me of my biology professor :D
The RF amp is required because a wire antenna is used, not a ferrite rod. The IF is 262.5 for better selectivity and the output single for simplicity and no shortage of power, as you said.
"Kiss You All Over" by: "Exile" was released in late summer 1978. Actually, "Exile" began their career around that time, as a "Soft Rock" band, and the song crossed over somewhat, onto the Country Charts! A few years later, of course; when "Exile" nearly went defunct as a "Soft Rock" band, they decided to "go Country" which gave them a whole new, successful, career!!!
I think the RFstage may help with limiting radiation of RF signals from the LO. Cars close to each other with converters close to antennas might be a problem. A good test would be take a RF amp radio and put it close to another, then try the same with a non RF amp radio.
I think that there is more voltage gain in the lower freq IF stages than in 455 or 10.7 mhz used for FM. The other comments are right about the use of an RF amp for sensitivity. However I think the reason for the lower IF frequency is so they can use lower frequency for the local osc . The lower freq of IF - the lower the beat freq osc has to be. This makes it much easier to match up to using all slug tuned tuning coils. They were also easy to make the mechanical memory possible. Try tuning a variable capacitor radio in a bouncy car and keep it tuned. Also with the lower IF freq some of the higher audio freq are lost giving a cleaner sound while the engine is running.
That's a shame that music playing stations disappear on AM and SW, I love to listen foreign music that is not available on mainstream media, there is an asian music radio station I listen to on 41m band in Estonia.
Build yourself a little internet radio, you can get stations from, well nearly everywhere by programming your preferences file. I have mine set for many great US Stations as well as German, Swiss, Netherlands, and one from Russia for that Marshall type music. Lots of them play old time radio programming with plenty of old Suspense, Lone Ranger, Have Gun Will Travel, the Great Gildersleve, Fibber McGee and Molly, that sort. Sure brings back the memories. One even plays recordings from Armed Forces Radio from Vietnam, I listened to AFVN for 13 months solid when I was in Nam on my little portable radio, man does that bring back memories.
About the 262.5 IF. I had an instructor comment about that once, and I don't remember exactly his thoughts. I want to say it had something to do with making the IF transformers more rugged. Different gauge wire perhaps. That's all I can come up with right now.
Hi,I love your videos! They are the best videos on restoration/repair on the net! I used to do some of this years ago---now I'm disabled and can't do what I used to unfortunately. I also agree with your comments regarding the media----it's really awful and a real shame. Sounds like AM radio in L A is more interesting than FM there. There are still little gems out there on AM. Thanks for the videos keep em' coming!
I built an 'ESR' meter, which uses an AC signal to measure up to 100 ohms, and has a list of values that indicate OK for a set of electrolytic capacitors and their respective working voltages, but the ultimate comparison is that of a new one, with that of the old.. By simply bridging with an electrolytic only a fraction of the desired capacitance (just 47uF, over where a 1000uF should be) with such great effect, was the turning point in diagnosis.. Perhaps the radio should have more 'air cooling', as in the engine.. ..especially with a 'class A' audio output..
I think that the purpose of an RF amp in a car radio was noise rejection, I've noticed the same feature in a lot of tube car radios as well, it certainly helps with noise rejection in a house radio, and in the case of a tuned RF amp stage it also makes it more selective. As for the 262 KC IF frequency, with also means a 262 local oscillator frequency, I can't say what that would do for interference or noise reduction, it would make the set more selective however. In terms of tube based car radios some used a 262 Kc IF, but I've run into others that used a 455-456-460 Kc IF as well. Also most tube car radios seem to use a push-pull output stage, usually 6K6s or 6AQ5s, I'm not sure if they were class A or class B amps however. A lot of car radios use permeable slug tuning, though some used tuned capacitors, almost every pocket transistors radio I've seen used a tuning cap. With a slug tuned set all that the have to do is add another coil, with a capacitor tuned set they need a third section in the tuning capacitor, and a coil, so that may explain why they added an extra IF amp stage and transformer.
AM and FM out here on the east coast are gone quickly, hard to find ELO, ARS, etc etc on the radio now. I know this is an old video, but as i go through your vids, just slinging a comment here and there!
