Editing Macintosh Classic II Capacitor Replacement Guide

The '''Macintosh Classic II''' is one of the machines that must be recapped. Its logic board uses surface-mount electrolytics that leak a conductive, corrosive electrolyte, and it also carries a 1/2&nbsp;AA lithium cell of the type that has a reputation for venting over the board. Recap-a-Mac's advice for an untouched example is blunt: if you do not know whether the battery has been changed or the capacitors replaced, see to it right away.<ref name="recapcii" />

The Classic and the Classic II share a power/sweep board but '''not''' a logic board, so the two halves of this guide have different scopes.

== Safety ==

{{Warning|'''The CRT anode holds charge after power-off.''' Discharge it before working on the power/sweep board, the anode lead or the CRT socket board — see [[CRT Discharge Procedure]].

'''The power/sweep board is a mains-connected switch-mode supply.''' CP1 (and, on 110&nbsp;V boards, CP13) is the primary reservoir, sitting at rectified mains potential and holding charge after the machine is unplugged. Measure across it before touching the primary side. Recapping this board is a normal repair — measure first, and read the next warning about its voltage rating.

'''The lithium battery can explode if mishandled.''' That is Apple's own wording.<ref name="APPLESS" />

Apple's US Service Source rates the machine at 100–120&nbsp;V AC, 47–63&nbsp;Hz, 100&nbsp;W maximum; 220&nbsp;V power/sweep boards were also produced and have their own part numbers.<ref name="APPLESS" />}}

== Do the Battery First ==

Apple's verification procedure is to remove the logic board, measure across the cell, and '''replace it if it reads below 3.0&nbsp;V'''.<ref name="APPLESS" /> The Apple part number for the cell is 742-0011.<ref name="APPLESS" />

Recap-a-Mac notes that the particular brand of 1/2&nbsp;AA cell Apple used in this family has a tendency to spray electrolyte across the logic board, in some cases doing damage that cannot be repaired.<ref name="recapclassic" /> Remove it before you do anything else. See [[Battery Explosion, Capacitor or Corrosion Damage]].

== Capacitor Inspection ==

Surface-mount electrolytics rarely bulge. Look instead for:

* Dark haloes or dried crust at the base of the cans.
* Dull or green solder joints on nearby IC pins.
* Thinned or missing traces, best seen under a loupe with light raking across the board.

See [[Capacitor Failure Symptoms]].

== Logic Board ==

Two variants exist, and they are easy to tell apart without a part number: the earlier board has '''four ROM chips''' in the bottom right corner and '''13''' surface-mount electrolytics; the later one has '''two ROM chips''' and '''17'''.<ref name="recapcii" />

<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:70%; text-align:center;"
|+ '''Classic II logic board (630-0055-B / 820-0326-B or 630-0401-B / 820-0401-B)'''
|-
! Reference !! Capacitance !! Voltage !! Fitted on
|-
| C3 || 47 µF || 16 V || Both
|-
| C4 || 47 µF || 16 V || Both
|-
| C5 || 10 µF || 16 V || Both
|-
| C6 || 10 µF || 16 V || Both
|-
| C7 || 10 µF || 16 V || Both
|-
| C8 || 10 µF || 16 V || Both
|-
| C9 || 1 µF || 50 V || Both
|-
| C10 || 10 µF || 16 V || Both
|-
| C11 || 10 µF || 16 V || Both
|-
| C12 || 10 µF || 16 V || Both
|-
| C13 || 47 µF || 16 V || Both
|-
| C14 || 10 µF || 16 V || Both
|-
| C15 || 1 µF || 50 V || Both
|-
| C21 || 10 µF || 16 V || 630-0055 only
|-
| C74 || 10 µF || 16 V || 630-0055 only
|-
| C79 || 10 µF || 16 V || 630-0055 only
|-
| C106 || 10 µF || 16 V || 630-0055 only
|}

Two independent sources agree on the totals. Console5 gives the designators above and flags the last four as fitted to board 630-0055 only;<ref name="c5cii" /> Recap-a-Mac's photographic guides, made from physical boards, count '''8&nbsp;×&nbsp;10&nbsp;µF 16&nbsp;V, 3&nbsp;×&nbsp;47&nbsp;µF 16&nbsp;V and 2&nbsp;×&nbsp;1&nbsp;µF 50&nbsp;V''' on the 13-capacitor board and '''12&nbsp;×&nbsp;10&nbsp;µF 16&nbsp;V, 3&nbsp;×&nbsp;47&nbsp;µF 16&nbsp;V and 2&nbsp;×&nbsp;1&nbsp;µF 50&nbsp;V''' on the 17-capacitor board.<ref name="recapciia" /><ref name="recapciib" /> Those tallies match exactly. Count the capacitors on your own board before ordering.

