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UV201
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Post subject: Re: Erla Reflex Radio Posted: Dec Sat 23, 2017 3:15 am |
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Joined: Nov Fri 30, 2012 3:35 am Posts: 564 Location: Phoenix, AZ
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See volume 1 of "Radio Manufacturers of the 1920s" by Alan Douglas, page 190 (Erla chapter). It shows several Erla reflex schematics including one that looks like it might be fairly close to this set. R/ John
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atwaterkent1
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Post subject: Re: Erla Reflex Radio Posted: Dec Sat 23, 2017 3:22 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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High Tension
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Post subject: Re: Erla Reflex Radio Posted: Dec Sat 30, 2017 8:03 am |
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Joined: Aug Sat 06, 2011 10:46 pm Posts: 110 Location: Kurri Kurri, N.S.W., Australia
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atwaterkent1, I'd consider that a keeper. Go ahead and learn from and enjoy it. My tastes have been leaning toward the 20's homebrew for some time, and I realize that many are one of a kind with their own story. That's right, there is not another just like it anywhere. Others may have the same parts, but that was someone's personal project and triumph.
Lindsey
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atwaterkent1
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Post subject: Re: Erla Reflex Radio Posted: Jan Fri 05, 2018 4:21 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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I didn't mean to mislead anyone. I hadn't purchased the radio at the time I posted, but was thinking about it and wanted feedback on the ERLA radios. I've purchased the book John recommended,taken Lindsey's advice and purchased the radio. After I check it out I will update everyone.
John, the schematic in the book does look very similar, it's too small to use obviously. I will keep searching for a schematic for it.
Thank you all for your comments.
_________________ Dan
Museum Curator https://roaringtwentiesantiqueradiomuseum.com/
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UV201
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Post subject: Re: Erla Reflex Radio Posted: Jan Fri 05, 2018 5:28 am |
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Joined: Nov Fri 30, 2012 3:35 am Posts: 564 Location: Phoenix, AZ
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Dan, The Erla chapter in the Douglas book (volume 1) shows that those (admittedly small) schematics were taken from "Radio in the Home", the November 1923 issue. The American Radio History website has that issue online: http://www.americanradiohistory.com/Arc ... 23-Nov.pdfDownload that PDF and look on page 12 and following, and you'll find an article and full-size schematic that's easy to read. It just takes a bit of digging. R/ John
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atwaterkent1
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Post subject: Re: Erla Reflex Radio Posted: Jan Fri 05, 2018 6:02 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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Thank you so much for your help John. I've downloaded the issue and will read it this weekend and see how many questions it answers for me. I'll update all in the near future.
_________________ Dan
Museum Curator https://roaringtwentiesantiqueradiomuseum.com/
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atwaterkent1
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Post subject: Re: Erla Reflex Radio Posted: Jan Sat 06, 2018 7:15 pm |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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Attachment:
1.jpg [ 224.19 KiB | Viewed 2540 times ]
Attachment:
3.jpg [ 57.2 KiB | Viewed 2540 times ]
Attachment:
4.jpg [ 54.6 KiB | Viewed 2540 times ]
Picked up radio today and pulled the chassis. Uses 45V B and 5v A for power. Tuning condensers have one plate with tuning independent from the others. Tubes are all 01A and check good.
_________________ Dan
Museum Curator https://roaringtwentiesantiqueradiomuseum.com/
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atwaterkent1
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Post subject: Re: Erla Reflex Radio Posted: Jan Sun 07, 2018 1:58 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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Hooked up power, antenna and ground to the radio. Getting a hum from the speaker and that's all. Checked the audio transformers and one of them has an open primary. Secondary's check 20K ohms. Now a newbie question. The radio frequency transformers (2) go into tube type sockets. I pulled them both and checked zero ohms between posts marked P&B and the posts marked G&A. I'm guessing G is ground, A is antenna. P and B posts are what?
The audio transformer with the bad winding is the one under the grid resistor. What are my options for fixing it. With a glass case on the radio I'd like it to look original of course.
