Modeline 405 line Monitor

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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sun Jun 19, 2022 11:29 pm

I have the horizontal scan up i am going to need a position control to work out the amount the correct adjustment to the 5 ohm resistor .
Also will be experimenting with the 2 capacitors on the input and yoke coil
Scans about 10 khz as i will be trying 405 line first when i get the raster correct
I am only using the push push power transistor end part of the 2 deflection circuits ,i just found i was getting better results screen size with a different circuit .
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Last edited by Harry Dalek on Fri Jul 08, 2022 4:26 pm, edited 1 time in total.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Thu Jul 07, 2022 2:18 pm

Well pretty much where i am up to shown here , i had a bit of trouble with getting the deflection amplifiers to work above a small raster size so looked into making it work .
i know i could ask but i wanted here to work it out this side of it my self and i am in no rush .
I think i can get close to full screen now increasing the value of a 100 ohm resistor across the horizontal deflection coil either way i am happy with results so far .
Testing around 405 line rates 10 khz 50 hz .



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Re: Modeline 405 line Monitor

Postby Harry Dalek » Fri Jul 08, 2022 4:21 pm

Bit more work on the monitor today, i was right about the resistor across the Horizontal deflection coil that's now given a full screen image ,its a bit touchy as the H size control variable resistor is the wrong value at 10k ,1k or 500 ohm would be a lot better the control need to be set about the 100ohm range .


Any case also looked into syncing today and was able to sync the H and V but have not tried it at the same time as i was working out what was need to hook the circuit up with out it effecting ramp.
I am looking into modulation of the control grid or cathode more than likely use same circuit as SSTV and Thylacine monitor so a few more things to look into before a 405 line image .
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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.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat Jul 09, 2022 4:51 pm

Today i have synced the monitor to the PC modeline 405 line scanning rates and swapped over to my original EHT supply sitting in front of the CRT here i was trying a bug zapper and variable supply to it just seeing what works better ,the fly back transformer is a touch more noisy positioning and blanking might fix that .
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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.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat Jul 16, 2022 6:04 pm

Well a little step forward and back in a way swapping to cathode modulation my raster shrinks but easier to modulate it seems with this tube.
I swapped horizontal deflection connections between the videos and voltage adjustments .
Even so the CRT is show up side down ! i just can't turn it at the moment and the yoke is glued in place from the factory



What you are seeing is 405 line mode line setting it had me stumped for a while why i was just getting part of the screen showing where as the 625 line mode line setting is full screen then i had a look at the settings in green that made sense ! in 405 line or this version of mode line part of the screen is just used to what it can do in its graphic card windows settings settings .
Well that's the reason i selected the clock as a subject !
So bit over the place just seeing now what i can and can't do what to tackle next onit as you can see a fair few things need working on. Magnetic deflected CRTs are easy to get going as far as the electron gun go's but very much harder on the deflection side than a electrostatic deflected tube well for me any way !

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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.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Thu Jul 21, 2022 10:02 pm

Bit more progress today ,i still have a worn trimmer in the size control for H i have to replace .
Blanking would be nice ! i need to look into .
Need to also invert the video, and the crt is up side for work on the deflection yoke connections /
I did hope to make this work on other systems but looks like this idea would be better for a larger electro static tube
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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.
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Re: Modeline 405 line Monitor

Postby acl » Fri Jul 22, 2022 6:30 pm

Looking good Harry.

Regards Chris Lewis
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat Jul 23, 2022 8:33 pm

acl wrote:Looking good Harry.

Regards Chris Lewis


Thanks Chris
i have to invert the video to it and am thinking those retrace lines or oscillations will disappear if and when i do this i tried some blanking but still there a bit really need to invert the video to see for sure .
Got this rotten covid my luck ! does not put me in the mood to do any thing but get back to it when i feel better .
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.
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Re: Modeline 405 line Monitor

Postby Steve Anderson » Sun Jul 24, 2022 12:02 pm

Harry Dalek wrote:Got this rotten covid my luck ! does not put me in the mood to do any thing....

Oh crap! I hope a speedy recovery...I too lose all interest in doing things, whatever the ailment is when sick.

Steve A.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sun Jul 24, 2022 6:21 pm

Steve Anderson wrote:
Harry Dalek wrote:Got this rotten covid my luck ! does not put me in the mood to do any thing....

Oh crap! I hope a speedy recovery...I too lose all interest in doing things, whatever the ailment is when sick.

Steve A.


