75 Yr Old Zenith AM/FM Vacuum Tube Radio Repair - 1949 Part 1 Model 7H921 [4k]
ฝัง
- เผยแพร่เมื่อ 10 ก.พ. 2025
- 1949 ZENITH AM/FM Tube Radio I picked up a few years ago finally on the bench. Sorry for the long break in videos! Lots going on and I do these when I can. Enjoy.
See the checklist which appears when status changes, for tracking what is discovered that needs addressing in Red, followed by Green when resolved.
NOTE: 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 any 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.
ACKNOWLEDGEMENTS AND REFERENCES:
[note: am in no way representing how these folks have shown doing these things - I don't even think they would approve.]
Schematics: Sams Publishing , Riders
Thanks to shango066 for championing the approach of "fix it first", before mass re-capping. See shango066 for many examples of that approach.
@shango066
Awesome discussion of bench safety including variacs and isolation transformers by Mr Carlson's Lab (highly recommended):
• Tech Tips Tuesday, Iso...
@MrCarlsonsLab
Modification method for a commercial Tripp Lite isolation transformer for tech-bench use by Todd Harrison, his channel is called ToddFun:
• ToddFun.com: Isolation...
@ToddFun
Camera: Canon G7X Mark III
Mic: Rode Micro
Video Editing Software: Power Director
Video Editor: just me
People interested in the following topics may be interested in the subject matter of this video: 1940s radios, Zenith Radio, Bakelite Radio, 1950s radios, tube radio repair, tube radio restoration, vacuum tube radio recapping, silver mica disease, SMD, silver ion migration, IF can repair, IF transformer repair, Radio, Zenith tube radio, radio recapping, valve radio, Vintage Radio, antique radio, old radio repair, vintage radio, shango066, mr carlson, radio repair and restoration, 1950s radio restoration, tube radio restoration, radio restoration videos, all American five radio, aa5, aa4, aa6, buy it fix it, repair cafe
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![Noisy 75 Yr Old Zenith AM/FM Vacuum Tube Radio Repair - 1949 Part 2 Model 7H921 [4k]](/img/tr.png)
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This was a really excellent video, learned so much about practical radio repairs. Thanks from Sydney, Australia.
Glad you enjoyed it. This Texan has actually been to Sydney several times. Beautiful city and really nice people. Happy new year.
Your back!!!!! The later models also have "FM" on the right side of dialface instead of "AM/FM". I have two. That one is in pretty good shape. That FM tuning setup can be a bugger. Really good to see you again!
Yes, I made it! Thanks. Been really tied up with things. Those with the FM only on the face, in spite of having both bands, are really interesting. Do your's have the crown or eagle emblems?
@ All have the crown. Funny I was working on a C705 Chassis G730 when I saw this vid drop. That permeability tuning design really stuck around! This radio is a 1960 and the tuning mechanism is unchanged.
It is a great work .❤
Good information. Thank you.
Just started viewing, I'm doing this radio now, it was in sorry shape, what I noticed was the filaments wiring breaking apart and I replaced the whole wiring strings, guess that 1940s wire insulation not so good anymore, thanks for very well produced videos.
Yes, many of the Zeniths had problems with rubber insulation which have become hard and brittle and are coming off. I was lucky on this set as I had just a few that were made with that wire, but some radios need a lot of wires replaced. Good luck. Thanks for the kind comment and happy new year.
Can I echo the shout out to Jim Burns. He's a warrior!
That's Bakelite. Series-string (aka, transformerless) sets can be dangerous to work on, due to the nature of them being hot chassis. NEVER touch a shaft that the knob has been removed, while the radio 📻 is plugged 🔌 in. This will give ya a very nasty (if not fatal) shock. There's that fifty-fifty chance of the radio being plugged in, with the plug reversed, making for a hot chassis set. Just be careful with transformerless radios 📻. Merry Christmas 🎅 🎄 and a very safe and Happy New Year. Your friend, Jeff.
I have a 1950 Zenith 7H922 (one number off) which has the newer style if cans that do get smd. It has a dial light, tone control and a handle. The 1940s Zenith if cans don't seem to get smd though as far as I know. Thanks for this video as this will help me with my rebuild of my own Zenith.
I better pay attention to this one as I have one from 1950 yet to be restored. Same tough to remove knobs.
Thanks. You are right about the knobs.
Hey PF, been in northern Indiana for a few days on a family Christmas get together and was unable to watch and comment before now. Gotta love those sets that fix themselves. LOL I've found on those early Zeniths with inductive FM tuners, they can cause a bit of noise as well. All in all though it sounds pretty good. :)
Happy new year Doug, and glad you had a great family Christmas get together. We missed our son and his new bride this Christmas but hope to go see them in San Jose sometime this spring. Yeah this radio just don't want to stay down for the count. I really like this model. More to come on this one, it has its challenges. Thanks for the comment and take care.
That crackling is like nails on a chalk board
Yeah, let's see if we can fix that. Happy new year.
I wish I would have seen this video before I found an old radio at the thrift store and plugged it in. Zzzzzzzzzzap!!
I have a Zenith 7H820 (chassis 7E01) from 1947. It has AM, the current FM and Armstrong's original prewar FM channels. It's a fairly rare set. Do you take any viewer repair work? I'm in Manhattan, but could ship the receiver to your location. Thanks. Great video!
Hello and firstly, thank you for the expression of confidence in my work; that is probably the nicest compliment I can receive, so I am grateful. That is a beautiful radio you have there and so glad you recognize its value - both FM bands - that only existed for a very short time; that's really great. Take good care of her. Unfortunately I am just covered up with backlog and can't take on anything else right now. Maybe someday, but for now I can't take it on. Thanks for watching and the kind note and hope you have a happy new year.
I have the same radio, but i cannot find the sams photofact for the radio. Would it be possible for you to make me a copy which I will gladly pay for, also where did you get the plastic dial cover, mine is swelled and shrunk. Yhank you
You can find the Photofact on samswebsite dot com for pdf download. For the 7H921, it was set 73 folder 16. The dial cover: dialcover dot com
Thanks for the comment and good luck with your's. Check out the other two in this series for some issues which your's may also have.