That definition seems to leave a lot of grey-area, doesn't it? I mean does "no longer available from the original source" mean that there's not a single chip left on the tables or just that no more new racks are being brought into play?

If it's the former case, then a chip only becomes obsolete at some arbitrary point in time after they've slowly disappeared from the tables. This may not be such an arbitrary point in the case of house chips, but for LE's, it could be very arbitrary. I mean, an LE chip might become obsolete on its day of issue if the run is very limited and they're all snatched-up immediately, right??

Still searching for a concrete definition...