Q RE: Monitor for old powerbook 540c

It uses the old ADB connector so it cannot be hooked up to a regular CRT without an adapter.

Actually ADB is the peripheral connection bus (for keyboards and stuff); the Apple-specific monitor connection was DB15 (as oposed to now-standard VGA, which is "HDDB15"--higher density). Assuming that you don't need some sort of specifc laptop adapter (that it just has a DB15 port on the back instead of some sort of high-density monitor output), then all you need is a Mac DB15 to VGA adapter, and you're good to go.

A quick search on Froogle for "Mac DB15 vga adapter" turns up piles, ranging from $20+ for new boxed brand-name ones to $3 used eBay specials (heck, I've sold those on eBay before).

*slaps forehead*
I get those confused for some reason. But yeah that's what you need.

Hmm... I happen to have had a 520c laying on my desk at work for months (still works! ...but not as a laptop--both batteries are dead), and after glancing at it tonight it has a non-standard monitor connector that looks a little like a fat HDMI connector (actually, a better analogy would be the video connectors that Nintendo uses on their consoles).

I assume that the PB came with an adapter from that port to a DB15, in which case tacking on one of the DB15 Mac to VGA adapters I mentioned will get you working. But if it didn't or you don't have it, you're going to have to track one down first, which may not be easy for something that old. Won't cost anything when you find one, but the finding's the challenge.

Of course, maybe the 540c uses a full-sized DB15 port--if it's a standard D shaped connector with a bunch of holes, you're fine. If it looks like an oval hole with a tab in the middle, you need an adapter (or, rather, TWO adapters).