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Breaking the 36MB RAM limit on the LCIII

mg.man

Well-known member
This simm has been tested and seem to work fine, and even fit's in the case too!
Hmm... OT, but I wonder if there would be enough headroom to fit this onto a Colo(u)r Classic II (or LC 550 / 575) logic board...

Macintosh-LC550.jpg

Unfortunately, the SIMM socket is vertical... and there's the matter of what's feeding that connector - is that just power, or something else?
 

max1zzz

Well-known member
the little connector is to pickup the two extra RAS signals from the bottom side of the board, the stick essentially functions as two 32MB simms stacked on top of each other

I don't have a CC to hand to check but i'll measure the height of the simm later if anyone wants to measure up a CC / CCII
I suspect it would work in the CCII as it is essentially a modified LC III form what I know of it, would need to have a look at a CCII board though to check if the extra RAS signals are available though
 

mg.man

Well-known member
the little connector is to pickup the two extra RAS signals
I think I did read that somewhere, but wasn't sure...
would need to have a look at a CCII board though to check if the extra RAS signals are available though
Indeed.

I'm not sure it would work on the CC "I", which, like the LC "I" is limited to 10Mb. I was wondering about the CC II since it also has the same 36Mb limit as the LC III. 🤔

i'll measure the height of the simm later
Perfect. Let me know and I'll have a gander inside my CC II.
 

mg.man

Well-known member
Thanks! ...but... ugg. Don't think this will be a goer. Here's a pic of the SIMM orientation in my CC II :
20220812_214406.jpg
The SIMM is right on the edge, and vertical. The one there now is a 32Mb, and is 25mm tall. Even if you deleted the fastening for the backplate (the 32Mb SIMM just clears it) there's only room for ~40mm max. And before you ask, the socket orientation would mean a "leaning" one would go to the left = won't work, would hit the side of the case. DRAT!!
 

max1zzz

Well-known member
Of course, there IS plenty of room to go up and right-angle to the right! 😄
Ooh, now what would be really cool would be to just make a SIMM with two 72pin sockets but that tab would still get in the way.... though it might be possible to slide the board in than install the RAM mmodules.

First off we would need to actually see if this mod will work on the CCII, I'm assuming since the CCII uses a Sonora derivative chipset it should be possible
 
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