You pretty much figured it was the monitor. If the monitor is a decent one, have it repaired. Unless, you plan to repair(you're capable) then go ahead but beware of hi-voltage, etc. You're problem is either the scan freq circuit or I/O panel. Either way, unless you have access to parts, you're pretty alone in trying to repair. The cost of repair(shop) may push you to replace or now is a good reason to try a LCD replacement. Of course, if you have warranty, use it. Cheap monitors can start at $79/17in. when on sale or not if shopped around for. Used monitors can be less or gotten cheaply, check local Goodwill or S. Army outlet shops.
I doubt there's anyone who can help me with this one, but I might as well take a shot in the dark.
I have a monitor that likes to shut off every 30 seconds... which means I have to "turn it off" then turn it back on again. The strange thing is its inconsistency with which it does this.
Initially I thought it might be a windows problem, because I noticed certain full screen apps (games) rarely if ever experience the monitor shut down - even if it's in the middle of one of its fits, I can start up Hitman Contracts, and the monitor lasts as long as the game does. Other full screeners aren't so lucky.
The monitor can run fine for hours, then it will start flipping out again. I'm pretty sure it's not a windows problem, because I tried the monitor on my sister's computer with the same result, and another old monitor on my computer without any trouble above and beyond what the old monitor already had.
I thought maybe it was an overheating problem - however, while the monitor will run fine for hours, then start its fits... other times, it'll have its fits for a good 10 or 20 minutes off a cold start... I play my full screener game without trouble, go back to the windows desktop, and oddly enough, it keeps running fine - then jumps back into its fits a couple of hours later.
IF I can avoid it, I'd really like to avoid junking the thing - I just lost a major source of income, so replacing the monitor won't be an option for awhile. I have nothing against going inside the monitor either, as the warranty is long since over and void. Like I said, this is a shot in the dark, but if anyone has any ideas, I'd really appreciate them... thanks very much.