Hi Manuel ! Thank You for another restaurationvideo, it is always interesting to see what other technicans can do and know ! "Radio Luxemburg" was in the 60s and 70s one of the best Radiostations for younger people and so it was very importatnt to find it on SW. So GRUNDIG spread the SW-Band (49m) so that we could find Luxemburg easyly ! So and now celebrate christmas with Your family and have much luck and nice things to restaurate in the new year !!🎄🎆✨
First of all, what a great radio! This model looks absolutely lovely. I find this period facinating where things were transitioning from older to newer technology. I am looking forward to seeing the final result on this one! And, oh man, talk about chasing your tail for hours!! It's really great that you share these experiences as it could one day save any of us hours of torment!!! Merry Christmas Manuel to you and your family. Have a great one and all the best for the New Year!! 🎄🎄🎄
I recently had a similar "DOH" experience while working on a very much simpler job i.e. replacing the lights on my trailer with LED units. I cut the old bulb wires and fitted bullet connectors then put connectors on the new LED wires and plugged it all together matching the colours taped the joints up stuffed it in a waterproof covering, easy peasy lemon squeazy, job done I thought. I plugged the trailer into the car and was greeted with nothing, zero, zip, zilch !!! I checked my wiring from the plug to the connectors checked the LED's and all was Ok. It took me hours to stumble on the problem. When I swapped the Black and the White leads on the LED's with their opposites on the wiring harness it all came to life. In trailer wiring harnesses the convention is white is the ground, on the LED units black is the ground as is normal in electronics. Cheers Eric
What an amazing problem, I know that I would have followed the same path as you. In the past I've had strange oscillation problems, but in the radio oscillator stage and I know just how long it can take to find them. I hope you and your family have a great Christmas 🎄. Look forward to part 2. Regards Nigel.
Grundig is one of the highest 👏 quality radios 📻 today. A novice "At Home" 🏡 repair, or a dishonest radio repair shop, probably contributed to the damage in the back of this radio. Merry Christmas 🎅 🎄 and a very safe and Happy New Year!! Your friend, Jeff!!
What a brilliant video!!! Blimey what a task you have! Major parts missing. I hope it was reflected in the price! Even your little "asides" are of great help e.g. when you explain the symbols used for the resistors. Everything so well explained. I just wish I had 1/10th of your knowledge. Hoping to make a start on my FRG 7 soon but even the alignment is requiring equipment required I don't have. Perhaps a simple recap will help its performance? May I take this opportunity to wish you and all your family a very happy Christmas and an even better New Year. Please keep the videos coming. Best wishes Lynton G4XCQ😁
If they’re really low value (up to about 2.2uF) I’d use film caps - they will actually work better than the electrolytics, and you don’t need to worry about polarity. This is the type I’m talking about: www.banzaimusic.com/MKT-Standard/
We all have gone down a rabbit hole like you did with this radio. I would say that someone changed the wire with a different color during a repair sometime in the past. I feel that it would be an extremely slim chance it happened at the factory. Have a wonderful Christmas holiday!
@@mistermac56 exactly. Anyone who works on old audio who hasn’t spent time chasing their own tail or going down a rabbit hole hasn’t worked on old audio for very long or is a liar.
you could see that the output was far more distorted in the first try even at the low level, well before it was taking off, after the fix a much nicer sign wave. I got confused at first as the output feed back worked as it seemed isolated but then noticed that the ground was at the top. Also the high lead from the output transformer is shown as black in the cct. Merry Christmas to you and your viewers.
Hi Manuel. TA = Tonabnehmer = record player, TB = Tonband = tape recorder, Aufnahme = record aka tape out, Wiedergabe = play aka tape or record player in. Just for the record :-) Have fantastic holidays!
"Stupid" is not what I saw. Overlooking something unconventional while 'assuming' is human. Thanks for all the hard work making these videos. You could, of course, just go on about your business and no one would know. But you take the time and I know how much that time taken amounts to. So double thanks.
Wow ! This was fascinating; The 2 Grundigs you already have are beautiful, their design remind me a bit of the Brauns (especially the one with the white face-plate). I feel for you with this one missing its condenser tuner, can't wait to see how you're going to replace it (I'm on the edge of my seat here :-) ). Now as for the so-called mistake you made, come on Manuel, we would have all made it ! I mean black for the ground is pretty universal, especially on speakers and output transformers. I've never seen them reversed like this. Pretty sure it wasn't like that from factory. But you brilliantly found the issue, not sure I would have picked it up. Great work as usual. Thanks for sharing this episode, have a wonderful Christmas with your bunch. Catch you on the next instalment :-)
I agree that the “Braun” look is definitely there. Probably why I really like them. As for the error, I know we all make them, and I also know we all feel a little stupid when we realise how simple the error was 😊 I am now convinced that it was like this from factory, because a closer look at the schematic shows clearly that the one connected to chassis is labelled “grun” and the signal wire is “Schwartz”.. really weird. Must be due to the feedback, because if you reverse it you’d get positive feedback and the radio would howl like crazy. Lesson learnt: check the schematic more closely 😊
@@electronicsoldandnew Ah ok I see, good point. It makes sense considering the feedback (I guess). Yeah, I myself often miss such details on the schematics, especially on the original German ones. We all learn as we go along as David always says :-)
Hi Manuel, just to tell you that I've got a scrapped Grundig SO 305 chassis that could have the same tuning capacitor. By the way I also wish you a Merry Christmas from Milan !
