OT - CRT's

[John Robertson]

On 2019/05/21 8:11 p.m., John Larkin wrote:

On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Well, actually, yes there is - a number of video shooting games require
CRT/Picture Tubes to work correctly. The reason is when the trigger is
pulled the game sends a white square (or a single frame screen flash) to
the screen that traces across each horizontal line as a marker for
position. This is detected by the opto in the rifle/pistol and the time
it is detected indicates where the gun was aimed...

The MAME emulations and the video upscalers don't do that well at all
with picture tubes so those few games which use a photocell receptor in
the pistol/rifle doesn't work with any LCD combo I have tried. I have
not tried very many as it seemed an exercise in futility.

Otherwise the only other advantage of tubes over LCDs is the 3:4 aspect
ratio is not easy to find in LCDs over 19". So pictures are squished a
bit except for MAME emulations or upscalers that allow you to adjust the
screen ratio.

Solutions in MAME involve changing the gun sensing position to use other
external processes.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

John Robertson <spam@flippers.com> wrote in
news:CMWdncUHU4mTAXnBnZ2dnUU7-YPNnZ2d@giganews.com:

The MAME emulations and the video upscalers don't do that well at
all with picture tubes so those few games which use a photocell
receptor in the pistol/rifle doesn't work with any LCD combo I
have tried. I have not tried very many as it seemed an exercise in
futility.

Light gun games do not work with LCD displays because they are
progressive scan devices. Maybe a couple other reasons.

I had a 37" CRT widescreen HDTV back in the first days of HDTV and it
would not work wither becuase of the progressive scan. It tried and
would catch shots sometimes, but generally failed.

 

John Robertson <spam@flippers.com> wrote in
news:CMWdncUHU4mTAXnBnZ2dnUU7-YPNnZ2d@giganews.com:

Otherwise the only other advantage of tubes over LCDs is the 3:4
aspect ratio is not easy to find in LCDs over 19". So pictures are
squished a bit except for MAME emulations or upscalers that allow
you to adjust the screen ratio.

Uh... It is 4:3 not 3:4.

And nearly ALL LCD display I am aware of will still render a 4:3
source. They simply do not "fill the screen" like so many layman TV
watchers "must have" or they feel shorted. Not realizing that it was
God whom shorted them on brain cells.

LCD works fine on game emulation short of the light gun variety. Big
deal.

 

[Sylvia Else]

On 21/05/2019 9:57 pm, Bob Engelhardt wrote:
> Is there still a use for CRT's?

Long lasting equipment?

I have scope from about 1985 that still works (did have to repair it
once, admittedly, and it hasn't seen that much use). Everything else
from that era is gone.

Sylvia.

 

[DJ Delorie]

DecadentLinuxUserNumeroUno@decadence.org writes:

Arcade machine restorations, especially 19" tubes. Even so far as to
remove the tube from a suitable TV and transplant the coils.

There are flat screens and PC with emulators to do that. Not
restore... UPGRADE.

I can play pacman or any of hundreds of other upright arcade games on
my 55" no problem. And it is the EXACT same game code, and is a
perfectly emulated process.

Yeah, most people say that. Except the people who restore old arcade
games and want a CRT instead of an LCD. You are not one of those people.

 

DJ Delorie <dj@delorie.com> wrote in
news:xn7eaj2qvx.fsf@delorie.com:

DecadentLinuxUserNumeroUno@decadence.org writes:
Arcade machine restorations, especially 19" tubes. Even so far
as to remove the tube from a suitable TV and transplant the
coils.

There are flat screens and PC with emulators to do that. Not
restore... UPGRADE.

I can play pacman or any of hundreds of other upright arcade
games on
my 55" no problem. And it is the EXACT same game code, and is a
perfectly emulated process.

Yeah, most people say that. Except the people who restore old
arcade games and want a CRT instead of an LCD. You are not one of
those people.

I loaded and unloaded 300 pacman a week, and if you were east of
the Miss you bought your Midway machines off that dock.

I saw the entire genre usher in first hand and played them every
day during lunch and worked on them when they came in broken and
worked on them in the field. Everything from reed switched '50s era
pinballs to shuffle board bowlers to pong to grag race to mach3 to
Dragon's Lair to modern multi-level pinballs and even pinball-video
game combos.

