Atari 520ST(M)
4MB RAM Expansion
Tested on C070243 Rev.I , your mileage may vary.
Important
-
The board needs fixing with a bodge wire
-
The expansion board must be installed
directly onto the motherboard.Using sockets won't leave enough
clearance for the keyboard
BOM
| Component | Value | Size | Package | |
|---|---|---|---|---|
| C1 - C6 | 100nF | 0805 | ||
| R1 - R2 | 68Ω | 0805 | ||
| R3 | 33Ω | 0805 | ||
| 2x | 5118160 DRAM | SOJ42 |
Installation
-
De-solder the existing RAM.
-
Solder the expansion board in place.
-
Solder the four wires from the expansion
board to the motherboard.Signals: MAD9, CAS1L, CAS1H, RAS1
MAD9 can usually only be found on the MMU
The CAS & RAS pins can be soldered to on the
underside of the motherboard as well as,
on some boards, on the topside as well.Name MMU Pin RAS1 18 CAS1L 21 CAS1H 22 MAD9 64