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There was a board called the VectorVGA that converted XYZ inputs to an VGA display (15 pin D connector output). It had color RGB inputs also so it could be used to replace color vector games (Atari Tempest etc.) to VGA. I don't think it's made anymore though. Maybe with some good searching more info can be found on it. The arcade gaming people mostly use the term vector for XY so that's another good search term.

Bob

On 2021-11-03 5:56 p.m., Roy Thistle wrote:

On Wed, Nov 3, 2021 at 12:27 PM, Jeff Dutky wrote:

magnetic deflection CRT which, if I recall my college physics correctly (no
guarantee at this late date) has lower deflection bandwidth

Hi Jeff:
Well... you'd be trying to drive an inductor (the deflection field coil, in the CRT yoke.)... and in this case Lenz is no friend to you.
I believe I have seen a vector display with magnetic deflection... I believe it is possible.

Yes, they exist, and one mass production use was arcade games. People still modify magnetic tubes for X/Y work (for example the 9" mono displays from some computers) because they're relatively plentiful and just not as awkwardly LONG. :)

--Toby

You could change the resistor, in the yoke, to fiddle with the time constant.., drive with current instead of voltage... wind/rewind a/the custom/deflection coil...or if you want a bandwidth of more than a few 10s of KHz... use use electrostatic deflection.
Cheers and all that too.

The Early Television Museum in Hilliard Ohio is likely the last repository of equipment and knowledge to rebuild TV jugs. However, the main problem is obtaining new gun assemblys. There have been talks with suppliers in Russia and China, but so far, nothing has transpired. I think the rarest jug on the planet is a good 15GP22, used in the very first color TVs. The failure is air leaking in through imperfect welds and glass-metal seals. I have heard picture tubes are still being made in India, whether this is true or if they would consider making rebuilding guns and supplies is unknown. It all may be an extinct art soon.

?? Bruce Gentry, KA2IVY

On Wed, Nov 3, 2021 at 12:27 PM, Jeff Dutky wrote:

magnetic deflection CRT which, if I recall my college physics correctly (no
guarantee at this late date) has lower deflection bandwidth

Hi Jeff:

Well... you'd be trying to drive an inductor (the deflection field coil, in the CRT yoke.)... and in this case Lenz is no friend to you.
I believe I have seen a vector display with magnetic deflection... I believe it is possible.
You could change the resistor, in the yoke, to fiddle with the time constant.., drive with current instead of voltage... wind/rewind a/the custom/deflection coil...or if you want a bandwidth of more than a few 10s of KHz... use use electrostatic deflection.

Cheers and all that too.
--
Roy Thistle

On Wed, Nov 3, 2021 at 04:14 AM, cheater cheater wrote:

how does he pull the stock out of the chuck while the lathe
is running? He does that around the two and a half minute mark.

There are two different kinds of tighten/release mechanisms on collet lathes. The more common kind requires you to stop the lathe and then turn a handwheel on the left end of the hollow drawbar by hand. The more production style has a lever that sticks forward, toward the operator, from the left side of the headstock. That lever pushes or pulls on a bearing to a rotating collar with a detent that does the tightening/releasing. I used to have access to a very nice Clausing lathe with that sort of quick release (not sure if that's the correct name) but I would often stop the lathe, pull the release lever to the right, and pull the part out of the collet without waiting for the chuck to stop spinning.

It never occurred to me that I could move a part without bothering to stop the lathe, but in hindsight it's now clear. While reaching in to grab a moving part is generally forboten, with a small smooth part, free in a collet, there's no real danger. I suspect Joe has that kind of lathe and that's exactly what he did.

On Wed, Nov 3, 2021 at 05:46 AM, Jean-Paul wrote:

Perhaps old CRTs can be restored somehow?

