5 ms·

In these machines +/-12V is only used for Audio op-amps, RS232 Line drivers and the floppy motor. everything else is running on the 5V rail.

• gbraad 3y ago
  That is not completely true. The opamps for sure, but the 12V rail is also used for external devices, eg harddisk, cd drive, expansion cards, etc. Too low current on the -12V rail can cause crackling sound. I use my A1200 machines mostly for this, although more using AHI than before.
  • bogantech 3y ago
    > 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...
    • gbraad 3y ago
      I thought the trapdoor (cpu slot) also exposed 12V, but just checked and I was wrong. Thanks for clarifying that the 12V rail might be sufficient.