[Collins] Transistor Question

[Gerald]

On Sat, 2005-07-02 at 14:10 -1000, pete wokoun, sr. wrote:
> Hello List,
>   I just recently stuck the circuits from my tubesters onto my website.  You 
> can find them at:
> 
> http://www.qsl.net/kh6grt/page4/tubesters/tubesters.htm
> 
> For some of the house number semiconductors, I was guessing at their 
> function since, like Jerry said, you can't find equivalents or even data for 
> them anywhere.
> 
> 73s, pete KH6GRT
> 
> 
> >From: Gerald <geraldj at ispwest.com>
> >To: collins at mailman.qth.net
> >Subject: Re: [Collins] Transistor Question
> >Date: Sat, 02 Jul 2005 17:46:07 -0500
> >
> >On Sat, 2005-07-02 at 17:35 -0400, Merle wrote:
> > > Hello to the list.
> > >
> > > I have a transistor I can not identify, wonder if anyone on the list has 
> >the information on this guy..??
> > >
> > > It is out of a " tubester "  that some people used in their Collins 
> >radios back a while ago.
> > >
> > > The numbers on it are: AT 5058 and on the other end of it is another 
> >number T 1402C or it might be TI  402C  anyway it is not in any of my 
> >reference books ! Any help would be appreciated.
> > >
> > > 73 and thanks
> > > Merle W1GZS
> > >
> >Without looking in older reference books, I'm fuzzily recalling that the
> >AT 5058 was the high voltage transistor essential to the tubester
> >operation. It went out of production with no comparable part being made
> >anywhere in the world (much like the US made double gate MOSFETs) which
> >caused tubesters to go out of production. With nothing comparable it
> >won't show in modern cross reference lists.
> >
> >Tubester circuits and parts lists were published in QST once upon a
> >time. I'm sure that QST is here somewhere.
> >--
> >73, Jerry, K0CQ, Technical Advisor to the CRA
> >All content copyright Dr. Gerald N. Johnson, electrical engineer
> >
As I recall the tubester circuits, the FETs generally could handle less
than 25 or 30 volts, and the bipolar transistor could handle 250 or 300
volts and served as the high voltage buffer. The FETs provided the
signal gain. Both small signal dual gate MOSFETs and high voltage
bipolar transistors are not being made today. I should have data on the
special parts in some pile or shelf around here.

Its good to see the circuits, since only a few were in QST.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer