Lg Flatron L1730s

Perhaps a bit atypical topic, considering the theme of the site and this forum, but you guys are very well-versed about electronics, and I value your opinion very much, so...
I have this LG monitor on hands, that only flashes the image for about a fifth of a second, then goes blank, with the power LED staying in it's on-state (constant green). Cycling the monitor on-off does nothing. The video cable and the power cable are positively fine.
If I pull out the video cable from either the vid card side or the monitor side, the 'check signal cable' box appears after a second or two, and remains clearly visible, slowly moving across the screen. If I leave it like this for a couple of minutes (5 tops), and reinsert the video cable, I get a stable image. OSD/controls work as intended, the colors, brightness, contrast are all fine. I've tested it for hours, it works flawlessly. However, if the monitor goes into power saving mode, and stays there long enough (about a minute or so), upon exiting power saving mode it again flashes the image for a split second and goes blank, until turned off, then turned on without a video cable present. You get the picture (no pun intended).
What gives? At first I thought the inverter was defective, but the backlight actually works, and works rather well. Obviously something needs to warm up before the monitor is ready to receive the video signal, but what should I look for? BTW, I've disassembled the thing, caps are all fine (also, they're all Samxon in this case), resistors all check out. Transistors and transformer are all fine, obviously, otherwise the monitor wouldn't even turn on. All the connections were fine (ribbon cable, power feed cables, etc.), and were cleaned, then carefully re-assembled, the monitor exhibits the same behavior after being put together.
I'm stumped. Any ideas?