I *DO* know the difference and I have seen both types today. Both
the full original restoration variety and the PC based emulated and
fed to a flat screen variety.

Sorry, but you are not knowledgeable on "what most people say".

Some lame rich fuck with a fully restored unit in his game room
that nobody ever uses so one day he can sell it for even more... a
collector... Oh boy. That is who you want to sell to.

I am more the hey me and my kids want to actually use this fucking
thing, and yes I will still get good money for it were I to ever
sell it type.

And in those old "restored" relics, do you go through and replace
ALL of the EL caps in them? If not you are lying to the person you
tell that you "restored it" to.

The old boards that drive those CRTs and the main PCBs in those
old relics are borderline functional, at best.

 

[Bill Sloman]

On Tuesday, May 21, 2019 at 9:58:13 PM UTC+10, Bob Engelhardt wrote:
> Is there still a use for CRT's?

Cathode ray tubes have been replaced in most of their applications.

Steerable electron beams are still handy - and if fact irreplaceable - in things like electron microscopes, electron beam microfabricators and electron beam welders.

You can - in theory - write finer lines with ion beams - the shorter matter wavelength and the more compact charge help - but electron sources have a lot more development behind them than ion sources.

--
Bill Sloman, Sydney

 

[whit3rd]

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:

On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update. That kind of display
does NOT function well with digitization. Clocking very much gets in the way of
the function.

Everything that digital does for you, it also does TO you.

 

[Steve Wilson]

whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD cannot provide, at rates that a 'video' screen
cannot update. That kind of display does NOT function well with
digitization. Clocking very much gets in the way of the function.

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square waves,
etc.

Moden method: Display a few cycles of one signal, trigger on the other. You
can get much finer resolution than provided by Lissajous figures, and track
very small phase changes over hours or days. You can measure the offset
directly in picoseconds or whatever is appropriate. This is difficult or
impossible to do with Lissajous figures.

 

[Tim Williams]

"whit3rd" <whit3rd@gmail.com> wrote in message
news:56bc7695-c7fe-4abc-9a14-b243cd975c62@googlegroups.com...

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update.

That's an old-fashioned opinion even for a /newsgroup/. Lissajous figures
disappeared in the late 30s as synced/triggered sweep took over. Combined
with how not-very-useful they are, it strains the imagination to believe
anyone here has actually, usefully, unironically used them. ;-)

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

 

[Steve Wilson]

whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 9:15:20 PM UTC-7, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figure...

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square
waves, etc.

Moden method: Display a few cycles of one signal, trigger on the other.
You can get much finer resolution than provided by Lissajous figures,
and track very small phase changes over hours or days. You can measure
the offset directly in picoseconds or whatever is appropriate. This is
difficult or impossible to do with Lissajous figures.

The trigger is an ASYNCHRONOUS event, but its capture by a DSO is
typically a SYNCHRONOUS event, happening on a clock edge. That's not
good for accurate timing. Digtization hurts the process.

I don't undersstand what you are talking about. Display both signals,
trigger on one. The one you trigger on will remain stationary. The other
will drift. Depending on the quality of the signals, it may take hours or
days to show much drift. The signals can be sine waves, square waves,
pulses, or any combination. You can't do that with Lissajous.

A knob adjustment while watching a Lissajous pattern is a lot quicker
than 'measure the offset directly' will ever be. The pattern dynamics
is a quicker informant than a digital readout for a human interface.

I've watched audio assembly-line workers, with a test generator putting
up a dozen patterns (for half a second each); they knew exactly what to
adjust and got to their goal in seconds. Probably, for audio, digital
timing wasn't a problem, of course.

Not many people make analog audio amplifiers these days.

 

[whit3rd]

On Tuesday, May 21, 2019 at 9:15:20 PM UTC-7, Steve Wilson wrote:

whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figure...

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square waves,
etc.

Moden method: Display a few cycles of one signal, trigger on the other. You
can get much finer resolution than provided by Lissajous figures, and track
very small phase changes over hours or days. You can measure the offset
directly in picoseconds or whatever is appropriate. This is difficult or
impossible to do with Lissajous figures.

The trigger is an ASYNCHRONOUS event, but its capture by a DSO is typically
a SYNCHRONOUS event, happening on a clock edge. That's not good
for accurate timing. Digtization hurts the process.