Well for me its like a cold and Coughing and a bit of aching its really strange how it comes and go's ,i got the 3 shots over the last few months the family all got it also apart from my youngest son William and so far so he might be lucky if we are careful .
Will get back to this when i can i also can't work on it as its in a room where William has he's play station we don't want to infect him
Thanks Steve i will be back !
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.
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Re: Modeline 405 line Monitor

Postby murphyv310 » Mon Jul 25, 2022 5:01 am

Hi.
I've now got this to work using a Dell Optiplex 780 with an ATI Radeon 2400 XT graphics card and Windows 10. All is well with the results bar one problem, the aspect ratio is wrong, when I slide Google across for example it's too big and I can't see the sides, same for YouTube until you select a video in full screen and then it's not too bad.
I'm not the most computer literate and was gobsmacked when after a few hitches it worked. The picture quality is awesome to be honest, I'm using an EX ITV test transmitter (fancy name for a high quality modulator). Any help would be greatly appreciated.
Cheers Trevor.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat Jul 30, 2022 3:29 pm

murphyv310 wrote:Hi.
I've now got this to work using a Dell Optiplex 780 with an ATI Radeon 2400 XT graphics card and Windows 10. All is well with the results bar one problem, the aspect ratio is wrong, when I slide Google across for example it's too big and I can't see the sides, same for YouTube until you select a video in full screen and then it's not too bad.
I'm not the most computer literate and was gobsmacked when after a few hitches it worked. The picture quality is awesome to be honest, I'm using an EX ITV test transmitter (fancy name for a high quality modulator). Any help would be greatly appreciated.


I think you fixed this problem via another forum Trevor ,but its pretty good what it can do with this video card just show others here what it can do and what you are using it for .

youtu.be/5B0NXuJSRi4
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.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat Jul 30, 2022 4:51 pm

Felt better today after a week of Covid first chance to look into having a go at tinkering again .
I have inverted the video now and i can see the lines on the screen are due to flyback as i at times can get rid of it just with a feed back capacitor, its a bit harder to do here from inverted so i will have to look into it again .
Line linearity is not to bad with no feed back from the deflection amplifier ,and well its my first go at a higher line rate monitor i suppose one of the newer 405 line monitors these days :lol: who says every thing gets better in time !
I am glad i didn't try to mount it in a case i will use this more than likely for research into and for a MK 2 make it a bit neater ,the circuit board ended up a bit messy for my liking ,its always the way when you have an idea but its all experimental ...i will see if i can do better .

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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.
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Re: Modeline 405 line Monitor

Postby Steve Anderson » Sat Jul 30, 2022 5:24 pm

Harry Dalek wrote:Felt better today after a week of Covid

Good! Those here that I know and have had it have recovered generally in the same time-frame...

Harry Dalek wrote:...the circuit board ended up a bit messy for my liking ,its always the way when you have an idea but its all experimental ...i will see if i can do better .

...that's always the case with first-builds or prototypes, often they descend into a mess due to changes/improvements, or "Opps. I dropped off there!" (A mistake). Get it electrically as you want it first, then 'tart it up' to look nice if that bothers you or you want to use it long-term, i.e. reliability. And document it so it can be easily understood and reproduced again by you or others.

Trying to reverse-engineer something you did a while ago is a headache! "Now why did I do that?" "What's that thing for?"...and so on...

This particularly applies to those who write software. If I write something without commenting it and I come back to it a while later it's generally quicker to re-write the whole thing again, with comments this time. Needless to say I perhaps over-comment these days, but boy, it's a life-saver! Similar to the way I add blue 'notes' to myself in my schematics during development. That's if you use a PC to create schematics, I haven't hand-drawn one since perhaps the 80s...

There are many free PCB applications which first require you generate a schematic, then generate the PCB layout and so on. Learn how to generate the schematic and stop there, assuming you're not going to make a PCB. Changes are so easy, and others can edit the files too. I don't use any myself, but I may have a go at Ki-CAD soon. Plenty of on-line tutorials for it and it generates Gerber files that the PCB house needs for manufacture if you wish. But the schematic is maybe the most useful part...

It (or anything similar) requires investment in terms of time to learn, but soon you realise it's worth it!

'Eagle' is perhaps the most used PCB design software professionally, but it is geared towards Hi-End applications, e.g. multi-layer PC motherboards and thus (to me anyway) has quite a steep learning curve. There is a free but limited version if you want to give it a go. But to me Ki-CAD seems an ideal starting point...this is not a commercial (again)!

...off-topic (yet) again!!

Steve A.
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat Jul 30, 2022 9:40 pm

Steve Anderson wrote:Good! Those here that I know and have had it have recovered generally in the same time-frame...
...that's always the case with first-builds or prototypes, often they descend into a mess due to changes/improvements, or "Opps. I dropped off there!" (A mistake). Get it electrically as you want it first, then 'tart it up' to look nice if that bothers you or you want to use it long-term, i.e. reliability. And document it so it can be easily understood and reproduced again by you or others.




HI Steve bit of a 2 part problem on this project first needed the video signal in the first place then something to view it on ,its as always a bit of Your circuits and bit of Klaas on the deflection amp ,i stick with what i know and bit of this and that like using the LM1881 for the which handles 405 sync fine it seems ,so a bit tacked together sections at that work well enough to get some thing up in Sync .

I really dislike magnetic deflection but its something to tame in my head i rather the electrostatic as so much easier to behave and control ,but its the price you pay for using these types of tubes .

Trying to reverse-engineer something you did a while ago is a headache! "Now why did I do that?" "What's that thing for?"...and so on...


All the time Steve ,its nice to have the schematic even better to have a copy working circuit but i am the same what i did gets lost in about a month dam that unwanted self erasable memory in my head ! :( glad its not just me !

Back to this i am pleased with results its not 100% but not made one before so an ok first try i wonder how it will go the second time ,don't have to make the power supply and have a easier idea of what to use or change .
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.
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