[Amps] [AMPS] 3-500z "glow blue"

[Roger]

Blue glow in most of the tubes we use would indicate the presence of 
gas, or the tube going gassy, but some tubes like the 6L6 normally run 
with a blue glow.
Would a small amount of glow in a 4-1000 hurt? Probably not, but I 
"don't think" it's a good indication for the future. OTOH some one with 
more savvy than I have really needs to answer that.

Now if you've boosted the plate voltage and you are getting a green 
glow, that's time to stop. We used to make X-Ray generator using the old 
bulb shaped tubes with the silvery getter on the inside of the top. Then 
we'd put a layer of Aluminum foil over the top of the tube. (these did 
not have any connection on top of the tube). We would then put 20-30,000 
volts + on the foil and the negative lead to the filament which was not 
powered. I don't remember at what voltage level soft X-Rays start but 
it's somewhat under 30KV.  This was part of a "how to" article in 
Scientific American back in the 50's.

73

Roger (K8RI)


Shon Edwards wrote:
> See:  http://www.jacmusic.com/html/articles/blueglow/blueglow.htm.
>
> On Wed, Apr 7, 2010 at 3:56 PM, DAVE WHITE <mausoptik at btinternet.com> wrote:
>
>   
>> If I key down with my 4-1000A amp tuned up, I can see a faint blue glow
>> around the glass, looking from above - but I thought that was normal
>>
>> Dave G0OIL
>>
>> --- On Wed, 7/4/10, Ryan Foster <foster.ryan at gmail.com> wrote:
>>
>> From: Ryan Foster <foster.ryan at gmail.com>
>> Subject: Re: [Amps] [AMPS] 3-500z "glow blue"
>> To: amps at contesting.com
>> Date: Wednesday, 7 April, 2010, 22:05
>>
>> I changed the subject so I don't hijack the thread.
>>
>> What does "Tubes do not glow blue" mean?  What don't I know about blue
>> glowing tungsten filaments?  I've never seen this and never heard of
>> it.
>>
>> --Ryan w8cya
>>
>>
>> On Wed, Apr 7, 2010 at 11:43 AM, JayKay <pcb4u at verizon.net> wrote:
>>     
>>> HI all
>>>
>>> Need some help. I have a friends SB220 that does not accept RF drive.
>>>       
>> Following info
>>     
>>> 1) Plate voltage good at tubes
>>> 2) Looks like 30 ohm parasitic resistors/cap (aftermarket) are good, both
>>>       
>> tubes
>>     
>>> 3) Relay closes...TUNE position plate idles at 100ma
>>> 4) When relay closed I do have a DC path from RF input via relay to tube
>>>       
>> just prior to .01uf coupling capacitor.
>>     
>>> 5) In standby RF path good from INPUT to OUTPUT
>>> 6) Tubes do not glow blue
>>> 7) The tubes appear OK (physically), passed the "shame next to ear" test
>>> 8) No grid current
>>> 9) Driving rig (TS950) shows INFINITE SWR which (to me) indicates an open
>>>       
>> or short (RF wise) in input.
>>     
>>> 10) 5 volt zener OK when relay energized
>>>
>>> I am thinking it could be the .01uf coupler to the filaments
>>>
>>> Thoughts?
>>>
>>> Jay
>>> W2IJ
>>>
>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>       
>>
>> --
>> "If someone has a gun and is trying to kill you, it would be
>> reasonable to shoot back with your own gun." -- The Dalai Lama, May
>> 15, 2001
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>>     
>
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