Good and large X-Y CRT?

T

Tim Shoppa

Guest
What oscilliscope-type CRT's are still being manufactured and
widely available today? I need something with electrostatic
deflection, and preferably with a big screen. Tektronix used to
sell 8" or 10" square faced instruments which were perfect for this.
I'd be satisfied with a bare tube, but would be happy if someone could
point me towards a source of old Tektronix big-screen X-Y scopes.

Looking around, I see that new 3RP1A's are being imported from China, otherwise
all the scope tubes I see seem to be replacements for brand X model Y scope
or pulls from old scopes. There seems to be a minor market in used
ATC-style vectorscopes which are somehow magnetically deflected? Don't
understand what's inside them and unless they're easily turned into X-Y
instruments I don't care.

Tim.
 
Tim Shoppa wrote:
What oscilliscope-type CRT's are still being manufactured and
widely available today? I need something with electrostatic
deflection, and preferably with a big screen. Tektronix used to
sell 8" or 10" square faced instruments which were perfect for this.
I'd be satisfied with a bare tube, but would be happy if someone could
point me towards a source of old Tektronix big-screen X-Y scopes.

Looking around, I see that new 3RP1A's are being imported from China, otherwise
all the scope tubes I see seem to be replacements for brand X model Y scope
or pulls from old scopes. There seems to be a minor market in used
ATC-style vectorscopes which are somehow magnetically deflected? Don't
understand what's inside them and unless they're easily turned into X-Y
instruments I don't care.

Tim.
Click to expand...
I have no idea what your application is, but you can still get used X-Y
monitors over in the vintage video arcade circles for under $500. If it can
apply to you, go post in reg.games.video.arcade.collecting for further details.
 
On Sunday 03 October 2004 06:26 pm, John Larkin did deign to grace us with
the following:

On 3 Oct 2004 17:31:17 -0700, shoppa@trailing-edge.com (Tim Shoppa)
wrote:

What oscilliscope-type CRT's are still being manufactured and
widely available today? I need something with electrostatic
deflection, and preferably with a big screen. Tektronix used to
sell 8" or 10" square faced instruments which were perfect for this.
I'd be satisfied with a bare tube, but would be happy if someone could
point me towards a source of old Tektronix big-screen X-Y scopes.

Looking around, I see that new 3RP1A's are being imported from China,
otherwise all the scope tubes I see seem to be replacements for brand X
model Y scope
or pulls from old scopes. There seems to be a minor market in used
ATC-style vectorscopes which are somehow magnetically deflected? Don't
understand what's inside them and unless they're easily turned into X-Y
instruments I don't care.

Tim.

Used Tek X-Y boxes show up on ebay fairly often; I've bought a couple.
But I've seen mostly smaller ones, not 8-10".

What are you making? Could you fake it with a computer monitor and
some ADCs?

I once worked with a unit that simulated sweep-scan on a raster display
Click to expand...
by adding a small coil on top of the vertical deflection coil, called
the 'bend board'. They actually had a little circuit that, when you
wanted to display a curved trace, you would write (80186 assembly)
to the "bend register" and it would introduce a little bend into
the trace, and literally smooth over the stairsteps. The segment
of the next scan line would be bent a little to line up with the
previous, and like that. It did look great, and some guy got a patent
for the circuit. But it requires modifying the monitor, and I'm pretty
sure there's a limit to how much "bend" can be applied, but it's a
thought.

And it was incredible fun to code for. ;-)

Cheers!
Rich
 
"Dave VanHorn" <dvanhorn@cedar.net> wrote in message news:<442dneAX36oQSf3cRVn-sg@comcast.com>...
I have no idea what your application is, but you can still get used X-Y
monitors over in the vintage video arcade circles for under $500. If it
can
apply to you, go post in reg.games.video.arcade.collecting for further
details.

I've yet to see a video game that ran electrostatic deflection.
Click to expand...
I'm "just" looking at Lissajous figures in the few MHz region. If
a video game monitor assembly uses a tube with magnetic deflection
but makes it look like a good old X-Y CRT as far as what I have to
feed into the assembly, then it'd work fine.

Tim.
 
John Larkin <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in message news:<hh91m0p7h4ph2tg5h4ms9d90e9i8plurau@4ax.com>...
What are you making?
Click to expand...
An analog computer that integrates the Lorentz equations while the user
tweaks the knobs that vary the parameters. Part of a museum display on
chaos and analog computing.

Could you fake it with a computer monitor and
some ADCs?
Click to expand...
In fact that's what I'm doing now:

1. As fast as I can (inner loop),
measure X and Y, go to that pixel and add, say, 100 units of brightness.
If it would go over the max value (255 for 8-bit pixels) then just
leave it at 255.

2. Every sixtieth of a second, "age" all the pixels to simulate
phosphor persistence by going over every pixel and multiplying
its brightness by 0.95.

Step 2 gives me a persistence of about a fifth of a second. A nice tweak
is that I can change the aging rate to give me effectively variable
persistence. While that's cute, it's not a necessity.