<gallery mode="packed" heights="250">
File:Classic II (A) recapping.jpg|Classic II 13-capacitor logic board
File:Classic II (B) Recapping.jpg|Classic II 17-capacitor logic board
</gallery>

== Power/Sweep Board ==

The Classic and Classic II share this board.<ref name="recapanalog" /> Apple lists '''four''' field-replaceable variants:<ref name="APPLESS" />

* 661-0597 — 110&nbsp;V, Rev. A
* 661-0599 — 220&nbsp;V, Rev. A
* 661-0651 — 110&nbsp;V, Rev. B
* 661-0652 — 220&nbsp;V, Rev. B

The bare boards carry their own numbers: 630-0395, 630-0420, 630-0525 and 630-0560.<ref name="c5395" /><ref name="c5560" />

{{Warning|'''CP1 is rated differently on 110&nbsp;V and 220–240&nbsp;V boards, and this matters.'''

On a '''110/120&nbsp;V''' board the mains input is a voltage doubler, and CP1 and CP13 are a '''series pair of 220&nbsp;µF 250&nbsp;V''' capacitors.

On a '''220–240&nbsp;V''' board there is no doubler. '''CP1 is a single 220&nbsp;µF 400&nbsp;V capacitor and CP13 is a jumper with no capacitor fitted at all.'''<ref name="c5560" /> Recap-a-Mac's photographic guide for a 240&nbsp;V board independently shows one 220&nbsp;µF 400&nbsp;V part and no 250&nbsp;V electrolytic anywhere on the board.<ref name="recapanalog" />

240&nbsp;V mains rectifies to roughly 340&nbsp;V DC. Fitting a 250&nbsp;V capacitor at CP1 on a 240&nbsp;V board puts it far over its rating, and it will fail — loudly, and possibly violently. Identify which board you have before you order parts.}}

=== 110/120 V board (630-0560, 120 V list; also 630-0395) ===

{| class="wikitable styled-table" style="width:80%; text-align:center;"
|+ '''Classic / Classic II power/sweep board — 120 V version'''
|-
! Reference !! Capacitance !! Voltage
|-
| CF1 || 47 µF || 25 V
|-
| CF2 || 220 µF || 16 V
|-
| CF3 || 1000 µF || 16 V
|-
| CF4 || 470 µF || 25 V
|-
| CL1 || 10 µF || 50 V
|-
| CL2 || 4.7 µF || 250 V
|-
| CL3 || 1 µF || 50 V
|-
| CP1 || 220 µF || 250 V
|-
| CP2 || 470 µF || 50 V
|-
| CP3 || 10 µF || 25 V
|-
| CP4 || 47 µF || 25 V
|-
| CP5 || 1 µF || 50 V
|-
| CP6 || 2200 µF || 10 V
|-
| CP7 || 1000 µF || 10 V
|-
| CP8 || 2200 µF || 16 V
|-
| CP9 || 470 µF || 25 V
|-
| CP10 || 470 µF || 25 V
|-
| CP11 || 220 µF || 50 V
|-
| CP12 || 1000 µF || 16 V
|-
| CP13 || 220 µF || 250 V
|-
| CP31 || 1000 µF || 6.3 V
|-
| CP34 || 1 µF || 50 V
|-
| CP35 || 1 µF || 50 V
|-
| CP36 || 2200 µF || 10 V
|-
| CP37 || 1 µF || 50 V
|}

From Console5's list for 630-0560.<ref name="c5560" /> Console5's list for the earlier 630-0395 differs in two places: CP2 is 1000&nbsp;µF 35&nbsp;V and CP11 is 220&nbsp;µF 25&nbsp;V on that board.<ref name="c5395" />

