Thank you for the detailed and understandable explanation. Will try this at home. Yes, I learned all of this once. Theoretically. That was at the beginning of the 90s, so no tubes but small silver tin cans: RF in, MPX out. If it didn't work: replace it. Btw: The silver tin cans came from South Africa. ;) It's nice to see your face now and then. That actually makes it more personal. And thank you very much for speaking such extremely understandable English. As a non-native speaker, that makes it very easy for me.
U.S. Military maintenance manuals quite often had ‘simplified’ circuit break outs to help technicians understand what was going on in the equipment they were working on. These simplified schematics were very useful. I was a USAF Calibration Laboratory (PMEL) technician. With time, it was possible to become quite proficient on many different types of equipment. But, we saw so much variety that it was difficult to do that over the entire spectrum of devices we encountered. So, the technical manuals had to be really good. For the most, they were. Those that weren’t were quickly brought up to par. When new items were introduced - either new equipment for existing systems, or new systems with new support equipment, the initial issue of the manuals often left a lot to be desired. Especially in the area of special-purpose, automated testers. So, I think your idea of simplification is a good one.
After coming back to this for the x to the nth time I must compliment you, this is a great reference and really helps to keep me on track, thanks again. Anyone not dealing with this regularly (like most of us doing this as a hobby) will benefit tremendously from this.
Seeing a lot more of your face lately. It's a nice change in format I think. It makes the videos feel a little more personal. Thank you for the great videos and thorough explanations .
Your videos and explanations are superb. I purchased a Grundig 2140U which is all original. Electronics was not my profession (retired medical doctor) but it has become my passion. I have almost finished the recapping with only the filter capacitors left to replace. Your series of restoration videos is the best continuing education in any field that I have found.. Thank you. Peter
Hello again Manuel. A superb explanation of the FM circuit. Isolating the FM on the schematic made it a lot easier for me to understand and easier to follow without the distraction of the other components. I think that this is a lot better if you are watching on a small screen. As always a pleasure to watch. Cheers Chris.
Manuel, Great lesson!!! I viewed all your previous videos with FM alignments methods, and this applying all of them it is an excellent compilation. Also, your explanation how FM works is very clear and useful to understand the whole process. I send you my congratulations and gratitude for your dedication from the south of the world, Chile. Warmest regards, José.
This got to be the best FM understanding to air in TH-cam. Its both thrilling and exciting. Your signal tracing strategy was like watching an espionage movie, omitting non hostile, slipping through stages and finding the best route prior reaching the target EABC80. Tell me sir, were you a secret agent in your past life 😂 I hope to bring across what shown here when I fix a Solid State FM radio. As always thumbs up sir.
Very informative, dear Manuel. These old radios have been made to optimize the application of all components for multiple use - best for FM and AM simultaneously! Thanks for your efforts and all the best to you and yours and all viewers in those crazy days.
A very clear explanation, and your graphically removing from view circuits not germane to the one you're working on is brilliant! Don't know why I didn't think of it myself, as I often use Photoshop's layering function to highlight circuit runs on the schematic that I've verified and components I've replaced. Now I can easily make additional layers for AM, FM, SW, RF, IF, AF, TA, TB and whatever sections and simply overlay them when I want to see how they interact with each other. BRILLIANT! This should speed my understanding of how these circuits work immensely!
Thanks for taking the time to explain the FM path in detail in the first 26 minutes. I knew a lot of it, still learned more because I miss the experience. There is not a lot from that era that is explained in this way. The FM discriminator is where I need to be for now, having trouble with one that spits out rubbish, even when the volume is on zero (AM OK). It seems that it interacts with the pre-amp triode for the first AF stage, or is over-steered by a prior stage. Will continue due to inspiration today ! ⚡
@@electronicsoldandnew No, with grid not connected the same happens, a 50Hz gibberish with leaking FM sound upon only the negative sine when the volume is zero. AM OK, and.... tube replaced with a new one. Busy for weeks with it, but don't you worry, I will get this somehow. Thanks for your input !
