Frame Sequential Cathode Ray Tube Project

Centralised area for notes about construction projects. Each project has its own sub-forum. In the sub-forums will be topics relevant to parts of that project (e.g., there might be a topic on CRT problems). If you start a construction diary, just post in the forum with your project name as the topic, and a moderator will create a sub-forum for your project.

Moderators: Steve Anderson, Dave Moll, Andrew Davie

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Fri Aug 31, 2018 10:06 pm

A chat with Gary i now understand whats happening with 400hz FSC 3 colour frames one after the other at that line rate so a bit of flicker on that one .
All the FSC systems on Video2NBTV being all experimental and for Gary more a personal experiment we have to be grateful to Gary letting us experiment with them in the first place.
A 1.2 khz system version as been made for me so i don't have to change any thing constructed really so big thanks to Gary for the help here .
download.wav
(30.37 MiB) Downloaded 57 times


So with that cleared up i have nothing really at the moment to view the 1.2khz line rate 12,5 hz frame rate FSC on .
PC wise so far apart from off line rate on B/w software seems to give best results on 48 line on Doms viewer as in i can see the the red blue and green frames one after the other i suppose .
man2_gif.gif
man2_gif.gif (45.85 KiB) Viewed 1403 times


I have been working on the the sync part of it bit more now circuit below using a Lm567 tone decoder, the Klaas and Steve's reworking of the sync slice circuit works fine as it is for 400 hz and seems to up to 3.6khz but to clean it up and use the higher line rate pulse i am using a 567 a reworking of this circuit for only 400hz .
The results seem fine ,but i do have to switch the capacitors on the 567 to change the working frequency range as expected .

I did run both circuits on 5 volts so far not 12 5 as shown so need to test that next my mistake on the circuit
Screen 00002.jpg
Screen 00002.jpg (9.5 KiB) Viewed 1403 times
Attachments
addtext_com_MDY1MDAxMzU2MDI.jpg
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Thu Sep 06, 2018 2:49 pm

I had a rather good small computer case i forgot about and looking into my lack of circuit board space i am Repurposing it here for this monitor ..good part the PSU is works i can make use of that .
The voltages for the tube its self the Trinitron i know the where abouts but what i make will have to be adjustable to take that into account not having a data sheet .
Television-Servicing-UK-1989-04-OCR-Page-0016.pdf
(30.15 KiB) Downloaded 50 times

Anode 1 needs something from 200 to 800v i will do this with another inverter up to 1kv i have a few 200v AC out handy i can use here to step up ..i do have a 1kv winding on one transformer i have handy to but rather not use it here ..think that was for a neon laser
Screen 00064.jpg
Screen 00064.jpg (34.06 KiB) Viewed 1377 times

For any one interested sorry its taking a while it will speed up soon as i have the power supply hooked up to the CRT having room and easy access to the boards does make more sense than having to pull every thing to bits to get a trimmer somewhere so it may not be beautiful it is practical :wink:
Attachments
DSCN6322.JPG
DSCN6322.JPG (135.36 KiB) Viewed 1377 times
anigif.gif
anigif.gif (619.27 KiB) Viewed 1377 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Tue Sep 11, 2018 9:11 pm

Been working on the power supplies ,having the PSU cuts a bit of that out .
Attachments
IMG_0011-crop.JPG
IMG_0005-crop.JPG
IMG_0006-crop.JPG
Last edited by Harry Dalek on Sun Sep 16, 2018 9:53 am, edited 1 time in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Fri Sep 14, 2018 12:42 pm

I didn't have much space in my original case and so didn't use its colour crt fly back transformer or look into it due to its size , at this point powering the CRT i have looked into it now and it seems silly not to use it as i can use the focus and screen voltages and the on board pots to control this .
So yesterday i knocked up a new power supply with it .
Just testing it below more for finding the transformers ground pin which it will spark to...so next will take some voltage readings .

Just using the idea on the right of the circuit ,they sort of use all the same idea on the secondary /
Attachments
MVI_0017_x264.mp4
(1.86 MiB) Downloaded 230 times
HT1uvphFQFcXXagOFbXD.jpg
HT1uvphFQFcXXagOFbXD.jpg (86.96 KiB) Viewed 1307 times
IMG_0012.JPG
Skema FA001wJ.jpg
Last edited by Harry Dalek on Sun Sep 16, 2018 9:49 am, edited 1 time in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Sun Sep 16, 2018 9:46 am

Good information as to what the extra red and grey HV wires are on the fly back Transformer good to know which is which.
redgreywires.jpg
redgreywires.jpg (94.65 KiB) Viewed 1291 times

I tested the the colour flyback transformer with a variable supply even with the HV probe its off range after 16kv so that's good ..i will have it on a variable supply so i can adjust it from low range to the CRT's operating range.
I finished hooking up the CRT plug ,i studied the video amplifier red green blue video amplifiers and i think i can use them as is with some slight modifications so that's good see how it go's.
So apart from the Heater all that's done ,mounting this EHT board in the case next ..then that's done out of the way .
Attachments
IMG_0018.JPG
IMG_0028.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Mon Sep 17, 2018 6:21 pm

