Hi beachycove,

Thanks for your good advice. Yes, sorry I neglected to mention it, - that was one of the very first things I tried, multiple times, to no avail. With all these vintage Macs hanging around, you can bet I have several editions of troubleshooting guide books on the shelves as well, Ted Landau's "Sad Macs..." editions especially, have proven to be invaluable over the years, as well as those CD-R compilations of service manual/take-apart guides that are available out there. The funny thing always is that, for the most part, any problem can be fixed unless there's a critical part that just cannot be found any longer. And the whole 500-series has its share of well-documented problems, mostly physical-staying-together (or not!) issues, many of which I've seen on other people's 520/540's. Sad. I guess I should really bite the bullet and get another known-working AC power adapter in order to rule that out. It's so sad to have the premier vintage Mac of my little group "off the reservation" so to speak.

kind regards,