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PowerBook Duo Capacitor Replacement Guide

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Duo 210/230/250 logic board, 820-0426-D, with its seven electrolytics marked (photo by Powerbook27364, annotated by MacDat)

Every PowerBook Duo uses surface-mount aluminium electrolytic capacitors on the logic board, and most of the colour and passive-matrix displays carry more behind the panel. Apple's Service Sources for the Duo give no component values, so the lists below come from owners who recapped their machines and from the MacDat and Console5 reference lists, which are secondary sources.[1] Where two sources give designators they agree with the counts in MacDat's lists, except where noted.

Should a Duo be recapped?

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Owners disagree on how urgent it is. MacDat says the 210, 230, 250, 270c, 280 and 280c must be fully recapped, because leaking electrolyte can short and permanently destroy the logic board.[2] In 2012 techknight found the capacitors of a 270c's DC-DC circuit starting to leak and urged every owner to recap, and mdeverhart advises not powering an unrecapped Duo, because the leaking parts sit in the battery-charging and regulation circuit.[3][4] Against that, Byrd on 68kMLA rated the Duos in 2019 as the most reliable 68k portables, with minimal leakage in Byrd's experience, and in 2025 jmacz found no sign of leakage on the LCD capacitors of a 280c.[5][6] Fizzbinn and chartreuse both found leaking parts on Duo 230s.[7]

Signs to look for are residue or a fishy smell around the cans, and corroded pads and vias.[8] chartreuse found the via for C35 eaten through next to a leaking C36, and needed a wire to bridge it.[7] See Capacitor Failure Symptoms.

Logic boards

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Duo 210, 230 and 250

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These three share the 820-0426 board.[2][7]

Duo 210/230/250 logic board electrolytics (board 820-0426-D)
Ref Capacitance Voltage Case (D × H) Notes
C2 100 µF 25 V 8 × 10 mm 100 µF 10 V on earlier boards[2]
C11 100 µF 25 V 8 × 10 mm 100 µF 10 V on earlier boards
C3 100 µF 35 V 10 × 10 mm
C5 100 µF 35 V 10 × 10 mm
C9 100 µF 35 V 10 × 10 mm
C14 330 µF 16 V 10 × 10 mm chartreuse gives this position as C8
C36 33 µF 25 V 6 × 6 mm Leaking on chartreuse's board

Designators are from Fizzbinn's 230; values and case sizes agree with MacDat. MacDat says a 25 V part can go in either 100 µF 25 V position whatever the board revision.[7][2]

Duo 270c

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Duo 270c logic board electrolytics
Quantity Capacitance Voltage Footprint Notes
4 100 µF 35 V 10 × 10 mm Filter on the 24 V input, according to techknight[3]
1 100 µF 25 V 8 × 8 mm
1 47 µF 35 V 8 × 8 mm
1 33 µF 25 V 6 × 6 mm 6 mm tall

The list and footprints are mitchW's; MacDat gives the same values. mitchW notes that replacements must be no taller than 10 to 11 mm.[8][9] techknight's 2012 count for a 270c has two 100 µF 25 V parts and no 47 µF part; check the board before ordering.[3]

Duo 280 and 280c

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Duo 280/280c logic board: red 100 µF 35 V, cyan 100 µF 25 V, lime 47 µF 35 V, pink 33 µF 25 V (photo by jmacz, annotated by MacDat)
Duo 280/280c logic board electrolytics
Ref Capacitance Voltage
C2 47 µF 35 V
C3 100 µF 35 V
C6 100 µF 25 V
C7 100 µF 35 V
C8 100 µF 35 V
C9 100 µF 35 V
C72 33 µF 25 V

Designators are Console5's for the 280c; MacDat gives the same values for the 280.[10][11]

Duo 2300c

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Duo 2300c logic board electrolytics
Ref Capacitance Voltage
C2 47 µF 35 V
C3 100 µF 35 V
C6 100 µF 25 V
C7 100 µF 35 V
C8 100 µF 35 V
C9 100 µF 35 V
C41 33 µF 25 V
C94 33 µF 25 V

Designators are Console5's. androda counted the same parts on a 2300c board, with the larger ones marked Nichicon and two cans marked "33 EHA"; 3lectr1cPPC later confirmed those as 33 µF 25 V. MacDat lists only one 33 µF part. Count the 33 µF cans on the board in hand.[12][13][14]

Displays and inverters

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Display electrolytics by model
Model Panel Electrolytics Source
210, 230 Sharp LM64N794 (FSTN) Eight 3.3 µF 35 V, C1-C8 Fizzbinn; MacDat[7][2]
250 Active-matrix greyscale None on the LCD; inverter not checked MacDat[2]
270c, 280c Sharp LQ9D041 Three 100 µF 6 V; six 47 µF 6 V; one 47 µF 16 V; one 33 µF 10 V; two 22 µF 10 V; one 10 µF 25 V; one 10 µF 16 V mitchW; MacDat[8][9]
270c, 280c inverter One 10 µF 35 V mitchW; MacDat[8][9]
280 Active-matrix greyscale None on the LCD or inverter MacDat[11]