I powered up the ZVS flyback driver to the crt today and pretty much repeated the original tube test i have better focusing this time,,,Still haven't got to mounting the deflection amplifier power transistors so just used the 50hz 6 v AC to the horizontal and vertical deflection yoke coils .
Getting there :roll: i am happier i can light up the tube ,even so focusing still needs some work .
Attachments
IMG_0032.JPG
IMG_0037.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Sun Sep 23, 2018 8:16 pm

Worked out the CRT supply now have focus and brightness control.
Not having worked on one of these tubes before learning as i go so i have to stop and think about whats happening on this tube stage every now and again .
i am seeing the 3 guns mixing the red green and blue to white light but the cathodes are all hooked up via the video amplifier collectors and adjusting some voltage evenly via them to get the electron guns to work ,the video amplifiers are very similar to Klass's SSTV version dual supply video amplifier .
Any case i was just interested to light the tube up under control at this stage .
The first video is EHT control i can see the colour lines are crossing each other not a dead R G B lines aperture grille as in the picture
180px-CRT_Phosphors.jpg
180px-CRT_Phosphors.jpg (6.21 KiB) Viewed 1248 times

below top picture is a shaow mask round holes then the tritron colour strips via a aperture grille
trinitron-mystery-popular-electronics-february-1972-3_small.jpg
trinitron-mystery-popular-electronics-february-1972-3_small.jpg (20.51 KiB) Viewed 1242 times

Screen 00073.jpg
Screen 00073.jpg (35.57 KiB) Viewed 1242 times


here is some control of brightness via the cathode side i mentioned the line is better focused to the eye than the camera does look thicker as the brighness is increased the over lapping being off does not help either rings on the tube neck might need and adjustment but not touching that yet .,
Attachments
MVI_0044_x264.mp4
EHT power supply regulator
(4.34 MiB) Downloaded 206 times
MVI_0045_x264.mp4
cathode control so far
(2.08 MiB) Downloaded 184 times
Screen 00072.jpg
Screen 00072.jpg (39.24 KiB) Viewed 1248 times
DOTPITCH.GIF
DOTPITCH.GIF (5.63 KiB) Viewed 1243 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Success and failure at the same time ....OH NO

Postby Harry Dalek » Wed Sep 26, 2018 6:45 pm

I had time to work on hooking up the defection amplifiers and got that going ,the scan coils are the wrong way around for vertical scanning any case happy with the first results here .
120 line below or close i forgot if i had frame rate on 10 or 12 hz
IMG_0064.JPG

IMG_0077.JPG

Below switching the line rates

Testing frame rates 10 12 hz below


Now for the bit i never wanted to happen ~! :oops: I obviously had EHT to high and on switching the monitor off the deflection circuits turned off quicker than the beam and i have raster burn i am devastated ! not like i have another one ..well not this size .
It does not stop it working but like any nasty accident a permanent reminder ...just have to live with it and keep on going with it
IMG_0109.JPG

IMG_0106.JPG
Attachments
MVI_0055_x264.mp4
(4.28 MiB) Downloaded 181 times
MVI_0080_x264.mp4
(8.23 MiB) Downloaded 190 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Sat Sep 29, 2018 7:47 pm

A little more work on this afternoon putting circuits boards back neatening wiring up, best i got out of the deflection circuit i will look more into this later on .
I found out you can't turn the deflection yoke as on a B/W tube due to the R G B line aperture grille it throws them all off so the colour mixing doesn't seem to work as well looks bad in any case if you try .
Knocked the eht voltage way down in pictures below one mistake is bad enough with this tube .
DSCN6376.JPG

DSCN6380.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Sat Oct 06, 2018 8:34 pm

Today i looked into using the colour guns individually ,
anigif.gif
anigif.gif (118.28 KiB) Viewed 1143 times


Well this part is easy ,but i am finding modulating the beam a little harder ,i found 2 ways to switch the guns on and off but the second seems more promising where all 3 are on as a B/w mixed raster and adjusting a voltage to any of the guns will increase or decrease the that colour...the other way i found just switched the individual guns either on or off no level change possible ..May be it could be PWM this way but i am trying for the other way as i did on the last monitor .
DSCN6438.JPG
DSCN6438.JPG (103.54 KiB) Viewed 1143 times

Bench and boards are a bit of mess at the moment trying stuff out .
I tried modulating one of colour guns but my video amplifier does seem to be doing any thing i need to get my scope on the collector of one the transistors they are a bit hard to get to so i will have to leave that for another day...
Attachments
DSCN6405.JPG
DSCN6405.JPG (450.85 KiB) Viewed 1143 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Klaas Robers » Sun Oct 07, 2018 5:46 am

If you really want to do frame sequential colour, you could modulate the cathode(s) with the video signal and alternately switch off two of the three guns by placing a negative switching voltage pulse on two of the three first grids. I assume that the Trinitron has one common cathode for the three guns. If it has three separate cathodes you can connect them all three together. The advantage is that for a black and white signal you can leave all three grids in the "on"-state and you don't need the switching voltages. So you need only one video driver transistor circuit. The switching voltages are logical 0 - 1 voltages.
User avatar
Klaas Robers
Frankenstein was my uncle.
 
