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Very neat potential solution for our 30-pin Macs and wanting ALL THE MEMORY

trag

Well-known member
I'd like to know just so I can put my mind at ease (as I don't engineer/build myself, this is just a fact my brain wants to know :p ), because after seeing several of these and a few other posts about this and how it's plaguing new builds for our old machines.

I went ahead and measured a few sticks of my of-the-time 30-pin RAM and my OEM SE/30 ROM SIMM I have and they're all 1.20–1.25 mm by my caliper measurement (margin of error is usually ±0.01 mm on mine). So I don't know if I'm measuring wrong (don't know how I could with the board thickness…) or if I have mutant sockets, or what the deal is. ¯\_(ツ)_/¯




Which part of

you really want 1.27 mm. or .050", but it seems difficult to find.


did you guys not understand?   Apology for appearing snarky.  Not really intended.

The specification for the 30 and 68 pin sockets is for boards with .050" thickness.   Converting .050" to mm yields 1.27.

Back when those SIMM sockets were current, printed circuit boards were still largely specified in inches, at least, in the USA and .050" was the specification.   If you manage to look up a datasheet for the sockets, you'll find it called out there as well.   

Everything went to .063" sometime around when memory moved to DIMMs, which is the common 1.6mm.

 

jessenator

Well-known member
The specification for the 30 and 68 pin sockets is for boards with .050" thickness. 


Everything went to .063" sometime around when memory moved to DIMMs, which is the common 1.6mm.


Thanks for that. Sorry, I guess I had just assumed it hadn't been specified here because the conversation kept going back to "1.2mm is too thin" :lol: And I just rolled along...

 

pfuentes69

Active member
Hello,
I see this an old topic, but I'd be interested on making some of these SIMMs for my SE/30
My plan would be to get some 72-pin SIMMs and remove the chips

Can anyone give me a hint for the right memory chip to use?
 

pfuentes69

Active member
In the video Adrian used Toshiba TC5117400CSJ DRAMs. The gerbers are here: https://github.com/UpLateGeek/Let-s-Make-Some-Memories

Garrett's Workshop also has a few layouts avaible here: https://github.com/garrettsworkshop/RAMSIMM-30

If you want to do that as a learning experience that's fine, otherwise @Siliconinsider is selling brand new ones on eBay: https://www.ebay.fr/itm/115309947646
Hello.
I already built 4MB SIMMs and upgraded my SE/30 successfully to 32MB

I was actually asking about the chips to make the 16MB SIMMs.

BTW, I made already some deals with SiliconInsider. I got from him VRAM and an expansion for my PowerBook… he makes very nice things
 

pfuentes69

Active member
So far I have been using them in the SE/30, IIci and Q950 without any major problems.

The only issue I have is with the thickness of the SIMMs. As with the ROM SIMMs 1.2mm seems to be slightly too thin and 1.6mm is pretty tough to get into some sockets.

Just like with ROM SIMMs 1.4mm would probably be perfect here.
Hi Bolle.
I'd appreciate if you can give some hint on the right memory ICs to use to make 16MB SIMMs.
Txs!
 

demik

Well-known member
Hello,

This information is available on Garret's Github. They are two variants of 16MB sticks. Both are using KM44C16104 chips, either in a SOJ or SOP package.
 

pfuentes69

Active member
Hello,

This information is available on Garret's Github. They are two variants of 16MB sticks. Both are using KM44C16104 chips, either in a SOJ or SOP package.
Thanks, I saw this, but I'm not expert and I'm looking for the particular reference of the SOP package, as it's easier to solder by hand.
When I made the 4MB SIMMs I wasted already some money because I got first the wrong package and I didn't want to make the same mistake again. :)
Also... Bolle's design seems simpler, and not sure if it would use the same chips.
 
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