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Power Macintosh 6500 Capacitor Replacement Guide

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Power Macintosh 6500 (photo)
Power Macintosh 6500. Photo: Ben Boldt, Wikimedia Commons, public domain

Apple's Performa/Power Macintosh 6400 and 6500 Series Service Source gives no capacitor list or schematic for the Power Macintosh 6500. It is module-level: logic boards, the power supply and the audio/monitor connection subassembly are ordered and exchanged as whole parts.[1] MacDat publishes a list and an annotated photograph for the logic board, given below. Apple and MacDat give no values for the power supply or the audio/monitor connection subassembly.[2]

The power supply carries mains voltage and its primary reservoir stays charged after the machine is unplugged. The supply is not auto-ranging: check the voltage switch on the back ("115" or "230") before the first power-up after any repair (p. 17).[1]

Boards and part numbers

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Power Macintosh 6500 modules (Apple exploded view, p. 232)
Module Apple part number
Logic board, 225 MHz 661-1322
Logic board, 250 MHz 661-1332
Logic board, 275 MHz 661-1320
Logic board, 300 MHz 661-1432
Power supply 661-1169
Audio/monitor connection subassembly 922-2547, replaced by 922-2996
Front panel control board 661-0139

Source: exploded view.[1] The 225 and 250 MHz boards also exist in reworked form (see below).

Logic board capacitors

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Power Macintosh 5500/6500 logic board 820-0816-D, from MacDat
Value Voltage Size (diameter × height) Qty Positions
47 µF 16 V 6 × 5 mm 12 C34, C38, C48, C55, C66, C98, C104, C110, C125, C133, C134, C135
100 µF 6.3 V 6 × 5 mm 6 C24, C25, C36, C37, C39, C100
100 µF 25 V 8 × 10 mm 1 C137

MacDat's list is a community list read from one board: a 250 MHz board, silkscreened 820-0816-D, with nineteen surface-mount aluminium electrolytics marked by designator on the photograph.[2] Apple's developer note describes one main logic board for the all-in-one Power Macintosh 5500 and the tower 6500, and says it is based on the Performa 6400's board but changed: EDO memory, SGRAM video memory, no RAM on the board and faster processors.[3] MacDat's list for the 5400/6400 board is different (four 100 µF 6.3 V and eleven 47 µF 16 V), so do not order parts for a 6500 from a 6400 list.[4] No source shows the 275 or 300 MHz board, so check those against the table before ordering. MacDat's view is that a 6500 does not strictly need recapping, though it is reasonable preventive maintenance.[2]

The three capacitors Apple does mention

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Apple's fix for blurry video at 832 × 624 and above on 6500s with serial numbers XB708xxxxx to XB723xxxxx depends on three red capacitors on the monitor board of the audio/monitor connection subassembly, just behind the monitor connector. If they are not there, Apple replaces the subassembly with 922-2996 (pp. 221–223).[1] Apple does not give their values, and the fix is a replacement part, not a capacitor fitted by the technician. The separate video jitter fault is a logic board rework identified by resistor R363, not a capacitor fault (pp. 217–220); see Power Macintosh 6500.

Inspection

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The logic board slides out after two screws on the rear panel are removed (pp. 136–138). The power supply needs the front bezel, expansion bay cover, top cover, left panel and left metal panel off (pp. 151–155).[1] Look for:

  • bulging or leaking electrolytics and residue on the pads (Capacitor Failure Symptoms)
  • corrosion round the clock battery on the logic board; Apple's documents disagree on whether it is alkaline or lithium, so read the pack before choosing a neutraliser (Power Macintosh 6500 General Maintenance)
  • scorched or cracked surface-mount parts

Procedure

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  1. Photograph each board and record the value, voltage rating, type and polarity of every part you intend to change.
  2. Unplug the machine and discharge the power supply's primary reservoir through a resistor, then confirm with a meter. Rectified 230 V mains charges it to about 325 V (230 × √2).
  3. Fit replacements of the same capacitance and at least the same voltage rating.
  4. Check polarity against the board, not against habit. On aluminium electrolytics the stripe marks the negative lead; on solid tantalum capacitors it marks the positive terminal.[5]
  5. Clean off flux and check for bridges and shorts before power-up.
  6. Set the voltage switch for the local supply, refit the top cover (Apple warns against running the machine without it, p. 104) and test.
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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 Apple Computer, Service Source: Performa/Power Macintosh 6400 and 6500 Series (1997), File:Powermac.perf 6400.6500.pdf; see Performa/Power Macintosh 6400 and 6500 Series Service Source. Page numbers are PDF pages.
  2. ↑ 2.0 2.1 2.2 MacDat, "Power Macintosh 6500 Capacitor Reference": logic board, 100 µF 25 V × 1, 100 µF 6.3 V × 6 and 47 µF 16 V × 12, surface-mount electrolytic, with diameters and heights; annotated photograph of board 820-0816-D sent in by Daan; "I don't have the power supply cap reference at this time" (secondary source; read 12 October 2026). The 5500 page carries the same list and photograph.
  3. ↑ Apple Computer, Developer Note: Power Macintosh 5500 and 6500 Computers (1997), chapter 1: the main logic board used in the 5500 and 6500 (PDF pp. 16, 19); "based on the logic board in the Macintosh Performa 6400", with Table 1-1 comparing the two (PDF p. 18). Hosted as File:Power Macintosh 5500 and 6500 Computers Developer Note (1997).pdf.
  4. ↑ MacDat, "Power Macintosh 6400 Capacitor Reference": logic board, 100 µF 6.3 V × 4 and 47 µF 16 V × 11 (secondary source; read 12 October 2026).
  5. ↑ KEMET, T491 Industrial Grade MnO2 datasheet, "Reverse Voltage", p. 15, content.kemet.com: "The positive terminal is identified on the capacitor body by a stripe".
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