Good Day Good work on this Set eh. I recognise that style of Cap You pulled. They were a cheap make back then. I have yanked many like that, & dozens of Hunts & T.C.C. that utilised low grade Seals, & Moisture gets in or the Dielectric leaks out. You are correct about why the Circuit differences between Pocket Radios (& House Radios vs Auto Sets: high interference rejection. Noise from Auto Generators & the Ignition primary & secondaries. . an Ocean of interference under the Hood & Signal variations while driving under Bridges & etc. You are correct for the most part; The Media Corporations that buy up AM Radio Stations kill off the good Music formats & substitute God awful endless "Info-mercials" & pointless Gab sessions. There are a FEW GOOD 99% Music (& DECENT Songs) here; (the new) AM 740 1150 CKOC 1240 CJCS 1460 CJOY 1580 CKDO "Durham's Classic Hits" All of these Stations have online listen option.
Perhaps one of the reasons for the single-ended output stage is so that the return wire from the speaker could be connected to the chassis of the car and use the car's ground as the speaker ground. (and cheap out on a piece of wire...)
Man, there are *no* AM music stations anywhere near me. I wish there were. You're lucky you have such a great one there -- hope it lasts awhile... On a different topic -- I've always been curious as to how those old mechanical "memory" push-button tuners worked. Could you make a video showing that, perhaps? Great vid -- thanks!
The only place where music on AM radio works is in the rural areas of the country, where FM can't travel very far. Believe me, when you're plowing the fields in the spring, the most annoying thing is when you get down in a low spot in the field, the FM will go out before the AM does.
Wow you have FM on your tractor? Guess it's been a long time since I worked for my Uncle haying, back then we were lucky if we had a headlight for work around Dusk, no cabs no radios, well if we took a break, the pickup had a radio in it, and that's where I kept my water jug. Of course this was back in the mid 1960's I am sure things are different now, my Uncle had machinery dating back to the 40's and early 50's on his farm, nothing modern, his pickup was a 49 Ford.
Enjoy your videos, and like to listen to the background sounds. You must live near a airport.? Again many thanks for taking the time for the great videos. 73 ...Leo
If this is a Class A Audio Output Stage wouldn't you expect the Output Transistors collector to be at about 6V under quiescent conditions on that schematic?It seems odd to me to have the current passed through the Output Transistor flowing to ground through the Audio Output Transformer's secondary winding.Did this make the Radio sound any better?
What happened to the circuit board? At the beginning it was all green and towards the end 16:32 there's a nice black scorch color there to the left where all the shiny new soldering was. Was there an accident? ;)
shango any info on a motorola mostar fm rec-trans, and a uniden force 10 watt rec-trans, good old equipment or no, they need antennas and cable, also a icom ic4at hand held uhf transceiver
Good video! It seams like you’re in the LA area by the stations you were receiving. I have a similar sapphire radio that I might need some work on. How can we get a hold of you or your shop? Thank you
I would love a Korean announcer playing English rock classics!!!! I can't understand Korean, but it still would be cool. Bendix, the same company that makes brakes for bicycles?
really enjoying these videos ... but do you have one where there is absolutely NOTHING GOING ON? ie. no hiss, no nothing??? I have a couple of Motorola 114s and 112s from the 1970s and can't get a peep out of them, although voltages at the transistors seem ok. Thanks in advance
David Cracknell Sure, if a coupling cap is open or something else. Checking voltages is fairly crude. Start by feeding audio or a test tone through a capacitor into the base of the output transistor and work your way back from there.
Many thanks for your swift reply. And greetings from London. I wanted to ask you how to feed an audio into radio to test, like you do from your phone - I presume you use a 3.5mm Jack lead to the phone and put the +ve lead to the cap and the -ve to the radio case?
I am trying to troubleshoot a Philco Ford AM only radio out of a 1967 Ford Mustang On the side of the radio its marked 7TPZ . It powers up and has audio but its squeal with static like its going into oscillation. With a 5 foot piece of wire I could get a local radio station weak not clear. If I connect it to my outside wire antenna the station drops out as though the radio was overloaded. I have been searching for the schematic but so far no luck. I checked the only 3 transistors with a meter in the diode mode and they look good. There is a germanium diode that measures good too. I certainly would appreciate anyone offering a schematic. I might be able to fix this. There is one large round capacitor. It looks like a multi-capacitor. I noticed its corroded on the top. Could use help with a schematic. Thanks
I have a Sapphire I from my 66 VW bug. I think it works...my issue is, the needle doesn't move consistently. I can move it to the left but it will not dial back to the right. The pushbutton will move the needle...not the dial. Any suggestions?
