I recently got a 600xl from ebay, and its not working at the moment. The rf adapter does work, and the unit does power up and display some color to the screen. In fact rotating R4 on the motherboard changes the color that is displayed on my tv.
After reading through a lot of posts here, I took out all the chips and reseated them, but that hasn't made a difference. The 600xl looks like it was stored in a garage, the rf shield had a lot of rust on it which is sanded off, and some of the chips have a little oxidation and/or rust on some of the pins. The power supply works fine. I have the ram chips coming for the 64k upgrade, so I was going to try those to see if they make any difference.
Any other suggestions of stuff to check? Should I just get another one, or a populated motherboard, and use this one for parts?
-Aaron