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Macintosh LC III+ Capacitor Replacement Guide: Difference between revisions

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Removed the copied C1-C17+C22 table: no capacitor list has ever been published for an LC III+ board. Replaced with Apple's Performa 460/466/467 specifications and shared part numbers, plus how to identify the board and which published list applies. C22 warning retained with citations
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{{Unverified data}}
The '''Macintosh LC III+''' is a 33 MHz version of the
Replacing the electrolytic capacitors (recapping) in the '''Macintosh LC III+''' is essential for long-term reliability.
[[Macintosh LC III|LC III]], sold to consumers as the '''Performa 460''', '''466''' and '''467'''. Its
surface-mount electrolytic capacitors have the same thirty-year-old leakage problem as the rest of the
family, and recapping it is essential maintenance.


== Known Factory Defect: C22 ==
'''Read your board number before you order parts.''' No capacitor list has ever been published for a
board identified specifically as an LC III+ board, and this page does not invent one. What follows is
what is actually documented, and how to work out which list applies to the machine in front of you.


'''Important:''' Like the LC III, the Macintosh LC III+ has a known manufacturing defect where '''capacitor C22 was installed with reversed polarity''' at the factory. The silkscreen marking on the PCB is printed backwards.
== What Apple documents ==


When replacing capacitors, install C22 with '''correct polarity''' according to the capacitor's markings, '''not''' the PCB silkscreen.
Apple services the LC III+ as part of the Performa 400 Series, alongside the Performa 400/405, 410, 430,
450 and 475/476.<ref name="ss-p400">Apple Computer, ''Service Source: Macintosh Performa 400 Series'' — covers the Performa 400/405, 410, 430, 450, 460/466/467 and 475/476. Hosted on this wiki as [[:File:Performa 400 series.pdf]]; see [[Macintosh Performa 400 Series Service Source]].</ref> For the Performa 460/466/467 Apple specifies:


== Symptoms of Capacitor Failure ==
<templatestyles src="Template:StyledTable/styles.css" />
 
{| class="wikitable styled-table" style="width:80%;"
* '''No audio''' — Most common early symptom
! Item !! Specification
* '''Distorted or crackling audio'''
* '''Boot failures or instability'''
* '''Visible electrolyte leakage''' — Brown or black residue around capacitors
* '''Corrosion on PCB traces'''
 
== Capacitor List ==
 
=== Logic Board Capacitors ===
 
The LC III+ uses the same capacitor layout as the LC III.
 
{| class="wikitable" style="width:80%; text-align:center;"
|+ '''Macintosh LC III+ Logic Board Capacitors'''
|-
! Designator !! Capacitance !! Voltage !! Notes
|-
| C1 || 1 µF || 50V ||
|-
| C2 || 1 µF || 50V ||
|-
| C3 || 10 µF || 16V ||
|-
| C4 || 10 µF || 16V ||
|-
|-
| C5 || 10 µF || 16V ||
| Processor || Motorola 68030, 33 MHz, 32-bit internal data bus, burst-mode RAM access, coprocessor socket
|-
|-
| C6 || 10 µF || 16V ||
| DRAM || 4 MB standard, expandable to 36 MB (80 ns or faster SIMMs)
|-
|-
| C7 || 47 µF || 16V ||
| ROM || 1 MB
|-
|-
| C8 || 47 µF || 16V ||
| VRAM || 512 K on board, upgradable to 768 K
|-
|-
| C9 || 47 µF || 16V ||
| Floppy drive || Apple SuperDrive, manual insert
|-
|-
| C10 || 47 µF || 16V ||
| Hard drive || 80 MB (Performa 460); 160 MB (466/467)
|-
|-
| C11 || 47 µF || 16V ||
| Power supply || Apple 661-1733 — the same universal 100–240 VAC supply used by the whole LC pizza-box family
|-
|-
| C12 || 47 µF || 16V ||
| Battery || Apple 742-0011, 3.6 V lithium half-AA
|-
| C13 || 47 µF || 16V ||
|-
| C14 || 47 µF || 16V ||
|-
| C15 || 100 µF || 6.3V ||
|-
| C16 || 100 µF || 6.3V ||
|-
| C17 || 100 µF || 6.3V ||
|-
| C22 || 47 µF || 16V || '''Factory reversed polarity — install correctly!'''
|}
|}


[[File:Mac LC III Recap Guide.jpg|center|thumb|600px|Macintosh LC III/III+ logic board capacitor locations. Note C22 silkscreen error. Source: [https://recapamac.com.au/macintosh-lciii/ Recap-a-Mac]]]
All of the above comes from Apple's Performa 400 Series exploded view and specification
chapters.<ref name="ss-p400" /> Note what this tells you: the chassis, the power supply and the battery are common
with the LC III, and the electrical specification of the LC III+ differs from the 25 MHz LC III only
in clock speed.
 