There was someone here who was restoring television CRTs.
When the electron-gun assemblies became unavailable, he stopped doing it. (It's one thing taking the neck of and re-coating the phosphor: It's something else, entirely re-building/building the gun cathode.)
Much of the technology (the 'fixins' and the 'makings') is unavailable, and forgotten.
I fear, restoring these old CRTs would be fearsomely expensive.
If you have to have a CRT and want a project (perhaps equal in work magnitude to the LCD solution?)... perhaps bodging in a more modern? magnetically deflected CRT? is possible. I believe, these type of CRTs are still available.

Cheers, and all that.

--
Roy Thistle

The shimmering I described was called "double traces" and a fix was described here:
/g/TekScopes/topic/77914568#175831
by Jack2015, where adjusting the value of R318 eliminates it.

I've tried it, and it does make a noticable improvement, but for me not as good as he had
and showed on youtube. That's just a comparator threshold, so I don't understand how
changing the step threshold could help.

Shows his collet closer

Bruce

ST:
not sure of NA price: $ 54 ? ( Euros ? )

manuals, data sheets:

hi Howard,

Good find, appreciated !
Looking forward to your additional finds.

What an interesting problem to be solved !


I just came across a 1986 patent, issued in 2005 that might be conceptually informative:



explanation and block diagrams; no schematics.

On that board, you really want to check the prices at Mouser, or Digikey, or see if you can buy from ST directly.

The board uses a DSI driven display, but it's not really designed to drive another display.? The display is about the size of a cell phone display, 800 x 480 in resolution.? He likely just used the A/D converters in the processor directly.? The board has a serial input (3.3v TTL, I2C, and SPI inputs).? You can use one of the USB connections as well.

You can put a larger display (with perhaps less resolution) on a Nucleo-144 board, but you'd have to do some design work and some programming to make it all fit together.

Harvey

Hello All-



I have located one of the XYZ to color LCD designs that I saw a few years
ago.



Please watch the designer's video to see his work demonstrated on an old HP
CRT based RF analyzer:







The system consists of an inexpensive processor development kit (less than
$100 if you shop around) and some trivial level shifters. Here is a link to
one listing for the board kit on eBay:







The developer has kindly made his source code fully public; the link to the
code is on the YouTube video page. It should be trivial to modify the code
to remove the HP specific functionality.



So, for anyone wanting to use a vintage slow scan speed CRT based device
which has a defective CRT (like a curve tracer) this design would be an
excellent and inexpensive starting point.



There are other designs out there which I will share when I find them...



Howard

garp66 wrote:

Is the Tek 576 CRT X Y display a true Vector display ?

I don't understand what the distinction is between an "X Y display" and a "true Vector display".

Most Tek scopes (of a certain age, at least) use electrostatic deflection CRTs, with varying amounts of extra stuff thrown in to get better performance under different conditions (e.g. higher bandwidth, faster "write time", etc.), but the basic technology is a picture tube with two dimensions of deflection ("X" and "Y") and an "extra dimension" of spot intensity (the "Z-axis"). The main alternative is a magnetic deflection CRT which, if I recall my college physics correctly (no guarantee at this late date) has lower deflection bandwidth, but can give wider deflection at the same tube length. Magnetic deflection also does not require that you put a conductor through the glass envelope to the deflection plates (since there aren't any), you just put electromagnetic coils around the outside of the tube, so the magnetic deflection CRTs are cheaper to manufacture and more reliable.

Both CRT technologies can be, and are, used to draw "true Vector" images, it's just a matter of how fast. Magnetic deflection is really good for TVs, which organize the image as a raster scan of relatively limited bandwidth. The highest bandwidth is the luminance data (something like 5 MHz), but that does not involve whipping the beam around in space, just modulating the beam current. The next highest bandwidth is the horizontal retrace which is (was?) limited to something like 10 kHz, which is nothing compared to what even the slowest Tek scopes can do (oldest and slowest scopes I have can deliver at least 500 kHz of both horizontal and vertical bandwidth).

