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

[Ryan Foster]

Oh, how slow of me :)

Thanks for answering.


On Wed, Apr 7, 2010 at 5:09 PM, Steve Katz <stevek at jmr.com> wrote:
> He meant they didn't look "gassy" (blue ionization inside the envelope).
>
> Actually, I've been PMing with Jay and the problem was the T-R relay.
> "One of the usual suspects."
>
> WB2WIK/6
>
>
> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]
> On Behalf Of Ryan Foster
> Sent: Wednesday, April 07, 2010 2:05 PM
> To: amps at contesting.com
> Subject: Re: [Amps] [AMPS] 3-500z "glow blue"
>
> 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