All measured against GND.
Am 28.08.2023 um 22:36 schrieb Max DN <flataeg...@gmail.com>:
Hi,
Could I check please? Those measurements are GROUND-to-Base of MPSW42's and POS250V-to-collector of MPSW42's ?
Il giorno lunedì 28 agosto 2023 alle 17:34:29 UTC+1 jörg ha scritto:
Please measure with your scope the deflection board.
At base and collectors of the MPSW42's.
250V line measured with x10 switch set at the probe.
Attached some pictures of my measurement with the code from above. Hope that helps a bit.
Made with Rigol screencapture utility.
XOUT: ![XOUT.png]() XOUTN: ![XOUTN.png]() POS250V line... XOUT-250: ![XOUT-250.png]() XOUTN-250: ![XOUTN-250.png]() YOUT: ![YOUT.png]() YOUTN: ![YOUTN.png]() YOUT-250: ![YOUT-250.png]() YOUTN-250: ![YOUTN-250.png]() On Monday, August 28, 2023 at 5:57:46 PM UTC+2 Max DN wrote:
Hello,
I have tested lines and circle only. They aren't indeed as neat as yours...
Pics attached.
Il giorno lunedì 28 agosto 2023 alle 16:12:14 UTC+1 jörg ha scritto:
The iniflg stuff is only to enable my HV and filament pws. You do not need it, I suppose.
On Monday, August 28, 2023 at 5:09:55 PM UTC+2 jörg wrote:
Could you please try that code:
I've got a Rigol DS1054Z too. So we can compare the scopes image.
void test_raw() { static int iniflg = 0; long c; if(iniflg == 0) { digitalWrite(EnaPwsPin, HIGH); // hv & heater pws enable iniflg = 1; } for(c=0; c!=3000; c++) drawACircle(0, 0, 1000); for(c=0; c!=7000; c++) drawRadialLine(0, 2000, 1024, 0); for(c=0; c!=7000; c++) drawRadialLine(0, 2000, 360, 90); } // main() void loop() { // main_loop(); test_raw(); }
![s1.png]() ![s2.png]() ![s3.png]() On Monday, August 28, 2023 at 4:56:11 PM UTC+2 Max DN wrote:
Another thing I don't understand is the following.
The left hand side of the display seems to be more blurry than the right hand side. I even tried to change CRT, same thing.
If I go back and use the previous transformer (hand-wound, so there will be some inconsistencies), the I do get double lines everywhere (and mode obvious on the right hand side of the screen).
I have tested again using a digital oscilloscope in XY mode and I don't see double lines, although it's difficult to tell for sure on a digital scope (Rigol DS1054Z).
Pictures attached (they are very close to what I actually see, no camera effects).
I have tried several things with no lack over the past 3 days (wife starting to get impatience I'm spending too much time in my mini-lab, as it happens).
Il giorno lunedì 28 agosto 2023 alle 11:27:51 UTC+1 Max DN ha scritto:
Hi Jörg, Grahame,
Thanks. Yes, I'm very pleased of getting this far, especially since this transformer wasn't an easy one for me to hand-wind. It's just this one last step missing to get a sharp picture.
Between NEG1240 and NEG1200 I have -38V with the CRT connected or -42V with no CRT connected. I tried connecting the GRID connected to NEG1200V via 20k resistor and I see smears as in your picture. If I leave the grid floating, I see a very blurred image as in your picture. If I connect the grid to NEG1240, I see nothing on the screen.
In the code, the BlankPin is set high/low only in 4 place (DoSeg function): - if I set BlankPin always HIGH, I measure 0V across NEG1200 and GRID;
- if I set BlankPin always LOW, I measure 40V across NEG1200 and GRID (pic attached). As per David's schematic, I have a 10k resistor on R11.
I had thought about something going on with blanking as when the code displays a long test, I see what I have in the video attached (although the camera accentuates the effect).
Il giorno lunedì 28 agosto 2023 alle 09:57:35 UTC+1 jörg ha scritto:
Edit: GRID floating or at -40V and Brightness at full
On Monday, August 28, 2023 at 10:44:39 AM UTC+2 jörg wrote:
Hi Max,
first of all, congrats to be that far with your project.
I think you are very close to success.
Could you please measure your voltage between the NEG1200V and GRID.
It should be, for testing, about 0V. In Blanking mode it should be about -40V.
In David's schematic it is R11.
Measurement NEG1200V and GRID, so measure across R11.
If you see a negative voltage, try to disable blanking with BLANK high.