Sounds like the string running through the dial pulleys is having trouble and slipping. Lubricating the pulley shafts as well as the dials they move could help. Can't hurt.
Due to their construction all capacitors are degraded on time, specially old paper-waxed and electrolytic capacitors, but also resistors and transistors are degraded; if you restore a radio you should check all them.
I'm looking at a Zenith TransOceanic from the late 1940's, and I'm in the St. Louis area. I'm willing to ship it, but I'm also willing to try a local place too. I'm willing to drive 50 miles to drop it off IF you know of someone you trust in the St. Louis area (but what are the chances of that?).
You are going to end up spending hundreds of dollars on something you will only really be able to use on the broadcast band. Shortwave is diminishing fast, there are fewer and fewer stations every year. If you ship it to me its going to cost you a minimum of 200 for the shipping and repairs.
This makes you wonder from whose basement in his house they're broadcasting LOL Some of the ones here AM stations are in Australia especially the Christian wants
An elderly gentleman who owned a Motorola dealership taught me the in's and out's of car radio repair during the mid-70's. He explained that they were forced to limit standard inductors to output circuits, RF (ignition interference) chokes, and tuning slugs. AM Auto radio IF circuits demanded "minimal length windings" because multi-frequency shielding was very difficult to incorporate into the transformer design, and that IF transformers almost always processed ignition noise better than the RF Oscillator/Detector feeds. Grounding of the IF can was a critical aspect of signal noise rejection, especially before resistive ignition wiring became available in the very late 1960's.
I also remember antenna trimming as being extremely critical way back when...
Hope this helps.
Thing was, for some reason FORD engines in the early days put out one hell of a lot of ignition signal, you could see them on the television when they drove into our farm yard, but only the FORDS other vehicles seemed to have solved that problem. I thought perhaps the same was involved in the build of radios to put inside such a static producing rig. I can still remember the lines and the pop pop pop on the speaker when FORDS pulled in to visit. When they just drove by some would be strong enough to interfere but not strong enough to be that annoying. Since there were only 3 farms on our old country road there was not a lot of through traffic to be had.
@Jerry Ericsson, were the 390/460 "big block brother/sister" pairing, the worst of the bunch?? Thanks for the reply, by the way....
The reason for car radios having an RF stage and the 262khz IF is simple. A car radio must be able to operate in between cities where it may be subject to interference from stations close to each other on the dial. Normally the FCC assigns stations so that in an urban area no two strong stations are next to each other on the dial. However in fringe areas all bets are off. A car radio MUST be sensitive as well as selective, it must be able to operate far from any cities and strong stations. That's why the RF stage, to pull in the distant stations. And that's why the 262khz IF, greater selectivity due to the higher Q possible with LF IF coils. Actually, I'd have expected them to have TWO IF stages at 262khz as well, but that might have made them TOO selective unless the IF coils were critically coupled and you'd need a TV like sweep generator to align them.
+Kenneth Scharf good info, keep it coming
+shango066 Forgot to mention that with that 262khz IF they NEEDED an RF stage to have sufficient image rejection on the high end of the dial. Early BCB superhets ALL had an RF stage and an IF of around 175Khz. During the depression they eliminated the RF stage to lower the cost, and raised the IF to 455Khz (about as high as it could go) to keep image rejection good. But auto radio design called for a different compromise in design.
Hi Shango. It Amazes me how people from other countries who have came here to live, care more about the goings on of our messed up government then most Americans do. You asked me once if I were a patriot, if loving this Country and hoping for something better than the lairs we call politicians these days makes me one than yes I am one. Great job on the radio repair.
shango066
Hi Shango.
No Nothing special about me. I am a nobody like 99% of the population .Never been rich,and I am not naive enough to think I can change the past or future. Things are the way they are and it's our own fault for not standing up for whats right. I have a Daughter and grand children, It's them I worry about. Though I know I can't do a damn thing about it. Not alone at any rate. You have no Ideal how many times I wished I didn't care like most. But yes you said you looked at my channel and wondered if I were a patriot, I guess due to my uploads and shares plus the many favorites I had.. I would like to see what this and other countries Could be. A fool yes, but no not a patriot if thats what one is as you stated.. Thank you for the reply. Take care.
shango066
Hi Shango. I would never take it that way. I have came to respect you and your style over the years I've watched your videos. I've learned alot and appreciate you taking the time to do these videos. Take care.
