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Old 03-05-2017, 09:26 PM
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Default Tube radio repair

Picked up a antique tube radio today. A Emud T7 tube radio.

Really the only two issues I'm having are some stations have more volume then others and the tuning eye doesn't change at all.
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Old 03-05-2017, 09:43 PM
Lew Hartswick Lew Hartswick is offline
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Quote:
Originally Posted by OldRedFord View Post
Picked up a antique tube radio today. A Emud T7 tube radio.

Really the only two issues I'm having are some stations have more volume then others and the tuning eye doesn't change at all.
The volume change is normal. It's an AM signal and as the signal gets weaker the volume is going to reduce. The AGC (automatic gain control) can only handle so much change. As to the eye, could be the (gee something like 6EU? )
tube itself or the connection to it from the output of the second detector. Vacuum tube radios are what I "grew up" with in the 1940s . What is the tube lineup??
...lew...
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Old 03-05-2017, 10:47 PM
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The tube lineup

EM80
ECC85
ECH81
EF89
EABC80
EL84
EZ80
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Old 03-06-2017, 08:26 AM
Lew Hartswick Lew Hartswick is offline
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Ah So. I didn't recognize the name so googling I see it's German. The tubes nos. didn't look familiar. :-) I tried to get a schematic from one of the links on google but it doesn't seem to work. I may try later to see if I can get one to download. If I can maybe MAYBE I can suggest some things to try. Are you familiar with working on the innards of such devices??
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Old 03-06-2017, 10:17 AM
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To a point I am familiar with them. Never worked on one yet but can point out the audio transformer and power transformer etc.

I downloaded a Sam's for the radio. I'll see about posting it here later after I get off work. Has schematic to the circuits and component locations.

I've spent many hours watching repair videos by YouTube creators Shango66 and radiotvphononut.

I thought about posting over on the antique radio fourm but I'm a member of enough now between here and four others.
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Old 03-06-2017, 08:12 PM
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Here is a PDF of the Sams for the radio.

The FM works for the most part. I thought it would pick up 95.5 FM WSBB which is a 40kw station. I guess the sensitivity is down.

AM and SW only produce a low hum through the speakers.
Attached Files
File Type: pdf 0473_8n.pdf (531.5 KB, 47 views)
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Old 03-06-2017, 08:46 PM
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I forgot all about Sams.

They must have had a huge organization to make all those manuals.

I remember working at a local electronics supply place 1982-84
and we had (3) tube testers, and sold about (40) picture tubes
a month (most rebuilt ones from channel master in N.Y. state somewhere)

Now it's all gone, we have computers, cell phones, internet, and Walmart.

Whoopie !
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Old 03-06-2017, 08:58 PM
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Too bad your not closer. My neighbor is an old time tube radio wizard. He has over 150 radios in his house. He has tuned up and repaired several old tube type radios for me. Unfortunately, he is not connected to the internet. He still watches B&W TV!!!
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Old 03-06-2017, 09:03 PM
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I'll bet he still uses a "rotary phone".....
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Old 03-06-2017, 09:03 PM
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hafe you tried hooking an antenna to it ? it has provision for an antenna for am and SWas well as a separate fm antenna.
IIRC I have worked on a few of those in the mid 70's and the tubes were not easy to get. If you need to substitute in more common tubes they will be 6XXX as the filament supply is 7 volts.
Nice radio good luck with it
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