Ancient video signal processing question

Thread Starter

kotlec

Joined Jun 26, 2022
48
Hi all

First time here.
I run into a problem that is out of my competences. Without your help Im stuck for ever.
Will try to be short. Old machinery from 80ties had CRT display. It is broken by now. It was fed signal by separate three wires : H-sync, V-sync and video itself.
How would you go about connecting another more modern monitor in place of CRT.
What I have tryed so far is combining separate signals in to one " composite " signal and feeding it to CVBS (AV) input of simple car rear view display.
That works somehow but but signal im getting is noisy and picture somewhat hard to read.
Is there any better way to solve ?
 

jeffkrol

Joined Dec 8, 2015
30
See if your output type matches one of the inputs listed..
You then at least have vga..
https://www.amazon.com/Mcbazel-Arca...ocphy=1028224&hvtargid=pla-422856440089&psc=1

- Input Signal Format: RGBS, RGBHV, YPbPr
- Input RGBS Format: 15kHz, 24kHz, 31kHz horizontal frequency signal automatic scanning
- Input RGBHV Format: 31k horizontal frequency signal
- Input YPbPr Format: 480i-60, 576i-50, 1080i-50, 1080i-60, 480p-60, 576p-60, 720p-50, 720p-60, 1080p-50, 1080p-60 automatic identification
 

Thread Starter

kotlec

Joined Jun 26, 2022
48
Welcome to AAC!

This is not that ancient. There is a good chance that you can have this working with a common VGA monitor.
Thank you MrChips
Are you saying that I can get away that easy with good result ? Cant believe ...
Something like this will work ?
1656253352216.png
 

MrChips

Joined Oct 2, 2009
26,504
Depends on the design and specifications of the original equipment and your replacement monitor.
Be aware that there are two TV standards, NTSC for North America and PAL for Europe.
You have many options:
1) replacement CRT
2) monochrome PC CRT screen with 9-pin connector
3) RGB VGA monitor with 9-pin or 15-pin connector
 

Thread Starter

kotlec

Joined Jun 26, 2022
48
Depends on the design
Original monitor or radther display was integrated in to machinery and has connector looking like nothing I have seen before or after. I have figured out what pin is what signal and just soldered wires directly to DIY mixer board .
Machine was build in Japan so TV standard is unknown , but was recognized by car monitor .
Shoul I try soldering wires directly to VGA computer monitor cable to try ? Or this will not work.
 

AnalogKid

Joined Aug 1, 2013
10,096
A VGA-to-HDMI or composite-to-HDMI adapter should be available at any computer store. I use one for my old VCR. $50 locally, $12 ebay. Little white box, external 5 V wall wart.

ak
 

jeffkrol

Joined Dec 8, 2015
30
Original monitor or radther display was integrated in to machinery and has connector looking like nothing I have seen before or after. I have figured out what pin is what signal and just soldered wires directly to DIY mixer board .
Machine was build in Japan so TV standard is unknown , but was recognized by car monitor .
Shoul I try soldering wires directly to VGA computer monitor cable to try ? Or this will not work.
Probably PAL.
"Someone" may be able to decypher based on chips.
Looks to be main controller,
https://pdf1.alldatasheet.com/datasheet-pdf/view/87406/HITACHI/HD6345P.html

One ic which is overwritten unfortunately does start PALxxxxx
 

MrChips

Joined Oct 2, 2009
26,504
Original monitor or radther display was integrated in to machinery and has connector looking like nothing I have seen before or after. I have figured out what pin is what signal and just soldered wires directly to DIY mixer board .
Machine was build in Japan so TV standard is unknown , but was recognized by car monitor .
Shoul I try soldering wires directly to VGA computer monitor cable to try ? Or this will not work.
Get your hands on any available computer screen or monitor and then tell us what you have.
 

MrChips

Joined Oct 2, 2009
26,504
Europe uses 50Hz AC line frequency
PAL is 625 scan lines at 25 frames per second (except PAL M).
I believe the only thing you need to be concerned with is the frame rate.
If your monitor is designed to accept 50Hz VSYNC then it should work.
 

Thread Starter

kotlec

Joined Jun 26, 2022
48
A VGA-to-HDMI or composite-to-HDMI adapter should be available at any computer store. I use one for my old VCR. $50 locally, $12 ebay. Little white box, external 5 V wall wart.

ak
Since I figure out how to connect lines to VGA , do you thing that addapter wil be able to recognise is it PAL o something else by itself ?
 

Thread Starter

kotlec

Joined Jun 26, 2022
48
I have old color LCD monitor in storage. Will it work If I connect VIDEO signal (besides V and H) to one of color lines ? Or I ned connect to all three somehow ? Sounds mad , but need to ask anyway :)
 

BobTPH

Joined Jun 5, 2013
5,248
I have old color LCD monitor in storage. Will it work If I connect VIDEO signal (besides V and H) to one of color lines ? Or I ned connect to all three somehow ? Sounds mad , but need to ask anyway :)
Try it. I think it will work either way. You can simply wire the video to all three, nothing extra required.
 

ronsimpson

Joined Oct 7, 2019
2,167
separate three wires : H-sync, V-sync and video
Most likely it is Black & White.
It would be nice to know the frequency on H-sync and V-Sync. This alone gives us much information.
Do you have an oscilloscope?
The Video could be in 0 to 1V or it could be "TTL" 0 to 5V range. Knowing this would help.
The video could be composite or just video. Can't tell with out an oscilloscope.

Several of my LCD TVs have inputs "H", "V", R, G, B. There is a chance the video speed is close enough to standard (one of the standards) so a TV will display it. For right now connect H, V, G only and see what happens.
 

Thread Starter

kotlec

Joined Jun 26, 2022
48
Yes monitor was monochrome (orange one).
I do have osciloscope. I will try to capture images from all three lines. May answer many questions.
Will try LCD monitor too. As far as I know one of sync signals can be wrong "inversion " as for car monitor to work I had to invert it.

Saying car monitor I mean this :
1656260991229.png1656260991229.png
 
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