From: [EMAIL PROTECTED]
Date: Tue, 06 Sep 2005 02:51:11 +0100
The ROM chips on my disassembled (dead) Mac Plus say:
[ROM-HI]
VTI 552 V0 9715Q
23512-1006
342-0341-A
(C) APPLE '83-'85
MEXICO-R
[ROM-LO]
VTI 603 V0 9765
23512-1007
342-0342-A
(C) APPLE '83-'85
MEXICO-R
Can anyone identify the version of these ROM chips from these numbers?
I wonder whether this ROM version is rare enough for someone to give the
board a home.
Perhaps someone can, but I can't. The relevant numbers would be the
342-0341-A and 342-0342-A numbers.
Besides, I always thought the Mac 128K and 512K had two 32Kbyte ROM
chips ("Laurel and Hardy"), and the Mac Plus had one 128K chip ("Mr. T").
What is this Mac Plus logic board doing with two ROM chips?
Nope, two ROM chips each. The ROM chips are 8 data bits wide, and
the Mac Plus has a 16 bit wide data bus, so it takes two 8 bit chips
to fill the 16 bit bus.
And from Apple's Tech Note HW_11 "Macintosh Plus ROM Versions"
"Macintosh Plus ROM history
Readers Digest® condensed version of Macintosh Plus ROM history, or
the truth according to Bo3bdar the everpresent:
1st version (Lonely Hearts, checksum 4D 1E EE E1 ):
Bug in the SCSI driver; won't boot if external drive is turned off.
We only produced about one and a half months worth of these.
2nd version (Lonely Heifers, checksum 4D 1E EA E1 ):
Fixed boot bug. This version is the vast majority of beige Macintosh Pluses.
3rd version (Loud Harmonicas, checksum 4D 1F 81 72):
Fixed bug for drives that return Unit Attention on power up or reset.
Basically took the SCSI bus Reset command out of the boot sequence
loop, so it will only reset once during boot sequence. This version
shipped with the platinum Macintosh Pluses.
And Bo3bdar saith: "Thou shalt not rev them damn ROMs no more!"
Later that same day...
Bo3bdar Saith Also:
Lonely Heifer was about a 2 byte change,
Loud Harmonica was about 30 byte change.
No other bug fixes in SCSI or elsewhere.
Modified object code directly.
Not possible to get a specific ROM since they are all the same part number.
Shouldn't rely on a specific ROM, there will be no upgrade."
Jeff Walther
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