I vacuumed out the G4 and reseated the RAM and got all three RAM chips... before that it only saw 2 of them.
Well hmmm… think you might have a memory problem? If the RAM was so marginal that an entire chip was not being seen, you're overdue for some maintenance.
If you don't already have any, go find a can of contact cleaner. Radio Shack is closing up…good place to look if you have one nearby.
Clean the sockets and the RAM chip contacts. Seat them and reseat them a few times.
If you have OSX on the machine, Google "Memtest Mac". There's a free downloadable utility that runs under Terminal to completely test all the RAM.