[R-390] 6080 in place of 6802 - RMS ???

[James Miller]

I did not see the strobe effect between the filament glow and the TV
scan rate.  Frankly, I think you're pulling our legs about that factor,
since the glow is a heating effect and would probably not dissipate that
rapidly (60 Hz). You are pulling our legs, aren't you?   But the slowly
walking "standing wave" seen in the vibrating filament illuminated by
the TV flicker was awsome to watch.  So that begs the question.  It
seems to me that using DC rather than AC would create less mechanical
stress on the filaments, I wonder why they didn't do that.  By the way,
where in the 390a is this 6080 tube used?  

mikea wrote:
> 
> On Wed, Jan 09, 2002 at 06:51:26PM -0500, James Miller wrote:
> > You know I just tried this (threw my back out again, darn it) and I see
> > the strangest effect when viewing the ballast tube in the glow of the
> > color TV.  The long slender filament actually seems to be vibrating,
> > like a wave.  Yes the phase locked TV scan frequency is a little
> > different than the line frequency, so this aliasing effect is clearly
> > noticable.  Could this 60 Hz vibration of ballast tube filaments be the
> > cause of premature failures?
> 
> Ah, a truly adventurous soul! I'm sorry about your back, maybe
> next time you should try it with an All-American 5, not a BA. ;=)
> 
> They do in fact vibrate, yes indeedy, and I would not be at all
> surprised if this were one of the failure factors. I also rather
> suspect that the vibration frequency for the ballast isn't quite
> 60 or 120 Hz, due to mechanical inertia.
> 
> Did you see any strobe effect between glowing filaments and TV?
> 
> --
> Mike Andrews
> mikea@mikea.ath.cx
> Tired old sysadmin since 1964
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