EDO SIMMS and CSMKII

obitus1990 · 04 October 2016, 02:54

I have a cyberstorm mark ii, populated with 64 megs of single sided EDO SIMMS. I'd like to upgrade it to 128MB, by using 32 MB modules. The problem is, I have gone through two different types (thicker chips and thin chips), but, neither of them will seat into the sockets. The chips on the back side of the modules will bottom out on the RAM socket when one places the module into the socket and then attempts to rotate it into place in the clips. The module will just lift right out.

Is there such an animal as a 32MB single sided SIMM? IF so, does anyone have a source in the US that sells them? EBAY has proven to be fruitless, as all the sellers have are double sided modules.

dirkies · 04 October 2016, 06:48

Mine do not have that issue and are double sided thick ones. Can you share a picture of your simms?

hooverphonique · 04 October 2016, 14:13

most (if not all) 2*2^n capacity modules will be double sided, as they are just two modules on one pcb.

obitus1990 · 04 October 2016, 15:58

Quote:

Originally Posted by dirkies

Mine do not have that issue and are double sided thick ones. Can you share a picture of your simms?

I will take photos of them when I get home this evening from work. Thanks!

obitus1990 · 05 October 2016, 05:04

Photos of modules as requested:

Type 1:

Type 2:

Kin Hell · 05 October 2016, 11:11

Both appear fine to me from the pics you show & but lets get one thing perfectly clear....

A 72 Pin SIMM is a 72Pin SIMM. There are various flavours of 72Pin Sockets, some being vertical, some leaning over....

But the fit is an Industry Standard. Chips should not foul in any kind of 72Pin socket.

Type 2 is very slim (Guessing EDO) & Type 1 is the Norm for any CSMkII & will take 4 x 32Mb Double Sided SIMMS just like you show.

I'm sure you are putting them in the socket the right way round because they can only fit one way.

Can you measure from the bottom side of the chips to the edge of the connectors?

I have a Type 1 32Mb Simm here that measures 7mm (1/4" USA) & fits perfectly in a CSMkII & CSMkIII

obitus1990 · 06 October 2016, 00:13

4mm.

TjLaZer · 06 October 2016, 00:53

Are your SIMM sockets slanted or vertical? I haven't had any issues installing any type of 32 MB Simms in mine

obitus1990 · 06 October 2016, 01:01

Tjlazer: Slanted. If they were vertical, there would be no issue.

Kin Hell · 06 October 2016, 12:07

I was being broad minded @ 7mm....

6.5mm with a ruler here & no spectacles on, but I rounded up to 1/4" (7mm) for ease & the USA still being largely Imperial....

But yeah, 4mm raked over at an angle is not clever. - Having said that, I'm surprised the Type 2 Slim Jim modules are doing the same?

Here's Micron Data Sheet on 72Pin SIMMS. Measurements @ the bottom of the page.

https://www.pjrc.com/mp3/simm/datasheet.html

I guess your SIMMS are more modern variants. Lets not forget, the Amiga 1200/4000's were using 32Bit 72Pin SIMM Technology whilst Mainstream PC's were still on 30pin 16Bit Technology.
Perhaps the PeeCee Industry fudged things along the way, much like IDE/SATA got called SCSI when employing RAID.

Sounds a bit cruel, but it appears you need some 0ld0r Style modules fella.

obitus1990 · 12 October 2016, 04:32

The issue was definitely the SIMMs being a little too "low profile." I found some EDO ram on Macsales.com, brand new, but, the distance from the bottom of the chips to the bottom of the contacts was almost 12mm. So, double sided and all, they fit perfectly. Woohoo, my 3000 has almost half a gigabyte of memory now

Kin Hell · 12 October 2016, 08:34

Nice!

04 October 2016, 02:54	#1
obitus1990 Registered User Join Date: May 2016 Location: Mandeville USA Posts: 203	EDO SIMMS and CSMKII I have a cyberstorm mark ii, populated with 64 megs of single sided EDO SIMMS. I'd like to upgrade it to 128MB, by using 32 MB modules. The problem is, I have gone through two different types (thicker chips and thin chips), but, neither of them will seat into the sockets. The chips on the back side of the modules will bottom out on the RAM socket when one places the module into the socket and then attempts to rotate it into place in the clips. The module will just lift right out. Is there such an animal as a 32MB single sided SIMM? IF so, does anyone have a source in the US that sells them? EBAY has proven to be fruitless, as all the sellers have are double sided modules.

