On Thu, 08 Apr 2010 08:27:19 -0500, The Daring Dufas
Exhausted material from the cathode itself.
Often you can SEE the crap flake off of a badly encrusuted cathode if
you tap on the neck of the tub sharply with a screwdriver handle while
the tube is in operation.
OH! You're referring to the barium deposits from the dispenser cathodes
that can cause a reduction of the G1 aperture diameter as well as K/G1
spacing. Sencore never mentioned this in their literature. Their shtick
was about the wearing out of the electron emitter surfaces themselves.
The tube tester had a rejuvenation function that would blast the guns
and you could see the sparkling through the neck of the picture tube.
On Thu, 08 Apr 2010 10:40:44 -0500, The Daring Dufas
Exposing a fresh layer by blowing off the dead stuff. Are you really
having this much trouble wrapping your head around something so
I would avoid getting too wrapped up in Sencore's "technical"
information. Sencore was sort of the "Rent to Own" of the electronics
world. Their main business was selling extremely over priced equipment
to little mom & pop repair shops who couldn't qualify for a business
loan to buy equipment. The Sencore stuff wasn't awful, but you could
get MUCH better stuff for a lot less money.
The VA-65, as an example, was an easy to use device for general
TV/video work, but couldn't even generate a genuine NTSC white window
test pattern. Unfortunately, most service manual photographs of
waveforms were made using a genuine NTSC white window pattern
generator, so comparing what was in the manuals to what you were
looking at on your Sencore was problematic.
The price of the VA-65, like all Sencore equipment, was absurd. If you
wanted one, buying from someone going out of business was the way to
And scopes? You could buy 2 or 3, 100 MHz Hitachis with far better
triggering, etc, for the price of a two channel 60Mhz Sencore scope.
But Sencore had the exclusive framistan electrode analyzer for
color CRT tubes. No one else had such a product. I had new and
used Sencore stuff that worked well and did the job. I wasn't
sending rockets into outer space. Now I have HP scopes laying
around along with other stuff I dreamed of owning. I recently
fixed up some HP TDR units for a friend to sell on eBay. The
things cost thousands of dollars way back when they were new
but some folks still like to use them. The little chart recorders
are so cute.
On Thu, 08 Apr 2010 13:56:46 -0500, The Daring Dufas
It sounds like we have both may have worked on a few TV's at some
I actually worked more on commercial video and audio equipment, but
there were always TV's as part of the mix, and I even went and got
licensed for consumer electronics, (Radio/TV/Antenna) even though I
really didn't need the license for what I was doing. I just figured it
was a good thing to have.
Which license did you get? Me along with a bunch of guys I knew
took a license course to help us ace our First Class FCC ticket
more than 30 years ago. We were already working on radio stations
and two way radio gear, the license just made us legal. The wacky
guy giving the course had a favorite made up word to describe any
mysterious, incomprehensible gadget. The word is "framistan" and
I've been using it ever since. I have a whole story about the
situations in which I use the word on "lay persons". *snicker*
On Thu, 08 Apr 2010 20:24:32 -0500, The Daring Dufas
It's basically my state's version of a CET. Covers me as a tech and
also as a dealer who employs techs. I think the test was written
during either the Truman or Eisenhower administrations. If you didn't
grow up working on tube equipment, the test would be a bit if a
challenge. I hear they bought an updated test about 15 years ago that
doesn't treat transistors as "new-fangled".
My late paternal great uncle was an army lifer and was in the
Army Signal Corp since they used two tin cans and a string. I
got a lot of stuff from the crusty old master sergeant. You can
imagine the tube stuff I got to play with as a kid. It's fun
to fool around with tube gear every now and then but DANG it's
gotten expensive. I remember when a horizontal output transistor
was $35.00 and the tube was $5.00. Now the same transistor costs
$1.00 or less and the darn tube is $50.00. At least the tube type
equipment will work after an EM pulse.
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