Modeline 405 line Monitor

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Modeline 405 line Monitor

Postby Harry Dalek » Sat May 14, 2022 4:55 pm

The idea behind say of a a 240 line or 405 line monitor is not so much the problems of making one but having some thing to display to it to make it work in the first place .
Once again modeline and a windows PC can ease the way into helping make one .
viewtopic.php?f=8&t=2548

In the above information you can see with the right video card you can output the video and separate line and frame sync for a home made 405 line monitor instead of using a mixed video with sync to a RF modulator to a old 405 line set which pretty much do not exist in my neck of the woods my idea is first make a monitor that uses the line and framing sync right from the pc video card ,make a video and sync separator later ,so much easier .

The whole idea comes down to first will my 2nd HDMi to VGA adaptor cooperate mode line says my newer Laptops Video chip is correct this is the 2 VGA ports taken care of .
Next will be with the modeline program output the correct wanted video system .

If that works it would be worth knocking together a monitor ,i can't use a old electrostatic tube do to the dot size is to large for coming system ,i have some magnetic tubes laying around so being able to do 625 line 405 will be fine for this project .
Now depends on how vintage we are going ? were the original 1936 405s television CRT tubes phosphor Green ,i have one of those handy not from the time but its phosphor is Green i will have a think about that one .
Always a way to do something not always the way you expect .
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 May 14, 2022 5:54 pm

If you have a laptop you can (maybe) make it a dual-screen system if it has an external (VGA/HDMI etc.) video output in addition to the in-built screen. My recently departed HP did, e.g. have Excel on one screen and Word on the other, the mouse cursor simply glides between the two screens.... I replaced it with a desktop PC with two HDMI outputs feeding two 23" monitors.

That's all fine and well. But, I very much doubt a PC can produce a 'true video' signal (405/525/625 etc.). Unless it's a specialised machine running some unique software/drivers. I could well be wrong, (I often am), otherwise why did so many people spend so much time in making standards converters for just such a use?

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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat May 14, 2022 9:00 pm

Steve Anderson wrote:If you have a laptop you can (maybe) make it a dual-screen system if it has an external (VGA/HDMI etc.) video output in addition to the in-built screen. My recently departed HP did, e.g. have Excel on one screen and Word on the other, the mouse cursor simply glides between the two screens.... I replaced it with a desktop PC with two HDMI outputs feeding two 23" monitors.

That's all fine and well. But, I very much doubt a PC can produce a 'true video' signal (405/525/625 etc.). Unless it's a specialised machine running some unique software/drivers. I could well be wrong, (I often am), otherwise why did so many people spend so much time in making standards converters for just such a use?

Steve A.


Had no problems with the dual Display that worked i haven't looked at the other computer yet but i think i have to adjust change the video chips frame rate from 60 to 50 hz this is one i am looking at is stuck on 60hz which makes the timing in modeline not possible i think for 50 25 hz systems .
I really am not sure Steve i can just see it works fine for 405 line ansd with modeline program 240 180 line also ,it has been mentioned in peter Scotts site its not perfect but can be adjusted to display
http://www.nostalgiatech.co.uk/Baird%20240%20lines.htm
Well thats the Question if it works why bother if not why are people using it ...i think it does come down to the video chip cooperating .
modeline editor below
http://www.geocities.ws/podernixie/htpc ... ne-en.html
The fellow below mentions every thing your thinking about price why cheaper
https://www.youtube.com/watch?v=ahzdx4KgWBg&t=2s
Attachments
Modeline 1708217.jpg
Modeline 1708217.jpg (48.64 KiB) Viewed 44 times
180 lines.jpg
180 lines.jpg (54.25 KiB) Viewed 44 times
Last edited by Harry Dalek on Sat May 14, 2022 9:15 pm, 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.
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Re: Modeline 405 line Monitor

Postby Steve Anderson » Sat May 14, 2022 9:14 pm

Well, it does seem that someone has spent a lot of time on this! What is not apparent at a quick glance is how it's done...

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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sat May 14, 2022 10:04 pm

Steve Anderson wrote:Well, it does seem that someone has spent a lot of time on this! What is not apparent at a quick glance is how it's done...

Steve A.


Well my limited knowledge the modeline program when you type in or copy paste a (a selected modeline into its program ) your video cards outputs it to which 2nd display you have selected . you then use this simple circuit to add the sync back to the new video signal of what ever system you programed into modeline ,the guys with old 405 line tvs feed this to a RF modulator then to their old 405 line television so the original idea .
Pretty easy to work out R G B video and V H sync
VGA.jpg
VGA.jpg (25.28 KiB) Viewed 42 times


Mode line was made for i think turning an old pc monitor into a old gaming system monitor varying systems they had over the years .

