Industrial Computer - Display issues

[Smooth Gecko]

This is a curly one that I put my hand up for.

An industrial backplane had blown its CRT monitor and replacements are not around.
The video card manufacturer has produced a new video card and flashed it to output CGA.
A new 15" LCD monitor was also acquired by the previous tech with CGA inputs.
Due to the age of the setup, documentation is slim and the backplane manufacturers have no help available for the product.

I have got the unit to boot with it's customary three beeps and now for the first time in months, something on the screen. The schematics were very hard to read and the 10 pin connecter had been connected incorrectly before I got there.
( I have been on it for three days, the owner just cannot get anyone that will / can help. )

Trouble is, it is just a one centimetre green square in the top left corner.
The OSD does work now, and I have gone through most of the adjustments, but none that are relevant to the issue we have.

The new monitor does have an auto detect and adjust feature that appears to get it right.
(The raster appears well located and the full size of the panel.)

There is a setting that I have not been game to touch.
"Phase" . It is at 0 and just increments.

I am holding out that the computer is working based on:
1 The three beeps that it apparently has always made.
2 If I input some numbers from the touch panel it changes which menu buttons etc beep
and react to button presses.
3 Some LEDS on the board are displaying when certain inputs are made.

I am using 6 wires from the 10 pin video connector on the card to the 10 pin CGA interface on the monitor,

WIRES DISPLAY VIDEO CARD

2 x Black Ground Ground
1 x Yellow V V
1 x White H/V H H
1 x Green G TTV
1 x Blue B C/V ( Composite Video )

I am lost as to what is going wrong but, feel that the Green is wrong. This is as it was when I was called in except that the wires are now on the other row of five pins on the video card as the Ground bus had been misidentified previously. ( one row of five pins are all connected to the ground bus & the yellow, white, green and blue were all connected to ground as I found it )

Would love to help this guy out, so if anyone has any ideas I would well appreciate hearing them.

 

[Lone99star]

This is a curly one that I put my hand up for.

An industrial backplane had blown its CRT monitor and replacements are not around.
The video card manufacturer has produced a new video card and flashed it to output CGA.
A new 15" LCD monitor was also acquired by the previous tech with CGA inputs.
Due to the age of the setup, documentation is slim and the backplane manufacturers have no help available for the product.

I have got the unit to boot with it's customary three beeps and now for the first time in months, something on the screen. The schematics were very hard to read and the 10 pin connecter had been connected incorrectly before I got there.
( I have been on it for three days, the owner just cannot get anyone that will / can help. )

Trouble is, it is just a one centimetre green square in the top left corner.
The OSD does work now, and I have gone through most of the adjustments, but none that are relevant to the issue we have.

The new monitor does have an auto detect and adjust feature that appears to get it right.
(The raster appears well located and the full size of the panel.)

There is a setting that I have not been game to touch.
"Phase" . It is at 0 and just increments.

I am holding out that the computer is working based on:
1 The three beeps that it apparently has always made.
2 If I input some numbers from the touch panel it changes which menu buttons etc beep
and react to button presses.
3 Some LEDS on the board are displaying when certain inputs are made.

I am using 6 wires from the 10 pin video connector on the card to the 10 pin CGA interface on the monitor,

WIRES DISPLAY VIDEO CARD

2 x Black Ground Ground
1 x Yellow V V
1 x White H/V H H
1 x Green G TTV
1 x Blue B C/V ( Composite Video )

I am lost as to what is going wrong but, feel that the Green is wrong. This is as it was when I was called in except that the wires are now on the other row of five pins on the video card as the Ground bus had been misidentified previously. ( one row of five pins are all connected to the ground bus & the yellow, white, green and blue were all connected to ground as I found it )

Would love to help this guy out, so if anyone has any ideas I would well appreciate hearing them.

I wish I could help but you lost me by only using six wires, I always thought CGA was a digital signal, you are showing a composite lead which I just can't figure.

I'm probably way off base so let me know how it works out, I'm very curious.

 

[Smooth Gecko]

Thank you, another clue.
The new video card had a link put in to output TTL for the CGA interface on the monitor.
Seems the that the wiring hasn't keep up with the TTL conversion.
I am really battling with it as my experience is limited.
Just feel for the owner that has a workshop & men that can't get on with their work.
Back to do some more reading. Ta for that.