Perfect timing, I was just scouring the forums for info on FM and this video popped up. I finally have a grasp of the FM circuit although I’m still struggling with how the AGC works. I noticed their is a part of your ratio detector circuit that goes from the top grid of the IF valve that also has a connection to the magic eye, so perhaps that is part of a gain control circuit. Thanks again, you continue to raise the bar, love your use of graphics.
Thanks, I just checked another schematic for a Schaub Lorenz Goldy similar to one you covered in a previous video. It gives a lot more detail on voltages and it shows that the line coming up from the magic eye eventually also connects to g3 of EF89 and it shows 2 voltages -8v for low signal and -5v for high signal so it seems the gain control is via g3 of EF89. Sorry for waffling on :)
Somehow I missed this video and it was something I wanted to see. Thanks for the detailed explanation and taking the time to do it Manuel. The part I was most interested in was how the ratio detector worked, I get what it does but the finer points allude me and I am yet to find a simple description. Thanks Manuel, the radio is looking good 👍
Well, I've got some homework for you :) This is a link to a book that will explain it all. I've actually ordered a copy (I don't like using others' work without them being compensated). Page 47 is the start of the FM detectors section. In that one chapter you'll get all the info you could possibly want to understand how these beasties work. Enjoy. www.smcelectronics.com/DOWNLOADS/1970-FMRADIOSERV.PDF
@@electronicsoldandnew Had a quick look at the ratio detector operating description and it made sense immediately, just dumb enough for me to understand. Thanks Manuel, now to read it from the start 👍😀
Manuel Good job, your multi color explanation of the FM circuitry and I like your trick of simplifying the circuit. Looked at the weather for Madeira the other day looks like you can get some pretty good wins, the howling sound would make nice background for your videos.
The wind sometimes does come through on the videos :) It's not very often that this happens, but we do get our fair share. The temperatures, however, are really a different story. We're sitting with 18 degrees C right now :)
Manuel, you'd make a great butcher, you chopped all the unwanted fatty/gristly bits of circuit away, leaving just the choices bits of the FM circuit to devour, great job done there. A great explanation, by you, on how to re-align an FM receiver, this really was a great video, Manuel....and a Happy New Year to you.
Hallo ! A very good explanation of a FM-alignment ! Thank You ! I know another very easy method to align the discriminator. Maybe You know it also, but I'll like to explain here also for some other people. You have to modulate the 10.7Mhz with an AM-Signal (1kHz for example) and than You have to align the outputcoil so that there is no audio to hear or to see by an oscilloscope in the audiopath. It's also a very simple way and works perfect also.
@@electronicsoldandnew thanks for the vedio i want to know to calibrate FM and AM where i will plug my frequency generator and voltmeter and why i put it on dc since i am going to measure a signal.
I LOVE that wood grained one!!! Would love to own it! Hey...by the way...my birthday is 21 April !!! ;-) I just "know" you desperately want to send it to me! Several times I have noticed that you mention things in a manner that is, to me, a bit apologetic, but I don't see anything for you to be apologizing for. The detail you go into is very helpful, educational, interesting, and useful! I feel you should be thanked far more than you are for the help you provide to many of us! Your videos are very helpful and interesting to me. I am a bit perplexed by something you said when describing connecting the generator to the tube (valve) using the shield on the tube. I thought you said that you connected the clips to the GRID of the tube and ground. I sort of "autocorrected" your statement to being that you connected to the shield around the tube and ground. Thereby injecting the signal to the grid inside the tube via the shield. Did I misunderstand something or am I correct? If I could afford the cost for the class, I would love for you to move here and teach a class on Electronics on several levels from Beginner to Advanced! You certainly have the talent!
Thank you for your kind words. Just to clarify, the signal must be connected to the metal shield that is around the tube. It is not really directly connected to any of the tube pins at all.
I suppose one good thing that may come from a THIRD Grundig of the same model - is that when your wife kicks you out you can get a place with a bigger workshop. Aaahhh silver linings can be hidden in the greyest of clouds. :-}}}
Hi Manuel, First off all a happy new year. Let's hope 2021 will be a better year for everyone. Very instresting how you manage the sensitivity. I allso like the look off this radio. Maybe you like to sell the light one to me 🤣🤣😅😂😂. Allso thought to build in a blu tooth receiver?
not really. in this radio it goes back to G3 of the EF89. In some it does more to prevent front end overload, and force the limiting action to only happen at the last stage before detection.