Or, just disconnect the GRID connection from the tube and connect it with a 20k resistor to NEG1200V.
You should see something like the picture attached.
In my setup, I see your described behaviour, if I have GRID floating (not connected) or constant at negative 40V.
I mean the over-blurred image.
![IMG01.jpeg]()
GRID floating or at -40V
![IMG02.jpg]()
GRID connected to NEG1200V via 20k resistor
On Monday, August 28, 2023 at 10:19:24 AM UTC+2 Grahame wrote:
It is an odd problem. I need to think a bit more. Unfortunately I
don't know David's software so I can't help with the draw
factors...
Grahame
On 27/08/2023 20:23, Max DN wrote:
Hi,
With the previous transformer I couldn't get a single focused
dot, only a small flat line. Changing with anode2 voltage would
move the dot left or right too (while all 4 deflection plates
where connected to A2). Very odd.
With new transformer and with the astigmatism set midway and
minimal brightness, the focus produces an even focus across the
travel range (expect the far ends, of course).
I have connected the 4 deflection plates to the final
acceleration anode, and the spot isn't really focused. I changed
the voltage on the astigmatism trimmer and I got a very focused
dot. When I switch back to run the full code, the screen is
blank and I can only see the picture if I increase brightness,
which would then lead to a dot having a ring around it, hence I
cannot get a focused picture.
I'm thinking that it may have something to do with glow
delays etc. Any suggestions on best timings please? I'm using a
3RP1A CRT.
I have played around with these parameters, with only minor
improvements if I increase 'glowDelay' slightly (which is odd,
as David uses this same CRT with these parameters):
const int motionDelay = 15; // how fast the beam will get there
before enabling
const int settlingDelay = 8; // let the beam finish its move
before turning on
const int glowDelay = 2; // usec to wait for beam to get
bright before moving [slightly better / brighter picture at 5]
const int circleSpeed = 200; // angular step; bigger makes
circles draw faster and more coarsely [slightly better picture at
150, worst/unstable at 100, not even focus/brightness across the
range at 200]
const int lineStride = 1; // linear step; bigger makes
lines draw faster and more coarsely
DAC update rate is about 1MHz on Teensy 3.6
Il giorno domenica 27 agosto
2023 alle 16:36:19 UTC+1 Grahame ha scritto:
Hi
I should have asked, I had assumed you had modded the
code.
It is a surprise that the transformer affected only the X
axis.
With the astigmatism set midway and minimal brightness,
does the focus pot produce the best focus at one end, or
at some point inside the travel range?
If you connect the 4 deflection plates to the final
acceleration anode, can you focus a really good spot?
Grahame
On 27/08/2023 14:21, Max DN wrote:
Thanks for your suggestions,
Grahame.
I just made a new transformer (a bit of a tricky one
to make given the many secondaries) and I no longer see
a double picture. However I cannot manage to get a sharp
and well focused picture either, no matter how I change
the potentiometers.
Nothing like the very neat picture of the scope clock
that I purchased from you a while back.
I'll keep on trying. The code should be fine, it's
the same that David Forbes posted for the clocks he
sells. I wanted to build this clock to learn about CRTs
in a clock and I like the compact design.
Il giorno domenica 27
agosto 2023 alle 12:46:56 UTC+1 Grahame ha scritto:
Hi Max
To me its not a PSU problem as it is one one axis
only. The deflection amplifiers are identical and
swapping their X and Y inputs shows they are not
the problem.
It seems to me that the problem is back in the
DACs or the code, that the X DAC (originally) is
drawing the image in one position and then drawing
it displaced slightly in another, perhaps one
refresh later.
If you try your scope in XY mode, then I find the
images are not very good on digital scopes or at
least the cheap ones I have access to :^( I have
an old analogue CRT based scope for when the
(cheap) digital one struggles.
Grahame
On 27/08/2023 12:35, Max DN wrote:
Hi Grahame,
Those are the images that I actually see with
my eyes, the camera is capturing it as I see it.
Nothing changes when I rotate the tube, only
the X-Y centers seem to move, which is fine and
it's easily adjusted.
I tried shielding the CRT, no change. No
other magnetic fields that I can tell other than
earth.
I switched X and Y DAC output pins from the
code, the issue persists (picture transposed and
issue is vertical as opposed to horizontal, 3rd
picture bottom right of the photo attached).
I didn't occur to me that the oscilloscope
has an XY-mode. I tried but cannot tell for sure
if the DAC outputs are ok, perhaps I don't know
how to get a crisp picture on the oscilloscope
(I'll look the manual).
