how much RAM is on this IIgs card

[derFunkenstein]

At VCF Midwest yesterday I picked up a really nice Apple IIgs, and aside from using a semi-emulated IIe in my LC III, this is the first Apple II to make its way home with me. So please pardon my ignorance.

It has a very large memory expansion card that is half-way populated. If I'm counting correctly, I would think that it has 2MB soldered and another 2MB installed (for a total of 4MB), but it's apparently being recognized with only 512k. If I go to the Control Panel with the card in, total RAM (between used and free) is 768k. And if I go to the Control Panel with this card removed, it adds up to 256k.

There are 16 empty sockets on the second row. The top row has 8 soldered chips that read:

MALAYSIA 8701
HM50256P-15
U221288

These are apparently made by Hitachi: https://www.datasheets360.com/part/detail/hm50256p-15/3949508474749148704/

The other chips installed into the sockets read:
HY530256LS-10
89444 KOREA

These are SK Hynix: https://www.datasheets360.com/part/detail/hy53c256ls-10/6174018365370067504/

Am I nuts? 16 x 256 should be 4096. Unless it's 256kbit which is 32kbyte, and then 32x16 = 512. Right now I'm leaning towards the latter. Good news is it passes all the self-test diagnostics and boots into System 4 off my Floppy Emu.

 

[Andy]

You should have 512k. The Apple IIGS Memory Expansion Card supports 256k, 512k, or 1MB depending on the installed chips. Unfortunately it doesn't support the larger sized chips. There's a manual for it with a little bit more info here https://mirrors.apple2.org.za/ftp.a... IIGS Memory Expansion Card Owner's Guide.pdf

 

[derFunkenstein]

Thank you very much, that's all very good info. That means the 512k that the system detects is correct. That PDF is super cool, as well. Thank you @Andy!