Editing Amstrad PPC640 Troubleshooting Guide (section)

== Start-up sequence ==
At power-on or reset the firmware shows "Please wait" on the LCD, whatever the switch settings, and adds a dot as it works through the self tests in this order:<ref name="trm" />
# ROS (system ROM) checksum
# DMA controller (8237)
# Interval timer (8253)
# System status ports (8255 emulation)
# Real-time clock (146818)
# Serial port UART (8250)
# Parallel printer port
# System RAM
# Interrupt controller (8259)
# Disc drives (each head is stepped to track 10)
# Keyboard interface
After the tests it shows the sign-on line with the RAM size and ROS version, for example "Amstrad Portable PC 640K (V1.8)", the time and date, and the time it was last used, then asks for a system disc in drive A.<ref name="ppcui">Amstrad plc, ''The Amstrad Portable PPC 512/640 User Instructions'' (US edition, first edition 1988). Hosted as [[:File:Amstrad PPC 512 PPC 640 User Instructions.pdf]], described at [[Amstrad PPC 512 / PPC 640 User Instructions]]. Batteries and alarms p. 9; switching on pp. 13–14; start-up p. 41; switching off p. 43; external monitor and switches pp. 317–318; troubleshooting pp. 327–328; hardware error messages p. 339.</ref><ref name="trm" /> A soft reset (Ctrl+Alt+Del) skips the system RAM and video RAM tests.<ref name="trm" />