[Hallicrafters] 0A2 question

[David Knepper]

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