***** America is *much* bigger than any politician, and will survive, the elected-and-appointed kooks who control its government. Things in America today aren't perfect by a long shot, that's for sure. But I will say that life in general is *a lot* better today than when it was, say, in 1967. This is from someone commenting here who was alive back then, perhaps others on this thread were around back then and remember those days, also. Think about all the advances in medicine, food production, automobile safety. Longer life expectancies, too! At the supermarket, adjusted for inflation, food in general, and produce in particular, is considerably cheaper now than it was then.
I live in Mexico my 1964 beetle has a saphire radio it works with 6 vcd and a wire resistor to convert 12vcd to 6vcd, I made a complete restore and cleaning all the circuit plate and lubricate the tuning parts, the radio works and looks great.
YEAH... So there it is!😁👍 The radio that brought to my ears FOR THE VERY FIRST TIME (Different Drum - The Stone Poneys). 1967 (on Linda G's) Volkswagen Beetle radio. (Her last name is "a color" that you get when you mix "Black" and "White" together. She was washing it in her driveway with the windows DOWN of course). I heard the Radio Station Jingle, THEN they "SEGGED" straight into it (with no talking over it) Excellent! ... WKNR... "Keener 13- Detroit"! I was 7 years old then. And, that song's been my constant companion ever since! (I looked in the Beetle, and YEP that was the radio)! I KNOW.. I BORED YOU, SORRY! :36
There’s still a few Music stations on AM in Reno. When I drove all the way down California the other day I was wholly disappointed there was no AM music!
Cool, dude I really like car repairs radio repairs. Thank you for posting this video.
You are probably one of the few people under 40 that understand how to set pushbuttons on a car radio :) Another cool video, thanks
I once read a manual for an 80's ford laser that used push button tuning, and it explained how to set them, turns out that procedure applies to most push button tuned car radios. I was in my late teens at the time
(several years ago)
I'm still under 40... and learned on one of my dad's old cars when I was a kid. Now I have my own old cars haha
Well, I know now.
It doesn't exactly help when the grease turns into cement and the buttons take the strength of a thousand men to push.
This is the help that sets up those regulations angle for am I remember whenever you some cars that didn't you get FM😅
I love the sound of CLASS A systems that is why I got a CLASS AA based system.
The RF stage was ahead of the converter stage to maximize the radio's sensitivity so it could pull in stations in the most fringe conditions.
Bendix was a major supplier of radios to Ford (prior to their acquisition of Philco) and Chrysler as well as Volkwagen. GM made their own radios at their Delco division in Kokomo, IN.
If you think AM music stations are bad in your area, here in Central CT, in the daytime, there isn't a single AM that can be picked up that has music.All boring talk; conservative, liberal, news, foreign language
. The only stations that have music are the Canadians that come in at night.
If I'm not mistaken prior to 1967 the beetles I had were 6 volt?
I was lucky because I found a 6 volt am/fm radio for my 1961 Bug. Wasn't stereo though.
I miss my old bug.
In the US, '67 was the switch to 12V.
Dunno if you guys cares but if you are stoned like me during the covid times you can watch all of the new movies on instaflixxer. Been binge watching with my girlfriend for the last couple of days xD
@Reuben Corey Definitely, been using InstaFlixxer for since december myself =)
I used to ride out to Ft. AP Hill with a buddy in his VW Bug, they were quite the car. I went to buy one used once, but there seemed to be a lot of oil leaking from the engine after our little test drive, so I bought an Opel instead. Loved my Opel Manta, she was a great car, but not the same as a bug. As far as AM Radio, I grew up listening to it, as we still have no FM here although before the pandemic there was talk of a new FM station starting here, that would be our first FM station ever. I have simply converted to Internet radio using a little ESP32 hooked to a converter, then through an amp to a couple small stereo speakers. I can program in about 70 stations before I screw up the preferences file and have to start over. Sounds great, and I have it all running off 4 slab batteries I recovered from my old Macbook Pro after spilling coffee into the unit while camping in the Mohave Deseret outside Oatman Arizona.
