Contrast and brightness? Otherwise TV technican knowledge is required...

Pin 7 is Green Ground, you'd think that just mean you got no green or incorrect green levels in your picture...

The other two are for VESA DDC, and shouldn't affect the ability to display a picture.

Are the pins broken off in either the desktop or laptop VGA sockets?

I think you're looking at it backwards. The marked pins are 4, 9, and 11... 9 is the 'key' pin and is missing on many monitor cables, and 4 and 11 have to do with monitor ID and aren't usually used on modern (post-'95, maybe longer) VGA stuff either.

Old Thrashbarg wrote:

I think you're looking at it backwards.

I think you're right!

😢

Actually, I did have to flip the image horizontally as when I compared my VGA port to the one in the image, it was the other way. The image as I show it, is the correct representation of my cable, with the first and third row of pins going the other way! 😒

I checked for broken pins in the devices and if the pins had fallen on the ground somewhere close to the machines, but no, there is nothing, and probably was nothing more than what there is now, AFAIK.

UPDATE: After further investigation, I disconnected the VGA cable from either machine, and also unplugged the power cable and tried in another source. I now have the green light with the NO SIGNAL box bouncing around on the screen. However, I soon as I try to connect to any device, the light goes amber, nothing on the screen and there is that ever so slight high-pitched screech/noise coming from the monitor - almost like it's trying to work something out. 😉

So it's not the tube - could it be the VGA cable? If so, how to replace this?

you may have broken connections in the cable or even bad solder connections on the main board. Doubtful anything is actually wrong with the monitor otherwise since you have OSD (on screen display)

I'd just open the case to the CRT but make sure it is discharged and check connections first. if not. I'd solder a new adapter plug to the main board and mount it to the case so you could use a removeable cable. This is a bit of work if you live in the states finding a new one is probably alot cheaper and less effort.

It turns out the problem is with the cable.

If I re-position my laptop at different heights, with the monitor cable plugged in, sometimes the screen is displayed, and then when I move it, it disappears. Moving the cable in certain, angles and positions, as well as different places down the cable, points to the problem at the end of the cable, close to the VGA plug.

As I don't have access to a soldering iron, is it an easy task to cut the cable back, and then re-wire the pins back onto the plug?

You should locate the broken wire by bending the cable when it's plugged in. Then just cut it off and solder another plug. Or rework it in any other possible way.