Apple's separate ''Macintosh LC Series / Quadra 605'' volume does not cover the LC III+ at all — it
stops at the LC III and the LC 475.<ref name="ss-lc">Apple Computer, ''Service Source: Macintosh LC Series / Quadra 605'' — Specifications, Troubleshooting, Take Apart, Additional Procedures and Exploded View chapters. Hosted on this wiki as [[:File:Quadra 605.lc series.pdf]]; see [[Macintosh LC Series/ Quadra 605 Service Source]].</ref> Neither volume contains component-level capacitor data for
any model, so Apple is not the source for capacitor values on any of these machines.


=== Power Supply Capacitors ===
== What is not documented ==


Refer to the [[Macintosh LC Power Supply Recap Guide]] for PSU-specific information.
Neither of the two community sources that carry per-designator capacitor lists for this family has an
LC III+ entry:


[[File:Mac LC PSU Recap Guide.jpg|center|thumb|600px|Macintosh LC power supply capacitor locations. Source: [https://recapamac.com.au/macintosh-lc-power-supply/ Recap-a-Mac]]]
* '''Recap-a-Mac''' publishes an annotated photograph of an '''820-0650-B''' board, captioned "Macintosh
  LC III (Performa 450)". It has no LC III+ page.<ref name="ram-lciii">[https://recapamac.com.au/macintosh-lciii/ Recap-a-Mac — Macintosh LC III (Performa 450)]. Annotated photograph of the 820-0650-B logic board, and Recap-a-Mac's note that C22 on the −5 V rail was fitted the wrong way round. Hosted on this wiki as [[:File:Mac LC III Recap Guide.jpg]]. Secondary source.</ref>
* '''Console5''' lists capacitors for boards '''630-0309''' (LC), '''820-0327-A''' (LC II) and
  '''820-0650-A / 820-0650-B''' (LC III). It has no LC III+ entry.<ref name="console5-lc">[https://wiki.console5.com/wiki/Macintosh_LC Console5 Wiki — Macintosh LC]. Community-maintained capacitor lists giving per-designator values for logic boards 630-0309 (LC), 820-0327-A (LC II) and 820-0650-A/B (LC III), and for six different LC-family power supplies. Secondary source: not an Apple document, but it agrees value-for-value with the independent Recap-a-Mac photographs.</ref>


== Capacitor Replacement Procedure ==
Boards sold in the trade as Performa 460/466/467 or LC III+ boards are commonly marked 820-0650-B, the
same number as the LC III board, but this wiki has not verified that on a bench and no published source
states it as fact. Treat it as a strong expectation to be checked, not as a given.


=== Tools Required ===
== How to work out which list applies ==


* Temperature-controlled soldering iron (recommended: 300-350°C)
# Take the logic board out and read the number silk-screened in the top-left corner, beside the Apple copyright notice.
* Fine tip for SMD work
# '''If it reads 820-0650''' (any revision suffix), use the eleven-capacitor list on [[Macintosh LC III Capacitor Replacement Guide]] — '''including the C22 warning''', which applies to that board and is the most important thing on this page.
* Desoldering braid or solder wick
# '''If it reads anything else''', do not assume. Photograph the board, read the value off each capacitor body before you remove it, and count what you find. A board that does not match 820-0650 is not covered by any published list, and this wiki would rather you measured than guessed.
* Flux (no-clean recommended)
* Isopropyl alcohol (99%)
* Soft brush (ESD-safe)
* Multimeter
* Replacement SMD electrolytic capacitors


