GX4000 cartridge

A cartridge for the + series

A cartridge system was introduced with the launch of the CPC+ series. This enabled developers to distribute games via cartridges on the new Amstrad. The cartridges are protected with the ACID chip.

EPROMs

All known manufactured cartridges contain EPROMs (rather than PROMs or ROMs). The cartridges can be fitted with different EPROMs in range of 32K through 512K (actually produced are only 128K..256K). The cartridge PCBs typically include six LK Links to match the PCB to the EPROM pin-outs:

 VCC ---LK1--- EPROM.A18 ---LK2--- CA18
 VCC ---LK3--- EPROM.A17 ---LK4--- CA17
 VCC ---LK5--- EPROM.A15 ---LK6--- CA15

Usually the following LKs should be installed:

 (----- EPROM -----) (------------------------ Links installed -------------------------)
 Type    Pins  Size   A15                    A17                    A18
 27C256   28    32K   LK5 (A15=VCC=High)     LK4 (A17=VCC=Supply)   N/A
 27C512   28    64K   LK6 (A15=A15=Address)  LK4 (A17=VCC=Supply)   N/A
 27C1001  32   128K   LK6 (A15=A15=Address)  N/A                    LK1 (A18=VCC=/PGM)
 27C2001  32   256K   LK6 (A15=A15=Address)  LK3 (A17=A17=Address)  LK1 (A18=VCC=/PGM)
 27C4001  32   512K   LK6 (A15=A15=Address)  LK3 (A17=A17=Address)  LK2 (A18=A18=Address)

Some cartridge PCBs don't have any LKs installed, instead, the etched circuit has hardwired connections between some of them. One could scratch them off, and then use the LK soldering points to reconfigure the board for eproms of other size.

Misc

RAM7, a French hardware developer, created a device to hack CPC Plus cartridges.

Pictures

GX4000 cartridges
Inside view of a CPC+ cartridge
Inside view of a CPC+ cartridge

Demonstration System

Amstrad released a Demonstration system for his retailer in order to show GX4000 games: the Amstrad CSD.

It was a 464plus motherboard, with an extra "daughter board) allowing the insertion of 12 games cartridges, plus an extra special cartridge acting as an OS.