1952 ABANDONED VACUUM TUBE RADIO REPAIR - WHY DID THEY QUIT? RESURRECTION OF A EMERSON 641B [4k]
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- Опубліковано 12 лип 2022
- This radio seems to have a history. It looks like it worked for about 10 years, had a little work done in the early 60s, and then in the last 5 or more years ago, someone was working on it but apparently gave up! Let's see if we can find out what caused that person to give up, and if we can carry the repair through to a playing radio once again.
Playlist for this radio:
• Emerson 641B
See the checklist which appears, when status changes, for tracking what is discovered that needs addressing in Red, followed by Green when resolved.
(UPDATE: I have repaired and restored this radio, see playlist) Someday I may electrically restore this radio, if so, a playlist has been created to help link the restoration video with this resurrection video. Turn on notifications to see it.
This is not instruction, it is for entertainment for people like me who enjoy watching projects and the experiences gained. If you attempt to do some of the things in this video you are at your own risk. I am using special tech-bench safety equipment not detailed here so don't take for granted you can just plug these old items in safely without them being checked and repaired correctly. Check out the link below to Mr Carlson's Lab video below.
Vintage organ donor:
GE C-403B for the audio output transformer
Acknowledgments and References:
Awesome discussion of bench safety including variacs and isolation transformers by Mr Carlson's Lab (highly recommended):
• Tech Tips Tuesday, Iso...
Modification method for a commercial Tripp Lite isolation transformer for tech-bench use by Todd Harrison, his channel is called ToddFun:
• ToddFun.com: Isolation...
Very clear and helpful discussion and demonstration of transformer measurement and characterization by Uncle Doug:
• Output Transformers: A...
Thanks to shango066 for championing the approach of "fix it first", before mass re-capping. Had the person who attempted this repair used that approach, they would have had a much better result. See shango066 for many examples of that approach.
@shango066
Schematic: Rider's
Camera: Canon G7X Mark III
Mic: Rode Micro
Video Editing Software: Power Director
Video Editor: just me - Розваги
![AUDIO OUTPUT TRANSFORMER PROJECT, SAVE ME! - VACUUM TUBE RADIO REPAIR - PART 2 Emerson 641B [4K]](http://i.ytimg.com/vi/q1DQVaXReX8/mqdefault.jpg)
![AUDIO OUTPUT TRANSFORMER PROJECT, SAVE ME! - VACUUM TUBE RADIO REPAIR - PART 2 Emerson 641B [4K]](/img/tr.png)
![Philco Model 20 Vacuum Tube TRF Radio Repair - 1930 - 93 Year Old Tube Radio - Part 1 [4K]](http://i.ytimg.com/vi/3CH9BM_bt_4/mqdefault.jpg)
![RCA Victor 1-X-51 Vacuum Tube Radio Repair 1951 - This was - Supposed - to be Easy! - Part 1 [4K]](/img/n.gif)
You can use a transformer from either a 5v or better, 9v, wall wart ac adapter as the audio output transformer replacement.
I learned a lot about transformers from this video. Thank you!
You are welcome. Watch part 2 when we take that transformer apart and try to fix it. Thanks for the comment!
Very nice work.I had the later version, with 4 - 6be6. An even later version had a 6ba6 in the second position.
Thanks for the video....been slowly learning how to go about troubleshooting these....Very helpful....Thanks...
Thanks Mike.
I enjoyed the output transformer repair attempt; like you said, nothing to loose. The new E-caps & pot control cleaning made a big difference. I'm still watching and enjoyed the troubleshooting, etc. Best, Don
Hello Don and thanks for stopping by! Enjoy your work. Thanks again.
Great job of troubleshooting the radio and finding the open primary winding. I always check for shorts and powering up the radio with the isolation transformer and variac to at lesast 90v to make sure it basically works before changing out every cap. I have used uncle Doug's method of finding turns radio for checking unknown transformers too.
Thanks Jim! Yes, I also like to do the transformer check, and then troubleshooting first and make sure it has what it takes to work, (I try to remember to check the coupling cap early though) and then if I restore it, do a section at a time to make it easier to find a mistake I made. That did indeed happen to me when working on a TrueTone AM/Phono unit. Had I done them all at once I would have then had to find out what was wrong with the whole radio. But in my case, I knew the radio was working, then I did those two caps, and then nothing. Where was the problem? Right there. Thanks again and hope you enjoy Part 2.
a real work bench i love it...
Yep, it's a real work bench alright. And so is the rest of my shop! Thanks for watching one of my videos. Check out the next one in this series where I tackle repairing that transformer with old rusty junk instead of a fancy coil winder. Thanks again.
You hinted over one of my sayings. It's already broke, I can't broke it more'er.
Surprising enough, I managed to fix more than I hadta trash.
Enjoyed this vid! I came over from Doug's DERB channel! I subbed!
Hi Tim, thanks for the note and for the sub! Glad you enjoyed it. There will be a Part 2...
...and Part 2 was just released. Hope you enjoy it. Thanks
It's funny, out of all the radios I have repaired over the years, I don't think I've ever run across one with a bad output transformer and you have encountered at least two that I know of. Patience is key for repair attempts like this. I am curious as to why you didn't think that replacement transformer would not work? Good job getting it going. :)
Hi Doug, thanks! Yes, just luck I guess. The little transformer I used does work, but its form factor is meant for a PC board mount, so I would like to find one which will be better for mounting by a screw or two which I would think would look better to me. (Also I think the original one, being a little larger, may handle higher power for the 6" speaker, giving better performance across the frequency range.) Thanks again.
