What capacity 30-pin SIMM are these?

[djc6]

When I boot this SE/30 I picked up, it shows as 2MB of RAM. I recapped the board, and it was 2MB before and after recapping.

Are these really 256KB SIMMs or is there some other issues- either with the logic board, or SIMM compatibility with the SE/30. I'm confused by the four chips.

The modules in bank B have the following on the manufacturer sticker:
2x8 -60
022797DL57627

The memory chips on the SIMM say:
USA N 9707
S414000JDJ -06

There is an additional square IC on each module:
16Y8H-15JC/4

I did find another post that talks about composite SIMMs, due the the presence of the PLD - maybe this is what I have?

https://68kmla.org/bb/index.php?threads/se-30-memory.234/post-4214

 

[Unknown_K]

2MB SIMMs.

Pull the 256K SIMMs out and see what you get.

 

[djc6]

I bought an upgrade ROM SIMM (Garrett's Workshop GW4402B) because I thought maybe with a 32-bit clean ROM SIMM I can use these weird SIMMs. I'm glad I got the Garrett's GW4402B because it has both System 6 and System 7 bootable ROM disks selectable from a DIP switch. I cannot boot System 7 ROM disk nor can I boot System 7 BlueSCSI image I have. However, when I select System 6 on the ROM SIMM - it boots! So its good to have both available for troubleshooting.

So, with the stock ROM and the RAM the system came populated with - I see 2MB of RAM when booting system 6 or system 7.

When I use the GW4402B ROM SIMM, I see 13MB when I boot system 6?? We know one bank is 1MB since its the stock apple RAM and they say 256KB each right on them. So does that imply the other SIMMs are 3MB? Is that even a thing?

Now that the machine works (I recapped it, had to replace UG8 because no video) I am comfortable buying new RAM. I was just curious about the modules previous owner tried to put in here.

 

[croissantking]

They’re non standard SIMMs and your SE/30 doesn’t like them. It should be reporting 9MB total.

 

[bibilit]

IIRC 2Mb ram modules are not fully supported by the SE/30 (only the IIsi can use those)

 

[zigzagjoe]

I believe those 2MB PAL modules are only necessary for IIx and II due an issue with the memory controller triggering the test mode that newer RAM chips had.

 

[David Cook]

I believe those 2MB PAL modules are only necessary for IIx and II due an issue with the memory controller triggering the test mode that newer RAM chips had.

I'd love it if that it is the case. But @Phipli doesn't think so...

2MB SIMMs don't work in most machines, including not working in the IIx, which is pretty much the same as a II.

The Apple Memory guide lists:
* Classic II
* Color Classic
* Color Classic II
* Macintosh LC
* Macintosh LC II
* Macintosh IIci
* Macintosh IIsi
* Macintosh IIvx/IIvi

The memory guide is limited to "officially" supported, so there may be other models that are compatible.