[AT] OT:(now tv)

[ken knierim]

  Funny how a lot of this "old technology" has been forgotten. I've been
working on a project that pretty much requires tubes. The original
control system, developed in the late 30's or early 40's is based on a
tube design. Another outfit tried replacing the older technology with
new, solid state designed stuff, and it wouldn't work right. 
  When we got the project, the stipulation was to use the original
design and build replacement parts to keep the original system
operational. They have all the test equipment to keep the old systems
running... tube testers and a mockup of the system so everything can be
tested individually. It's a rather complex mechanical and electrical
system and I can see why the folks trying to replace just parts of the
system would have issues. I also got to learn and in some cases re-learn
some stuff about tubes in the process. 
    After learning how this system works, I have to say that my hat's
off to the great engineers that made this type of thing work (at least
20 years before I was born!). We take SO much for granted these days
when designing stuff... I see what they went through to control a motor
closed-loop on an aircraft. Transformers and motor-generators and phased
control of a motor. This would be a good teacher of control systems
theory colliding with the limits of available technology.
    It's a turbosupercharger controller. I have taken an old
point-to-point wiring design and put it on a circuit board for the
amplifier. It goes on radial engines used on some 4-engine aircraft used
during WWII. It's a walk through history and technology. 

Ken


On Sat, 2006-01-28 at 19:42, Dean VP wrote:
> Ralph:
> 
> Yep, I remember the test patterns and the test tone. No 24 hour TV like we
> are so used to today. I also remember the waiting period for the tube based
> electronics to warm up. Solid state electronics changed all that. Remember
> the service men that would come out with their container of replacement
> tubes, etc? And their tube tester! 
> 
> I started designing solid state based circuits in 1962 in industry after
> being primarily trained in Vacuum Tube theory. The improved performance and
> significantly improved reliability was so pronounced that I consider it one
> of the major milestones in technology development. If the consumers knew,
> when the first TV sets came out, how close they were to potentially failing,
> no one would have bought one. It is a bit amazing how well they worked in
> their time.  But then servicing equipment was accepted. Today, if a piece of
> electronics fails it gets thrown away.  
> 
> Dean A. Van Peursem
> Snohomish, WA 98290
> 
> Forbidden fruits create many jams!
> 
> www.deerelegacy.com