I am using a switching power supply to feed
the whole circuit and the Teensy is receiving a
+5 from a rectified output of the same
transformer that also provides +250VDC to a
multiplier chain. If the issue was badly
filtered power, I should see a very noisy
picture, I'd assume. Instead of two sharp
pictures almost overlapping. Somehow how don't
seem to be able to balance focus vs astigmatism.
Il giorno
domenica 27 agosto 2023 alle 10:42:38 UTC+1
Grahame ha scritto:
Hi
Is that image of the face - showing the
image offset twice in the X direction only
- what you see with your eyes or is it a
camera artefact?
If it is real, what happens when you
rotate the tube?
It is interesting that it seems to occur
in the X direction only. If you feed the X
and Y data from the DACs into a scope in
XY mode do you see a good image or this
offset one.
Do you have any strong alternating
magnetic fields near by? example soldering
iron base station...
Grahame
On 27/08/2023 01:31, Max DN wrote:
Ok, I'm back. Been
busy with work.
I managed to purchase a Teensy 3.6
and I have the scope clock running. For
some reason, I am not able to get a
crisp picture, no matter how much I try
to balance focus vs astigmatism vs
brightness.
Could it be that my hand-wound
transformer is creating some noise? It's
quite a complex transformer (at least
for me). I guess I could check the
voltages with the oscilloscope but I
worry that I accidentally put 1200V on
the oscilloscope. I'm using the
schematic published by David at Cathode
Corner, I built the transformer by trial
and error. For the heather I'm using a
stabilised 6.4VDC using a
buck-converter, which I thought should
help, but no!
Any suggestions on how to stability
the picture? Attached a couple of
photos.
Il
giorno lunedì 10 luglio 2023 alle
16:54:15 UTC+1 gregebert ha scritto:
Sounds
like the CRT-related stuff is fine
(congratulations, BTW), and you have
issues with the DAC. Have you checked
the linearity of the DAC ? The best
way to start is to run all DAC codes,
starting from 0 and incrementing to
the top, and verify the waveform is a
stair-step. I suggest leaving each
value for about 10usec to allow more
than enough time for the DAC and
amplifiers to settle. Which DAC are
you using ? My only experience is with
8-bit parallel-input DACs, and I had
no problems with it (ADCs, on the
other hand, are a different
story....). If you see erratic
behavior, post the findings and we can
figure out next steps.
If the DAC is operating
correctly, then my first suspect is
the range/offset of your DAC. You
might not be able to drive it
rail-to-rail due to the design of
the level-shifters/deflection amps.
In that case, try to narrow-down the
range where the DAC is driving the
CRT as-expected.
On
Sunday, July 9, 2023 at 3:42:21 AM
UTC-7 Max Di Noi wrote:
Hey, Adrian, let
me knew if you find that Teensy
3.6.
I'm not having
much luck with a teensy 4.1 +
external DAC using SPI. Nor I
can see any issues at all in
the code.
The connections
are simple enough but it
cannot draw a circle (as a
test) on my CRT using the open
source code that Cathode
Corner published. Indeed, when
I test the DAC output on the
oscilloscope looks irregular,
whereas the SPI lines seems to
behave as expected. Odd.
If I input two
sine waves into the deflection
amplifiers using my signal
generator, then I can get a
circle on the CRT, that proves
that power supply, level
shifters and deflection
amplifiers should be fine.
-------- Original message
--------
Date: 10/06/2023 17:17
(GMT+00:00)
Subject: Re: [neonixie-l]
ScopeClock with teensy4.0
I think I have an
unused teensy 3.6.
It may take some time to
track it down but I'd
happily swap it for a 4.1 if
that simplifies things for
you.
Here is the schematic
of the SCTV rev E, which
uses the Teensy 4.1.
Thanks for your
prompt reply David.
I have already
printed my board for
a Teensy 3.6. I have
no issues soldering
tiny smd components
assuming that I can
get an LTC22632! I
may design a small
PCB to super-impose
the Teensy 4.1 over
the existing
footprint and
layout. In doing so,
I could add the dual
DAC on this new
adapter board. I can
see CS is connected
to pin10 but where
are CLK and SDI of
the LTC2632
connected? I don’t
see them in the
code. Yes, It would
be great if you
could post diagram
for SCTV-E for
Teensy 4.1 please.
