Macintosh SE Capacitor Replacement Guide

The Macintosh SE logic board rarely needs recapping. Recap-a-Mac, who publish recapping guides for the compact Macs, say its axial electrolytics do not suffer the leakage of the surface-mount parts in later models. The parts that do need attention are the PRAM battery, the analogue board and the power supply. The Macintosh SE FDHD has the same boards, and the Macintosh SE/30 shares the analogue board and power supply.

Safety

The CRT anode holds a charge after the machine is switched off. Discharge it before working on the analogue board, video board or anode lead; see CRT Discharge Procedure.

The power supply is a separate mains-powered module. Its primary reservoir is a 620 µF 400 V capacitor, or a series pair of 330 µF 200 V capacitors, depending on which supply is fitted. These hold a charge after the machine is unplugged: measure across them before touching the primary side.

Apple warns that the lithium PRAM battery can explode if it is handled or disposed of improperly.

PRAM battery first

Apple rated the SE's lithium cell for seven years. Its test: remove the logic board, measure the cell on the 10 V DC range, and replace it below 2.8 V. Early boards have a 3 V half-AA cell soldered in by pigtail leads, later boards a 3.6 V half-AA cell in a holder. A leaking cell corrodes traces as badly as a leaking capacitor; see Battery Explosion, Capacitor or Corrosion Damage.

Inspection

Look for bulging tops, electrolyte crust at the leads, and staining or corrosion on the board around each part. See Capacitor Failure Symptoms.

Logic board

The logic board (bare board 820-0176 or 820-0250) has eleven electrolytics.

Macintosh SE logic board 820-0176 / 820-0250

Reference	Capacitance	Voltage
C4	33 µF	16 V
C11	33 µF	16 V
C13	33 µF	16 V
C16	33 µF	16 V
C32	33 µF	16 V
C34	33 µF	16 V
C36	1 µF	50 V
C37	33 µF	16 V
C38	33 µF	16 V
C62	33 µF	16 V
C86	33 µF	16 V

Console5's community kit list gives the designators; Recap-a-Mac's photograph of an 820-0176-B board marks the same ten 33 µF 16 V positions and C36 as 1 µF 50 V.

Macintosh SE logic board 820-0176-B with the electrolytic positions marked (Recap-a-Mac guide image)

Analogue board

The SE does not have the Macintosh Plus power/sweep board. Its analogue board, power supply and video board are three modules, with the same Apple part numbers in the SE and SE/30: 661-0371, 661-0370 and 982-0024. Thomas Lee notes that the horizontal and video circuits are close to the Plus design but the vertical and power supply circuits are completely different, so a Plus capacitor list does not fit.

Three sources give the analogue board electrolytics: Apple's analogue board drawing hosted here as File:Classic Analog Board Schematic.pdf (internal title "SE30_Analog_Board"; despite the file name it is not a Classic drawing, since the Classic has a combined power/sweep board with no separate supply), Console5's list for board 630-0147, and the Appendix E parts list in Larry Pina's Macintosh Repair & Upgrade Secrets. Apple's drawing and Console5 agree on every value; Pina lists 25 V parts at four positions where Apple and Console5 give 16 V, which is a higher rating and safe to fit.

Macintosh SE and SE/30 analogue board electrolytics

Reference	Apple drawing and Console5	Pina, Appendix E	Notes
C2	100 µF 16 V	100 µF 25 V	radial
C7	100 µF 16 V	100 µF 25 V	radial
C9	1000 µF 16 V	1000 µF 16 V	radial
C11	33 µF 16 V	33 µF 16 V	axial
C13	220 µF 16 V	220 µF 16 V, 105 °C	radial
C14	4700 µF 16 V	4700 µF 16 V	radial
C15	3.9 µF 35 V, non-polarised	3.9 µF 35 V HF non-polarised	see below
C18	22 µF 50 V	22 µF 50 V	axial
C19	10 µF 160 V	10 µF 160 V	radial
C22	100 µF 16 V	100 µF 25 V	radial
C24	220 µF 16 V	220 µF 16 V, 105 °C	radial
C25	100 µF 16 V	100 µF 25 V	radial

The BOMARC schematic of the SE analogue board hosted here, File:Fan, CRT Board.jpg (board 820-0206-B / 630-0174-C), shows the same values wherever they are legible. Pina's Appendix F lists the CRT socket board; it has no electrolytics.

C15

C15 is the non-polarised capacitor in series with the horizontal yoke and width coil L2. Console5 marks it bipolar, low-ESR. Pina gives it as 3.9 µF NP 25/35 V HF and fits a 3.9 µF NP 100 V HF part to stop the fault returning; his 1990 parts list also accepts 100 V and 125 V metallised polyester and 125 V polypropylene parts from Nichicon and Panasonic. Do not fit a polarised electrolytic here.

Pina's failure sequence for C15 (pp. 159–161):

1. Poor horizontal linearity: items on the left wider than items on the right.
2. A few minutes after startup, a vertical line on the right with diagonal lines; left on, the picture darkens and the machine starts to smoke.
3. A bright vertical line instead of a picture, again followed by smoke.

Check yoke plug P1 at the same time; Pina says it may be burnt at the later stages.

Power supply

The power supply module (Apple 661-0370) was made by three suppliers: Sony, Hitachi and Astec. Identify yours from the maker's name and model on its label before ordering parts. The Apple number does not settle it: Apple's Module Identification manual says the module label carries assembly number 699-5047, and a maker of replacement supplies lists 699-5047 on both the Astec AA13800 and the Sony CR-44, and 631-5105-A on the Hitachi. The lists below are Console5's capacitor-kit lists, community lists read from boards.

