# CPC 464+ with 128kB RAM

The PCB of the CPC 464+ is already prepared for using 128kB of RAM. So it is quite easy to upgrade to 128kB.

WARNING: You do this project at your own risk!

The following tools are needed:

- 1 Screwdriver,
- 1 soldering iron,
- some tin flux

Needed electrical components:

- 2 * RAM 41464-12
- 1 * Resistor 33ohm / 1/8 Watt
- 1 * Resistor 10kohm / 1/8 Watt
- 2 * Capacitor 0.1µF

If you don't want to solder your RAM-Chips directly to the PCB you also need 2 IC-sockets (18pin).

First, you have to search for the following positions on the PCB: R28, R55, C12, C13, IC12 and IC13

At this positions, you have to remove the tin flux from the solderpoints.

Now you can connect the electrical components to the PCB:

- 10kohm → R28
- 330ohm → R55
- 0,1µF → C12 and C13
- RAM → IC12 and IC13

The IC's have to be connected with the same orientation as the already existing RAM's.

You can test the new RAM-bank with the program below.

Listing:

    10 MODE 2:DEFINT b-z
    20 PRINT"Bank:":PRINT:PRINT"Address: &     OK!"
    30 FOR bank=&C4 TO &C7
    40 LOCATE 6,1:PRINT bank-&C3
    50 FOR adr=&4000 TO &7FFF
    60 LOCATE 11,3:PRINT HEX$(adr,4);
    70 wert=255:GOSUB 120
    80 wert=0:GOSUB 120
    90 OUT &7F00,&C0
    100 NEXT:NEXT
    110 PRINT:PRINT"All banks OK!":END
    120 OUT &7F00,bank:POKE adr,wert
    130 OUT &7F00,&C0:POKE adr,255-wert
    140 OUT &7F00,bank:wert2=PEEK(adr)
    150 OUT &7F00,&C0
    160 IF wert2<>wert THEN PRINT" ERROR!!!";:END
    170 RETURN

Wolfgang Noisternig aka "The Cranium"