Author Topic: Tube radio help!  (Read 1497 times)

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Offline ELS122Topic starter

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Tube radio help!
« on: September 11, 2019, 02:04:08 pm »
I broke the inductor for this radio and I don't know what value it is. and is there a way to bypass it?
 

Offline trevatxtal

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Re: Tube radio help!
« Reply #1 on: September 11, 2019, 03:54:29 pm »
Your circuit diagram appears to be a Audio stage of a radio.
You do not indicate what inductor is broken Values of all components appear to be on the diagram.
Please add more information.
 

Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #2 on: September 11, 2019, 04:56:20 pm »
there is only one inductor in this schematic, it's the one connected to the cathode of the triode!
 

Offline schmitt trigger

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Re: Tube radio help!
« Reply #3 on: September 11, 2019, 05:11:57 pm »
Air core or ferrite core?

If it is air core, with the number of turns, diameter and length, there are online calculators which would allow to estimate its inductance.

A photo would help.
 

Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #4 on: September 11, 2019, 06:34:47 pm »
it's a ferrite core, and 2 of them in series. but it has multiple layers is wound tightly whit thin wire
« Last Edit: September 11, 2019, 06:45:04 pm by ELS122 »
 

Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #5 on: September 12, 2019, 01:21:25 pm »
One of the 2 inductors looks like this
 

Offline schmitt trigger

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Re: Tube radio help!
« Reply #6 on: September 12, 2019, 01:45:45 pm »
You mentioned there are two in series? Measure the good one.

You will require a LCR meter. This may be the perfect excuse to get one if you already don't own one. Nowadays, you can find many low cost devices on Ebay or Alibaba. True, they are not precision instruments, but I don't think the inductor value is very critical.

In the position it is attached it appears like a high frequency rolloff. The key factor here is that it should be able to sustain a DC current without saturation. Likely 10 mA or less. That is the reason it is a rod core one.
 
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Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #7 on: September 12, 2019, 02:12:10 pm »
But it will probably take moths for the meter to arrive meanwhile can I just try different inductors to see what works? Could that damage something?
 

Offline cvanc

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Re: Tube radio help!
« Reply #8 on: September 12, 2019, 02:30:02 pm »
Can you simply re-wind the bad one?

One of the two is broken, and the other one is OK, correct?

Do they appear identical?

How is the broken one damaged?

Can you just unwind the broken one while counting the turns of wire?  Then measure the diameter of the wire with calipers and determine the correct replacement gauge.  Buy what we over here call 'magnet wire' but it might have other names elsewhere.

More photos would help.
 

Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #9 on: September 12, 2019, 02:36:23 pm »
yes there identical and no it can't be rewound, it's glued so hard that it just rips off and the damaged one has the wires ripped off, I tried connecting them back but whit no luck!
 

Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #10 on: September 12, 2019, 03:01:21 pm »
Here are some photos, the good one already had ripped of wires but I could resolder this one
 

Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #11 on: September 12, 2019, 03:05:47 pm »
Here is the coil next to a Philips driver for size reference
 

Offline ELS122Topic starter

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Re: Tube radio help!
« Reply #12 on: September 13, 2019, 10:59:09 am »
I dissected a car relay and put in a ferrite core in it, it fits really well in the shield can and now gonna try it out. maybe it will work the winding amount seems about the same!
 


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