Editing Amstrad PC1640 (section)

=== Display and switches ===

The internal graphics adaptor (IGA) gives 640 × 350 graphics in 16 of 64 colours on the PC-ECD, CGA and 200-line EGA modes on the PC-CD, and 80-column text with 9 × 14 characters on the PC-MD.<ref name="sm" /> A bank of ten DIP switches on the back of the system unit sets the starting mode for the monitor in use, the font, the monitor type and the ROM size; switch 10 disables the IGA so that a separate display card can be used.<ref name="sm" /><ref name="dip">John Elliott, [https://www.seasip.info/AmstradXT/pc1640dip.html "PC1640 DIP switches"], seasip.info, 12 April 2003. Retrieved 2026-10-02. SW1–SW5 hardware emulation and initial mode, SW6–SW7 font, SW8 monitor type, SW9 32K EGA ROM, SW10 disabling the internal adaptor and selecting the add-on card type.</ref> The video socket is a 9-way D type; switch 8 grounds pin 2 or routes the secondary red signal to it, depending on the monitor.<ref name="trm1" /> The ECD monitor has its own cooling fan.<ref name="wp" /><ref name="dosdays" />

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''Monitors (service manual pp. 2, 35–47)'''
! Monitor !! Type !! Mains fuse !! Presets for the computer's rails
|-
| PC-MD || Monochrome || F501, 3.15&nbsp;A time-lag || VR501, VR502, VR504, VR505, VR507
|-
| PC-CD || Colour, 0.42&nbsp;mm dot pitch || F501, 3.15&nbsp;A time-lag || VR601–VR604, VR606
|-
| PC-ECD || Colour (EGA), 0.31&nbsp;mm dot pitch || F501, 3.15&nbsp;A || VR601–VR604, VR606
|}