Thank you for the detailed and understandable explanation. Will try this at home.
Yes, I learned all of this once. Theoretically. That was at the beginning of the 90s, so no tubes but small silver tin cans: RF in, MPX out. If it didn't work: replace it. Btw: The silver tin cans came from South Africa. ;)
It's nice to see your face now and then. That actually makes it more personal.
And thank you very much for speaking such extremely understandable English. As a non-native speaker, that makes it very easy for me.
Glad you enjoyed it. Thanks
U.S. Military maintenance manuals quite often had ‘simplified’ circuit break outs to help technicians understand what was going on in the equipment they were working on. These simplified schematics were very useful. I was a USAF Calibration Laboratory (PMEL) technician. With time, it was possible to become quite proficient on many different types of equipment. But, we saw so much variety that it was difficult to do that over the entire spectrum of devices we encountered. So, the technical manuals had to be really good. For the most, they were. Those that weren’t were quickly brought up to par. When new items were introduced - either new equipment for existing systems, or new systems with new support equipment, the initial issue of the manuals often left a lot to be desired. Especially in the area of special-purpose, automated testers. So, I think your idea of simplification is a good one.
Thank you.
After coming back to this for the x to the nth time I must compliment you, this is a great reference and really helps to keep me on track, thanks again. Anyone not dealing with this regularly (like most of us doing this as a hobby) will benefit tremendously from this.
That is great to hear. Thanks.
Your movies are pure gold. It is a pity that I did not have such teachers at school ...
😊 thanks
Seeing a lot more of your face lately. It's a nice change in format I think. It makes the videos feel a little more personal.
Thank you for the great videos and thorough explanations .
My pleasure
Your videos and explanations are superb. I purchased a Grundig 2140U which is all original. Electronics was not my profession (retired medical doctor) but it has become my passion. I have almost finished the recapping with only the filter capacitors left to replace. Your series of restoration videos is the best continuing education in any field that I have found.. Thank you.
Peter
My pleasure. Glad to have helped.
A really super explanation, thank you. Good to see you on the intro, makes it all more personal.
😊
Hello again Manuel. A superb explanation of the FM circuit. Isolating the FM on the schematic made it a lot easier for me to understand and easier to follow without the distraction of the other components. I think that this is a lot better if you are watching on a small screen. As always a pleasure to watch. Cheers Chris.
Glad it was useful. Thanks
Manuel, Great lesson!!! I viewed all your previous videos with FM alignments methods, and this applying all of them it is an excellent compilation. Also, your explanation how FM works is very clear and useful to understand the whole process. I send you my congratulations and gratitude for your dedication from the south of the world, Chile. Warmest regards, José.
Thank You José. Gracias.
An excellent description of how it works and how to adjust it - my first time here but I will be coming back!
welcome aboard 😊
Fabulous video. In a mere 30 minutes I think I finally understand FM receiver theory. Your instructor skills are amazing!!
Thanks
This got to be the best FM understanding to air in TH-cam. Its both thrilling and exciting. Your signal tracing strategy was like watching an espionage movie, omitting non hostile, slipping through stages and finding the best route prior reaching the target EABC80. Tell me sir, were you a secret agent in your past life 😂
I hope to bring across what shown here when I fix a Solid State FM radio. As always thumbs up sir.
Not a secret agent, just a real nerd 😊
Very informative, dear Manuel. These old radios have been made to optimize the application of all components for multiple use - best for FM and AM simultaneously! Thanks for your efforts and all the best to you and yours and all viewers in those crazy days.
Thank you Stefan. All the best.
A very clear explanation, and your graphically removing from view circuits not germane to the one you're working on is brilliant! Don't know why I didn't think of it myself, as I often use Photoshop's layering function to highlight circuit runs on the schematic that I've verified and components I've replaced. Now I can easily make additional layers for AM, FM, SW, RF, IF, AF, TA, TB and whatever sections and simply overlay them when I want to see how they interact with each other. BRILLIANT! This should speed my understanding of how these circuits work immensely!