Great repair video. Thanks for posting. Interesting bias set up. Like the TO3 embossing, on the right hand side of the radio casing too.
Nice Job on that. VW's are simple yet weird. I remember having to diagnose a no headlight problem on a '70s VW. Took me forever to figure out that they were on a fuse, not a breaker. Of course I had to order the fuse because nobody stocked those pointy ceramic things. I had to laugh out loud at AM 1230 👍 Sounded EXACTLY like the radio I remember... I hated it so much then, but miss it now. Brought back memories. Heck, even the DJ reminded me of my biology professor :D
The RF amp is required because a wire antenna is used, not a ferrite rod. The IF is 262.5 for better selectivity and the output single for simplicity and no shortage of power, as you said.
09:44 That's cool the way the fabric of the speaker's cone can be seen all rippling and wavy and stuff when music plays.
Yup.... makes a cool visual interaction. :-)
"Kiss You All Over" by: "Exile" was released in late summer 1978.
Actually, "Exile" began their career around that time, as a "Soft Rock" band, and the song crossed over somewhat, onto the Country Charts!
A few years later, of course; when "Exile" nearly went defunct as a "Soft Rock" band, they decided to "go Country" which gave them a whole new, successful, career!!!
I think the RFstage may help with limiting radiation of RF signals from the LO. Cars close to each other with converters close to antennas might be a problem. A good test would be take a RF amp radio and put it close to another, then try the same with a non RF amp radio.
Thank you for demonstrating and sharing your knowledge! You fix...I learn!
Classical music on AM. I'd be OK with that in my area.
I think that there is more voltage gain in the lower freq IF stages than in 455 or 10.7 mhz used for FM. The other comments are right about the use of an RF amp for sensitivity. However I think the reason for the lower IF frequency is so they can use lower frequency for the local osc . The lower freq of IF - the lower the beat freq osc has to be. This makes it much easier to match up to using all slug tuned tuning coils. They were also easy to make the mechanical memory possible. Try tuning a variable capacitor radio in a bouncy car and keep it tuned. Also with the lower IF freq some of the higher audio freq are lost giving a cleaner sound while the engine is running.
That's a shame that music playing stations disappear on AM and SW, I love to listen foreign music that is not available on mainstream media, there is an asian music radio station I listen to on 41m band in Estonia.
Build yourself a little internet radio, you can get stations from, well nearly everywhere by programming your preferences file. I have mine set for many great US Stations as well as German, Swiss, Netherlands, and one from Russia for that Marshall type music. Lots of them play old time radio programming with plenty of old Suspense, Lone Ranger, Have Gun Will Travel, the Great Gildersleve, Fibber McGee and Molly, that sort. Sure brings back the memories. One even plays recordings from Armed Forces Radio from Vietnam, I listened to AFVN for 13 months solid when I was in Nam on my little portable radio, man does that bring back memories.
Wow I love that triple power supply. Awesome!
About the 262.5 IF. I had an instructor comment about that once, and I don't remember exactly his thoughts. I want to say it had something to do with making the IF transformers more rugged. Different gauge wire perhaps. That's all I can come up with right now.
Love the hard drive noise on your pc....
Hi,I love your videos! They are the best videos on restoration/repair on the net!
I used to do some of this years ago---now I'm disabled and can't do what I used to unfortunately.
I also agree with your comments regarding the media----it's really awful and a real shame.
Sounds like AM radio in L A is more interesting than FM there. There are still little gems out there on AM. Thanks for the videos keep em' coming!
I built an 'ESR' meter, which uses an AC signal to measure up to 100 ohms, and has a list of values that indicate OK for a set of electrolytic capacitors and their respective working voltages, but the ultimate comparison is that of a new one, with that of the old.. By simply bridging with an electrolytic only a fraction of the desired capacitance (just 47uF, over where a 1000uF should be) with such great effect, was the turning point in diagnosis.. Perhaps the radio should have more 'air cooling', as in the engine.. ..especially with a 'class A' audio output..
