Editing Amstrad CPC 464 Troubleshooting Guide (section)

== Power-On Behaviour and Boot Sequence ==

A healthy CPC 464 with firmware v1.0 (mask ROM IC103 part 40009 for the English-language model) goes through this sequence at power-on:

# +5 V rail comes up at J104. The Z80 CPU at IC111 receives its reset pulse from the Gate Array (IC116, 40007/40010) via RC network around C302.
# The Gate Array initialises the 6845 CRTC (IC108, HD6845SP) and the 8255 PIO (IC107, M5L8255AP-5).
# CRTC generates horizontal and vertical sync; the Gate Array generates RGB output from video RAM (the upper 16 KB of system RAM, IC121&ndash;IC124 HM4864).
# The Z80 reads from IC103 (32 KB mask ROM containing OS + Locomotive BASIC 1.0) starting at address 0000h.
# After ROM initialisation, the system displays the boot screen:
#: "'''Amstrad 64K Microcomputer (v1)'''<br>"&copy; 1984 Amstrad Consumer Electronics plc<br>"and Locomotive Software Ltd."<br>"BASIC 1.0"<br>"Ready"<br>
# The cursor appears, and the system is ready.

For Schneider-branded units the first line reads "Schneider 64K Microcomputer (v1)" instead, but the firmware is otherwise identical.

If any step fails, the system either remains dark, shows a corrupted screen, or hangs without producing the "Ready" prompt.