 

[Lone99star]

"The new video card had a link put in to output TTL for the CGA interface on the monitor"

What kind of link?
Are you talking about a device to convert analog to digital?
Is the video card a VGA/EGA card converted to output a CGA signal?

 

[Smooth Gecko]

Some images that may help someone else help me.

 

[Smooth Gecko]

Sorry, not a device, just a hard link on the PCB. I believe it was an MGA CRT monitor . Two wires.
Now we have a CGA interface on the new monitor and the card was built with this in mind.
The instructions were to break a link and create another for TTL use.
This has been done.

 

[Lone99star]

I looked at this again this morning, I just don't see how this can work.
The monitor requires separate RGB analog input, the video card has a composite output, the composite output is a composition of all three signals.
The schematics of the video card are really hard to see but it doesn't look like CGA. The old monitor probably was using a single composite signal, that would be the two wires you mentioned earlier, one wire actually carried the video and control signals, the other wire was simply a ground.

Let me know how it's going.

Have you considered going back to the original configuration and connecting a monitor with RCA jacks(small tv) just to get your customer up and running until the signal details can be worked out.

 

[Smooth Gecko]

Really appreciate your help. Lone99star
Still trying to get more info from the video card manufacturer.
Apparently the new card has been built differently to supply TTL so the schematic may not match what I have now.
The card manufacturer did say it should work on CGA.
About going to a small TV, I will try and arrange one this morning and try with the old video card.
It is really just a lack of specific knowledge that I am battling. With the old TV and two wires I may be able to wire it up
My concern then would be the sync H 15.624 V 50.
Is that likely to be in the ballpark?

 

[Lone99star]

Really appreciate your help. Lone99star
Still trying to get more info from the video card manufacturer.
Apparently the new card has been built differently to supply TTL so the schematic may not match what I have now.
The card manufacturer did say it should work on CGA.
About going to a small TV, I will try and arrange one this morning and try with the old video card.
It is really just a lack of specific knowledge that I am battling. With the old TV and two wires I may be able to wire it up
My concern then would be the sync H 15.624 V 50.
Is that likely to be in the ballpark?

What kind of ports do you have on the old video card, a pic may help.
Take a look at this http://en.wikipedia.org/wiki/Color_Graphics_Adapter, its basic stuff but towards the end of the page is a pinout for a db9, I was hoping there was an RCA output.

 

[Smooth Gecko]

Ta Lone99star,
Having a look at that site now. There is no port as such on the card, just two rows of 5 pins as in that schematic which is almost unreadable. The original image is no better, if I try and zoom it gets worse.
I am starting to see what you mean about the wiring, the more I learn the less probable it seems.
The previous tech said we were just to use the green signal as it was only green on black.

 

[coreyspeed]

should you not be using all 10 of the connectors as they all have a connection on them that provide a service to the video signal ?

 

[Lone99star]

should you not be using all 10 of the connectors as they all have a connection on them that provide a service to the video signal ?

This may be the case, the standard CGA pinout uses 8 pins of a DE9 connector. 3 of these pins are RGB, 1 H sync, 1 V sync, 1 intensity, 2 grounds and 1 pin is reserved(not used). The reserved pin was used for composite output to a TV. From what I can tell the machine was using a monochrome monitor so in reality it only required use of 5 pins, the monochrome monitor probably used the reserved pin and none of the RGB pins.

The biggest problem I see here is the new video card requires use of a composite output and the new monitor requires use of the RGB leads.

This is a tough one, I wish I had it on my bench, I love that antique stuff.

 

[Smooth Gecko]

One row of the pins ( five of them ) are common ground. The others are marked as in the images I posted, not that they can easily be identified from there.
After a lot more studying and blowing an old TV yesterday, I was thinking that I need a composite monitor too. There is no RGB output from the card so a composite monitor is on my hit list now.
Maybe you can confirm Lone99star, a colour or monochrome should work if the H freq is right?

 

[Smooth Gecko]

Hi Five Lone99star

Got it with two wires into an RCA socket on an old television,
Finding a better monitor tomorrow that has a remote so I can break into the service menu and make some adjustments, but its back at work as from today.

 

[Lone99star]

Good job.
Now lets sort out the CGA issue.
I have been on spring break with the kid.