_________________ Dan
Museum Curator https://roaringtwentiesantiqueradiomuseum.com/
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Chas
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 2:42 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 15554 Location: S. Dartmouth MA 02748-1225 USA
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Check the carborundum detector, normally, that type of detector is used with bias, often adjustable bias. See if it still tests as a diode. The radio will not work if the detector is not working. If the carborundum detector is not functional a 1N34 or similar can be used as a temp, but no bias.
See your "3,jpg" lower left the cartridge with the thumb screws says "Carborundum".
Try to find data on the cartridge, these may be "restorable" and adjustable. Typically, a carborundum works with high mechanical pressure. That cartridge may be spring loaded. Like a can of clown peanut brittle...
I have some raw carborundum crystal, it detects by bearing down a couple of ounces with a steel point.
If the audio transformer shells can be taken apart, try a careful disassembly, there may be a broken wire from the terminals to the windings. If the winding has a 1/2 x 1/2" core there are replacement windings available to fit on the core, then get covered by the old case.
As far as the RF transformers they must have continuity plate side and grid side, generally lower than 100 ohms.
Again, if these can be disassembled there will either be a broken wire or corrosion. The windings are relatively coarse so rewinding is possible.
Chas
_________________ List' & I will Enchant Thine Ear
Last edited by Chas on Jan Sun 07, 2018 2:53 am, edited 1 time in total.
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 2:49 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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Chas
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 2:57 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 15554 Location: S. Dartmouth MA 02748-1225 USA
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Missed my editing,
Look in the lower left of 3.jpg ,it is the cartridge with the thumb nuts on each end. That is the detector, no tube is used for a detector in this radio...
Therefore, there is no grid leak...
Do you have a schematic for this radio?
Chas
_________________ List' & I will Enchant Thine Ear
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 2:59 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:07 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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Haven't been able to come up with a readable schematic yet. Here's what's on the carborundum - No.30 , a couple numbers I can't make out followed by a space and the number 44.
_________________ Dan
Museum Curator https://roaringtwentiesantiqueradiomuseum.com/
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:13 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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Chas
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:15 am |
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Joined: Jan Thu 01, 1970 1:00 am Posts: 15554 Location: S. Dartmouth MA 02748-1225 USA
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I got it or at least a piece that proves that there is no bias on the carborundum. Attachment:
3 tube erla.png [ 134.62 KiB | Viewed 2521 times ]
Look for the Diode symbol to the left of the upper right audio transformer... It IS possible the Carborundum is in trade name only and there is Galena inside. Look at the page 13 of the quoted article and a picture shows an ERLA fixed detector, that FWIK is a galena... BTW the success of the radio is very dependent on this detector. Unlike a tube that can be operated marginally, the diode works or it don't... Not a radio to play when there is a nearby electrical storm, POP goes the diode... If transformer repairs are needed pay strict attention to the polarity of the windings. IF a plate/B+ or Grid /A connections get swapped there will be a 180 inversion of the signal, that may cause the set to oscillate uncontrollably. If that happens swapping any pair will correct it. However, it will disturb the bus wiring and may create additional problems. The swap or correction should occur within the audio transformer. Chas Alan Douglas recovered a glass paneled homebrew reflex from the local dump early in his radio hobby. He had to make a new glass front panel. It was displayed proudly in his radio room for many years...
_________________ List' & I will Enchant Thine Ear
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:32 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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Attachment:
200d.jpg [ 226.77 KiB | Viewed 2521 times ]
That's not it. Scroll down a little further to last drawing on page. It's more of a drawing than a schematic. Attachment:
300d.jpg [ 224.51 KiB | Viewed 2521 times ]
_________________ Dan
Museum Curator https://roaringtwentiesantiqueradiomuseum.com/
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:33 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:35 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:37 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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atwaterkent1
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Post subject: Re: Erla Reflex Radio-Could Use Some Advice on Repair Posted: Jan Sun 07, 2018 3:42 am |
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Joined: Sep Mon 18, 2017 2:23 am Posts: 6735 Location: Plymouth, MI
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