Editing Apple IIGS (section)

== Power supply ==
Apple describes the IIGS supply as having "the same four-supply, switching, load-sensing design as the Apple II, II Plus, and IIe models".<ref name="iigs-hw" />

{| class="wikitable"
|-
! Parameter !! Apple's published figure
|-
| Input || 107 to 132 V AC
|-
| +12 V || 1 A
|-
| &minus;12 V || 0.25 A
|-
| +5 V || 4 A
|-
| &minus;5 V || 0.25 A
|}

'''The chirp is the protection working, and a no-load condition sets it off too.''' Apple's own description: the load-sensing circuitry stops the supply "whenever this circuitry detects a short '''or a no-load condition'''", and "the supply will emit two audible chirps per second" until the situation is corrected or the supply is switched off.<ref name="iigs-hw" />

Two chirps a second therefore means one of three things: something downstream is shorted, nothing is connected at all, or the supply itself has failed. '''Bench-testing a IIGS supply with nothing attached will make it chirp, and that is correct behaviour, not a fault.''' Put a load on it before drawing conclusions.