But using a whole PC running full-throttle on this seems a bit of a
waste, and defeats the simplicity of the analog multipliers and
integrators used to solve the Lorentz equation. I was kind-of hoping
to find a common X-Y CRT that will be available for a while into the
future. I found the 3RP1A and was hoping to find something bigger.

Tim.
 
On Monday 04 October 2004 03:04 am, Tim Shoppa did deign to grace us with
the following:

"Dave VanHorn" <dvanhorn@cedar.net> wrote in message
news:<442dneAX36oQSf3cRVn-sg@comcast.com>...
I have no idea what your application is, but you can still get used X-Y
monitors over in the vintage video arcade circles for under $500. If
it can
apply to you, go post in reg.games.video.arcade.collecting for further
details.

I've yet to see a video game that ran electrostatic deflection.

I'm "just" looking at Lissajous figures in the few MHz region. If
a video game monitor assembly uses a tube with magnetic deflection
but makes it look like a good old X-Y CRT as far as what I have to
feed into the assembly, then it'd work fine.

Well, they're probably horrendously expensive these days unless you
Click to expand...
can find a video game collector - "Star Wars" and something like "Frenzy"
or something, were vector displays. In fact, I think "Asteroids" was
a vector display, monochrome.

They have very sparse deflection coils, and mongo current drivers.
Like, DC-100's KHz flat. But as long as it doesn't break, it's great!

Good Luck!
Rich
 
Tim Shoppa wrote:
"Dave VanHorn" <dvanhorn@cedar.net> wrote in message news:<442dneAX36oQSf3cRVn-sg@comcast.com>...
I have no idea what your application is, but you can still get used X-Y
monitors over in the vintage video arcade circles for under $500. If it
can
apply to you, go post in reg.games.video.arcade.collecting for further
details.

I've yet to see a video game that ran electrostatic deflection.

I'm "just" looking at Lissajous figures in the few MHz region. If
a video game monitor assembly uses a tube with magnetic deflection
but makes it look like a good old X-Y CRT as far as what I have to
feed into the assembly, then it'd work fine.

Tim.
Click to expand...
Yes, EM deflection. The B&W units (Electrohome G05 series) come in 19" and 13"
sizes, and are pretty much self-contained. You should be able to pick up a
working used unit for around $250 or so.

Theory of operation:
http://www.gamearchive.com/Video_Games/Manufacturers/Atari/monitors/e_g-05/g-05_descr.txt
 
On 4 Oct 2004 03:23:48 -0700, the renowned shoppa@trailing-edge.com
(Tim Shoppa) wrote:

John Larkin <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in message news:<hh91m0p7h4ph2tg5h4ms9d90e9i8plurau@4ax.com>...
What are you making?

An analog computer that integrates the Lorentz equations while the user
tweaks the knobs that vary the parameters. Part of a museum display on
chaos and analog computing.

Could you fake it with a computer monitor and
some ADCs?

In fact that's what I'm doing now:

1. As fast as I can (inner loop),
measure X and Y, go to that pixel and add, say, 100 units of brightness.
If it would go over the max value (255 for 8-bit pixels) then just
leave it at 255.

2. Every sixtieth of a second, "age" all the pixels to simulate
phosphor persistence by going over every pixel and multiplying
its brightness by 0.95.

Step 2 gives me a persistence of about a fifth of a second. A nice tweak
is that I can change the aging rate to give me effectively variable
persistence. While that's cute, it's not a necessity.

But using a whole PC running full-throttle on this seems a bit of a
waste, and defeats the simplicity of the analog multipliers and
integrators used to solve the Lorentz equation. I was kind-of hoping
to find a common X-Y CRT that will be available for a while into the
future. I found the 3RP1A and was hoping to find something bigger.

Tim.
Click to expand...
Some of the low-end analog scopes use Hitachi flat-face rectangular
tubes- not sure what size they go up to. If I was tasked with sourcing
such a thing for small-scale production (no fun, I'm sure), I'd try to
do it from Asia.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
John Woodgate <jmw@jmwa.demon.contraspam.yuk> wrote in message news:<7yH7KGEr8RYBFwqi@jmwa.demon.co.uk>...
I read in sci.electronics.design that Tim Shoppa <shoppa@trailing-
edge.com> wrote (in <bec993c8.0410031631.55979ae9@posting.google.com>)
about 'Good and large X-Y CRT?', on Sun, 3 Oct 2004:
Click to expand...
The LBO9C Alignment Scope / X-Y Display Module is equipped with a
9-inch screen. LB09C is made by Leader, not sure about the bandwidth,
but was in production like 2-3 years ago. Same Leader that made the
low cost chinese or taiwanese scopes.

If you find some cheap, please let me know so I can mothball my Tek
606
I actually used to do vector graphics for a living, doing laser shows,
and still have the 5K worth of custom vector control stuff, including
8 channel digital tape and a 68040 based PCI card that rides a PC bus
to do the real time math. Of course nothing done for laser shows gets
out of the high audio bandwidth, because of the mechanics of the
galvanometer scanners, yet we can get 16 bit 3D wireframe with up to
1200 points per frame, and still cram it into audio with almost no
flicker.

Steve Roberts
 
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