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C't 512 KB internal RAM expansion

228 bytes removed, 11:54, 7 May 2010
/* Installation Guide */
1x 47 Ohm resistor
=== Step 1 * '''DRAM Replacement''' - Replacing Replace the RAM ===sixteen old 64Kx1 DRAM chips by new 256Kx1 DRAMs. The chips have same pinouts, only pin 1 is changed (old: NC, new: A8 row:column address signal).
The old 64Kx1 DRAMs have same pin* '''PAL Replacement''' -outs as Replace the old PAL by the new 256Kx1 ones daughterboard. Most signals connect to the PAL socket (exceptgreen in schematic), pin 1 was NC a extra few wires connect elsewhere on old chipsmainboard (red), on new chips it's A8 of RAS:CAS addresses; aka A16as an optional "bonus" feature,A17 of linear addressesthe circuit contains logic for a 3rd floppy drive (blue).
* Replace the old RAMs by the new RAMs.<gallery>* Wire pin 1 (formerly NC) of all RAMs to GND (allowing to test the circuit after Step 1) (later on, it will be wired to RASFile:CAS A8 in Step 2)CPC6512 ct magazin schematic.png|Schematic === Step 2 - Daughterboard Logic === The original article has been confusing on this part. It basically said that one needs "four additional connections", but without giving too clear info on which signals are to be connected to which locations. * Replace the old PAL by the new daughterboard (containing the new PAL, and the 2 logic chips and 3 resistors). [[File:CPC6512 ct magazin schematicpcb.png]]jpg|PCB</gallery>
== Compatibility Problems ==
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