I think that the purpose of an RF amp in a car radio was noise rejection, I've noticed the same feature in a lot of tube car radios as well, it certainly helps with noise rejection in a house radio, and in the case of a tuned RF amp stage it also makes it more selective. As for the 262 KC IF frequency, with also means a 262 local oscillator frequency, I can't say what that would do for interference or noise reduction, it would make the set more selective however. In terms of tube based car radios some used a 262 Kc IF, but I've run into others that used a 455-456-460 Kc IF as well. Also most tube car radios seem to use a push-pull output stage, usually 6K6s or 6AQ5s, I'm not sure if they were class A or class B amps however. A lot of car radios use permeable slug tuning, though some used tuned capacitors, almost every pocket transistors radio I've seen used a tuning cap. With a slug tuned set all that the have to do is add another coil, with a capacitor tuned set they need a third section in the tuning capacitor, and a coil, so that may explain why they added an extra IF amp stage and transformer.
AM and FM out here on the east coast are gone quickly, hard to find ELO, ARS, etc etc on the radio now. I know this is an old video, but as i go through your vids, just slinging a comment here and there!
Good Day
Good work on this Set eh.
I recognise that style of Cap You pulled. They were a cheap make back then. I have yanked many like that, & dozens of Hunts & T.C.C. that utilised low grade Seals, & Moisture gets in or the Dielectric leaks out.
You are correct about why the Circuit differences between Pocket Radios (& House Radios vs Auto Sets: high interference rejection. Noise from Auto Generators & the Ignition primary & secondaries. . an Ocean of interference under the Hood & Signal variations while driving under Bridges & etc.
You are correct for the most part; The Media Corporations that buy up AM Radio Stations kill off the good Music formats & substitute God awful endless "Info-mercials" & pointless Gab sessions.
There are a FEW GOOD 99% Music (& DECENT Songs) here;
(the new) AM 740
1150 CKOC
1240 CJCS
1460 CJOY
1580 CKDO "Durham's Classic Hits"
All of these Stations have online listen option.
Perhaps one of the reasons for the single-ended output stage is so that the return wire from the speaker could be connected to the chassis of the car and use the car's ground as the speaker ground. (and cheap out on a piece of wire...)
I think those capacitors were made by Callins and I've seen many of them that were cracked and dried out.
Man, there are *no* AM music stations anywhere near me. I wish there were. You're lucky you have such a great one there -- hope it lasts awhile...
On a different topic -- I've always been curious as to how those old mechanical "memory" push-button tuners worked. Could you make a video showing that, perhaps?
Great vid -- thanks!
The only place where music on AM radio works is in the rural areas of the country, where FM can't travel very far. Believe me, when you're plowing the fields in the spring, the most annoying thing is when you get down in a low spot in the field, the FM will go out before the AM does.
Wow you have FM on your tractor? Guess it's been a long time since I worked for my Uncle haying, back then we were lucky if we had a headlight for work around Dusk, no cabs no radios, well if we took a break, the pickup had a radio in it, and that's where I kept my water jug. Of course this was back in the mid 1960's I am sure things are different now, my Uncle had machinery dating back to the 40's and early 50's on his farm, nothing modern, his pickup was a 49 Ford.
Cool anecdote.
I think the RF amp stage is to improve sensitivity of the radio to offset the antenna's shortness. Could be wrong on that though.
Enjoy your videos, and like to listen to the background sounds. You must live near a airport.? Again many thanks for taking the time for the great videos. 73 ...Leo
I have a 67 Sapphire 12 V that may need to be repaired. Shango066 would you be interested in checking it out for me.
That transistor like outline on the left hand upper front is that a transistor.
Great Video Thanks.
If this is a Class A Audio Output Stage wouldn't you expect the Output Transistors collector to be at about 6V under quiescent conditions on that schematic?It seems odd to me to have the current passed through the Output Transistor flowing to ground through the Audio Output Transformer's secondary winding.Did this make the Radio sound any better?
Yes, Exile band
I subscribed for the intelligent commentary.
Must be syndicated. I pulled in a similar station scanning the dial last time I drove between Dallas and Kerrville. Can't remember what the freq. was.
67 was the first year of 12 volts for VW.
