[Hallicrafters] 0A2 question

[Mark Bell]

Right.  I suggest using a thermister.

Mark K3MSB

----- Original Message ----- 
From: "David Knepper" <cra at floodcity.net>
To: <wb8jkr at juno.com>
Cc: <hallicrafters at mailman.qth.net>
Sent: Sunday, November 28, 2004 7:58 AM
Subject: Re: [Hallicrafters] 0A2 question


> You should remember that when you go to a solid-state rectifier, those
> filter capacitors really take a jolt or what is referred to as "in-rush
> voltage."
>
> Using a vacuum rectifier, the filter capacitors are "gradually" brought up
> to operating voltage.  My choice is to keep it as it is.
>
> Dave, W3ST
> Publisher of the Collins Journal
> Secretary to the Collins Radio Association
> www.collinsra.com
> Nets:  3805 Khz, Monday/Wednesdays 8 PM EDST
>           14250 Khz Saturday, 12 Noon EDST
>
> ----- Original Message -----
> From: <wb8jkr at juno.com>
> To: <Hallicrafters at mailman.qth.net>
> Sent: Sunday, November 28, 2004 7:27 AM
> Subject: [Hallicrafters] 0A2 question
>
>
> >
> >   I remember about 30 years ago, I replaced the 5U4
> > LV rectifier tube in my HT-37 with a homemade
> > SS replacement consisting of  4-1KV 2.5 amp diodes
> > (HEP-170) and a series 10 watt 200 ohm resistor. This
> > combination should have been the equivalent of the 5U4
> > tube however, I remember when I turned the transmitter
> > on the 0A2 would flash over for a very brief amount of time.
> >  I stopped using the solid state replacement and went back to
> > the 5U4, never trying it again.
> >  My question is, does anyone know if the 0A2 has a certain
> > finite amount of time it requires to ionize, and until the
> > gas in the tube actually ionizes maybe the voltage input to the
> > regulator soars too high and caused the flash over?
> >  I'm thinking of trying the same thing again, but thought maybe
> > because of the above problem it would be wiser to use a
> > string of three 50 volt 5 watt zeners in place of the 0A2, thinking
> > the zeners would conduct faster than the 0A2.
> >
> >  Any thoughts?
> >
> > 73,  Mark  WB8JKR
> >
> > ______________________________________________________________
> > Hallicrafters mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
> > Help: http://mailman.qth.net/mmfaq.html
> > Post: mailto:Hallicrafters at mailman.qth.net
> > ----
> > List Administrator: Duane Fischer, W8DBF **for assistance**
> > dfischer at usol.com
> > ----
> > Hallicrafters Collectors International: http://www.w9wze.org
>
> ______________________________________________________________
> Hallicrafters mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Hallicrafters at mailman.qth.net
> ----
> List Administrator: Duane Fischer, W8DBF **for assistance**
> dfischer at usol.com
> ----
> Hallicrafters Collectors International: http://www.w9wze.org
>