=== Procedure ===
== C22 ==


# '''Remove the logic board''' — Disconnect all cables, remove screws, and carefully lift the board.
If your board is an 820-0650, one capacitor position — '''C22''', the bulk capacitor on the
# '''Document capacitor positions''' — Note polarity markings before removal.
−5 V rail — has both its factory placement and its PCB silkscreen reversed, and the
# '''Clean the area''' — Remove any leaked electrolyte with isopropyl alcohol.
replacement must go in the opposite way round to the silkscreen. This has been verified with a multimeter
# '''Remove old capacitors''' — Heat one pad while gently lifting the capacitor. Alternate between pads.
and cross-checked against the LC, LC II and LC 475 boards, which are wired correctly. Fitting a tantalum
# '''Clean the pads''' — Remove old solder with desoldering braid. Clean with IPA.
in the silk-screened orientation has been reported to pull the −5 V rail down to about
# '''Inspect for damage''' — Check traces and vias for corrosion.
−2.3 V with the capacitor drawing around 1.3 A.<ref name="ddb">Doug Brown, [https://www.downtowndougbrown.com/2024/11/the-capacitor-that-apple-soldered-incorrectly-at-the-factory/ “The capacitor that Apple soldered incorrectly at the factory”], 26 November 2024. Continuity and voltage measurements showing that C22 on the LC III board has its positive terminal on −5 V and its negative terminal on ground; comparison with the LC, LC II and LC 475 boards, which are wired the other way round; and the reported consequences of fitting a tantalum in the silkscreened orientation.</ref> The full explanation, the circuit
# '''Install new capacitors''' — Observe polarity. '''For C22: ignore the PCB silkscreen.'''
description and the continuity check you can run yourself are on
# '''Clean residue''' — Remove flux with isopropyl alcohol.
[[Macintosh LC III Capacitor Replacement Guide]].
# '''Test continuity''' — Verify no shorts between +5V, +12V, and ground.
# '''Reassemble and test'''


== Important Notes ==
== Power supply, battery and procedure ==


* '''C22 silkscreen error''' — The PCB marking is wrong. Install based on the capacitor's polarity marking.
Common to the whole family and documented on [[Macintosh LC Capacitor Replacement Guide]]: the shared
* '''Polarity matters''' — SMD electrolytics will fail if installed backwards.
Apple 661-1733 supply and its six known vendor variants, the removal and fitting procedure, and the
* '''Use equivalent or better specs''' — Match capacitance; voltage rating can be equal or higher.
742-0011 lithium battery, which Apple says to replace below 3.0 V.<ref name="ss-lc" /><ref name="ss-p400" />


== Related Pages ==
== Related pages ==


* [[Macintosh LC III+]]
* [[Macintosh LC III+]]
* [[Macintosh LC III Capacitor Replacement Guide]] — the list for the 820-0650 board
* [[Macintosh LC III+ General Maintenance]]
* [[Macintosh LC III+ General Maintenance]]
* [[Macintosh LC III+ Troubleshooting]]
* [[Macintosh LC III+ Troubleshooting]]
* [[Macintosh LC Capacitor Replacement Guide]] — shared procedure, power supply and battery
* [[Macintosh Performa 400 Series Service Source]]


== External Resources ==
== References ==
 
<references />
* [https://recapamac.com.au/macintosh-lciii/ Recap-a-Mac: Macintosh LC III Capacitor Guide] (same board as LC III)


[[Category:Apple Vintage Computers]]
[[Category:Apple Vintage Computers]]
[[Category: Capacitor Replacement Guides]]
[[Category:Capacitor Replacement Guides]]
{{Navbox-AppleVintage|state=collapsed}}

Revision as of 00:41, 23 September 2026

The Macintosh LC III+ is a 33 MHz version of the LC III, sold to consumers as the Performa 460, 466 and 467. Its surface-mount electrolytic capacitors have the same thirty-year-old leakage problem as the rest of the family, and recapping it is essential maintenance.

Read your board number before you order parts. No capacitor list has ever been published for a board identified specifically as an LC III+ board, and this page does not invent one. What follows is what is actually documented, and how to work out which list applies to the machine in front of you.

What Apple documents

Apple services the LC III+ as part of the Performa 400 Series, alongside the Performa 400/405, 410, 430, 450 and 475/476.[1] For the Performa 460/466/467 Apple specifies:

Item Specification
Processor Motorola 68030, 33 MHz, 32-bit internal data bus, burst-mode RAM access, coprocessor socket
DRAM 4 MB standard, expandable to 36 MB (80 ns or faster SIMMs)
ROM 1 MB
VRAM 512 K on board, upgradable to 768 K
Floppy drive Apple SuperDrive, manual insert
Hard drive 80 MB (Performa 460); 160 MB (466/467)
Power supply Apple 661-1733 — the same universal 100–240 VAC supply used by the whole LC pizza-box family
Battery Apple 742-0011, 3.6 V lithium half-AA

All of the above comes from Apple's Performa 400 Series exploded view and specification chapters.[1] Note what this tells you: the chassis, the power supply and the battery are common with the LC III, and the electrical specification of the LC III+ differs from the 25 MHz LC III only in clock speed.