Great video! I have to ask what is that watch your'e wearing? In addition to fixing radios , I'm a vintage watch enthusiast. Great dial. What year is the watch from? what brand? I just found your channel, house is overflowing with old radios.
Hi Barry, glad you like the video. Hope you get a chance to see Parts 2 and 3... The watch is a soviet-era "Majak or Mayak" which I understand is "Lighthouse" in russian. It is an 16 jewel movement from the mid to late 50s. It was probably made by the 1st Moscow Watch Factory. It came here via a seller in Ukraine. Elsewhere on my channel you will see a couple of interesting radios I got from Ukraine (made in soviet-era Latvia) as well as a mantle clock which I repaired/serviced. Thanks for the comment.
Often you can use 70.7 volt line matching transformers to replace output transformers. They are not perfect, but will work. Find one with a half watt tap on the high side.
When you reach out on the web be sure to print out all the Riders pages on a radio you are working on. Emerson
page 21-11 has both the voltage readings off the tube pins and resistance readings off the tube pins charts. I wish all
Riders schematics contained that info. Now that you found the audio transformer is bad (open primary) you should
have no trouble finding a replacement in your stash of spare parts sometimes with speakers. Thank goodness I got a
stash like you! Rewinding transformers is a real PITA to do as far as I'm concerned. Man those wire windings are tiny!
Like you methods of repair and troubleshooting!
Hi, thanks for watching. Yes I got them from Nostalgia Air which had the pages from various volumes, so I had the info and even printed it all off and it was at my side. But I confess to just grabbing the schematic and running off to do the repair. I do use the voltages at the socket pins sometimes, but frequently I am at a lower input voltage so the numbers are not quite right. But knowing that 3 volts makes a lousy plate voltage for an output tube is useful - right? Too bad about that little white GE clock radio, I had ambitions of fixing it and giving it to a niece, but it turned out to be a terrible shape. A rare instance of where the case was better than the internals. Thanks again!
@@PracticallyFixed Sometimes you get something that just can't be saved but is a good parts source so kudos to you for doing the right thing there. New at this but if you copy voltage numbers of pins on the copy of the schematic in red ink and that way it is all on one page. Learned that from another older YTer. Yes I subscribed.
That's a good idea, thanks. Some of these have the pin voltages right on the same page as the schematic. Resistances too. I would like to get to where I can repair by the smell test. e.g. "Hey, that voltage is too low; that current is too high; hey that's an RF tube not a rectifier (haha)" Thanks for subbing! Keep commenting too.
dont know if you have the patience or not, but people have rewound those. Just have to keep track of the number of turns and what awg wire as you unwind it and rewind it with the same (or close as it dont have to be perfect)
Hi. Thanks for the comment and suggestion. Please take a look at Part 2 where I give it a try with rusty junk and improper tools. Thanks again!
@@PracticallyFixed oh didn't know there was a part 2. Ill have to watch that. Sounds cool.
Great, here is the link to Part 2: ua-cam.com/video/q1DQVaXReX8/v-deo.html
There are three parts to that radio restoration. Hope you get a chance to see them. Thanks again!
Were I to face the problem with the output transformer, I believe I would mount that small transformer on a piece of circuit board then mount the board onto the radio. THis would make for a solid mount, run the wires to the circuit board and you have an updated system. Just a thought, I love these videos and do a bit of collecting of tiny radios rather then the old tube type. I do have one tube set that I attempted to replace the caps but lost my way so now I have a case that I am planning on converting to a WIFI set playing old tunes from an old radio.
Hi Jerry and thanks for the note. That is a good suggestion and may do that when I get around to using that transformer. Watch the next episode on that radio as we wonder, what if we look inside the original transformer..., and fall down the rabbit hole. Don't give up on that old radio, its good to learn. (Brand and model #?) Get a schematic here (www.nostalgiaair.org/Resources/). Be up to speed on electrical safety from the links I give as a minimum and be systematic. If you want to get it to work with WIFI from the radio's own amp, you do a lot of the work anyway. Thanks again.
How can you do any work on that cluttered bench?
"What clutter?" - Igor
Practically Fixed whats a easy tube radio to work on for a beginner?
Hi Brian. Get something cheap! I would say a point to point wired (vs PC board), 5 tube series string set called "All American 5" AM radios that has all its tubes there. Late '40s RCA tabletop set is a good place to start. Starting out I would suggest avoiding a set with a printed circuit board as they are not as easy to work on in my opinion due to traces lifting off the board. Stick with AM as FM requires more test equipment. Avoid a radio with a metal case (such as some Hallicrafters) due to shock hazards. Also avoid one with a power transformer, which gets into many hundreds of volts. Read up and view the recommended videos I give in the video descriptions for safety as tube equipment has dangerous voltage levels. Get an isolation transformer and make a dim bulb tester or don't try it. Find schematics free on nostalgiaair.com under Resources. I am not trying to show how to repair these I just show my projects to entertain people like me who enjoy watching projects like these unfold. There are great channels to learn working on and understanding these: @allamericanfiveradio (go to Rick's "Thank You All" video where he will show where to find and download his free ebook on these radios - it is outstanding); @RestoreOldRadios; @MrCarlsonsLab; and @xrayTonyB are just a few. "Antique radio restoration guide, 2nd Ed." by David Johnson is also excellent and has great info on choosing sets to work on and getting started.
I wonder why they didn't use a 12AX7 as a Transformerless push pull to drive the speaker via a 470uf Electrolytic capacitor
Does the AX7 make enough power?
Don’t know but a high impedance transformer should give enough drive to drive a speaker possibly if you get the transformer out of old car radios that used the 12v tubes that also used a B+ of 12v