A knob adjustment while watching a Lissajous pattern is a lot quicker than
'measure the offset directly' will ever be. The pattern dynamics is a
quicker informant than a digital readout for a human interface.

I've watched audio assembly-line workers, with a test generator putting up
a dozen patterns (for half a second each); they knew exactly what to adjust
and got to their goal in seconds. Probably, for audio, digital timing wasn't
a problem, of course.

 

Steve Wilson <no@spam.com> wrote in
news:XnsAA57296B863Eidtokenpost@69.16.179.22:

whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figures, after all, depend on
vertical/horizontal matching, which an LCD cannot provide, at
rates that a 'video' screen cannot update. That kind of
display does NOT function well with digitization. Clocking very
much gets in the way of the function.

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses,
square waves, etc.

Moden method: Display a few cycles of one signal, trigger on the
other. You can get much finer resolution than provided by
Lissajous figures, and track very small phase changes over hours
or days. You can measure the offset directly in picoseconds or
whatever is appropriate. This is difficult or impossible to do
with Lissajous figures.

One would have to use those old polaroid hoods for the scope and
take successive snapshots and then hand timestamp, measure and
analyse them. Yeah, sure...

 

[Tim Williams]

"Bill Sloman" <bill.sloman@ieee.org> wrote in message
news:72ea37a2-bac1-4bd1-8d95-0d214c45f73c@googlegroups.com...

On Tuesday, May 21, 2019 at 9:58:13 PM UTC+10, Bob Engelhardt wrote:
Is there still a use for CRT's?

Cathode ray tubes have been replaced in most of their applications.

Steerable electron beams are still handy - and if fact irreplaceable - in
things like electron microscopes, electron beam microfabricators and
electron beam welders.

You can - in theory - write finer lines with ion beams - the shorter
matter wavelength and the more compact charge help - but electron sources
have a lot more development behind them than ion sources.

That, and sputtering -- analogous to the difference between a blast of
compressed air or a sandblaster!

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

 

[whit3rd]

On Tuesday, May 21, 2019 at 10:16:08 PM UTC-7, Steve Wilson wrote:

whit3rd <whit3rd@gmail.com> wrote:

I've watched audio assembly-line workers, with a test generator putting
up a dozen patterns (for half a second each); they knew exactly what to
adjust and got to their goal in seconds. Probably, for audio, digital
timing wasn't a problem, of course.

Not many people make analog audio amplifiers these days.

Audio amplifier tests are performed with analog signals.
At a few seconds per unit, not many people were EVER involved in testing
those audio products.

 

[whit3rd]

On Tuesday, May 21, 2019 at 10:33:05 PM UTC-7, Tim Williams wrote:

"whit3rd" <whit3rd@gmail.com> wrote in message
news:56bc7695-c7fe-4abc-9a14-b243cd975c62@googlegroups.com...
On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update.

That's an old-fashioned opinion even for a /newsgroup/. Lissajous figures
disappeared in the late 30s as synced/triggered sweep took over.

Finding out if two oscillators are locked, it's handy.
There's some modern work on the subject:

<https://youtu.be/rtR63-ecUNo>

 

[Jan Panteltje]

On a sunny day (Wed, 22 May 2019 11:39:32 +1000) it happened Sylvia Else
<sylvia@email.invalid> wrote in <gkjnikFn553U3@mid.individual.net>:

On 21/05/2019 9:57 pm, Bob Engelhardt wrote:
Is there still a use for CRT's?

Long lasting equipment?

I have scope from about 1985 that still works (did have to repair it
once, admittedly, and it hasn't seen that much use). Everything else
from that era is gone.

Sylvia.

Yes, the Trio 10 MHz dual channel I bought in 1979 still works and is used
as my main scope.

For RF I use my analyzer that is basiclaly an USB DVB-T stick and some software I wrote.
http://panteltje.com/panteltje/xpsa/index.html

GHz no problem, just downconvert:
http://panteltje.com/pub/qo100_narrow_band_snr.gif
those are received SSB signals at about 10.4 GHz downconverted to about 740 MHz...

It is the player, not the instrument.