Apple's separate Macintosh LC Series / Quadra 605 volume does not cover the LC III+ at all — it stops at the LC III and the LC 475.[2] Neither volume contains component-level capacitor data for any model, so Apple is not the source for capacitor values on any of these machines.

What is not documented

Neither of the two community sources that carry per-designator capacitor lists for this family has an LC III+ entry:

  • Recap-a-Mac publishes an annotated photograph of an 820-0650-B board, captioned "Macintosh
 LC III (Performa 450)". It has no LC III+ page.[3]
  • Console5 lists capacitors for boards 630-0309 (LC), 820-0327-A (LC II) and
 820-0650-A / 820-0650-B (LC III). It has no LC III+ entry.[4]

Boards sold in the trade as Performa 460/466/467 or LC III+ boards are commonly marked 820-0650-B, the same number as the LC III board, but this wiki has not verified that on a bench and no published source states it as fact. Treat it as a strong expectation to be checked, not as a given.

How to work out which list applies

  1. Take the logic board out and read the number silk-screened in the top-left corner, beside the Apple copyright notice.
  2. If it reads 820-0650 (any revision suffix), use the eleven-capacitor list on Macintosh LC III Capacitor Replacement Guide — including the C22 warning, which applies to that board and is the most important thing on this page.
  3. If it reads anything else, do not assume. Photograph the board, read the value off each capacitor body before you remove it, and count what you find. A board that does not match 820-0650 is not covered by any published list, and this wiki would rather you measured than guessed.

C22

If your board is an 820-0650, one capacitor position — C22, the bulk capacitor on the −5 V rail — has both its factory placement and its PCB silkscreen reversed, and the replacement must go in the opposite way round to the silkscreen. This has been verified with a multimeter and cross-checked against the LC, LC II and LC 475 boards, which are wired correctly. Fitting a tantalum in the silk-screened orientation has been reported to pull the −5 V rail down to about −2.3 V with the capacitor drawing around 1.3 A.[5] The full explanation, the circuit description and the continuity check you can run yourself are on Macintosh LC III Capacitor Replacement Guide.

Power supply, battery and procedure

Common to the whole family and documented on Macintosh LC Capacitor Replacement Guide: the shared Apple 661-1733 supply and its six known vendor variants, the removal and fitting procedure, and the 742-0011 lithium battery, which Apple says to replace below 3.0 V.[2][1]

References

  1. ↑ 1.0 1.1 1.2 Apple Computer, Service Source: Macintosh Performa 400 Series — covers the Performa 400/405, 410, 430, 450, 460/466/467 and 475/476. Hosted on this wiki as File:Performa 400 series.pdf; see Macintosh Performa 400 Series Service Source.
  2. ↑ 2.0 2.1 Apple Computer, Service Source: Macintosh LC Series / Quadra 605 — Specifications, Troubleshooting, Take Apart, Additional Procedures and Exploded View chapters. Hosted on this wiki as File:Quadra 605.lc series.pdf; see Macintosh LC Series/ Quadra 605 Service Source.
  3. ↑ Recap-a-Mac — Macintosh LC III (Performa 450). Annotated photograph of the 820-0650-B logic board, and Recap-a-Mac's note that C22 on the −5 V rail was fitted the wrong way round. Hosted on this wiki as File:Mac LC III Recap Guide.jpg. Secondary source.
  4. ↑ Console5 Wiki — Macintosh LC. Community-maintained capacitor lists giving per-designator values for logic boards 630-0309 (LC), 820-0327-A (LC II) and 820-0650-A/B (LC III), and for six different LC-family power supplies. Secondary source: not an Apple document, but it agrees value-for-value with the independent Recap-a-Mac photographs.
  5. ↑ Doug Brown, “The capacitor that Apple soldered incorrectly at the factory”, 26 November 2024. Continuity and voltage measurements showing that C22 on the LC III board has its positive terminal on −5 V and its negative terminal on ground; comparison with the LC, LC II and LC 475 boards, which are wired the other way round; and the reported consequences of fitting a tantalum in the silkscreened orientation.
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