=== 220/240 V board (630-0560, 240 V list; also 630-0420, 630-0525) ===

{| class="wikitable styled-table" style="width:80%; text-align:center;"
|+ '''Classic / Classic II power/sweep board — 240 V version'''
|-
! Reference !! Capacitance !! Voltage
|-
| CF1 || 47 µF || 25 V
|-
| CF2 || 220 µF || 16 V
|-
| CF3 || 1000 µF || 16 V
|-
| CF4 || 470 µF || 25 V
|-
| CL1 || 1000 µF || 25 V
|-
| CL2 || 4.7 µF || 250 V
|-
| CL3 || 1 µF || 50 V
|-
| CL11 || 47 µF || 16 V
|-
| CP1 || 220 µF || '''400 V'''
|-
| CP2 || 470 µF || 50 V
|-
| CP3 || 10 µF || 25 V
|-
| CP4 || 47 µF || 25 V
|-
| CP5 || 1 µF || 50 V
|-
| CP6 || 2200 µF || 10 V
|-
| CP7 || 1000 µF || 10 V
|-
| CP8 || 2200 µF || 16 V
|-
| CP9 || 470 µF || 25 V
|-
| CP10 || 470 µF || 25 V
|-
| CP11 || 220 µF || 50 V
|-
| CP12 || 1000 µF || 16 V
|-
| CP13 || colspan="2" | '''Jumper — no capacitor fitted'''
|-
| CP34 || 1 µF || 50 V
|-
| CP36 || 2200 µF || 10 V
|-
| CP37 || 1 µF || 50 V
|-
| CV2 || 470 µF || 10 V
|}

Console5 publishes this as the 240&nbsp;V list for 630-0560, and the same list without the CP13 note as 630-0525.<ref name="c5560" /><ref name="c5525" /> Recap-a-Mac's photographic guide for a 240&nbsp;V board agrees on every value and quantity except the 1&nbsp;µF 50&nbsp;V positions, where it marks two where Console5 lists four (CL3, CP5, CP34, CP37).<ref name="recapanalog" /> Check your own board.

[[File:Mac_classic_analog_recap.jpg|thumb|694x694px|Macintosh Classic / Classic II power/sweep board recapping guide (240&nbsp;V version)|center]]

Recap-a-Mac also warns that an earlier revision of this board exists with a slightly different neck-board connector and one or two capacitors different from the guide above, and that besides capacitors these boards suffer cracked solder joints, corrosion and short circuits from leakage, and failure of the DIP ICs '''IF1''', '''QP1''' and '''JP1'''.<ref name="recapanalog" />

=== Voltage adjustment ===

Apple's Service Source for the Classic and Classic II contains Video and Yoke adjustment procedures and no voltage adjustment, and publishes no rail tolerances for the machine.<ref name="APPLESS" /> Recap-a-Mac reports that the output voltage can be adjusted using the variable resistor '''PP1''' on the power/sweep board.<ref name="recapanalog" />

== Replacement Capacitors ==

For the logic board, Recap-a-Mac uses solid tantalum at the same values:<ref name="recapclassic" />

* 1&nbsp;µF 50&nbsp;V — KEMET T491B105K050AT
* 47&nbsp;µF 16&nbsp;V — KEMET T491D476K016AT

Why that class of part:

* '''Solid tantalum''' has no liquid electrolyte and cannot leak. It fails '''short''', so derate generously — a part rated well above the rail it sits on is far less likely to be driven into failure by a switch-on surge.
* '''Solid polymer aluminium''' also has no liquid electrolyte and typically fails '''open''' rather than short, which is gentler on whatever is downstream, and has lower ESR. It is the safer failure mode for vintage hardware.
* '''Ordinary aluminium electrolytic''' matches the original footprint exactly and is the cheapest option, but it will eventually leak again.

On the logic board, check the physical footprint before ordering. Space around several of the 10&nbsp;µF positions is tight and a wider can will sit over its own pads, making it impossible to solder properly. There is also exposed plastic at the bottom edge of the board next to a cluster of capacitors, which is very easy to melt with a soldering iron.<ref name="recapccii" />

For the power/sweep board use 105&nbsp;°C-rated aluminium electrolytics from a known manufacturer throughout, and match or exceed the rating printed on the part you removed.

== Capacitor Replacement Procedure ==

# '''Remove the logic board''' and take the battery off it.
# '''Discharge the CRT''' before touching the power/sweep board — see [[CRT Discharge Procedure]].
# '''Confirm CP1 has discharged''' before working on the primary side.
# '''Remove the surface-mount capacitors''' by alternating heat between the terminals while tilting the can gently, or with hot air and the plastic shielded. Twisting a can off cold takes the pads with it.
# '''Clean thoroughly''' with 99&nbsp;% isopropyl alcohol and a soft brush until a clean swab comes away clean.
# '''Inspect and test''' continuity across every trace that ran under or beside a capacitor, and repair breaks before fitting anything new.
# '''Fit the new parts''' the right way round. On a tantalum the stripe marks '''positive'''; on an aluminium electrolytic it marks '''negative'''.
# '''Check for shorts''' across each rail before applying power.

Tools are listed on [[Recommended Tools]].