The CRTs used in most oscilloscopes (again, of a certain age) use electrostatic deflection because it allows you to move the beam across the face of the CRT much more rapidly than you can with magnetic deflection, and that's what gives the oscilloscope its sensitivity and bandwidth. You can use a magnetic deflection CRT to build an oscilloscope, but it would be bandwidth limited in the CRT (not sure what that limit would be, but it could be quite low, as most TV picture tubes (except some really early ones) were engineered for high deflection angle and low deflection bandwidth, because everybody likes a bigger screen on their TV, but nobody needs, or needed, higher frame rates, PAL and NTSC transmission being defined the way they were).

There never was (that I know of) a standard for X-Y displays like there was for raster displays (nothing like PAL, NTSC, composite video, etc.), you just had two or three inputs that took voltages in some specified range, and you pumped your signals of interest through appropriate attenuation or amplification to meet those requirements. You did have data terminals (e.g. the Tek 4000 series) that took vector drawing commands over a serial connection, but they just drove a standard CRT in the end (not sure if the CRT in a 4010 is electrostatic or magnetic, since there was bistable storage and you didn't really need to update the display very rapidly).

The curve tracers are not drawing the curves at ridiculously high bandwidth, in fact, some of them (e.g. the 7CT1N) use (to me) surprisingly low bandwidths (I guess this is to be able to reliably test even very slow power semiconductors? Would sweeping collector current at 500 Hz really stress out even the slowest transistor or diode?) so they could have used either electrostatic or magnetic deflection, but I expect that most models use electrostatic deflection (maybe not the 372, which looks like an 11000-series scope?), because Tek was already making scads of those for use in oscilloscopes.

-- Jeff Dutky

Is the Tek 576 CRT X Y display a true Vector display ?

Is the correct terminology:

' A vector XYZ CRT to LCD converter ' ?

Does anyone have the Tek 576 CRT display specifications, voltages, currents, frequencies ?

Hi Toby-



Agreed. The link I sent was incorrect; it is to a raster to raster board. My
second email apologized for this error, and I apologize again for any
inconveniences.



I am aware of some true XYZ to raster (LCD) boards which were popular a few
years back for retrofitting HP spectrum analyzers. I had data sheets and
manufacturer links which need to be found.



There are also many high-end xyz to raster boards used in military
applications such as radar conversion or aircraft display upgrades. These
are still currently manufactured, but are very expensive.



Regards-



Howard

hi Toby,

Yes, ...looks like we need a module for XYZ .... for the Tek 576 to get to a LED or LCD display.

Can anything inexpensive and readily available, be shoehorned -in ( modified ) for our needs ??


**
The Mike's Arcade web site provides some schematics for B&W & Colour CRT's that some of the converters ( mentioned by Howard ) can be used with:
Obviously, these are for older arcade CRT's... { provided for info only } :



Unless Howard or others might have an idea of how to hack the McBazel for the Tek 576 ??
Is there a hidden X-Y input on that board ??

On 2021-11-03 11:50 a.m., garp66 wrote:

Mcbazel Arcade Game
See:

As others have mentioned, every reference to "Mcbazel" I can see (I don't see it on the site you linked) is to a RASTER to RASTER converter that does not help with XYZ conversion as needed by the topic under discussion.

--T

Mcbazel Arcade Game

See:

thanks Howard,
rick ( ay )





Mcbazel Arcade Game RGB/CGA/EGA to VGA HD Game Video Output Converter Board for Arcade Game Monitor to CRT LCD PDP Projector

Brand: Mcbazel

$24.90

Possible Optical Encoder (OE) :

I am a fan of the simple HP small, light, compact OE's that might be retrofitted into the Tek 576 CT for such a enhancement project:

It is so light and mass-less that I think a simple plastic tubing or rod extension, perhaps epoxied to the end of the existing shaft could be fitted & drive the HP HEDS 5640 encoder for this purpose ?

See:
HP HEDS 5640 #A13:







rick