MacDat warns against ceramic replacements on the LCD boards, saying they have caused drifting contrast on some displays because their capacitance changes with voltage.[2] Owners have done otherwise and reported good results: Fizzbinn fitted 3.3 µF 35 V MLCCs to a 230 panel, and mitchW replaced the leaking 10 µF on a 270c inverter with three 4.7 µF 50 V MLCCs in parallel. chartreuse kept to electrolytics on a 230 panel, 3 mm through-hole parts with the leads bent down as the originals were.[7][8] On the 280c panel, jmacz found that a polymer capacitor of the original size could be knocked loose by gripping the lid and suggested low-profile polymer tantalums instead.[6]

Trackball

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Early Duo trackball boards carry one 10 µF 6.3 V electrolytic in a case that looks like a tantalum, and it leaks. Later boards use a 22 µF 10 V tantalum and need nothing.[2]

Power adapter

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MacDat's list for the Duo adapter (M2693) is a 560 µF 35 V, a 100 µF 400 V, a 27 µF 35 V and a 10 µF 50 V radial electrolytic, all 105 °C. Some adapters also contain a RIFA filter capacitor, which cracks and smokes with age.[15] Warning: the adapter's primary side runs at mains voltage, and the 400 V capacitor can hold a dangerous charge after unplugging. Discharge it before working on the board.

Procedure

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  1. Strip the Duo to the logic board as described on PowerBook Duo General Maintenance. On a 270c techknight had to remove the metal frame around the capacitors near the adapter socket to reach them.[3]
  2. Photograph the board and note the value, voltage and polarity of every capacitor before removing anything.
  3. Remove the old parts without lifting pads. Fizzbinn melted a small amount of ChipQuik with plenty of flux into each joint, which stayed liquid long enough to lift each can off with a single iron; the tightly packed cans made the twist-off method risky.[7]
  4. Clean all residue with isopropyl alcohol and check every pad and nearby via for corrosion. Repair broken tracks or vias with wire before fitting new parts.[7]
  5. Fit the new capacitors with the correct polarity. A higher voltage rating at the same capacitance is safe; a lower one is not.[13] Keep within the height limit under the frame.[8]
  6. Reassemble, align the battery contacts, and check the adapter and battery before the first power-up.[1]

Parts owners used

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  • Fizzbinn (230, polymer, Mouser): 647-PCH1E101MCL4GS for the 100 µF 25 V positions; 647-PCZ1V101MCL6GS for 100 µF 35 V; 647-PCH1D331MCL6GS (330 µF 20 V) for C14; 667-25SVPK33M for C36; 810-C3216X7R1V335M6A MLCCs for the panel.[7]
  • chartreuse (230, electrolytic, Digi-Key): UWG1V101MNL1GS for 100 µF 35 V; UWG1C331MNL1GS for 330 µF 16 V; UCL1E101MCL6GS for 100 µF 25 V; UMT1V3R3MCD2TP for the 3.3 µF panel positions.[7]

After the recap

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  • Adapter: 24 to 25 V at the plug, dropping no more than 1 to 2 V under load.[1]
  • Battery: 12 V on a charged pack.[1]
  • Boot and leave the machine running on the adapter; check that the backlight, sound and trackball work, and that it sleeps and wakes. See PowerBook Duo Troubleshooting.
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References

