I have an Apple IIe P.A.L, board number 870-0073A dated 1982. Its also marked B607-0664.
I am having some problems with 80 character mode in that if I type in PR#3 it goes into 80 column mode, but after about 10 minutes the machine becomes unstable and I get on screen graphics corruption, or missing columns (Every other one) and from time to time the card just become unavailable.
It seems to be thermal as powering off for a short while allows everything to work as normal again, even if only for 10 minutes.
I have 2 cards, a RAM2E II from Garrets Workshop, and a standard remake of the 80 column/64K card. The problem occurs with both cards so I'm confident it's the machine and not the cards.
I'm trying to find a decent schematic for my specific machine, but not having any luck (Mine has the CPU bottom left corner, and the AUX slot in the middle(ish) of the board in front of slot 3) so if anyone can point me a a schematic for this specific machine I'd be grateful.
BTW I do have a number of schematics and PDFs of books, but all seem to be different revisions to mine and don't show the aux connector and what's connected to the socket.