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PowerBook 140 Capacitor Replacement Guide

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The driver board on a Sharp FSTN panel from a PowerBook 140, 145, 160 or 165, with the capacitors to replace circled (MacDat)

The PowerBook 140, PowerBook 145 and 145B have no electrolytic capacitors on their logic boards. The parts that fail are small surface-mount electrolytics on the driver board along the lower edge of the LCD panel, two capacitors on the backlight inverter and one on the trackball.[1] When the LCD capacitors leak, the screen goes black or white with the backlight on and the contrast control stops working, or the contrast drifts and never settles.[2][3] Apple's Service Source works at module level and gives no capacitor values; the lists here come from MacDat and owners' repairs.[4]

The same panel, inverter and values are used in the PowerBook 160 and 165.[5] The PowerBook 170's active-matrix panel has none; on the 170 only the inverter's 47 µF 16 V part and the trackball's 10 µF 16 V part are electrolytic.[6]

Identify the display

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Apple used three FSTN panels in these machines, each with its own inverter and display cable.[4]

  • Rev. A, part 661-0706: plastic rear cover, display cable connector along the outer edge of the circuit board; blue inverter 699-0271. Owners identify it as the Sharp LM64P51.
  • Rev. B, part 661-0681: circuit board exposed at the rear, connector near the centre; red inverter 699-0272. Owners identify it as the Hitachi LMG5200XTFC.
  • Rev. C, part 661-0745: plastic rear cover, connector along the outer edge; inverter 922-0025. Owners identify it as the Sharp LM64P58 or LM64P582.[4][7]

MacDat's list below is for the Sharp panels. MacDat found no electrolytics on the Hitachi panel.[1]

Capacitor list

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LCD driver board (Sharp LM64P51 and LM64P58)

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LCD capacitors[1]
Value Count Type Position on the board
3.3 µF 35 V 9 Surface-mount electrolytic Three groups of three: two groups at the left end near connector JP1, one at the right end near JP2
22 µF 35 V 1 Surface-mount electrolytic Left of the block marked DC/DC CONVERTER
100 µF 6 V 1 Surface-mount electrolytic Right of the DC/DC converter block

Positions are from MacDat's photograph, in which a "+" in the silkscreen marks each positive pad. The can markings in the same photograph read 22 µF 35 V and 100 µF 6 V. Zarwox measured about 28 V from the DC/DC converter on a 145's panel.[1][8]

Backlight inverter board

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The inverter board, with the 47 µF electrolytic (red) and the 33 µF polymer (purple) circled (MacDat)
Inverter capacitors[1]
Ref Value Type Notes
C4 47 µF 16 V Low-profile radial electrolytic Replace
C1 33 µF 10 V Low-profile radial polymer MacDat: rarely fails

desertrout gives these designators for the two parts beside the contrast slider.[9]

Trackball

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One 10 µF 16 V radial electrolytic on the trackball board. MacDat notes it rarely fails.[1]

Choosing replacements

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Owners disagree over the 3.3 µF parts. MacDat recommends tantalums, because ceramic capacitors lose capacitance under DC bias and have caused contrast drift on some LCDs.[1] Ferrix97 found surface-mount electrolytics worked slightly better than ceramics, while Rajel, using all ceramics on the advice of an engineer, pointed out that tantalums have higher ESR than either.[3] A tantalum recap does not rule out contrast trouble: Zarwox's 145 still had a cold-start contrast fault afterwards.[8] Whatever type is fitted, match the capacitance, use at least the original voltage rating and check that the part fits the pad and the space between the panel and the housing.

Procedure

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Remove the display assembly from the computer before working on it. Work with the main battery out and the adapter disconnected throughout.

Remove the LCD panel

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  1. Shut down with the Shut Down command, disconnect the adapter, slide open the battery door and pull out the main battery.[4]
  2. Remove the two plastic plugs from the display bezel and the two T-8 Torx screws under them. Pull the bezel down and away to free it from the tabs at the top, and lift it off.[4]
  3. Cover the keyboard with a clean cloth. Remove the four T-8 screws holding the display, lift it out of the housing and EMI shield, and lay it face down on the keyboard.[4]
  4. Lift the locking tab on the display connector and disconnect the display cable. The cable on a 140 or 145 is stuck to the back of the display with adhesive near the connector and near the backlight end; pry it off carefully at those points.[4]
  5. Disconnect the inverter cable from the backlight cable and lift the display away.[4]

Replace the LCD capacitors

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  1. Note the polarity of each capacitor from the "+" marks on the board before removing anything.[1]
  2. Remove the old capacitors. The pads are small and lift easily; Ferrix97 uses a solder sucker in place of wick for this reason.[3]
  3. Clean every trace of electrolyte and corrosion from the board with isopropyl alcohol, including the pins of the nearby driver chips and under the flex cables that join the driver board to the glass. Residue left there shorted fine-pitch pins on one 145 and kept the screen black after its recap.[9]
  4. Fit the new capacitors, positive to the "+" pad, and check each joint.

