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128Mb 72-pin Amiga RAM

Okay .. so LC475/575 uses 72pin FPM simms. It likes 60ns or better. It can grok parity SIMMS but ignores the parity.

There's two types of SIMM's lurking. FPM and EDO.

FPM gets about 40-50mb/s data rates. EDO (extended data out) will get 50-60mb/s. Not all EDO SIMMS will retard back to FPM mode. Some will.

Amiga's don't do EDO to my knowledge. Even the 68060 accels still run stuff in FPM mode. My Blizzard-060 and the Apollo-040 and the WarpEngine-040 I have all only grok FPM.

My bet is that they'll work. It's an 8-chip so it's not parity. It's 50ns so it'll probably get refreshed at 70ns or slower in the 575.

Larger SIMMS will draw more current.

I've used 128mb Parity simms in my 475 and q605 before so you should be fine. I snaffled a bunch of old HP NetServer's which was quad PentiumPRO systems with 12 sockets of ram and 128mb FPM's. They've served me well for the old mac's, running some in my SGI, RS/6000 and one of my older alpha's a AlphaStation 4/200 (but that requires an SRM hack to see more than 32mb, but it will talk to all six slots with 128mb).

So, not a bad deal. I'd give it a 90% chance of working.

This one is dead similar to mine: http://www.ebay.com/itm/HP-NetServer-LX-Pro-Memory-Module-128MB-72pin-24-chip-60ns-Parity-SIMM-D4893A-/121997405470?hash=item1c679cad1e:g:CsAAAOSwQjNW-gBg

Sadly the taller simms start to interfere mechanically in some of the cases.

Good luck!

 
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The one annoying thing trag's linked module (and others like it) is that it's too tall for the Color Classic II!  It runs in to the chassis when you try to slide the logic board tray back in.

(Yes, I was trying to give my CC2 more RAM, and the only >16 MB SIMM I have is an 'extra tall' one like that.)

 
Is the problem just while sliding the tray in, or would it also interfere once the tray is fully installed? I'm not familiar with the layout of the CC (onor CCII) but on the earlier classic Macs, with some tall uprades they were fine once they were installed in the chassis but you couldn't get them in because they wouldn't slide under the rear frame member. The answer was to seat one edge of the logic board in the right or left side rail, and then lift the other side into place, prying the other rail of the frame outward with a scewdriver, just enough to sneak the board into position. In other words one lifts the board into place from underneath rather than sliding it in from the rear.

Would this technique work on the CCII?

 
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On the Colour Classic (CC) chassis with a CCII, LC550, or LC575 logic board, the ram slot is longitudinal. A slightly overheight module will interfere with the left mounting point for the port cover screw. Some people will cut it off. A module that is somewhat taller still will not clear the top of the logic board bay for the whole length of the case, above which is the speaker and floppy drive. The original CC logic board uses 30-pin SIMMs and has a 10MB address limit, so oversize modules aren't an issue.

I imagine the CC chassis is probably the tightest fit above the logic board.

 
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