[AMRadio] AMRadio Digest, Vol 121, Issue 15


james.liles at comcast.net james.liles at comcast.net
Mon Feb 24 21:36:23 EST 2014


Hi Louis:

I have some some Sylvania OA2's that are radio active.  The difference in 
behavior is there is no over shoot at turn on.  They transition smoothly at 
exactly the same voltage.  I believe this enables them to tolerate some 
filtering without oscillation.

Kindest regards Jim K9AXN



-----Original Message----- 
From: Poli, Louis (US SSA)
Sent: Monday, February 24, 2014 11:32 AM
To: amradio at mailman.qth.net
Subject: Re: [AMRadio] AMRadio Digest, Vol 121, Issue 15

Jim;

All you need do is measure the DC voltage at the pins.
It will regulate it very well, and there are only two pins used in these 
tubes.

The 0A2 will measure at 150 Vdc, and the 0B2 will measure at 108 Vdc.
I think the orange glow is of the 0B2 type; however if they were designed to 
use the same gas then they will have the same color.

But no issue, look up both these at Franks' electron tube pages.
It will be Frank dot Pocnet dot net.

All the tubes beginning in zero are this class. There aren't many.

Check the Base diagram of any you look at.
Some are full size octal base types; like the 0D3 and 0C3.

Here is a little bit of trivia.
The 0C3 is slightly radioactive.

To fire a plasma in tubes like this; reliability was greatly enhanced if you 
put a trace of a radioactive gas in the envelope too. I think it is a 
radioactive isotope of helium.

The radiation (alpha/beta particles) emitted will constantly keep the other 
gas slightly ionized; so turn on was quite reliable.

Regards,
Louis

-----Original Message-----
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[mailto:amradio-bounces at mailman.qth.net] On Behalf Of 
amradio-request at mailman.qth.net
Sent: Sunday, February 23, 2014 12:00 PM
To: amradio at mailman.qth.net
Subject: AMRadio Digest, Vol 121, Issue 15

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Today's Topics:

   1. Tube ID (Jim Wilhite)
   2. Re: Tube ID (Rob Atkinson)
   3. Re: Tube ID (Larry Szendrei)
   4. Re: Tube ID (Rob Atkinson)


----------------------------------------------------------------------

Message: 1
Date: Sat, 22 Feb 2014 16:42:28 -0600
From: "Jim Wilhite" <w5jo at brightok.net>
To: "AM Radio Discussion List" <amradio at mailman.qth.net>
Subject: [AMRadio] Tube ID
Message-ID: <2039AD411845495EB68553640EEDFC00 at JimPC>
Content-Type: text/plain; charset="iso-8859-1"

I have a voltage regulator that is not marked except for the following: 
816B997.  In circuit it glows bright orange.

My memory fails me at the moment, is it an OA2?  It is a 7 pin miniature 
tube.

The OB2 glows a purple color but I forget what color the OA2 glows, or for 
that matter what this tube may be if not an OA2.

Jim
W5JO

------------------------------

Message: 2
Date: Sun, 23 Feb 2014 07:02:40 -0600
From: Rob Atkinson <ranchorobbo at gmail.com>
To: Jim Wilhite <w5jo at brightok.net>
Cc: AM Radio Discussion List <amradio at mailman.qth.net>
Subject: Re: [AMRadio] Tube ID
Message-ID:
<CALWD7Z5hoR_0gj2h3Bzw9sr+5TMaUSN9HbVFkB4REZfgsjpJZQ at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Hi Jim,

I think I'd measure the voltage at that tube's socket and stick a known VR 
tube in there for that voltage and see what happens.  But, my knowledge is 
somewhat limited.  I guess a VR tube with neon in it
would glow orange.   5651 and 5651A are miniature neon VR tubes I
think.  90C1 or 85A2?

73

Rob
K5UJ

On Sat, Feb 22, 2014 at 4:42 PM, Jim Wilhite <w5jo at brightok.net> wrote:
> I have a voltage regulator that is not marked except for the following: 
> 816B997.  In circuit it glows bright orange.
>
> My memory fails me at the moment, is it an OA2?  It is a 7 pin miniature 
> tube.
>
> The OB2 glows a purple color but I forget what color the OA2 glows, or for 
> that matter what this tube may be if not an OA2.
>
> Jim
> W5JO
> ______________________________________________________________
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