Interesting that
you are redesigning
the transformer. I
managed to hand-wire
mine and seems to
work well. The 6.3V
for the heater is
the one that I’m not
too sure how to
calibrate exactly,
since the SMPS… It
shines a bit too
bright at the moment
and voltage drops to
2V, so that’s not
healthy for the
heater filament. I
can remove a few
turns but not sure
what is the ‘exact’
RMS V I’m looking
for given the spikes
of the SMPS at
100Khz, I’ll
continue to
experiment on that
using a 6.2V 500mA
lightbulb to avoid
damaging the CRT.
Thanks again for
updating the
schematic when you
get a chance, it’ll
save me so much time
to experiment.
Hi.
The SCTV with
the Teensy 4.0
uses an
LTC2632 dual
DAC. This uses
SPI to load
the X and Y
values. It's
about half the
update rate of
the built-in
DACs in the
previous
Teensy 3.6, so
I had to
change the
step size in
the drawing
routines.
Unfortunately
this chip is
tiny, so it's
hard to
solder.
I
am in the
process of
redesigning
the
transformer
and circuit
board to be
more friendly
for kit and
DIY use. I
want to make
the PC board
with through
hole parts,
since people
enjoy
soldering
those
together.
I
will see if I
can post the
latest SCTV
schematic
diagram to my
website today.
I've been
traveling a
lot lately.
True, but the schematic is SCTV rev. C which is for
Teensy 3.6.
Does anyone
have the
schematic for
using Teensy
4.1? Just
designed a
clock based on
SCTV-rev and
custom
transformer
but of course
I have now
realised that
Teensy 3.6 is
impossible to
get...
Il
giorno sabato
11 marzo 2023
alle 18:41:05
UTC SD ha
scritto:
David Forbes has the schematic on his website, and
the firmware
on Github. I
did not see
that Jörg was
making kits,
in fact he
said he didn't
want to make
kits, but
perhaps make a
PCB available,
so I do not
know why
people are
asking for
kits.
On
Friday, March
10, 2023 at
3:42:49 PM
UTC-5 liam
bartosiewicz
wrote:
The
schematic and
software would
be good enough
for me,
personally
I
also have some
interest in a
kit
On
Friday, March
10, 2023 at
10:00:11 AM
UTC-5 Richard
Arndt wrote:
Yep... put me down too for a Scope Clock kit of
parts :-)
Making the H/W
& S/W open
source would
be cool too!
I think
selling PCB's
& parts in
kit form
without
enclosure,
places FCC
requirements
on the user to
not cause RF
interference.
Isn't that how
SparkFun and
Adafruit can
sell assembled
PCBs without
FCC
certification?
On
Thursday,
March 9, 2023
at 9:19:56 AM
UTC-5 Paul
Andrews wrote:
Do
you plan on
publishing the
software (on
GitHub for
example)?
The
tube is a RFT
B7 S4-01
It‘s
from an EO174A
Oscilloscope.
Nice
green and
pretty good to
focus and
linearity to
the edges.
I
do not plan a
kit or selling
like david
forbes do.
First of all,
it is
initially his
design and
software.
Second, I do
not have the
will and time
to go through
all the
regulations
EU/Germany has
for selling
such
electronics.
I
could share
the PCB if I
order the
next batch,
but it is not
finished, yet.
I
plan to add
ESP32 for NTP
and web
config.
On
Sunday, March
5, 2023 at
8:02:28 PM
UTC+1 Nicholas
Stock wrote:
Definitely
not off-topic!
I think
everyone on
this forum
appreciates
that post,
well done. I
really like
the starfield
effect. What
tube were you
using? Looks
like it has
very good
linearity
across the
whole
screen....
Cheers,
Nick
Hi !
Really
interesting
and great
work. Looks
really good
and its a
„want to
have“.
Would be
interested in
pcb and code
too , if
possible a kit
too.
Thank
you.
Michail
Wilson schrieb
am Samstag, 4.
März 2023 um
15:11:01
UTC+1:
I
am very
interested as
well.
Would
love to have
the code and
pcb design and
even a kit.
I
read through
the posts, but
didn’t see
anything other
than the
video.
Thumbs up on
it too. 😊
Michail
Wilson
206-920-6312
yes, I will
share the
code. I have
moved it to
the VS Code
IDE with
PlatformIO. I
do not like
the Arduino
IDE much. It
should run on
david's
hardware, too.
Do yo you have
build the
hardware
already?
On
Friday, March
3, 2023 at
5:12:46 AM
UTC+1 David
Forbes wrote:
I
was able to
change to a
Teensy 4.1
with a 2
channel 12 bit
SPI DAC in my
latest
version. I had
to reduce the
DAC rate by
half. It looks
just as good
as the old
version. Of
course, the
DAC I chise is
already
unobtanium.