Great. Enjoy the process.
Great demonstration, Manuel! Thank you for sharing!
My pleasure Tony. I wish you all the best for this new year.
Excellent information and clearly explained! My humble thanks M Caldeira. 👍
pleasure
Thanks for a good explanation of FM tuning and alignment.
pleasure
An excellent explanation of the Mixer, IF and detection circuit, thanks very much for improving my understanding of this Manuel
my pleasure
simple and comprehensive explanation ;) thanks for the efforts to make it so :)
pleasure
Thanks for taking the time to explain the FM path in detail in the first 26 minutes. I knew a lot of it, still learned more because I miss the experience. There is not a lot from that era that is explained in this way.
The FM discriminator is where I need to be for now, having trouble with one that spits out rubbish, even when the volume is on zero (AM OK). It seems that it interacts with the pre-amp triode for the first AF stage, or is over-steered by a prior stage. Will continue due to inspiration today ! ⚡
Good luck. Remove the connection to the triode grid, and see if it starts to behave differently by checking the detector capacitor voltage for change.
@@electronicsoldandnew No, with grid not connected the same happens, a 50Hz gibberish with leaking FM sound upon only the negative sine when the volume is zero. AM OK, and.... tube replaced with a new one. Busy for weeks with it, but don't you worry, I will get this somehow. Thanks for your input !
pls let me know what it was when you get it sorted out. I’m curious.
@@electronicsoldandnew I don't have a FM modulated RF generator, only AM, and that is a showstopper. When I do find the culprit, you will know.
👍🏼
Thank you,thank you and thank you again for those explanations ...
Merci merci et bonne année.
Merci
Nice to see you again..
😊
Great video, looking forward to your video about the RF section.
I have a 2147 with RF problem and hopefully it will help me to sort it out.
👍🏼
Perfect timing, I was just scouring the forums for info on FM and this video popped up. I finally have a grasp of the FM circuit although I’m still struggling with how the AGC works. I noticed their is a part of your ratio detector circuit that goes from the top grid of the IF valve that also has a connection to the magic eye, so perhaps that is part of a gain control circuit.
Thanks again, you continue to raise the bar, love your use of graphics.
the trick to finding the agc voltage is to work back from the magic eye. In this case it comes from the -ve lead of the ratio capacitor.
Thanks, I just checked another schematic for a Schaub Lorenz Goldy similar to one you covered in a previous video. It gives a lot more detail on voltages and it shows that the line coming up from the magic eye eventually also connects to g3 of EF89 and it shows 2 voltages -8v for low signal and -5v for high signal so it seems the gain control is via g3 of EF89. Sorry for waffling on :)
No problem 😊😁
Very nice presentation!
Thanks
Very thorough and informative.
👍
A precious and extremely useful video, a model of good practice, incredible video, congratulations!!!
Thank you 😊
Somehow I missed this video and it was something I wanted to see. Thanks for the detailed explanation and taking the time to do it Manuel. The part I was most interested in was how the ratio detector worked, I get what it does but the finer points allude me and I am yet to find a simple description. Thanks Manuel, the radio is looking good 👍
Well, I've got some homework for you :)
This is a link to a book that will explain it all. I've actually ordered a copy (I don't like using others' work without them being compensated).
Page 47 is the start of the FM detectors section. In that one chapter you'll get all the info you could possibly want to understand how these beasties work.
Enjoy.
www.smcelectronics.com/DOWNLOADS/1970-FMRADIOSERV.PDF
@@electronicsoldandnew Had a quick look at the ratio detector operating description and it made sense immediately, just dumb enough for me to understand. Thanks Manuel, now to read it from the start 👍😀
Thanks so much. I have been looking for this information everywhere. 1st. Class.
thanks
Manuel Good job, your multi color explanation of the FM circuitry and I like your trick of simplifying the circuit.
Looked at the weather for Madeira the other day looks like you can get some pretty good wins, the howling sound would make nice background for your videos.
The wind sometimes does come through on the videos :)
It's not very often that this happens, but we do get our fair share. The temperatures, however, are really a different story. We're sitting with 18 degrees C right now :)
Great training material, you can really share your knowledge and experience. Great respect and thanks!