Posts: 1405
Joined: Wed Jan 24, 2007 8:42 pm
Location: Valkenswaard, the Netherlands

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Sun Oct 07, 2018 10:37 am

Klaas Robers"]If you really want to do frame sequential colour, you could modulate the cathode(s) with the video signal and alternately switch off two of the three guns by placing a negative switching voltage pulse on two of the three first grids.I assume that the Trinitron has one common cathode for the three guns.


Hi Klass the Trinitron tube has 3 separate Cathodes and a common control grid
trinitron-mystery-popular-electronics-february-1972-4.jpg
trinitron-mystery-popular-electronics-february-1972-4.jpg (33.39 KiB) Viewed 1128 times


If it has three separate cathodes you can connect them all three together. The advantage is that for a black and white signal you can leave all three grids in the "on"-state and you don't need the switching voltages.So you need only one video driver transistor circuit. The switching voltages are logical 0 - 1 voltages.


Yes all 3 cathodes are separate and depending on which way i do it you can have as you mention a B/w raster or use the 3 guns one at a time ,the Frame Sequential switching part and such i have not used yet no point till i can modulate the cathodes or as i am trying to do just one till i know this works .
i am going to try and use your SSTV video modulation circuit as its work on the deep image SSTV and the Thylacine magnetic deflection monitor , but i am going to have to look into this if i can today whats happening here .
Last edited by Harry Dalek on Sun Oct 07, 2018 5:14 pm, edited 3 times in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Sun Oct 07, 2018 5:10 pm

At the moment on the crt plug board there still is the original circuit for cathode modulation with the 3 video amplifier transistors as shown below ...
ccrt2.JPG
ccrt2.JPG (153.37 KiB) Viewed 1124 times


Pretty much the circuit on the board below the 3 18k resistors on the positive are all connected up and same goes for the emitters 470 ohm no connection end they are not to ground so i thought it must be to a negative supply .

CCRT.jpg
CCRT.jpg (58.59 KiB) Viewed 1124 times


Power supply for the video amplifier transistor same as below 100 volts connected up it drops to around 57 volts .
I did try to see if i could use it as is and incorporate it your circuit Klass leaving the cathode 2.7k resistors ...the 18k is not to far off the 22k and i added resistance to the 470 ohm to bring that up ,i did notice a mistake i have made as that 470 ohm resistor is between the emitter and the 330 ohm resistor .
Screen 00078.jpg


Scope hooked up to the collector of the C2330 video amplifier transistors getting 4 volt waveform out only ,,,i will correct the circuit to the schematic and try again ...output seemed more due to the negative supply than the 100 volts as that could be adjusted lower with similar results but that's just what i am seeing circuit as is ...as in the sstv schematic always worked fine so more than likely my tinkering at fault .
Since i have no data for the tube at all its all experimental adjusting a voltage on the cathode from ground which seems beam is fully on and more towards the positive it should start to extinguish cut the beam if i am not mistaken ..an experiment to test the correct range is some thing would be good a correct procedure .
Also if i have not got the control Grid a correct voltage range i would think this would effect the results seen or over ride the cathode test ...
All i can do is try and jot down the results and see if there is a pattern to the correct path ,i must be close as i can at least bring up a display .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

Re: Frame Sequential Cathode Ray Tube Project

Postby Harry Dalek » Fri Oct 19, 2018 6:32 pm

Have not posted for a while but have been working on this but try as i might i had no luck on the crt modulation side yet ,noticed a resistor a 470k on the CRT board for G1 which i missed will remove .
i have rebuilt the modulation circuit so i am not stuck with cathode modulation via the CRT plug board circuit ,i am going to gut that .
I would like to see if the grid 1 works better and just switch the cathodes on and off later for the colour side , i just need to get the modulation side for a mono result going first which is more important for now .
So any one following i have not given up just trying to deduce my mistakes to zero ! :lol:
Added or moved the circuit to this board just make it easier on testing it before i do CRT testing again .
Attachments
33.jpg
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

A rethink

Postby Harry Dalek » Sun Nov 18, 2018 10:30 pm

Playing around with the scope tv i wanted to put together a analog circuit to do the same thing as the DAC and as i built it i thought i may as well see how it go's here as well .
Tested the new analog circuits just for the hell of it on normal NBTV and FSC on my scope tv 32 line FSC display on the scope in B/w of cause :wink:

The video switching rethought here for this ,slowed right down for testing below ...sorry about the kids noise back ground
Attachments
MVI_0620_x264.mp4
(1.36 MiB) Downloaded 47 times
Joined.MP4
(3.26 MiB) Downloaded 53 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
Posts: 3861
Joined: Fri Sep 26, 2008 4:58 pm
Location: Australia

PreviousNext

Return to Construction Diaries - Electronic Televisions

Who is online

Users browsing this forum: No registered users and 1 guest

cron