The wild goose chase you went on shows how easy it is to end up with connections between nodes that must not be connected at all when using mains powered test equipment. But what is more important; it shows how easy one can forget that a lot of the mains powered test gear will introduce earth ground into the circuit it connects to. And this could lead to dangerous situations, when due to this it bypasses mains isolation provided by an isolation transformer. This is why not only am I an advocate of using isolation transformers, but also using handheld test gear if possible. The tests performed in this video could have just as well been performed using a battery powered audio tone generator like the FG-100 DDS for 15 bucks and a handheld scope like the Zoyi ZT-702 for 70 bucks. Even a child toy dso-0138 kit scope for 14 bucks and a XR2206 sine triangle square wave generator kit for less than 8 dollars would have been sufficient to view the audio response of this amplifier. And none of this handheld test gear would have led on this wild goose chase and none of it has the potential to defy the mains isolation downstream of an isolation transformer.
I've been re-looking at the setup that I'd like. Still got to purchase a Variac. Here's the point that's got me wondering. I was watching your use of your sig-gen and oscilloscope, which you stated had a mains earth. When connected to the DUT are you not effectively bypassing the earth safety afforded by your isolation transformer? Note I specifically re-watched your build of your updated dim bulb unit and also checked that you had the earth and isolation bypass in the safe position before posting this.
Yes and no 😊 The chassis becomes earth, but at that point you’re in danger of being zapped by the B+, so it’s already there between any high voltage point and the chassis
@@electronicsoldandnew That's partly my point. At that stage the isolation has become pointless. A greater capacity isolation transformer able to power the DUT and test gear might be a solution at a significant cost. However I think that maintaining full awareness of what you're doing and the potential dangers at each stage is safer.
You are right! See bottom left hand corner of the schematic (switching diagram) at 18:13. Diskant (German) means amongst others soprano (the opposite of bass).
First of all, merry Christmas to you as well! Secondly, as a very beginner, I see that you are typically replacing polarized capacitors with electrolytic capacitors (makes sense). But if you are replacing a non-polarized capacitor, what capacitor type do you use then? It might be that I have missed this in the back to basics series. Thank you!
@@electronicsoldandnewis there a particular reason for that choice? Or would, for example, a bipolar electrolytic capacitor also work? As long as the voltage rating and capacitance are correct of course.
I haven’t .its totally a UA-cam function and I’ve noticed that it becomes available only some time after the video is published. Try again, it may already be there.
![75 Yr Old Zenith AM/FM Vacuum Tube Radio Repair - 1949 Part 1 Model 7H921 [4k]](http://i.ytimg.com/vi/KEVE4Ptb41Y/mqdefault.jpg)
Thanks again for inspiring myself and others to bring these old German radios back to life. All the best for the New Year.
Kevin
Thank you 🙏 I appreciate it. Happy New Year.
Hi Manuel ! Thank You for another restaurationvideo, it is always interesting to see what other technicans can do and know ! "Radio Luxemburg" was in the 60s and 70s one of the best Radiostations for younger people and so it was very importatnt to find it on SW. So GRUNDIG spread the SW-Band (49m) so that we could find Luxemburg easyly !
So and now celebrate christmas with Your family and have much luck and nice things to restaurate in the new year !!🎄🎆✨
Thank you. And thanks for the info on radio Luxembourg… I knew there was a reason but couldn’t remember what it was 😊
Merry Christmas Manuel! Excellent video as always!
Thank you 🙏
First of all, what a great radio! This model looks absolutely lovely. I find this period facinating where things were transitioning from older to newer technology. I am looking forward to seeing the final result on this one! And, oh man, talk about chasing your tail for hours!! It's really great that you share these experiences as it could one day save any of us hours of torment!!! Merry Christmas Manuel to you and your family. Have a great one and all the best for the New Year!! 🎄🎄🎄
Thanks 👍 wish you and your family a fabulous Christmas and New Year
Merry Christmas to you and the loved ones.
