Good to know. My headache came down somewhat. I will try the newest on I have.

So what I can call signal that is originally on machine ? 15khz monochrome VGA ? Or what ?

 

Today I tryed newer PC monitor on VGA. All I got was " No Signal "

http://tinyvga.com/vga-timing
I found this table with frequencies for VGA and there was no 15khz at all. All were listed in Mhz range. Or I am looking wrong dirrection
Can it be that I will not be able to use VGA ?

 

Today I tryed newer PC monitor on VGA. All I got was " No Signal "

http://tinyvga.com/vga-timing
I found this table with frequencies for VGA and there was no 15khz at all. All were listed in Mhz range. Or I am looking wrong dirrection
Can it be that I will not be able to use VGA ?

What is shown in that link is pixel clock. This is not the HSYNC frequency.

Look at this link instead:
http://15khz.wikidot.com/

 

Look at this link instead:
http://15khz.wikidot.com/

Look at the column "15khz RGB" and "comments".
Look for something like "syncs to 15 kHz in NTSC" I do not know what " Just used a simple RGB to VGA adapter" means. When they say " no other powered devices " I think they are talking an adapter that converts to a VAG type connector and has no electronics in it. Look for comments like 15khz or NTSC because that is what you need!

 

May be kind of this
https://sites.google.com/site/h2obsession/CBM/C128/rgbi-to-vga

Also reading that article I noticed they mention analog signal . Do I have analog ?

 

The meaning of the words "analog" and "digital" depend on the context in which they are used. This can be very confusing.

In reality, all voltages are analog.
In general analog refers to signals that can have a range of voltages whereas digital refers to signals that are given fixed voltages to represent discrete states.

To make things confusing, HSYNC and VSYNC would be considered to be digital since they have only two states, ON and OFF. However when compared to something such as HDMI which is digital they would be analog.

 

Do I have analog ?

In the video world, it is common for separate sync to be "digital" in the range of 0 to 3 volts. "TTL level"
Video comes in may flavors. What you have is "analog". If the signal is terminated with 75 ohms to ground you will see a 0.8 volt signal. (maybe 1V or 0.6 but in that range) If there is no termination resistor the signal will be 1.6 to 2 volts p-p.

 

Ron, should I try this ? I redraw it to be sure I got it right.

 

Once more I put attempt to record more useful osciloscopgraphy.
I believe this is video that machine outputs.


Now Vsync + composite. Is it Ok if sync is negative signal ? Monitor strugles to sync unless I set output signal to max on machine.

One more shot

Hsync


Played a lot with signal levels and am stuck. If I get more or less nice characters on screen then sync has hard time to catch. And vice versa. Tryed to implement Rons update, but possibly made mistake in schematics and nothing worked. Will keep trying though.