Editing Acorn Archimedes A3020 Troubleshooting Guide (section)

== ⚠️ Mains warning ==

The A3020's power supply is built onto the main PCB, so '''the board carries mains voltages'''. Disconnect the mains lead before removing the cover, and discharge the PSU primary bulk capacitor before probing the left-hand (power) end of the board. After any internal work, re-apply the earth-continuity and DC-insulation (class 1) safety tests.<ref name="sm" />

[[File:Acorn Archimedes A3020 circuit diagram (1 of 3).png|center|thumb|680px|Acorn A3020 "Heron E" main PCB circuit diagram, sheet 1 of 3 (drawing 0194,500/C), showing the ARM250, the RISC OS ROMs, the PCF8583 battery-backed RAM/RTC, reset circuitry, the IDE and floppy interfaces and the filtered +5 V supply. Sheets 2 and 3 are also on the wiki.]]