Macintosh IIx RAM configuration issues

[LazarusNine]

I purchased 8x 2MB RAM chips for my Mac IIx from WeLoveMacs and no matter what combination I try, I can't get any of the chips to register. Essentially, any combination outside of the original 8x 1MB configuration leads to the error chimes. I've spent loads of time on various forums and websites suggesting specific combinations, but none of those have worked thus far. In the configurations in which I use only 4 2MB chips, I've made sure that I tried different 2MB chips multiple times in order to help eliminate some of the chance that one or more chips might be bad. Any suggestions? Here's what I've tried:

8x 1MB (Bay A and B ) - WORKS

8x 2MB (A and B ) - DOESN'T WORK

4x 1MB (A) and 4x 2MB (B )- DOESN'T WORK

4x 2MB (A) and 4x 1MB (B )- DOESN'T WORK

4x 2MB (Bay A only) - DOESN'T WORK

4x 2MB (Bay B only) - DOESN'T WORK

It's worth noting that the computer doesn't get past the error chimes with any of those configurations (except of course the 8x 1MB configuration). I have Mode 32 installed. The chips don't need to be PAL chips, as far as I know, because they're only 2MB each. Any help would be appreciated.

Regards,

LazarusNine

P.S. Can the RAM in the IIx be used in an SE/30? If so, it's worth noting that I face the exact same issues with the SE/30, but the RAM was purchased specifically for the IIx (as it was advertised).

 

[LazarusNine]

Well, this is annoying. Just stumbled across this document, which apparently states that the IIx doesn't allow for 2MB modules. Sooooo, I was sold on a lie. http://tech-insider.org/mac/research/acrobat/9204.pdf

 

[pathw]

> Sooooo, I was sold on a lie

I tried to buy 4MB PAL SIMMS from Memory Ten (== WeLoveMacs), and could not get anything to work. They did refund my money however, so I doubt that it is lying so much as insufficient information. They lost money on me from paying the shipping for both sets of memory that they sent me. I was thinking of trying the 2MB PAL SIMMs next - I won't waste my time now (though I though that I saw somewhere the 2MB was a possibility).

 

[pathw]

Don't know if you can find the "Apple Memory Guide, November 2000" (memguide.pdf - don't know where I found it, but I downloaded it this last July), but it also indicates:


[SIZE=10pt]Supported Sizes in MB : [/SIZE][SIZE=10pt]256K, 1, 4, 16 [/SIZE]

[SIZE=10pt]so no 2MB SIMMs indicated there either.[/SIZE]

 

[yuhong]

Yea, there is a reason why DRAM capacity quadrupled when Mostek style DRAM was more common and only doubled after SDRAM replaced it. In fact, I don't think having different number of row and column bits caught on until DIMMs with the x8 chips needed it.

 

[Unknown_K]

I have 2 working IIx machines but don't recall RAM configurations in them. I can check later in the week when I mess around with my Q650.

 

[LazarusNine]

I have 2 working IIx machines but don't recall RAM configurations in them. I can check later in the week when I mess around with my Q650.

Yeah, that would be awesome, thanks!

 

[LazarusNine]

> Sooooo, I was sold on a lie

I tried to buy 4MB PAL SIMMS from Memory Ten (== WeLoveMacs), and could not get anything to work. They did refund my money however, so I doubt that it is lying so much as insufficient information. They lost money on me from paying the shipping for both sets of memory that they sent me. I was thinking of trying the 2MB PAL SIMMs next - I won't waste my time now (though I though that I saw somewhere the 2MB was a possibility).

Yes, I used strong words. I don't think WeLoveMacs was wantonly deceiving me. It's just a shame that they sell the 2MB chips under the IIx heading. Still, it's kind of my fault for not doing my homework.

 

[pathw]

> Still, it's kind of my fault for not doing my homework.

It is unclear to me (at this point) whether they really know what kind of memory works in the Mac II (and Mac IIx). They pointed me at documentation ("have you read this?") that I did know about and which was irrelevant. It is not to their benefit to be sloppy this way, but it's as if they are expecting customers to figure what memory works and what doesn't. Sounds like a poor business plan to me.

 

[Unknown_K]

Got one of my IIx's up and it has 8MB of RAM (and a dead 5.25" HD it seems) so I wasn't able to test 4MB or bigger SIMMs on it.

 

[LazarusNine]

Thanks for checking, Unknown_K. Sorry to hear about your dead drive.

pathw: Yeah, I tend to agree. Coupled with the fact that their shipping rates abroad are astronomical, I'll likely be limiting future purchases to few or none.

 

[pathw]

I bought 4 4MB SIMMs on e-bay that worked in my Mac II (yay me), so I am up to 20MB now. This was a pull from a Mac II, and I do not know if the seller has access to any more. You might ask him though:

http://stores.ebay.com/macmemoriesstore/

Note that he seems knowledgeable and, at least, knows where the memory came from. This is how I learned that the 4MB SIMMs were from a Mac II. The 2MB SIMMS that he was selling at the same time were a pull from a Mac IIsi. I see that he has more 2MB memory for sale at the moment (but no 4MB? - I didn't look very closely), but don't know if anything would be suitable for a Mac IIx (or if any 2MB memory works in a Mac IIx).

 

[pathw]

Also, check out http://home.earthlink.net/~gamba2/mac2config.txt- no 2MB SIMM option listed there either. (Says that you can get 16MB PAL SIMMs to work with just the PMMU and MODE 32 ... think I'll stop with what I've got.)

 

[yuhong]

Also, check out http://home.earthlink.net/~gamba2/mac2config.txt- no 2MB SIMM option listed there either. (Says that you can get 16MB PAL SIMMs to work with just the PMMU and MODE 32 ... think I'll stop with what I've got.)

16MB PAL SIMMs would be easy to make in the same way as 4MB PAL SIMMs. BTW, the PMMU is required because of how MODE32 maps bank B using it to workaround problems in the original Mac II ROM which would normally limit the RAM to 8MB. The Mac IIx ROMs that also ships with the FDHD upgrade fixes these problems.