Editing Macintosh IIvi (section)

== Hardware ==
=== Logic board ===
Apple's logic board part is 661-0760 for the IIvi (661-0759 IIvx, 661-0761 Performa 600).<ref name="ss" /> On the IIvi board Recap-a-Mac photographed (820-0373-A), the cache SRAM positions and the FPU socket are empty.<ref name="ram">{{cite web |url=https://recapamac.com.au/macintosh-iivi/ |title=Macintosh IIvi |publisher=Recap-a-Mac |access-date=2026-09-30}} Annotated photograph of logic board 820-0373-A, hosted here as [[:File:Mac IIvi Recap Guide.jpg]]: 6 × 47 µF 16 V surface-mount and 2 × 220 µF 16 V axial; replacement parts KEMET T491D476K016AT and Vishay MAL213825221E3; notes leaky capacitors and exploding batteries on the IIvi.</ref> The VASP chip combines video, memory mapping, sound and glue logic, and a 68HC05 microcontroller runs ADB, the clock, parameter RAM and soft power.<ref name="dn" /> Software must use the Gestalt Manager to find out whether a IIvi has an FPU.<ref name="dn" />

Because RAM is tested and sized before video starts, the screen stays blank for a while at start-up, longer with more RAM fitted.<ref name="dn" />

=== Accelerator slot ===
The 120-pin slot takes accelerator cards. Apple warns that it is not compatible with processor-direct cards for other Macintosh models and that fitting one may damage the card and the computer; cards must stay within 5 W.<ref name="dn" /> Low End Mac notes that the IIvi cannot take a cache card, but can take an accelerator.<ref name="lem" />

=== SCSI and CD-ROM ===
An active terminator on the logic board terminates the internal bus when no external device is attached. The 3.5-inch hard drive must be terminated; a device in the 5.25-inch bay must not be. Apple's internal CD-ROM uses SCSI ID 3.<ref name="dn" />

=== Power supply ===
Apple part 661-0758, shared with the IIvx and Centris 650; Apple Rescue of Denver lists it as Apple 614-0009, 112 W, made by Delta (SMP-120EB) or Astec (AA16870).<ref name="ss" /><ref name="arod">{{cite web |url=https://applerescueofdenver.com/products-page/macintosh-to-powerpc/shop-by-model-desktop/macintosh-iivi-iivx-power-mac-7100-quadra-650/quadra-650-iivi-iivx-power-mac-7100-performa-600-power-supply/ |title=Quadra 650, IIvi, IIvx, Power Mac 7100, Performa 600 – Power Supply |publisher=Apple Rescue of Denver |access-date=2026-09-30}}</ref> Its ratings from Apple's developer note are on [[Macintosh IIvi General Maintenance]]. Apple publishes no rail tolerances and no adjustment.<ref name="ss" />

=== Battery ===
A lithium backup battery keeps the clock and PRAM when the machine is unplugged.<ref name="dn" /> Apple's test: measure on the 10 V DC range and replace the battery below 2.8 V.<ref name="ss" /> Recap-a-Mac's IIvi board photograph shows heavy corrosion around the battery holder.<ref name="ram" />

=== Capacitors ===
Logic board 820-0373-A has six 47 µF 16 V surface-mount electrolytics and two 220 µF 16 V axials.<ref name="ram" /> See [[Macintosh IIvi Capacitor Replacement Guide]].