Macintosh SE/30 Capacitor Replacement Guide

Every Macintosh SE/30 logic board has leaking capacitors: the surface-mount electrolytics vent an electrolyte that creeps under nearby chips and eats traces and vias, and the longer a board is left the more likely the damage goes beyond what a recap fixes. The analogue board and power supply, shared with the Macintosh SE, are covered after the logic board.

Safety

The logic board lifts out once the cover is off and can be recapped away from the CRT. Discharge the CRT before working on the analogue board, the video board, the anode lead or the CRT socket board; 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 stay charged after the machine is unplugged: measure across them before touching the primary side.

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

PRAM battery first

Take out or test the half-AA lithium PRAM cell before anything else. Apple's test: remove the logic board, measure the cell on the 10 V DC range, and replace it below 2.8 V. Pina gives the cell as a 3.6 V snap-in type. A leaked cell damages traces in the same way as a leaked capacitor. See Battery Explosion, Capacitor or Corrosion Damage.

Inspection

On an SE/30, assume the capacitors have leaked and look for how far the electrolyte has travelled:

• Dark haloes or dried crust around the base of the surface-mount cans.
• Dull, grey or green solder joints on nearby IC pins.
• Thinned or missing traces near the capacitors, best seen with a loupe and light across the board.

See Capacitor Failure Symptoms.

Logic board

The SE/30 logic board, bare board 820-0260, has thirteen electrolytics: eleven surface-mount parts and two axials.

Macintosh SE/30 logic board 820-0260

Reference	Capacitance	Voltage	Type
C1	47 µF	16 V	SMD
C2	470 µF	16 V	Axial
C3	47 µF	16 V	SMD
C4	47 µF	16 V	SMD
C5	47 µF	16 V	SMD
C6	1 µF	50 V	SMD
C7	47 µF	16 V	SMD
C8	47 µF	16 V	SMD
C9	47 µF	16 V	SMD
C10	47 µF	16 V	SMD
C11	220 µF	16 V	Axial
C12	47 µF	16 V	SMD
C13	47 µF	16 V	SMD

Console5's community kit list gives the designators; Recap-a-Mac's photographic guide counts ten 47 µF 16 V, one 1 µF 50 V, one 220 µF 16 V and one 470 µF 16 V; and the macse30mlb schematic redraw's power-connector sheet shows C1, C7, C8, C9, C10, C12 and C13 as 47 µF and C11 as 220 µF. The two axials are through-hole parts, not the leaking surface-mount type, but they are on the list.

Macintosh SE/30 logic board capacitor positions (Recap-a-Mac guide image)

Board layouts

Earlier boards have a socketed 68030; later boards have a soldered, dark grey CPU, and on those the 47 µF capacitor near the ROM slot sits above the slot instead of below it.

Where the damage goes

Recap-a-Mac reports two areas from repeated repairs:

• the video multiplexer circuit, the row of Ux8 chips below the large axial capacitor (UA8, UB8, UC8 and UD8 in the redraw's pin matrix);
• the RAM multiplexers marked "F258" above the ROM slot. With known-good RAM and Sad Mac chimes, suspect one of these.

Check continuity along every trace that runs under or beside a capacitor before the board is powered again. A broken via left behind a recap leaves a board that still fails.

Replacement parts

Recap-a-Mac's choices for this board:

• 1 µF 50 V: KEMET T491B105K050AT tantalum
• 47 µF 16 V: KEMET T491D476K016AT tantalum
• 220 µF 16 V axial: Vishay MAL213825221E3
• 470 µF 16 V axial: Vishay MAL211835471E3

Analogue board

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

Apple's schematic of this board is hosted here as File:Classic Analog Board Schematic.pdf. The file name is wrong: the PDF's internal title is "SE30_Analog_Board", it carries a handwritten "SE30 Analog Board" note, and it shows the separate power supply and the hard-disk power connector that the Macintosh Classic does not have. Its electrolytic values agree with Console5's list for board 630-0147 in every position.

Macintosh SE and SE/30 analogue board electrolytics

Reference	Capacitance	Voltage	Notes
C2	100 µF	16 V
C7	100 µF	16 V
C9	1000 µF	16 V
C11	33 µF	16 V	axial
C13	220 µF	16 V
C14	4700 µF	16 V
C15	3.9 µF	35 V	non-polarised; see below
C18	22 µF	50 V	axial
C19	10 µF	160 V
C22	100 µF	16 V
C24	220 µF	16 V
C25	100 µF	16 V

Pina's 1990 parts list for the SE analogue board gives 25 V at C2, C7, C22 and C25; see Macintosh SE Capacitor Replacement Guide#Analogue board.

C15

C15 is the non-polarised capacitor in series with the horizontal yoke and the 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. Do not fit a polarised electrolytic here.

Pina's failure sequence (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.

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. The same modules are used in the Macintosh SE.

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. 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/30 does 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
Display blinks out, white lines flash, tapping the cabinet makes it recur (SE/30)	CRT socket board loose on the tube neck	Check the fit; secure it with a dab of hot glue	158

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. Remove the logic board and take the battery off it.
2. Remove the old surface-mount capacitors. Alternate heat between the two terminals while tilting the can, or use hot air with the surrounding parts shielded. Twisting a can off cold takes the pads with it.
3. Clean the whole area with isopropyl alcohol and a soft brush, repeatedly, until a clean swab picks up no residue.
4. Check continuity along every trace that ran under or beside a capacitor, and repair breaks with fine wire before fitting anything.
5. Fit the new parts the right way round. On a tantalum the band marks the positive end; on an aluminium electrolytic the stripe marks the negative end.
6. Check each rail for shorts before applying power.
7. Discharge the CRT before starting on the analogue board.

Tools are listed on Recommended Tools.

Module part numbers

From Apple's exploded view for the SE/30:

Module	Apple part number
Analogue board	661-0371 (same as SE)
Power supply	661-0370 (same as SE)
Video board	982-0024 (same as SE)
Logic board	661-0527
CRT and yoke	076-0103
Front bezel	630-5499

Sources

Apple's Macintosh SE/30 Service Source is a module-level manual: procedures, the 2.8 V battery threshold and module part numbers, but no component values and no voltage adjustment. Component values come from Console5, Recap-a-Mac, Apple's analogue board drawing and the macse30mlb redraw of the logic board schematic (Macintosh SE/30 Logic Board Schematic).

Related pages

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