What happened to the circuit board? At the beginning it was all green and towards the end 16:32 there's a nice black scorch color there to the left where all the shiny new soldering was. Was there an accident? ;)
uf da good catch... torch method of de soldering I presume
Hahahaha yeah! Unusual for Shango to solder with a TIG welder.
shango any info on a motorola mostar fm rec-trans, and a uniden force 10 watt rec-trans, good old equipment or no, they need antennas and cable, also a icom ic4at hand held uhf transceiver
Good video! It seams like you’re in the LA area by the stations you were receiving. I have a similar sapphire radio that I might need some work on. How can we get a hold of you or your shop? Thank you
455 if picked up noise from street car wires. tuned rf makes it more sensitive.
I would love a Korean announcer playing English rock classics!!!! I can't understand Korean, but it still would be cool. Bendix, the same company that makes brakes for bicycles?
great work
How long have you worked on electronic stuff? You seem to have extensive knowledge.
Good request shingle
I have this same radio, also having a low volume problem. Do you still fix these?
really enjoying these videos ... but do you have one where there is absolutely NOTHING GOING ON? ie. no hiss, no nothing??? I have a couple of Motorola 114s and 112s from the 1970s and can't get a peep out of them, although voltages at the transistors seem ok. Thanks in advance
David Cracknell Sure, if a coupling cap is open or something else. Checking voltages is fairly crude. Start by feeding audio or a test tone through a capacitor into the base of the output transistor and work your way back from there.
Many thanks for your swift reply. And greetings from London.
I wanted to ask you how to feed an audio into radio to test, like you do from your phone - I presume you use a 3.5mm Jack lead to the phone and put the +ve lead to the cap and the -ve to the radio case?
ground to the case and capacitor in series with the signal source to keep any dc voltage from feeding back into the source
I am trying to troubleshoot a Philco Ford AM only radio out of a 1967 Ford Mustang On the side of the radio its marked 7TPZ . It powers up and has audio but its squeal with static like
its going into oscillation. With a 5 foot piece of wire I could get a local radio station weak not clear. If I connect it to my outside wire antenna the station drops out as though the radio was overloaded. I have been searching for the schematic but so far no luck. I checked the only 3 transistors with a meter in the diode mode and they look good. There is a germanium diode that measures good too. I certainly would appreciate anyone offering a schematic. I might be able to fix this. There is one large round capacitor. It looks like a multi-capacitor. I noticed
its corroded on the top. Could use help with a schematic. Thanks
good RFantenna gain
I have a Sapphire I from my 66 VW bug. I think it works...my issue is, the needle doesn't move consistently. I can move it to the left but it will not dial back to the right. The pushbutton will move the needle...not the dial. Any suggestions?
Sounds like the string running through the dial pulleys is having trouble and slipping. Lubricating the pulley shafts as well as the dials they move could help. Can't hurt.
Did I miss the part where you changed the capacitor?
Hi there, I do like radios do you like RCA? That’s a cool brand.😊
Why is it always a problem with the capacitors?
Due to their construction all capacitors are degraded on time, specially old paper-waxed and electrolytic capacitors, but also resistors and transistors are degraded; if you restore a radio you should check all them.
It's probably not always capacitors. Electrolytics, maybe. Other times it's tubes, diodes, transistors, resistors, etc.
Would you happen to know of a place that repairs radios that you trust? Maybe even yourself? Please advise.
kinda vague, what type of radio what area etc
I'm looking at a Zenith TransOceanic from the late 1940's, and I'm in the St. Louis area. I'm willing to ship it, but I'm also willing to try a local place too. I'm willing to drive 50 miles to drop it off IF you know of someone you trust in the St. Louis area (but what are the chances of that?).
You are going to end up spending hundreds of dollars on something you will only really be able to use on the broadcast band. Shortwave is diminishing fast, there are fewer and fewer stations every year. If you ship it to me its going to cost you a minimum of 200 for the shipping and repairs.
what is the small #4 on the dial?
represents 540 kHz, low end of the dial.
20:27 FM... on AM!
That AM station could be pirate as there very big as well as FM pirate radio also,
This makes you wonder from whose basement in his house they're broadcasting LOL Some of the ones here AM stations are in Australia especially the Christian wants
How odd there is a classical music station on AM. How do the classical snobs tolerate that?
In makina hermanico
Seems like a lot of Mexican stations there.
Koreans are being like the Vietnamese they're rocking the 80s like the Vietnamese rock the 70s there and be it no more
lol soo random that you have a korean station ? wtf