Thanks
I recently had a similar "DOH" experience while working on a very much simpler job i.e. replacing the lights on my trailer with LED units. I cut the old bulb wires and fitted bullet connectors then put connectors on the new LED wires and plugged it all together matching the colours taped the joints up stuffed it in a waterproof covering, easy peasy lemon squeazy, job done I thought. I plugged the trailer into the car and was greeted with nothing, zero, zip, zilch !!! I checked my wiring from the plug to the connectors checked the LED's and all was Ok. It took me hours to stumble on the problem. When I swapped the Black and the White leads on the LED's with their opposites on the wiring harness it all came to life. In trailer wiring harnesses the convention is white is the ground, on the LED units black is the ground as is normal in electronics.
Cheers Eric
😊 yep, we all do it sometime
Merry Christmas, to you and your Ladies, may you New Years Eve be spent listening to your favorite group over a fine Portuguese wine.
We’re sitting around a wine-abundant table right this minute 😊 and the music … actually Mary Hopkins is singing “those were the days” 😊
Merry christmas also for you & your family Manuel, boas festas
Obrigado 😊
What an amazing problem, I know that I would have followed the same path as you. In the past I've had strange oscillation problems, but in the radio oscillator stage and I know just how long it can take to find them.
I hope you and your family have a great Christmas 🎄. Look forward to part 2.
Regards Nigel.
👍
Grundig is one of the highest 👏 quality radios 📻 today. A novice "At Home" 🏡 repair, or a dishonest radio repair shop, probably contributed to the damage in the back of this radio. Merry Christmas 🎅 🎄 and a very safe and Happy New Year!! Your friend, Jeff!!
Thanks
Manuel, outstanding video. Merry Christmas to you and your family.
Thanks
A very happy Christmas to you and your family , Take care
👍
What a brilliant video!!!
Blimey what a task you have! Major parts missing. I hope it was reflected in the price!
Even your little "asides" are of great help e.g. when you explain the symbols used for the resistors.
Everything so well explained. I just wish I had 1/10th of your knowledge.
Hoping to make a start on my FRG 7 soon but even the alignment is requiring equipment required I don't have. Perhaps a simple recap will help its performance?
May I take this opportunity to wish you and all your family a very happy Christmas and an even better New Year.
Please keep the videos coming.
Best wishes
Lynton G4XCQ😁
Thank you Lynton.
If I were you, I’d try the recap first on your set and leave the alignment for now. You may be pleasantly surprised 😊
@@electronicsoldandnew Great idea but struggling to find the low value electrolytics. any suggestions? Lynton,
If they’re really low value (up to about 2.2uF) I’d use film caps - they will actually work better than the electrolytics, and you don’t need to worry about polarity. This is the type I’m talking about: www.banzaimusic.com/MKT-Standard/
@@electronicsoldandnew thanks for that info young man. Time to resume the search.👍
Wishing you and family MERRY CHRISTMAS Rob
👍
We all have gone down a rabbit hole like you did with this radio. I would say that someone changed the wire with a different color during a repair sometime in the past. I feel that it would be an extremely slim chance it happened at the factory. Have a wonderful Christmas holiday!
Thank you
@@mistermac56 exactly. Anyone who works on old audio who hasn’t spent time chasing their own tail or going down a rabbit hole hasn’t worked on old audio for very long or is a liar.
😊 true
Walnut has a slightly greenish tint to it and teak is generally reddish even if it has some greenish stripes.
👍
you could see that the output was far more distorted in the first try even at the low level, well before it was taking off, after the fix a much nicer sign wave.
I got confused at first as the output feed back worked as it seemed isolated but then noticed that the ground was at the top.
Also the high lead from the output transformer is shown as black in the cct.
Merry Christmas to you and your viewers.
👍
Hi Manuel. TA = Tonabnehmer = record player, TB = Tonband = tape recorder, Aufnahme = record aka tape out, Wiedergabe = play aka tape or record player in. Just for the record :-)
Have fantastic holidays!
Thank you. I should know these terms by now, but I don’t 😊
"Stupid" is not what I saw. Overlooking something unconventional while 'assuming' is human. Thanks for all the hard work making these videos. You could, of course, just go on about your business and no one would know. But you take the time and I know how much that time taken amounts to. So double thanks.
👍
😢 when I saw the hack job someone did on such a beautiful radio.
Yes, quite a shame
Maestro, another video with comedy value? 😂😂😂
😊
Oh! That's tragic!
We’ll sort her out
I'd have cried...
😊
Wow ! This was fascinating; The 2 Grundigs you already have are beautiful, their design remind me a bit of the Brauns (especially the one with the white face-plate). I feel for you with this one missing its condenser tuner, can't wait to see how you're going to replace it (I'm on the edge of my seat here :-) ). Now as for the so-called mistake you made, come on Manuel, we would have all made it ! I mean black for the ground is pretty universal, especially on speakers and output transformers. I've never seen them reversed like this. Pretty sure it wasn't like that from factory. But you brilliantly found the issue, not sure I would have picked it up. Great work as usual. Thanks for sharing this episode, have a wonderful Christmas with your bunch. Catch you on the next instalment :-)
I agree that the “Braun” look is definitely there. Probably why I really like them.
