Re: ... What IIe motherboard needed for double-hires?

[Rubywand <rubywand@swbell.net>]

Jon Bettenct writes ...
> 
> I was on Rubywand's web site, under the "How can I tell what version my
> computer is?" section, and I saw the information about serial numbers and
> Double Hi-Res Graphics. I was wondering, is an Apple //e with serial
> number 607-0187-A able to display these graphics? 607-0187-A is the serial
> number on my Apple //e.
> 
 ....

     Thanks for bringing this up. Probably, the IIe part of the "How can I tell
what version my computer is?" could stand a bit of clarification.

     As Matthew observed, there is wide agreement that a Revision B motherboard
(or whatever came later) is required. However, there is some question about
what serial/part numbers go with which Revision-- an "A" in the number you find
on a board does not always seem to mean that the board is Revision A. (I don't
know what revision corresponds to 607-0187-A.)

     Evidently, the Rev A boards were produced for just the first year or less
after release of the IIe. So, if your IIe is a post-1983 model, it is likely to
have a Rev B motherboard.

     According to Don Worth (in SoftTalk, July 1983), besides a Rev B
motherboard, you also need to have an Extended 80-col Card installed and to
have a jumper on the pins at J1 in order to get double-hires.

     Supposedly, if you have a Rev A motherboard and jumper the pins on the
Extended 80-col Card, your system will not work at all. At least one user, Dave
Althoff, has suggested jumpering the pins as a means of checking whether or not
you have a the Revision A motherboard-- i.e., if you do, your system won't
work; if your system works okay, you have at least a Rev B board.

     Possibly someone has tried converting a Rev A motherboard to Rev B. If so,
it would be interesting to know how the attempt worked out.



Rubywand