Strange DRAM module, Want to replace it by 72 pin SIMM, need advice.

mzu2006@gmail.com · electronics forum beginner Joined: 05 Jul 2006 Posts: 1

Recently I scavenged an old 486 laptop.
It boots and says it is "Media Magic PN315/DSTN". BIOS detects 8mb of
RAM. I want to put it to work somehow, but first i would like to put in
more memory. The beast has 2 slots filled with strange memory modules.
I never met such things before.
http://129.25.13.57/Image1.jpg
http://129.25.13.57/Image2.jpg

It looks like FP memory. I found the datasheet on the chip used
(424400) and tracked the pinout with a tester. Each
of the modules seem to have 32-bit wide data bus, 4 CAS signals to
strobe the column address for each individual byte, and 1 RAS. So it is
pretty much like 72pin SIMM, though with only one RAS signal. (By the
way, I checked through JEDEC JESD-21C standard. It lists a lot of wierd
memory module configs but none with 60 pins x 32 bit on it. So the
memory does not conform to JEDEC.)

On both memory slots CAS signals different, as well as RASes. All other
signals are common to both slots. I just wonder if a bit of soldering
will enable me to use a regular 72 pin SIMM in here. Am I understanding
correctly, that wiring just one RAS signal to the SIMM will simply
allow me to use just half of memory?

--
rm -rf /mnt/windows

Franc Zabkar · electronics forum Guru Joined: 01 May 2005 Posts: 616

On 5 Jul 2006 09:42:42 -0700, mzu2006@gmail.com put finger to keyboard
and composed:

Google