Monitor goes dark after a few seconds - why is that?

My parents' screen suddenly turns very dark a few seconds after being switched on, so that you can only guess at the outlines of open windows.

The problem occurs both with Windows and on my Ubuntu laptop, also with different cables (VGA). Earlier I tried different combinations of settings (resolution, update rate) and then it worked, now it doesn't work again (i.e. This was just a coincidence and it works every 10th switch on or something).

Why is that and is there anything else you can do about it? All I can imagine is a problem with the power supply (but all the cables are properly inserted in the sockets).

Is it maybe the standby mode? Maybe set too short a time?

No, it happens after 2 or 3 seconds and, as I said, under different operating systems. In addition, without a change in energy saving options, there was a time when everything worked.

The lighting in the monitor is in A *** …

The LCD panel is illuminated from behind and when this lighting is gone, you see nothing more…

There's not much you can do, because most of the time the inverter is defective and it can be found, it will be difficult…

It is cheaper to buy a new monitor…

"… There's not much you can do…"

That it has to do with the inverter is correct, but often leakage currents from defective electrolytic capacitors are the cause… And you can exchange them for a few euro. If you can't do it yourself, you go to a repair cafe!

But why is it sometimes then? Well, a repair is not really worth it, the screen was quite old and I also had one left to give to my parents. If I should still need a monitor, I try other electrolytic capacitors.

Yes, you may be right, but in this day and age, be honest, who does it…

We live in a throwaway society…

I personally would fix it and if I had to install an LED stripe instead of the mini neon tube…

That will be a loose contact… Cold soldering point and so…

If you can solder well, you can fix that too…

I work in a repair cafe myself and try, at least as far as possible, to face this throwaway company. Monitors are definitely being repaired and I always have a corresponding ELKO set with me… Let's hope that he will stop by!

This is the backlight of the monitor. The monitor will still be so old that the cold cathode tubes are used for lighting.

So that it starts up quickly, the tubes are overloaded in the first few seconds, so to speak, so that they get warm quickly and immediately emit a lot of light. If the electronics then switch to normal operation, either the tubes or the electronics fail, the tubes only glow.

You can replace the tubes and their control electronics - you should always do this together - but that costs more than buying a new monitor. The spare parts also cost more than a used, barely used monitor on Ebay.

P.S.:

Replacement electronics cost between € 20 and € 70 depending on the model. Tubes again € 20 to € 50. And for € 150 you can get a really good NEW monitor!

Another tip:

To check whether it is the backlight or something else (e.g. TFT "dead") simply put a strong flashlight directly on the screen. If you can see a (decent) picture all around, it is definitely the backlight.

It is best to note the tip well, because especially on machines with a built-in screen you can diagnose and call the customer service or go as a customer service with a suitable spare part (inverter board, new tubes). This then avoids extra travel for diagnosis. The machine operator can quickly try it out with a powerful flashlight.