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Macintosh IIvi Capacitor Replacement Guide

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The Macintosh IIvi logic board Recap-a-Mac photographed, 820-0373-A, has eight aluminium electrolytic capacitors, and Recap-a-Mac notes that the IIvi is not "immune from leaky capacitors and exploding batteries".[1] Apple's developer note covers the IIvx, IIvi and Performa 600 together and draws one block diagram for all three: the cache RAM, cache control and clock generation are fitted on the IIvx, only the clock generation on the Performa 600, and shunts in their place on the IIvi. The IIvx has the 68882 FPU as standard; on the IIvi and Performa 600 it is optional, in a socket on the board.[2] On the IIvi board in Recap-a-Mac's photograph the cache RAM positions and the FPU socket are empty.[1] Macworld describes the IIvx as having "the same basic logic board" as the Performa 600, and Console5 sells one logic board capacitor kit for all three machines.[3][4] Apple's Service Source and developer note give no capacitor values.[5][2]

Signs of failure

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  • Residue or corrosion around the surface-mount capacitors and on nearby pads.
  • A leaking battery does similar damage; on the board Recap-a-Mac photographed, the holder (BT1) and the area around it were destroyed.[1]
  • For the symptoms of failed capacitors see Capacitor Failure Symptoms; for Apple's fault charts see Macintosh IIvi Troubleshooting.

Logic board capacitor list

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Mac IIvi Recap Guide
Macintosh IIvi logic board 820-0373-A with the electrolytic capacitors marked (Recap-a-Mac)
Macintosh IIvi logic board 820-0373-A (Recap-a-Mac)
Quantity Value Type Where Replacement used by Recap-a-Mac
6 47 µF 16 V Surface-mount electrolytic Two beside the SCSI and floppy connectors; four along the left edge near the ports KEMET T491D476K016AT tantalum
2 220 µF 16 V Axial electrolytic Near the power connector at the top of the board Vishay MAL213825221E3

Values and positions are from Recap-a-Mac's photograph of IIvi logic board 820-0373-A.[1] MacDat's IIvi and IIvx pages list the same eight parts, and its photograph of a IIvx board shows them in the same places.[6] A higher voltage rating in the same size is acceptable. On a tantalum the bar marks the positive end, the opposite of an aluminium electrolytic.[4]

Power supply

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The supply is Apple part 661-0758, shared with the Macintosh Centris 650 and Quadra 650.[5][7] Open the supply and read the maker and model before ordering parts: the Macintosh Centris 650 Capacitor Replacement Guide has Console5's list for the Delta SMP-120EB version and its primary reservoir pair, and no list for the Astec AA16870 version. Apple's ratings for it are on Macintosh IIvi General Maintenance.

The supply works from rectified mains and its reservoir capacitors hold a charge after it is unplugged. Discharge them and confirm with a meter before working on the primary side.

Procedure

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Apple's take-apart order is top cover, power supply, internal chassis, reset/interrupt switch and speaker, then the logic board.[5]

  1. Loosen the captive screw at the rear, slide the top cover forward about an inch and lift it off.[5]
  2. If a CD-ROM drive is fitted, squeeze its side tabs and pull it forward an inch or two. Remove the screw from the rear bezel, prise the latch away from the base of the power supply, and lift the supply firmly out.[5]
  3. Disconnect the floppy, SCSI power and SCSI data cables (and the CD-ROM cables if fitted), remove the two screws holding the internal chassis, swing its front up until it is vertical and lift its tabs out of the bottom case.[5]
  4. Lift the centre tab of the reset/interrupt switch and ease the switch up and away from the front of the case. Disconnect the speaker cable from the logic board and remove the speaker's screws.[5]
  5. Remove the screw in the centre of the logic board, slide the board forward about half an inch and lift it out.[5]
  6. Photograph the board and note the polarity of every capacitor. Remove the old parts, clean off any electrolyte, check the pads and tracks, and fit the new capacitors observing polarity.
  7. Refit the board by placing the centre of its rear edge in the plastic bracket and sliding it straight back, and seat the internal chassis's bottom corners in the guides in the case.[5]
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References

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  1. ↑ 1.0 1.1 1.2 1.3 Macintosh IIvi, Recap-a-Mac—link(accessed 2026-09-30) Annotated photograph of Macintosh IIvi logic board 820-0373-A (bar-code label 630-0375-B), hosted here as File:Mac IIvi Recap Guide.jpg: 6 × 47 µF 16 V surface-mount, 2 × 220 µF 16 V axial; the cache RAM positions (silkscreened SRAM-8KX8 and TAGRAM) and the FPU socket are empty; replacement parts KEMET T491D476K016AT (47 µF 16 V tantalum) and Vishay MAL213825221E3 (220 µF 16 V axial).
  2. ↑ 2.0 2.1 Apple Computer, Macintosh IIvx Developer Note (1992), also covering the Macintosh IIvi and Performa 600, File:Macintosh IIvx IIvi and Performa 600 Developer Note.pdf; see Macintosh IIvx IIvi and Performa 600 Developer Note. Printed pages 2-3 (features, and Table 1-1 comparing the three models) and 7 (Figure 1-1, block diagram: SRAM, cache control and clock generation on the IIvx, clock generation on the Performa 600, shunts on the IIvi).
  3. ↑ Charles Seiter, "Macintosh IIvx", Macworld, December 1992, pp. 206-207, archive.org: the IIvx has "the same case, the same basic logic board" as the Performa 600.
  4. ↑ 4.0 4.1 Macintosh IIvx / IIvi / Performa 600 SMD Tantalum and Axial Main PCB Cap Kit, Console5—link(accessed 2026-09-30) Surface-mount tantalum and axial electrolytic kit for IIvx, IIvi and Performa logic boards; the marking bar on a tantalum indicates the positive side.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Apple Computer, Macintosh IIvx, Macintosh IIvi, Performa 600 Service Source, File:Macintosh iivx.vi.perf 600.pdf; see Macintosh IIvx/IIvi/Performa 600 Service Source. Take Apart, PDF pp. 26-51: top cover p. 26; power supply pp. 27-29; internal chassis pp. 30-36; speaker pp. 47-48; logic board pp. 49-51. Exploded View p. 76.
  6. ↑ MacDat, "Macintosh IIvx Capacitor Reference" and "Macintosh IIvi Capacitor Reference" (accessed 2026-10-12): both list 2 × 220 µF 16 V axial and 6 × 47 µF 16 V surface-mount electrolytics and say the logic board must be recapped; the IIvx page's reference photograph (from MrFahrenheit) shows a IIvx board with the cache RAM and 68882 fitted and the eight capacitors circled. Secondary source.
  7. ↑ Quadra 650, IIvi, IIvx, Power Mac 7100, Performa 600 – Power Supply, Apple Rescue of Denver—link(accessed 2026-09-30) Apple 614-0009, 661-0758, 112 W; Delta SMP-120EB or Astec AA16870.


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