> the 12V rail is also used for external devices, eg harddisk, cd drive, expansion cards, etc External drives should have their own power supply and indeed the

> the 12V rail is also used for external devices, eg harddisk, cd drive, expansion cards, etc External drives should have their own power supply and indeed the A590, A570, GVP drives etc all do. The A500/A2000 Technical Reference (page 227) shows that the 12V current limit on the expansion connector is 50mA The A600/1200 don't even have the expansion connector Page 5 of the TRM specs the -12V supply at 100mA > Too low current on the -12V rail can cause crackling sound. Maybe if the current is zero TRM: https://archive.org/details/CommodoreAmigaA500A2000TechnicalReferenceManual https://archive.org/details/CommodoreAmigaA500A2000Technical...