Thank you
Manuel, you'd make a great butcher, you chopped all the unwanted fatty/gristly bits of circuit away, leaving just the choices bits of the FM circuit to devour, great job done there. A great explanation, by you, on how to re-align an FM receiver, this really was a great video, Manuel....and a Happy New Year to you.
Thank you.
Hallo !
A very good explanation of a FM-alignment ! Thank You !
I know another very easy method to align the discriminator. Maybe You know it also, but I'll like to explain here also for some other people.
You have to modulate the 10.7Mhz with an AM-Signal (1kHz for example) and than You have to align the outputcoil so that there is no audio to hear or to see by an oscilloscope in the audiopath. It's also a very simple way and works perfect also.
Yes, the AM rejection method works well too. thanks.
Excellent work again. I learnt a heap thanks
pleasure
pleasure
Brilliant!!! Manuel superándose en cada video y ahora "dando" la cara :)! Sigue así! Slds.
Gracias
Clever man. Well done.
👍
Great explanation!
thanks
Great explanation! Thanks
pleasure
That's very educational, thanks.
pleasure
Fascinating! Thanks a lot.
pleasure. And guess what the mailman dropped off 😊 Thank you.
@@electronicsoldandnew The pick glows in the dark! ;-)
👍
Excellent of the basics of FM alignment.
👍
Thank you very much
👍
@@electronicsoldandnew thanks for the vedio i want to know to calibrate FM and AM where i will plug my frequency generator and voltmeter and why i put it on dc since i am going to measure a signal.
Very good video....thanks 👍🙂
👍🏼
Very good. C38 doesn't just shunt: it tunes the tank in the cathode circuit. Q probably still very broad but say VHF band only.
👍
I LOVE that wood grained one!!! Would love to own it! Hey...by the way...my birthday is 21 April !!! ;-) I just "know" you desperately want to send it to me!
Several times I have noticed that you mention things in a manner that is, to me, a bit apologetic, but I don't see anything for you to be apologizing for. The detail you go into is very helpful, educational, interesting, and useful! I feel you should be thanked far more than you are for the help you provide to many of us! Your videos are very helpful and interesting to me.
I am a bit perplexed by something you said when describing connecting the generator to the tube (valve) using the shield on the tube. I thought you said that you connected the clips to the GRID of the tube and ground. I sort of "autocorrected" your statement to being that you connected to the shield around the tube and ground. Thereby injecting the signal to the grid inside the tube via the shield. Did I misunderstand something or am I correct?
If I could afford the cost for the class, I would love for you to move here and teach a class on Electronics on several levels from Beginner to Advanced! You certainly have the talent!
Thank you for your kind words.
Just to clarify, the signal must be connected to the metal shield that is around the tube. It is not really directly connected to any of the tube pins at all.
I suppose one good thing that may come from a THIRD Grundig of the same model - is that when your wife kicks you out you can get a place with a bigger workshop. Aaahhh silver linings can be hidden in the greyest of clouds. :-}}}
good point 😊
Hi Manuel, First off all a happy new year. Let's hope 2021 will be a better year for everyone. Very instresting how you manage the sensitivity. I allso like the look off this radio.
Maybe you like to sell the light one to me 🤣🤣😅😂😂. Allso thought to build in a blu tooth receiver?
Not selling one of these ... I think I’ll have a soccer team if these soon 😊
I will be adding BT to it, yes.
@@electronicsoldandnew Pitty but I understand. Any Idea where I can get the blu tooth module you use in the radios?
I’m running out of these, and the last order I placed was lost. I have not forgotten 😊
@@electronicsoldandnew Thanks for the update
Ok, you sir have a problem. Its called GAS (gear aquisition syndrome) I believe. And a wonderful wife that allows it :)
Yes, I’ve got her well trained 😃
Don't say that to loud.
😊
AGC in FM? no it is used for AM only.
not really. in this radio it goes back to G3 of the EF89. In some it does more to prevent front end overload, and force the limiting action to only happen at the last stage before detection.
@@electronicsoldandnew I was wondering where the FM limiter lives.