Hello,

I have a question regarding a CRT monitor which I couldn't quite find the answer to on http://www.repairfaq.org/.

I don't believe it's the usual brightness loss of a CRT over time where phosphors lose their efficiency but wish to confirm my doubt.

The problem manifests in the following way: After a power-on the display seems to have solid brightness levels. However, displaying a full white picture dims the display over a period of some 30 seconds - the picture noticeably loses brightness.

Now if I display a full black picture for a few minutes and then display a full white again, the brightness is back, but starts to fade again like described in the prior paragraph.

Can you please confirm that this is a problem with some driver circuit, or is this in fact an aging CR tube?

Thanks,
Vedran.