Power supply: Sony CR-44M

Reference	Capacitance	Voltage
C162	620 µF	400 V
C164	4.7 µF	350 V
C165	4.7 µF	350 V
C168	100 µF	16 V
C257	4700 µF	16 V
C258	6800 µF	10 V
C259	470 µF	16 V
C261	2200 µF	16 V
C262	3300 µF	10 V
C263	2200 µF	16 V
C264	470 µF	16 V
C265	47 µF	25 V
C266	2200 µF	16 V
C269	1 µF	50 V
C270	22 µF	25 V
C275	22 µF	25 V
C276	22 µF	25 V
C279	470 µF	16 V

Power supply: Hitachi (board 820-0385-A)

Reference	Capacitance	Voltage
C101	10 µF	25 V
C102	10 µF	25 V
C206	620 µF	400 V
C304	10 µF	25 V
C305	1000 µF	25 V
C306	470 µF	16 V
C307	1000 µF	10 V
C308	4700 µF	10 V
C309	1000 µF	16 V
C310	1000 µF	16 V
C311	470 µF	16 V
C312	470 µF	16 V
C401	100 µF	25 V
C402	10 µF	25 V
C404	22 µF	16 V
C408	10 µF	25 V
C412	100 µF	10 V

Power supply: Astec AA13800

Reference	Capacitance	Voltage
C7	330 µF	200 V
C8	330 µF	200 V
C19	220 µF	25 V
C21	47 µF	63 V
C23 or C25	470 µF	16 V
C24	1200 µF	10 V
C25 or C28	220 µF	16 V
C31	2200 µF	16 V
C32	47 µF	25 V
C35	470 µF	16 V
C36	1200 µF	10 V

Console5 prints "C23 or C25" and "C25 or C28" as shown; check the silkscreen on your board. It also notes that some Astec supplies have three 4700 pF metallised-paper (RIFA) Y-class safety capacitors, which should be replaced whenever found. The BOMARC SE schematic labels the supply connector P3 "to Apple # 699-5047 S.M.P.S. module" and does not name a maker.

Rails and adjustment

Apple's output limits for the SE and SE/30 supply are +5 V 4.85–5.20 V, +12 V sweep 11.50–12.50 V, +12 V disk 11.50–12.80 V and −12 V −13.20 to −10.80 V. There is no voltage adjustment: Apple's Adjustments chapter covers the yoke and the video controls (brightness, size and focus). The R56 trimmer in Apple's Macintosh Plus procedure is the single voltage-adjust control of the 128K/512K/Plus power/sweep board, where it moves +5 V and +12 V together; the SE and SE/30 do not have that board. A supply outside these limits needs repair.

Analogue board faults by component

Pina's The Dead Mac Scrolls gives the SE and SE/30 analogue board faults with replacement part specifications.

Symptom	Component	Specification	Page
No startup sound, dark display, hissing or sizzling	CR2 shorted (0.00–0.01 Ω)	Barrel rectifier GI854, silicon, 600 V 3 A; Pina fits an MR824 (400 V 5 A)	147
No startup sound, dark display, no noise	CR3 shorted; then Q2 burnt; then flyback T2	CR3 as CR2; Q2 is the BU406D horizontal output transistor	148
Right side shakes during disk access or when a window opens	CR2, then Q2	As above	156–157
Startup sound, fan and disk run, display dark, brightness does nothing	R22 open	470 kΩ, ½ W, 5 %	150
Dim vertical line	R19 burnt	220 Ω, ¼ W, 5 %; resolder linearity coil L3 with fresh solder or it recurs	162
Poor linearity, then a bright vertical line and smoke	C15, yoke plug P1	3.9 µF NP HF; fit a 100 V part	159–161

A single vertical line is a collapse of the horizontal sweep: C15, R19, L3 or P1. A single horizontal line is a collapse of the vertical sweep, around the TDA1170 vertical deflection IC at U2. Switch off at once in either case.

Procedure

1. Discharge the CRT; see CRT Discharge Procedure.
2. Remove the logic board, and the battery from it, before cleaning or reworking it.
3. Measure the power supply's primary capacitors and confirm they are discharged before opening it.
4. Photograph each board before removing anything.
5. Desolder with a temperature-controlled iron and wick or a desoldering pump; clean the pads and check for corrosion under each part.
6. Fit the new parts with the negative stripe to the negative pad. C15 is non-polarised.
7. Inspect for bridges and dry joints, and check each rail for shorts before applying power.

Tools are listed on Recommended Tools.

Module part numbers

From Apple's exploded view for the SE:

Module	Apple part number
Analogue board	661-0371 (same as SE/30)
Power supply	661-0370 (same as SE/30)
Video board	982-0024 (same as SE/30)
Logic board	661-0530 (exchange boards 661-0526 and 661-0536)
CRT and yoke	076-0103
Chassis	805-0938

Sources held on this wiki

Apple's Macintosh SE Service Source is a module-level manual: it gives procedures, the 2.8 V battery threshold and module part numbers, but no component values. Component values for the analogue board come from Apple's analogue board drawing, the BOMARC schematic and Pina's Macintosh Repair & Upgrade Secrets, whose appendices list the Macintosh (Plus) analogue board in U.S. and international versions and the SE analogue board and CRT socket board. Appendix E also names the tube as a Samsung 10ATY4N white antiglare CRT.

Related pages

• Macintosh SE
• Macintosh SE Troubleshooting
• Macintosh SE General Maintenance
• Macintosh SE/30 Capacitor Replacement Guide
• Macintosh SE Service Source
• The Dead Mac Scrolls
• Macintosh Repair & Upgrade Secrets
• Battery Explosion, Capacitor or Corrosion Damage
• Capacitor Failure Symptoms
• CRT Discharge Procedure
• Recommended Tools