As for the error, I know we all make them, and I also know we all feel a little stupid when we realise how simple the error was 😊 I am now convinced that it was like this from factory, because a closer look at the schematic shows clearly that the one connected to chassis is labelled “grun” and the signal wire is “Schwartz”.. really weird. Must be due to the feedback, because if you reverse it you’d get positive feedback and the radio would howl like crazy. Lesson learnt: check the schematic more closely 😊
@@electronicsoldandnew Ah ok I see, good point. It makes sense considering the feedback (I guess). Yeah, I myself often miss such details on the schematics, especially on the original German ones. We all learn as we go along as David always says :-)
👍
7:51 I hope those stickers will come back (36:22)
Yes, they will
Sr. Caldeira como posso adquirir essa placa retificadora. O Sr. envia ?Obrigado.
Vê o vídeo do projecto, onde dou o link para as placas na PCBway.
@@electronicsoldandnew Obrigado
Hi Manuel, just to tell you that I've got a scrapped Grundig SO 305 chassis that could have the same tuning capacitor. By the way I also wish you a Merry Christmas from Milan !
Thank you. I’ve got a few actually, so I think it’ll be OK.
The wild goose chase you went on shows how easy it is to end up with connections between nodes that must not be connected at all when using mains powered test equipment. But what is more important; it shows how easy one can forget that a lot of the mains powered test gear will introduce earth ground into the circuit it connects to. And this could lead to dangerous situations, when due to this it bypasses mains isolation provided by an isolation transformer. This is why not only am I an advocate of using isolation transformers, but also using handheld test gear if possible. The tests performed in this video could have just as well been performed using a battery powered audio tone generator like the FG-100 DDS for 15 bucks and a handheld scope like the Zoyi ZT-702 for 70 bucks. Even a child toy dso-0138 kit scope for 14 bucks and a XR2206 sine triangle square wave generator kit for less than 8 dollars would have been sufficient to view the audio response of this amplifier. And none of this handheld test gear would have led on this wild goose chase and none of it has the potential to defy the mains isolation downstream of an isolation transformer.
👍
Merry xmas to you and your family to. See ya.
👍
I've been re-looking at the setup that I'd like. Still got to purchase a Variac.
Here's the point that's got me wondering. I was watching your use of your sig-gen and oscilloscope, which you stated had a mains earth.
When connected to the DUT are you not effectively bypassing the earth safety afforded by your isolation transformer?
Note I specifically re-watched your build of your updated dim bulb unit and also checked that you had the earth and isolation bypass in the safe position before posting this.
Yes and no 😊 The chassis becomes earth, but at that point you’re in danger of being zapped by the B+, so it’s already there between any high voltage point and the chassis
@@electronicsoldandnew That's partly my point. At that stage the isolation has become pointless. A greater capacity isolation transformer able to power the DUT and test gear might be a solution at a significant cost. However I think that maintaining full awareness of what you're doing and the potential dangers at each stage is safer.
Ideally, one could use a battery powered signal generator and scope, but up go the 💵
@@electronicsoldandnew Didn't get the last bit, but thank you for replying. I wish you best compliments for the season.
EM87 can be hard to find. Luckily the chinese 6E2 is a direct replacement and they are much cheaper.
👍
Bass / Disk maybe means Bass / Diskant (Treble). Maybe something otherwise known as Loudness ? But I do not know for sure..
You are right! See bottom left hand corner of the schematic (switching diagram) at 18:13. Diskant (German) means amongst others soprano (the opposite of bass).
Makes sense as it switches in and out a capacitor, which would cut the bass.
👍👍
👍
@@electronicsoldandnew - I know frustrations also!
First of all, merry Christmas to you as well! Secondly, as a very beginner, I see that you are typically replacing polarized capacitors with electrolytic capacitors (makes sense). But if you are replacing a non-polarized capacitor, what capacitor type do you use then? It might be that I have missed this in the back to basics series. Thank you!
Usually film capacitors, such as these www.banzaimusic.com/Nichiden-Audio-Cap-0-001uF.html
@@electronicsoldandnewis there a particular reason for that choice? Or would, for example, a bipolar electrolytic capacitor also work? As long as the voltage rating and capacitance are correct of course.
why did you turned off audio dubbing? it was so comfortable
I haven’t .its totally a UA-cam function and I’ve noticed that it becomes available only some time after the video is published. Try again, it may already be there.
@electronicsoldandnew thank you Manuel! I love your channel