Re: Overlay Revisions

[shack@onyx.southwind.net (Randy Shackelford)]

David Empson (dempson@atlantis.actrix.gen.nz) wrote:
: In article <41k7bh$6gh@freenet.vancouver.bc.ca>,
: Robert Lee_Kwen <trebor@freenet.vancouver.bc.ca> wrote:
: > Is there any different between the Apple II overlay card that has the 
: > chip 344SOO47 - A    Copyright Apple 86 or
: > 
: > chip 344SOO47 - B    Copyright Apple 87

: That chip is the "Mega II", which is basically an Apple IIe
: motherboard (minus the processor and RAM) in a single chip.  It is
: also used in the IIgs.  My ROM 1 IIgs (originally a ROM 0) has a 1985
: version of this chip, with no letter after the "344S0047", but there
: is an "A" at the bottom of the legend.

: I don't want to pull open my ROM 3 just at the moment, so I can't
: compare it.

My just-purchased ROM 3 box is sitting here with the lid off, and it has the
- A mega II. It appears to be a newer ROM 3 than the one I got three years ago,
which has sockets too short for one of the ROM chips so four more pin things
were added at the end. This ROM 3 has sockets longer than the chips so four
pins on each socket are empty. Wonder what that's all about.
--
Randy Shackelford                                 I was internet
shack@southwind.net                               when internet wasn't cool