Hi, maybe a bit offtopic.
I've put some
effort in
using the
teensy4.x to
run the scope
clock based on
david forbes
one.
The teensy3.6
based one is
running on my
own hardware
for a while.
But because of
CPU shortage
and the use of
the teensy3.6
internal
DAC's, I was
curious to get
the stuff up
and running on
the faster
teensy 4.x
CPU.
In this
approach I'm
using a
parallel
driven 12 bit
4 channels
DAC. The usage
of a serial
DAC was too
slow and I did
not get DMA up
and running on
teensy4.x.
Anyway, this
works and I
like it.
Video: https://youtu.be/HYwgyYnQUxw
--
You received
this message
because you
are subscribed
to the Google
Groups
"neonixie-l"
group.
To unsubscribe
from this
group and stop
receiving
emails from
it, send an
email to neonixie-l+...@googlegroups.com.
--
You received
this message
because you
are subscribed
to the Google
Groups
"neonixie-l"
group.
To unsubscribe
from this
group and stop
receiving
emails from
it, send an
email to neonixie-l+...@googlegroups.com.
--
--
You received
this message
because you
are subscribed
to the Google
Groups
"neonixie-l"
group.
To unsubscribe
from this
group and stop
receiving
emails from
it, send an
email to neonixie-l+...@googlegroups.com.
--
You received
this message
because you
are subscribed
to the Google
Groups
"neonixie-l"
group.
To unsubscribe
from this
group and stop
receiving
emails from
it, send an
email to neonixie-l+...@googlegroups.com.
To view this
discussion on
the web, visit
https://groups.google.com/d/msgid/neonixie-l/2a132d1e-a9de-47a0-bbfd-4d2bb62f4c75n%40googlegroups.com.
--
You received
this message
because you
are subscribed
to the Google
Groups
"neonixie-l"
group.
To unsubscribe
from this
group and stop
receiving
emails from
it, send an
email to neonixie-l+...@googlegroups.com.
To view this
discussion on
the web, visit
https://groups.google.com/d/msgid/neonixie-l/CAPbqtveDqghW5iOyBAeuj1gZJ2RfXyYhX0%3DMpCH9%3DgG4b2Q4Ng%40mail.gmail.com.
You received this
message because you are
subscribed to the Google
Groups "neonixie-l"
group.
To unsubscribe from this
group and stop receiving
emails from it, send an
email to neonixie-l+...@googlegroups.com.
To view this discussion
on the web, visit https://groups.google.com/d/msgid/neonixie-l/67621F9A-A7FD-4414-9E92-51574D45C3A9%40gmail.com.
--
You received this message
because you are subscribed
to the Google Groups
"neonixie-l" group.
To unsubscribe from this
group and stop receiving
emails from it, send an
email to neonixie-l+...@googlegroups.com.
To view this discussion on
the web, visit https://groups.google.com/d/msgid/neonixie-l/CAPbqtvcD%3DtpJi7hJjcMi1kF7zna48z4M050QXTBetWMOXB6DYA%40mail.gmail.com.
--
You received this message
because you are subscribed to
the Google Groups "neonixie-l"
group.
To unsubscribe from this group
and stop receiving emails from
it, send an email to neonixie-l+...@googlegroups.com.
--
You received this message because you are
subscribed to the Google Groups
"neonixie-l" group.
To unsubscribe from this group and stop
receiving emails from it, send an email to
neonixie-l+...@googlegroups.com.
--
You received this message because you are
subscribed to the Google Groups "neonixie-l"
group.
To unsubscribe from this group and stop receiving
emails from it, send an email to neonixie-l+...@googlegroups.com.
--
You received this message because you are subscribed to
the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails
from it, send an email to neonixie-l+...@googlegroups.com.
--
You received this message because you are subscribed to the Google
Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it,
send an email to neonixie-l+...@googlegroups.com.
--
You received this message because you are subscribed to a topic in the Google Groups "neonixie-l" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/neonixie-l/rjislNgmNS0/unsubscribe.
To unsubscribe from this group and all its topics, send an email to neonixie-l+unsubscr...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/7c6c638a-b3ed-4694-ac85-d3d17f9c8f0bn%40googlegroups.com.
--
You received this message because you are subscribed to the Google Groups "neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/F5FBC055-6A9C-4C3A-81DC-D61480DFBF1B%40gmail.com.
|
