Posted by ???? on May 17, 2001 at 17:42:01:
In Reply to: A3000のメモリー増設、教えてください。 posted by 蘭 雑 on May 17, 2001 at 13:30:18:
: 現在、２５６Ｋｂのメモリーを抜き去りＺＩＰを４組８枚４ＭＢを慎重に差し込みましたが認識されません。ジャンパー類は色々と試してみましたが、間違っているかも知れませんので諸先輩方のお教えをお待ち致します。助けてください！２週間も蓋が開きっぱなしです。
http://www.lava.net/~avathar/Amiga/A3000Data.HTML#MEMORY
Chip RAM for Amiga 3000 Desktop
Via the U267-U274 DIP package sockets...
Density Name Package Speed Pcs/Bnk Banks/Total
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
256Kbit x 4 44256 20 pin DIP 120ns 8 1/1MByte
These can be either Static Column or Page Mode access type DRAMs.
It does not matter which type, there is no speed degredation. These are
very common chips, and you can find them on older VGA boards for PCs.
They're also the same kind used on the A2091 RAM and SCSI board. Chip RAM
autoconfigures without jumpers.
Fast RAM for Amiga 3000
Via the U850D-U857D DIP package Bank 0 Sockets...
256Kbit x 4 20 pin DIP 80ns 8 1/1MByte
1Mbit x 4 20 pin DIP 80ns 8 1/4MBytes
Via the U850-U881 ZIP package Bank 0-3 Sockets...
256Kbit x 4 20 pin ZIP 80ns 8 4/4MBytes
1Mbit x 4 20 pin ZIP 80ns 8 4/16MBytes
These should all either be Static Column or Page Mode.
As noted above, some A3000's shipped with 1MByte of FAST memory in
DIP package, waiting to be transplanted into the sockets for CHIP RAM, once
more FAST RAM was installed. Those FAST memory sockets are the U850D-U857D
20 pin DIP places, Bank 0. This bank is electrically mapped to Bank 0
U850-U857, 20 pin ZIP sockets. As a result, one can make a three megabyte
A3000 configuration by putting 256Kbit x 4 chips into the FAST RAM DIP
sockets without buying ZIPs. Or a six meg setup, using 1MBit x 4 chips.
The DIP FAST sockets cannot be used with the ZIP sockets all together, as
the two Bank 0 areas are basically pinned to each other (as noted by the
same component numbers, one set with a D for DIP). One could have 4MBytes
of DIPs for FAST, then another 12MBytes of FAST in ZIPs placed into Banks
1-3, but not 4MBytes in the DIP area and 16MBytes in all four ZIP banks.
256Kbit and 1Mbit banks cannot be mixed. One cannot have 4MBytes of
1Mbit chips, and then 1MByte via another bank of 256Kbit chips. Of
course, one can't mix individual chips either! All four banks are either
low or high density banks.
Jumper J852 selects the size of the RAM, and 1-2 designates 1Mbit
sizing. 2-3, further from the arrowhead, denotes 256Kbit