[AMRadio] Tube ID

Larry Szendrei ne1s at securespeed.us
Sun Feb 23 09:42:46 EST 2014

The OC2 is a 7-pin miniature that glows bright orange; it's a 75-volt 

If you have access to a TEk 575 or similar curve tracer it's very easy 
to measure, also it's almost as easy with a bench supply, current 
limiting/voltage dropping resistor, and a voltmeter.


On 2/23/14 8:02 AM, Rob Atkinson wrote:
> 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

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