Replace the inverter capacitors

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  1. Remove the main battery, the I/O door and the top case. The top case has five Torx screws in the bottom case: a T-8 for the small screw at the rear connector panel and a T-10 for the rest. Lift the case and disconnect the interconnect cable.[4]
  2. Remove the inverter shield if one is fitted, take out the two inverter screws, pull the board straight up off the interconnect board and disconnect the inverter cable.[4]
  3. Replace C4, and C1 if you choose.
  4. On refitting, set the brightness and contrast pots and the actuators in the top case to their extreme outer positions so they line up. Apple asks for an inverter shield on every machine; it is also Apple's cure for floppy read and write errors.[4]

Reassemble

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  1. Refit the display and reconnect its cable. Route the inverter cable behind the top-right corner of the hinge on the right clutch so it is not pinched.[4]
  2. When refitting the top case, fold the interconnect cable as Apple shows; Apple warns that a cable folded the wrong way can short.[4]

After the recap

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Check that the contrast control works across its range. 3lectr1cPPC found a small movement of the slider gave a visible change after his recap; Spode's recapped 145 changed little until the end of the travel, which the thread put down to a worn slider.[9] Some drift while the panel warms up is normal.[3] A picture that flickers or shows two black lines when the bezel is squeezed needs Apple's display cable shim; see PowerBook 140 Troubleshooting#Video.[4]

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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 MacDat, "Capacitor Reference - PowerBook 140" and "Capacitor Reference - PowerBook 145/145B" (retrieved 2026-10-02). No electrolytics on the logic board; LCD 100 µF 6 V ×1, 22 µF 35 V ×1, 3.3 µF 35 V ×9 (surface mount); inverter 47 µF 16 V low-profile radial electrolytic and 33 µF 10 V low-profile radial polymer, which rarely fails; trackball 10 µF 16 V radial, rarely fails; prefers tantalums to ceramics on the LCD because ceramics lose capacitance under DC bias and can cause contrast drift; the rare Hitachi LCD has no electrolytics. Secondary source.
  2. ↑ 68kMLA forum thread "Powerbook 140 screen contrast black", October 2020. bibilit: replace the capacitors on the back of the LCD and two on the inverter. Community experience.
  3. ↑ 3.0 3.1 3.2 3.3 68kMLA forum thread "PowerBook 145B (also for 140, 160, 145) Display Capacitor Replacement Video Tutorial", October 2014 to March 2017. Ferrix97: inverter 33 µF 10 V and 47 µF 16 V; surface-mount electrolytics worked a little better than ceramics for him; uses a solder sucker because wick can lift the fragile pads. Rajel: every 3.3 µF part on his LCD had leaked; recapping the LCD stopped the drift; a flux pen helps. Community repair reports.
  4. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 Apple Computer, PowerBook 140/145/145B/170 Service Source, hosted here as File:PowerBook 140, 145, 145B and 170 Service Source.pdf (see PowerBook 140, 145, 145B and 170 Service Source). PDF page numbers: display compatibility matrix p. 4; Main Battery pp. 58-61; I/O Door pp. 62-63; Top Case pp. 64-66; Inverter Board pp. 82-86; Display pp. 107-116; Shim Installation pp. 147-154. Module-level only; no component values.
  5. ↑ MacDat, "Capacitor Reference - PowerBook 160" (retrieved 2026-10-02). Same LCD, inverter and trackball values as the 140 and 145. Secondary source.
  6. ↑ MacDat, "Capacitor Reference - PowerBook 170" (retrieved 2026-10-02). Logic board and screen solid-state; inverter 47 µF 16 V low-profile radial; trackball 10 µF 16 V radial. Secondary source.
  7. ↑ 68kMLA forum thread "PowerBook 140, 145, 145B, 160, 165 LCD Displays", February 2022 to April 2024. desertrout: Rev. A Sharp LM64P51, Rev. B Hitachi LMG5200XTFC, Rev. C Sharp LM64P58/LM64P582; Rev. B needs its own cable and inverter; bibilit: cables differ in thickness between screens. Community experience.
  8. ↑ 8.0 8.1 68kMLA forum thread "Powerbook 145 global contrast issues", April 2025 to March 2026. Zarwox: after a tantalum recap the contrast was wrong from cold and settled after about an hour; the DC/DC converter on the LCD board gives about 28 V and is sensitive to temperature; new capacitors on its output made no difference, and the fault later disappeared on its own. alexGS: residue around the converter can cause temperature-sensitive faults. Community repair report.
  9. ↑ 9.0 9.1 9.2 68kMLA forum thread "PowerBook 145: No contrast AFTER recap", January 2022. desertrout: inverter in the top case next to the battery and speaker, two screws, pulls up off the interconnect board; C1 33 µF 10 V and C4 47 µF 16 V next to the contrast slider. mdeverhart: leftover electrolyte under fine-pitch chips and flex cables; cleaning cured a no-contrast fault after a recap. Community repair report.


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