Hello all. I'm new here and just learning about the Apple II; forgive my ignorance. I have the opportunity to purchase an original II. It has serial number A2S1-22012 and is board revision 820-0001-07. It appears to have onboard Integer ROMs (only four??) and an Applesoft firmware card. The owner believes the mainboard was replaced at some point, but he's adamant that it's still a "real" original II. I have another contact who believes this is a II Plus mainboard in a II's case, making it clearly much less valuable/desirable. Below you'll find all the pictures I have of the unit. I have several obervations/questions:
1) The owner expalined to me that some late II's did come from Apple with a Rev 7 mainboard, despite the fact that this board was technically developed for the II Plus. He also said that some early II Pluses came with Rev 4 boards. (Looking through the registry, this does appear to be true. Why would Apple do this?) He believes the mainboard in his unit is not original because having a Rev 7 board does not seem to square with a serial number of 22,xxx. According to the Apple II registry, this SN would suggest a Rev 3 or Rev 4 board. Looking through the registry, I'm very confused... One would expect a fairly orderly progression of board revisions and increasing SN, however that's not what I see. Looking back over the previous 10,000 or so numbers before this one, I see Revs 2, 3 and 4 randomly and in roughly equal proportions. Looking forward, I see Rev 3s, then Rev 4s, and it isn't until SN 66,8xx (almost 45k units past the unit in question) that I see a Rev 7. Would you agree that for this reason alone, it is highly unlikely that this unit was born with the Rev 7 mainboard that now sits in its case?
2) It's my understanding that one of the only physical differences between a II mainboard and a II Plus is the ROM. IIs had Integer ROM, II Pluses had Applesoft. One would imagine, then, that when Apple used a Rev 7 board in a II it would get Integer ROMs, and that very same board in a II Plus would get Applesoft ROMs. This board seems to have onboard Integer ROM, further evidenced by the fact that someone installed an Applesoft firmware card. If the mainboard had been pulled from an II Plus, wouldn't it already have onboard Applesoft ROM? Isn't this evidence that perhaps the unit did come from Apple with this board? It's hard to imagine that someone would purposely downgrade their II Plus board before transplanting it.
3) Are there any other physical differences between a II and a II Plus mainboard?
4) Is there any definitive way to tell if a particular mainboard came with a particular case? Is the serial number found on the mainboard anywhere?
5) It's my understanding that the power supply currently in this unit is not period correct. Is that true? If so, that seems to make it more likely that this is a Frankenstein II.
6) In this article, the section 'More Hardware Add-ons' says that the Rev 7 mainboard was released for the Apple II Plus in 1981. The board in my pictures clearly has 1979 on it. Is that a typo?
7) A highly subjective question, but what monetary value would you put on this machine, including the drives and monitor in the pictures?
That's all I can think of for now! Thanks so much for any detective work you can help me out with!