The monitor is an AMW X1900DS and has just started exhibiting a fault: the screen goes blank. If I change the resolution (via my other monitor), the screen appears for a few seconds, but fuzzily, and a buzzing noise is heard from the monitor before it goes blank. The signal indicator stays on. The same happens if I turn the monitor off then on. Clearly the monitor is not syncing to the signal. Is this something I can fix?
If you’re lucky, you have a loose cable. (And I doubt you’re lucky.)
The most common cause of failure for modern LCD monitors (not counting abuse/spills/etc.) are bad capacitors. I’ve seen monitors with bad caps that have problems not too different from yours.
The next most likely problem is a bad power supply. (Which itself might be cause by a bad cap but it could be something else.)
Maybe a 50% chance that a knowledgeable person can find the problem and fix it without too much cost or trouble.
Was the monitor working with your current setup earlier?
If not, how about checking the refresh rate? Some monitors do not gracefully handle rates not supported natively. You could also try fiddling around with the resolution. Since the display does come on for sometime before it conks out.
ftg’s suggestions are probably closer to the problem. I remember a bad cap in my power supply that made a horrifying buzzing noise similar to what you describe.