1966 Mag: Build NE-2 Neon Bulb Computer - scan available

[Chuck Guzis]

On 28 Jul 2007 at 10:44, William Donzelli wrote:

> Limiting inrush is useless for nearly every tube made, as the
> filaments are made to deal with it anyway. The only tubes I know of
> that required some sort of inrush protection were a few of the very
> large transmitting types from the 1940s - the kind whose filament
> current ratings are in the hundreds of Amps. Some of them even had
> specific power up and power down sequences. With some of the huge
> tubes later on, there was inrush protection, but that was to protect
> the transformer, not the tube.

Surgistors were very popular in the 50's as either an add-on for TV 
receivers or as part of the original chassis.
 
> As far as I know, computers did not use mercury vapor rectifiers. In
> all the ones I have seen, or seen documents for, the rectifiers have
> been gas types. When I was recently poking my nose into Pierce's 709
> power unit (7mumblefoo?), I saw that IBM used C16J thyratrons - a
> whole flock of them. Which probably makes that power unit the most
> costly piece to retube these days.

I don't know about the 1600 volt supply for the Univac Solid State 
machines for the clock output stage.  That might be a possibility, 
but I can't find a reference.  Weren't some mercury vapor thyratrons 
used to drive some printer and punch coils in the early systems?

Cheers,
Chuck