How big would a tube dvd player be

[Glenn Gundlach]

"Jerry G." <jerryg50@hotmail.com> wrote in message news:<c5lf29$5vh$1@news.eusc.inter.net>...

I worked on those early machines. I was involved with the early generation
of the solid state machines. In the basement they had the old tube type
VTR's destined for scrap. The models I was familiar with were the AVR1 and
the AVR2. There was another model that we had, that I cannot remember the
exact model number. This is about 30 years ago!

These machines were using tape reels that were 2 inches wide, and about 14
inches in diameter. I think the reels weighed in at a wapping 10 to 15 lbs.
The heads were on air bearing assemblies. There were air pumps for each
machine. I remember we were always sending out the heads to get them
rebuilt.

This generation of VTR was not very stable, and maintenance was almost daily
on each machine. When the operator started up on his shift, he had to go
through the set-up of the tracking and levels, or the picture would be
unstable or have banding (bands in the picture). Infact, these machines were
so unstable, that they had to be set-up every 3 to 5 hours during the coarse
of the day. VTR's didn't get very stable until they started to use computer
logics in them that could keep the alignment to track according to the
technical set-up from the master standards tape. Along with this, there had
to be many improvements starting from the design of the mechanics, through
to the electronics. These early generation of VTR machines were very
expensive to maintain, and to operate. For the maintenance of 14 machines
there was a staff of 18 service technicians sharing 3 shifts over 24 hours
with overlaps in their schedules.
big snip

I had VR-2000s and 1200s 25 years ago and they did not require setup
every 3-5 hours, not by a long shot. A problem with 1021 intersync was
that the adjustments all interacted BUT if you do the sequence 2-3
times in the same sitting, it would be OK for more than 6 months,
typically 9. The best thing we ever did to the machines was hide the
allen wrench to set tip projection. I did that after using an ACR-25
for a few years. Nobody ever dicked with penetration on those heads
and they worked fine. The experiment worked on the VR-2000 and head
life went up to an average of 1800 hrs (ferrites from Video Magnetics,
Spin Physics, CMC) We had house air (cleaned and dried) with Air-Vac
venturi units for the guide vacuum, no separate pumps-- too much work
and noise.

Digital machines have a wider tolerance of idiot operators but you
have to be a bit better detective to track down some of the problems.
Still, dirt and wearout are the same as ever.

Ah, the good old days.... (not really, just different)
GG

 

[Ken Weitzel]

Glenn Gundlach wrote:

"Jerry G." <jerryg50@hotmail.com> wrote in message news:<c5lf29$5vh$1@news.eusc.inter.net>...

I worked on those early machines. I was involved with the early generation
of the solid state machines. In the basement they had the old tube type
VTR's destined for scrap. The models I was familiar with were the AVR1 and
the AVR2. There was another model that we had, that I cannot remember the
exact model number. This is about 30 years ago!

These machines were using tape reels that were 2 inches wide, and about 14
inches in diameter. I think the reels weighed in at a wapping 10 to 15 lbs.
The heads were on air bearing assemblies. There were air pumps for each
machine. I remember we were always sending out the heads to get them
rebuilt.

This generation of VTR was not very stable, and maintenance was almost daily
on each machine. When the operator started up on his shift, he had to go
through the set-up of the tracking and levels, or the picture would be
unstable or have banding (bands in the picture). Infact, these machines were
so unstable, that they had to be set-up every 3 to 5 hours during the coarse
of the day. VTR's didn't get very stable until they started to use computer
logics in them that could keep the alignment to track according to the
technical set-up from the master standards tape. Along with this, there had
to be many improvements starting from the design of the mechanics, through
to the electronics. These early generation of VTR machines were very
expensive to maintain, and to operate. For the maintenance of 14 machines
there was a staff of 18 service technicians sharing 3 shifts over 24 hours
with overlaps in their schedules.

big snip

I had VR-2000s and 1200s 25 years ago and they did not require setup
every 3-5 hours, not by a long shot. A problem with 1021 intersync was
that the adjustments all interacted BUT if you do the sequence 2-3
times in the same sitting, it would be OK for more than 6 months,
typically 9. The best thing we ever did to the machines was hide the
allen wrench to set tip projection. I did that after using an ACR-25
for a few years. Nobody ever dicked with penetration on those heads
and they worked fine. The experiment worked on the VR-2000 and head
life went up to an average of 1800 hrs (ferrites from Video Magnetics,
Spin Physics, CMC) We had house air (cleaned and dried) with Air-Vac
venturi units for the guide vacuum, no separate pumps-- too much work
and noise.

Digital machines have a wider tolerance of idiot operators but you
have to be a bit better detective to track down some of the problems.
Still, dirt and wearout are the same as ever.

Ah, the good old days.... (not really, just different)
GG

Hi...

Guess I go back much further than you do... can't
recall model numbers, but pretty sure they were
single digit

Tip penetration was a top panel adjustment, no tools
required...

Back in my time there were no third party
head sources - just send it back to Redwood
City for re-building or buy yet another.

And I respectfully think you have the vacuum and
air bearing supply memories reversed... how do you
clean and dry vacuum air?

In any case, our pumps were both kept a good
distance from the machine...

Take care.

Ken

 

[Mike Tomlinson]

In article <107rsmhs88pipf9@corp.supernews.com>, exray <dontspamme-
exray@coqui.net> writes

One of the greatest problems with computers built from vacuum tubes was
reliability; 90% of ENIAC's down-time was attributed to locating and
replacing burnt-out tubes. Records from 1952 show that approximately
19,000 vacuum tubes had to be replaced in that year alone, which
averages out to about 50 tubes a day!

There's a modern equivalent to ENIAC's (un)reliability. It's called
Microsoft Windows. |-)

--
A. Top posters.
Q. What's the most annoying thing on Usenet?

 

[Sam Goldwasser]

Mike Tomlinson <mike@NOSPAM.jasper.org.uk> writes:

There's a modern equivalent to ENIAC's (un)reliability. It's called
Microsoft Windows. |-)

Don't give ENIAC a bad name. It was much more reliable.

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