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  1. ↑ 1.0 1.1 1.2 1.3 Apple Computer, PowerBook 200 Series Service Source, hosted here as File:PowerBook Duo 200 Series Service Source.pdf (see PowerBook Duo 200 Series Service Source); and PowerBook 2300 Series Service Source, File:PowerBook Duo 2300c Service Source.pdf (see PowerBook Duo 2300c Service Source). Neither contains schematics or component values. Logic board removal: 200 Series PDF pp. 135-139; 2300c PDF pp. 105-109.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 MacDat, "PowerBook Duo 210 Capacitor Reference", with the near-identical pages for the 230 and 250 (retrieved 2026-10-02). Logic board: one 330 µF 16 V (10 × 10 mm), three 100 µF 35 V (10 × 10 mm), two 100 µF 25 V (8 × 10 mm; 100 µF 10 V on earlier boards), one 33 µF 25 V (6 × 6 mm), all surface-mount electrolytics; 210/230 LCD: eight 3.3 µF 35 V low-profile electrolytics; the 250's LCD has none; early trackball: one 10 µF 6.3 V; do not fit ceramic capacitors to the LCD, because they cause contrast drift. Secondary source.
  3. ↑ 3.0 3.1 3.2 3.3 68kMLA forum thread "Notice to Powerbook Duo Users!", techknight, nvdeynde and others, February-March 2012. 270c: seven aluminium electrolytics, six of them in the power circuit, starting to leak; techknight's count four 100 µF 35 V, two 100 µF 25 V and one 33 µF 25 V; the 35 V parts filter the 24 V input; low-profile parts needed for clearance; 280c LCD capacitors leaking or with high ESR. Community repair report.
  4. ↑ 68kMLA forum thread "Powerbook Duo 280c …recap (how? ...where??)", December 2021 to January 2022. mdeverhart on the location of the leaking capacitors and the risk of powering an unrecapped board. Community opinion.
  5. ↑ 68kMLA forum thread "Powerbook Duo 230 Advice", October-November 2019. Byrd: Duos the most reliable 68k portables, with minimal capacitor leakage in his experience. Community opinion.
  6. ↑ 6.0 6.1 68kMLA forum thread "Powerbook Duo 280c + Accessories Maintenance", jmacz, March 2025. Recap of a 280c logic board, Sharp LCD and inverter with polymer capacitors; no leakage found; a polymer part on the LCD broke loose when the lid was gripped; low-profile polymer tantalums suggested instead. Community repair report.
  7. ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 68kMLA forum thread "PowerBook Duo 230 repair and preventive maintenance", Fizzbinn (May 2021, reposted July 2021) and chartreuse (August 2021). Duo 230 board 820-0426-D: C2, C11 100 µF 25 V; C3, C5, C9 100 µF 35 V; C14 330 µF 16 V (chartreuse: C8); C36 33 µF 25 V; Sharp LM64N794 panel, C1-C8 3.3 µF 35 V; replacement part numbers; removal with ChipQuik; leaking C36 and panel capacitors; damaged via at C35. Community repair report.
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 68kMLA forum thread "PowerBook Duo 270c Restoration", mitchW, September 2023. 270c logic board: four 100 µF 35 V (10 × 10 mm), one 47 µF 35 V (8 × 8 mm), one 100 µF 25 V (8 × 8 mm), one 33 µF 25 V (6 × 6 mm, 6 mm tall), all no taller than 10-11 mm; inverter one 10 µF 35 V, found leaking and replaced with three 4.7 µF 50 V MLCCs in parallel; Sharp LQ9D041 panel list. Community repair report.
  9. ↑ 9.0 9.1 9.2 MacDat, "PowerBook Duo 270c Capacitor Reference" and "PowerBook Duo 280c Capacitor Reference" (retrieved 2026-10-02). Logic board: four 100 µF 35 V, one 100 µF 25 V, one 47 µF 35 V, one 33 µF 25 V; Sharp LQ9D041 LCD: three 100 µF 6 V, one 47 µF 16 V, six 47 µF 6 V, one 33 µF 10 V, two 22 µF 10 V, one 10 µF 25 V, one 10 µF 16 V; inverter: one 10 µF 35 V. Secondary source.
  10. ↑ Console5 TechWiki, "Macintosh PowerBook 280c" (retrieved 2026-10-02). C2 47 µF 35 V; C3 100 µF 35 V; C6 100 µF 25 V; C7, C8, C9 100 µF 35 V; C72 33 µF 25 V; sold as a surface-mount polymer kit. Secondary source.
  11. ↑ 11.0 11.1 MacDat, "PowerBook Duo 280 Capacitor Reference" (retrieved 2026-10-02). Logic board as the 280c; the 280's LCD and inverter board have no electrolytics. Secondary source.
  12. ↑ Console5 TechWiki, "Macintosh PowerBook 2300c" (retrieved 2026-10-02). C2 47 µF 35 V; C3 100 µF 35 V; C6 100 µF 25 V; C7, C8, C9 100 µF 35 V; C41, C94 33 µF 25 V. Secondary source.
  13. ↑ 13.0 13.1 68kMLA forum thread "PB Duo 2300c and 270c Capacitor list", androda, Challenger 1983, 3lectr1cPPC and others, January 2021 to July 2023. 2300c board: four 100 µF 35 V, one 100 µF 25 V, one 47 µF 35 V, two 33 µF parts marked 33 EHA, confirmed as 25 V; a higher voltage rating is safe at the same capacitance. Community repair report.
  14. ↑ MacDat, "PowerBook Duo 2300c Capacitor Reference" (retrieved 2026-10-02). Four 100 µF 35 V, one 100 µF 25 V, one 47 µF 35 V, one 33 µF 25 V; a recap may bring a dead 2300c back to life. Secondary source.
  15. ↑ MacDat, "PowerBook Duo AC Adapter (M2693) Capacitor Reference" (retrieved 2026-10-02). Secondary source.


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