Some one worked out it could be used for this interest as well .
Does come down to using the correct video card but to experiment you never know unless you try .
Might get no where with this but worth a look .
https://www.mythtv.org/wiki/Modeline_Database
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 » Sun May 15, 2022 9:47 am

This was grabbed off another forum as is to explain the system converting idea .....................read below

Default Generating 405 line video using a Windows PC
I’ve started a thread in the appropriate part of the forum about the restoration of this Cossor 918

This thread is about how I generate the 405 line programmes you see displayed on it.
https://youtu.be/T2oNculjoQc

Kat Manton did some work about 10 years ago with selected nVidia graphics cards under Linux, Jim Beacon was involved with testing and demonstrating the result, the project, known as FOTH tv, certainly worked, but a decade has gone by and most enthusiasts still prefer to convert from one obsolete television standard to our even more obsolete (but well loved) standard.

Now I am not criticising the system converters such as the excellent Aurora (desperately trying not to step on anyone’s toes here), what I am saying is that having the ability to output any stored still or moving image or indeed live webcam, from a PC at 405 (or indeed any other standard) is no small thing.

Anyhow, I chanced on a comment here discussing the FOTHtv project
http://forum.radios-tv.co.uk/viewtop...t=1973&start=0

near the bottom of that page Michael Watterson says,
“Allegedly there is a Windows driver!” and a link to:
http://www.geocities.ws/podernixie/h...deline-en.html


Allegedly? I needed to know one way or the other!

I had lying around a Dell Optiplex 780 with Windows XP Pro and an empty PCI Express slot.
I also had, from another machine, a dual-head nVidia Quadro NVS 285 graphics adapter.
So I put the card in, and installed the latest XP driver from the nVidia website.

I am thinking, if this works, I can have my primary monitor on 1280x1024 or whatever I choose, and an “extended desktop” on the 405 line set!

So I made a VGA to composite converter by cutting a VGA cable in half and splicing in three resistors and a capacitor:
http://www.geocities.ws/podernixie/htpc/vga2video.gif
If your source material is in monochrome you can omit the 100R, 150R, 390R & 20R resistors. To be honest you can’t tell much difference even with colour sources, but purists will want the correct RGB matrixing.

So, with some trepidation, I pasted Kat Manton’s 405 “modeline” into the WinModelines window.


Modeline "405i50" 8.10 664 680 752 800 377 378 385 405 -hsync -vsync interlace


and connected my crude adapter output directly to the grid of the video output valve of my newly restored Cossor 916 (I have yet to build a VHF modulator)

THE SET WAS OF COURSE POWERED VIA AN ISOLATION TRANSFORMER AND THE CHASSIS EARTHED.

I selected my secondary display in WinModelines and, with a little trepidation, clicked the little arrow...

Well, knock me over with a feather, it worked immediately, after twiddling the Horizontal and Vertical holds I had the Windows desktop wallpaper 405 line High Definition (if not HD).

But it gets even better.
If you’ve watched my Youtube presentation it is clear there is something else going on,
And it’s this, Combitech VidBlasterX Trial
http://www.vidblasterx.com/ It’s a full featured TV studio and runs on my normal monitor and outputs to the secondary 405 monitor.

It must be pointed out that VidBlasterX Trial is free-trial software, not free software. The licence terms are here
http://videoblaster.com/vidblasterhe...Licensing.html

The free trial period appears to be defined by this sentence only:
“It is therefore essential to take advantage of the Trial edition (equivalent to the Studio edition with all its features fully functional) so as to ensure that VidBlaster is suitable for your particular application before purchasing.”


OK, I may well have had a little luck on my side, especially having a spare PC, and what turned out to be a suitable graphics card, but this project was easy, bordering on the trivial, and I am left wondering why something like this is not being more widely used to serve pictures to vintage TV sets, especially museum exhibits.

Work to do.
On the computer that I am typing this I have a similar dual-head card, an nVidia Quadro NVS 290.
No doubt that will work in the XP machine, but WinModelines will not work on this Windows 10 machine, nor could I make it work with Windows 7 pro 64 bit.

I need to have a VGA monitor connected to both outputs when the PC boots, in order that both ports are enabled. This is a bit inconvenient, so I need to somehow fool card that two vga monitors are connected at bootup when there is only one real monitor. I tried by connecting the DCC data and clock pins 12><12 and 15><15 together on the 15 pin VGA interfaces. It looked like it worked as two monitors were showing in the nVidia control panel, but closer examination showed that the phantom monitor was detected as DVI not VGA. I’m probably going about this the wrong way. Any ideas?


Graham.
G3ZVT
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 » Sun May 15, 2022 10:15 am

Asking Graham a while back on the pci cards that work with mode line
I initially had success with the nVidia Quadro NVS 285 under Windows XP
to get it working under Windows 7, I had to change the card to a ATI Radeon HD 2400 Pro.
The results on the 405 line picture were exactly the same in both cases.

They are dual monitor cards but most do that and what makes them different ? i think they are gaming video cards and so can be programed to odd rates ,you can really only go here with what others have used that works .

Edit well a ATI Radeon HD 2400 Pro on the way 30 bucks including the postage its an older card these days but worth it if it works .
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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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Harry Dalek
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Re: Modeline 405 line Monitor

Postby Harry Dalek » Sun May 15, 2022 5:55 pm

more reading on Peter Scott using modeline for 240 line Baird
https://www.vintage-radio.net/forum/sho ... ht=FOTH+tv
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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.
User avatar
Harry Dalek
"Fester! Don't do that to 'Thing'"
 
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