Re: odd cards

["Paul Grammens" <grammens@svn.net>]

Quadrajet1 <quadrajet1@aol.com> wrote

>
>    I have upgraded many computers over the years, and know for a fact some
> Apple's don't like the 2 or 3 chip SIMMs.  I am not saying you can put
them in
> one particular machine with a certain kind, but as a general rule stay
away
> from them on old machines.  I have had success with some, and others I
have
> not.  Here's a old document straight from Apple TIC Archives:
>

>
> The following models do work properly with these two-chip SIMMs:
>
> * Macintosh Classic II
> * Macintosh SE/30
> * Macintosh LC/LC II
> * Macintosh IIsi
> * Macintosh IIcx
> * Macintosh IIci
> * Macintosh IIvx/IIvi
> * Macintosh Quadra 700
> * Macintosh Quadra 900/950
>
>
>    I don't fully agree with the list, but hey, it's from the horses mouth.
>

OK, note that the Mac Plus is not on the list, and it's the first Mac to use
SIMMs. I just went out to the garage and grabbed a Plus, case cracker and a
handful of 3 chip SIMMs I've scrounged from PC's.

I opened 'er up and found it had four  9 chip 1 meg SIMMs.  (There goes the
myth that 9 chip parity SIMMs "won't work in a Mac.") I tried several sets
of  3 chip SIMM's, all booted fine, ran an application, and showed the full
4 megs of RAM.
There goes the myth that "three chip SIMMs won't work in a Plus." I also
tried a pair each of 9 chip and 3 chip SIMMs, that worked too, though I
prefer to use matched sets.
I'm an empiricist. If it works, it works. If it doesn't work, try
measuring/adjusting the 5 volt level or trying a set of known good SIMMs.
Maybe some 3 chip SIMMs won't work in some hardware, for some reason, but
until you try several sets and check the supply voltage, I wouldn't consider
it proven.
I just checked, and the Plus is still working fine now that it's warmed up.
-Paul