And I have to stress again and again,
you can test a 9V battery with your tongue !
;-)

 

[Jan Panteltje]

On a sunny day (Tue, 21 May 2019 18:51:36 -0500) it happened "Tim Williams"
<tiwill@seventransistorlabs.com> wrote in <qc22t1$e98$1@dont-email.me>:

"Bob Engelhardt" <BobEngelhardt@comcast.net> wrote in message
news:qc0p400j4m@news3.newsguy.com...
Is there still a use for CRT's?

Yes. They remain in demand among console gamers -- lots of old games are
still played, on original hardware, and most panel TVs have terrible
latency.

There's probably tens, maybe hundreds of thousands of "let's play"-ers and
speedrunners and "classic" gamers out there, hardly a large market by the
game industry's standards, but probably a sizable portion of the CRT resale
market.

Trinitron monitors still command reasonable prices on eBay. I've always
been tempted to get a 2048x1536x85Hz beast, but they don't come up all that
often and typically sell for $250.

Tim

As to latency, OLEDs are getting cheaper (about 1000$ for 55 inch IIRC),
but will suffer some burn-in for gaming.
I almost bought one last week...
Picture is stunning.

 

[Jan Panteltje]

On a sunny day (Tue, 21 May 2019 23:27:25 -0700 (PDT)) it happened whit3rd
<whit3rd@gmail.com> wrote in
<f1f36f87-0875-413c-856d-b72e2a85f7f4@googlegroups.com>:

On Tuesday, May 21, 2019 at 10:33:05 PM UTC-7, Tim Williams wrote:
"whit3rd" <whit3rd@gmail.com> wrote in message
news:56bc7695-c7fe-4abc-9a14-b243cd975c62@googlegroups.com...
On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:

Yes. Lissajous figures, after all, depend on vertical/horizontal
matching, which an LCD
cannot provide, at rates that a 'video' screen cannot update.

That's an old-fashioned opinion even for a /newsgroup/. Lissajous figures
disappeared in the late 30s as synced/triggered sweep took over.

Finding out if two oscillators are locked, it's handy.
There's some modern work on the subject:

https://youtu.be/rtR63-ecUNo

Coool,
but if you use Linux, install xine, run
xine audio_file.wav
then bring up the menu with a right mouse click
select audio - > visualizations -> goom
then you get this display in color, dynamicaly changing in all sort of patterns:
http://panteltje.com/pub/xine_audio_visualizations_goom.png

You can also select scope or FFT.

 

[Jan Panteltje]

On a sunny day (Tue, 21 May 2019 21:56:46 -0700 (PDT)) it happened whit3rd
<whit3rd@gmail.com> wrote in
<a28b4b34-43a5-4491-b6f4-d138f8fa3c92@googlegroups.com>:

On Tuesday, May 21, 2019 at 9:15:20 PM UTC-7, Steve Wilson wrote:
whit3rd <whit3rd@gmail.com> wrote:

On Tuesday, May 21, 2019 at 5:11:33 PM UTC-7, John Larkin wrote:
On Tue, 21 May 2019 07:57:52 -0400, Bob Engelhardt
BobEngelhardt@comcast.net> wrote:

Is there still a use for CRT's?

No.

Yes. Lissajous figure...

Everything that digital does for you, it also does TO you.

Lissajous figures require sine waves. Doesn't work with pulses, square waves,
etc.

Moden method: Display a few cycles of one signal, trigger on the other. You
can get much finer resolution than provided by Lissajous figures, and track
very small phase changes over hours or days. You can measure the offset
directly in picoseconds or whatever is appropriate. This is difficult or
impossible to do with Lissajous figures.

The trigger is an ASYNCHRONOUS event, but its capture by a DSO is typically
a SYNCHRONOUS event, happening on a clock edge. That's not good
for accurate timing. Digtization hurts the process.

A knob adjustment while watching a Lissajous pattern is a lot quicker than
'measure the offset directly' will ever be. The pattern dynamics is a
quicker informant than a digital readout for a human interface.

I've watched audio assembly-line workers, with a test generator putting up
a dozen patterns (for half a second each); they knew exactly what to adjust
and got to their goal in seconds. Probably, for audio, digital timing wasn't
a problem, of course.

mm
yes,
but I am playing with an audio narrow band 90 degrees phase shift network,
and on my analog scope a circle is not enough to measure how many degrees it is off.
Analog scopes have distortion and gain differences between channels too.
So back to the analyzer...