06 October 2016, 12:07	#10
Kin Hell 0ld0r Git Join Date: Mar 2009 Location: Cornwall, UK Posts: 1,581	I was being broad minded @ 7mm.... 6.5mm with a ruler here & no spectacles on, but I rounded up to 1/4" (7mm) for ease & the USA still being largely Imperial.... But yeah, 4mm raked over at an angle is not clever. - Having said that, I'm surprised the Type 2 Slim Jim modules are doing the same? Here's Micron Data Sheet on 72Pin SIMMS. Measurements @ the bottom of the page. https://www.pjrc.com/mp3/simm/datasheet.html I guess your SIMMS are more modern variants. Lets not forget, the Amiga 1200/4000's were using 32Bit 72Pin SIMM Technology whilst Mainstream PC's were still on 30pin 16Bit Technology. Perhaps the PeeCee Industry fudged things along the way, much like IDE/SATA got called SCSI when employing RAID. Sounds a bit cruel, but it appears you need some 0ld0r Style modules fella. Last edited by Kin Hell; 06 October 2016 at 12:33.

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04 October 2016, 06:48	#2
dirkies Zone Friend Join Date: Aug 2002 Location: Belgium Age: 51 Posts: 1,296	Mine do not have that issue and are double sided thick ones. Can you share a picture of your simms?

04 October 2016, 14:13	#3
hooverphonique ex. demoscener "Bigmama" Join Date: Jun 2012 Location: Fyn / Denmark Posts: 1,624	most (if not all) 2*2^n capacity modules will be double sided, as they are just two modules on one pcb.

05 October 2016, 05:04	#5
obitus1990 Registered User Join Date: May 2016 Location: Mandeville USA Posts: 203	Photos of modules as requested: Type 1: Type 2:

05 October 2016, 11:11	#6
Kin Hell 0ld0r Git Join Date: Mar 2009 Location: Cornwall, UK Posts: 1,581	Both appear fine to me from the pics you show & but lets get one thing perfectly clear.... A 72 Pin SIMM is a 72Pin SIMM. There are various flavours of 72Pin Sockets, some being vertical, some leaning over.... But the fit is an Industry Standard. Chips should not foul in any kind of 72Pin socket. Type 2 is very slim (Guessing EDO) & Type 1 is the Norm for any CSMkII & will take 4 x 32Mb Double Sided SIMMS just like you show. I'm sure you are putting them in the socket the right way round because they can only fit one way. Can you measure from the bottom side of the chips to the edge of the connectors? I have a Type 1 32Mb Simm here that measures 7mm (1/4" USA) & fits perfectly in a CSMkII & CSMkIII

06 October 2016, 00:13	#7
obitus1990 Registered User Join Date: May 2016 Location: Mandeville USA Posts: 203	4mm.

06 October 2016, 00:53	#8
TjLaZer Registered User Join Date: Sep 2004 Location: Tacoma, WA USA Age: 52 Posts: 1,921	Are your SIMM sockets slanted or vertical? I haven't had any issues installing any type of 32 MB Simms in mine

06 October 2016, 01:01	#9
obitus1990 Registered User Join Date: May 2016 Location: Mandeville USA Posts: 203	Tjlazer: Slanted. If they were vertical, there would be no issue.

12 October 2016, 04:32	#11
obitus1990 Registered User Join Date: May 2016 Location: Mandeville USA Posts: 203	The issue was definitely the SIMMs being a little too "low profile." I found some EDO ram on Macsales.com, brand new, but, the distance from the bottom of the chips to the bottom of the contacts was almost 12mm. So, double sided and all, they fit perfectly. Woohoo, my 3000 has almost half a gigabyte of memory now

12 October 2016, 08:34	#12
Kin Hell 0ld0r Git Join Date: Mar 2009 Location: Cornwall, UK Posts: 1,581	Nice!

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