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Re: NEON- Re: Hg on solid state again



> Part of me believes their story.  I find it hard to believe someone who
> spend 10's of thousands (100's even) on production and not test a
> transformer for use on Hg units.
> 
> I'll probably try the HV lead-switch thing.  I'll try it exactly ONCE.

Dear John, 

don't believe that will work. Mercury migration on solid state can have two 
mainly resons: 
1) the duty cycle of the high frequency is NOT 50-50 for each half-wave. 
   That's the point on most cheap units, thus the duty cycle will vary with 
   loading. Can't imagine any installer carrying an oscilloscope to check 
   when the unit is in service, perhaps when operating on a long, long ledder
   to reach the roof sign. 
    (BTW: some years ago, the british SINCLAIR Co., yes the ones with the
     ZX81 computer, had a micro-oscilloscope, 1.5 inch screen, battery powered,
     for abt. $200. Hadn' that money in the age of 14 to buy one, thus I had 
     bought a big one for $800 at the age of 13...)

2) Unequal work function of the electrodes in the tube. 
   This will cause self-rectifying and so a direct current component 
   overlayed to the high frequency AC. Mostly on long tubes when improperly 
   bombed. Reversal of the leads will do nothing to them. 
   Core and coil will cure, thus deionization can take place and reignition 
   can cause other properties at the electrode (no "hopt spot")
  
   If it HAS to be a solid state unit, you may insert a capacitor to block 
   the DC component. But be aware of the high voltage charges which may build up.#
   Check in the shop before experimenting on site. 
   I'm sorry not to have experience with inserting caps in electronic xfrmrs. 
   But they must have a very low tan delta, or they may blow up...

Hope this helps a nickel,

Marcus



> 
> > >Without getting into any details and for fear of sounding to commercial,
> > >I will only suggest you try a different brand SS-xformer. Mercury
> > >migration can be avoided.
> 
> In general, I've had very good experience with electronics.  I got this
> Bertonee by mistake, when my distributor sent it instead of a Neonix
> 6000.  My fatal words:  "Ah, don't worry about it."  I've used Neonix,
> TFT, and Allanson SS's on many signs with no Hg migration problems.
> 
>   -JOhn
>
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