== Module Part Numbers ==

From Apple's exploded view for the Classic, Classic II and Performa 200:<ref name="APPLESS" />

* Logic board — 661-0596 (1&nbsp;MB, Classic) or '''661-0672''' (2&nbsp;MB, Classic II and Performa 200)
* Power/sweep board — 661-0597, 661-0599, 661-0651 or 661-0652 as listed above
* Lithium battery — 742-0011
* CRT and yoke assembly — 076-0546
* Floppy drive — 661-0474

== Related Pages ==
* [[Macintosh Classic II]]
* [[Macintosh Classic / Classic II General Maintenance]]
* [[Macintosh Classic / Classic II Troubleshooting]]
* [[Battery Explosion, Capacitor or Corrosion Damage]]
* [[Capacitor Failure Symptoms]]
* [[Macintosh Floppy Drive Maintenance]]
* [[CRT Discharge Procedure]]
* [[Recommended Tools]]

== References ==
<references>
<ref name="APPLESS">Apple Computer, ''Macintosh Classic / Classic II / Performa 200 Service Source'', hosted here as [[:File:Macintosh Classic - Classic II.pdf]]. Specifications (Electrical), Additional Procedures — Battery Verification (3.0&nbsp;V threshold and the explosion warning), Adjustments (Video and Yoke only), and the Exploded View parts list. Apple's Service Source is module-level: procedures, thresholds and field-replaceable-unit numbers, not component values.</ref>
<ref name="c5cii">Console5 TechWiki, "Macintosh Classic II" — logic board 630-0055-B / 820-0326-B or 630-0401-B / 820-0401-B. https://wiki.console5.com/wiki/Macintosh_Classic_II Secondary source — a vendor cap-kit list, not Apple documentation.</ref>
<ref name="c5395">Console5 TechWiki, "Mac Analog Board: 630-0395". https://wiki.console5.com/wiki/Mac_Analog_Board:_630-0395 Secondary source.</ref>
<ref name="c5525">Console5 TechWiki, "Mac Analog Board: 630-0525". https://wiki.console5.com/wiki/Mac_Analog_Board:_630-0525 Secondary source.</ref>
<ref name="c5560">Console5 TechWiki, "Mac Analog Board: 630-0560", which publishes separate 120&nbsp;V and 240&nbsp;V lists including CP1 at 250&nbsp;V versus 400&nbsp;V and CP13 as a jumper on the 240&nbsp;V board. https://wiki.console5.com/wiki/Mac_Analog_Board:_630-0560 Secondary source.</ref>
<ref name="recapcii">Bruce / Recap-a-Mac, "Macintosh Classic II (Rev A)". https://recapamac.com.au/macintosh-classic-ii-a/ The 13-capacitor / four-ROM versus 17-capacitor / two-ROM distinction. Secondary source.</ref>
<ref name="recapciia">Bruce / Recap-a-Mac, "Macintosh Classic II (Rev A)" recapping guide — 8&nbsp;×&nbsp;10&nbsp;µF 16&nbsp;V, 3&nbsp;×&nbsp;47&nbsp;µF 16&nbsp;V, 2&nbsp;×&nbsp;1&nbsp;µF 50&nbsp;V. https://recapamac.com.au/macintosh-classic-ii-a/ Secondary source, values photographed from a physical board.</ref>
<ref name="recapciib">Bruce / Recap-a-Mac, "Macintosh Classic II (Rev B)" recapping guide — 12&nbsp;×&nbsp;10&nbsp;µF 16&nbsp;V, 3&nbsp;×&nbsp;47&nbsp;µF 16&nbsp;V, 2&nbsp;×&nbsp;1&nbsp;µF 50&nbsp;V. https://recapamac.com.au/macintosh-classic-ii-b/ Secondary source.</ref>
<ref name="recapanalog">Bruce / Recap-a-Mac, "Macintosh Classic I + II Analog Board (220V – 240V version)". https://recapamac.com.au/macintosh-classic-analog/ Capacitor values and quantities for the 240&nbsp;V board including the single 220&nbsp;µF 400&nbsp;V part, the PP1 voltage adjustment, the IF1 / QP1 / JP1 DIP IC failures, and the warning about an earlier board revision. Secondary source.</ref>
<ref name="recapclassic">Bruce / Recap-a-Mac, "Macintosh Classic". https://recapamac.com.au/macintosh-classic/ The 1/2&nbsp;AA battery failure mode in this family, and the KEMET tantalum part numbers. Secondary source.</ref>
<ref name="recapccii">Bruce / Recap-a-Mac, "Macintosh Colo(u)r Classic II". https://recapamac.com.au/macintosh-colour-classic-ii/ The warning about melting the exposed plastic at the bottom edge of the board while soldering. Secondary source.</ref>
</references>

[[Category:Apple Vintage Computers]]
[[Category:Capacitor Replacement Guides]]