Re: Two ROM 01s?

[shack@deimos.frii.com (Randy Shackelford)]

Rubywand (rubywand@swbell.net) wrote:

: > ....  Recently, I saw a post about two
: > versions of the ROM 01.  It was in regards to a certain mouse that only worked
: > with the later version. .... Any idea how to tell which ROM 01 I have ....


:      It sounds like you are talking about the ADB Controller IC mod which Apple 
: introduced in its later-1987 ROM-01 GS. (Too many of the earlier ADB Controller 
: IC's turned out to be glitchy over a range of room temperatures.) This was a 
: hardware mod. (I do not know whether a corresponding firmware/ROM mod was done.)

:      The ADB Controller changeover is not mentioned in the early version of the 
: IIgs Harware Reference Manual (1987).  According to the manual, the GS uses an 
: M50740 ADB IC. In a later edition of the manual, the ADB IC for the "256kb GS" 
: (ROM-01) is still the M50740; for the "1MB GS" (ROM-03) it is shown as the 
: M50741.

:      Meanwhile, the ADB IC on our Woz edition GS is labeled (on the IC and 
: motherboard) as "344S0048-A". Our machine has the ROM-01 Upgrade; but, since the 
: IC is soldered to the motherboard, the upgrade did not include an ADB IC 
: swap-in.

:      Could ADB IC differences explain problems with a piece of software? 
: Certainly, In the case of the Kensington TurboMouse ADB trackball, the 
: difference between the older and newer ROM-01 ADB IC's was significant-- so, TM 
: will not work satisfactorily on older ROM-01 machines.

:      Very few pieces of software communicate directly with the ADB Controller. 
: Software which does and which expects to find an M50740 or M50741 ADB Controller 
: might well be expected to work incorrectly on a machine with the older 
: controller whether or not there are any differences in ROM code.  

I have in front of me the logic board which came in my ROM 0 signature edition
I recently bought, my ROM 01 //e upgrade (whose board apparently dates from 
close to the end of the 01 production run), and a ROM 3. The chip labeled 
"KBD GLU" on each board has the same part number, 344S0048-A. On the chip 
labeled "KBD MICRO", I have three different numbers:

ROM 0 board: 341S0345-C (c) APPLE 86
late ROM 01 board: 341S0345-D (c) APPLE85-87
ROM 3 board: 341S0632-2 M50741-160FP

I surmise that the board in my //e upgrade is late in the production run
since it has a CMD 65816 as do most ROM 3s, while earlier ROM 0/01s use
a GTE part.
--
Randy Shackelford                                 
shack@frii.com