Macintosh SE/30 Capacitor Replacement Guide

Every Macintosh SE/30 has leaking capacitors. Not most — all of them. The surface-mount electrolytics on the logic board vent a conductive, corrosive electrolyte that creeps under adjacent ICs and eats traces and vias, and the longer a board is left the greater the chance the damage goes beyond what a recap will fix. This is the single most important fact about the machine, and it is why the logic board comes first on this page and the analogue board second.

Do the Battery First

Remove or check the 1/2 AA lithium PRAM cell before anything else. Apple's procedure is to remove the logic board, measure across the cell on the 10 V DC range and replace it if it reads below 2.8 V. A leaked cell produces exactly the same kind of trace damage as a leaked capacitor, in the same part of the board. See Battery Explosion, Capacitor or Corrosion Damage.

Capacitor Inspection

On an SE/30 the question is not whether the capacitors have leaked but 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 — electrolyte attacks the joint before it attacks the trace.
• Missing or thinned traces near the capacitors, best seen under a loupe with light across the board.
• Bulging tops are not a reliable sign on these parts; they usually leak from the base without deforming.

See Capacitor Failure Symptoms.

Logic Board

The SE/30 logic board, Apple part 820-0260, carries thirteen electrolytic capacitors: 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

Two independent sources agree. Console5 gives the designators above; Recap-a-Mac's photographic guide, made from physical boards, counts 10 × 47 µF 16 V, 1 × 1 µF 50 V, 1 × 220 µF 16 V and 1 × 470 µF 16 V. The two axials are easy to overlook — they are ordinary through-hole parts, not the leaky surface-mount cans, but they are on the list.

Macintosh SE/30 logic board capacitor locations

Board revisions

Recap-a-Mac notes a layout difference worth knowing before you follow a photograph: earlier boards have a socketed 68030; later boards have a dark grey soldered CPU, and on those the 47 µF 16 V capacitor near the ROM slot sits above the slot rather than below it.

Where the damage goes

Two areas take the brunt, both flagged by Recap-a-Mac from repeated repairs:

• The video multiplexer circuit — the row of Ux8 ICs below the large axial capacitor. Look closely for damaged traces and dried electrolyte around those pins. Faults here are common.
• The RAM multiplexers — the ICs marked "F258" above the ROM slot. If you are getting Sad Mac chimes with known-good RAM, suspect one of these rather than the memory. See Sad Mac Error Codes.

Trace continuity around every capacitor should be checked with a meter before the board is powered again; a recap that leaves a broken via behind produces a machine that still does not work and a repairer who concludes, wrongly, that the recap failed.

Replacement parts

Recap-a-Mac's own 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

Solid tantalum and solid polymer parts have no liquid electrolyte and cannot leak. Tantalum fails short; polymer usually fails open, which is gentler on whatever is downstream. Either is a reasonable choice here provided the voltage rating is comfortably above the rail.

Analogue Board

The SE and SE/30 do not use the Macintosh Plus power/sweep board. The Plus combines supply and sweep circuitry on one board; the SE and SE/30 split them, with a separate metal-cased power supply module alongside a much smaller analogue board and a separate video board. Apple's exploded views give the same part numbers for all three modules in both machines: analogue board 661-0371, power supply 661-0370, video board 982-0024.

Thomas Lee puts the relationship precisely: on the SE and SE/30 the horizontal and video circuits are virtually identical to the Plus, but the vertical and power supply circuits are completely different. A capacitor list taken from a Plus will not match an SE.

The bare analogue board is marked 630-0147. Console5 lists twelve electrolytics on it.

Macintosh SE / SE/30 analogue board 630-0147

Reference	Capacitance	Voltage	Notes
C2	100 µF	16 V
C7	100 µF	16 V
C9	1000 µF	16 V
C11	33 µF	16 V
C13	220 µF	16 V
C14	4700 µF	16 V
C15	3.9 µF	35 V	Bipolar (non-polarised), low ESR. See below.
C18	22 µF	50 V
C19	10 µF	160 V
C22	100 µF	16 V
C24	220 µF	16 V
C25	100 µF	16 V

C15 is not an ordinary capacitor

C15 is the high-frequency, non-polarised capacitor in the horizontal sweep circuit, and it is the single most commonly failed part on this board. Larry Pina specifies it as 3.9 µF NP 25/35 V HF and recommends fitting a 3.9 µF NP 100 V HF part instead, to stop the fault returning. Console5 likewise flags the position as bipolar, low-ESR. Do not fit an ordinary polarised electrolytic here.

Its failure sequence, from Pina:

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

Check the yoke plug P1 at the same time; Pina notes it is often burned by the time C15 has failed.

Power Supply

The power supply is a separate module (Apple 661-0370), and three different units were fitted. Identify yours from the label before ordering anything. Console5 publishes a list for each.

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: Apple 820-0385-A / Hitachi

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: Apple 699-5047 / 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 notes that some — not all — ASTEC supplies were built with three 4700 pF metallised-paper RIFA Y-class safety capacitors, and that these should always be replaced when found. The ambiguous designators in that last table ("C23 or C25", "C25 or C28") are reproduced as published; check your own board's silkscreen.

Note the primary-side ratings: 620 µF 400 V in the Sony and Hitachi units, and a series pair of 330 µF 200 V in the ASTEC. Those parts sit at rectified mains potential and hold charge after power-off.

There is no voltage adjustment

Apple's Service Source for this machine contains Yoke and Video adjustment procedures and nothing else — no voltage adjustment, and no rail tolerances. The adjustable trimmer R56 belongs to the Macintosh 128K/512K/Plus power/sweep board, which is a different board in a different machine; there is no equivalent control here. The video controls on the SE and SE/30 analogue board are brightness, width, height and focus.

If the rails are out of specification on one of these machines, the supply module is at fault and needs repair or replacement — there is nothing to turn.

Analogue Board Faults by Component

Larry Pina's The Dead Mac Scrolls documents the analogue-board faults of the SE and SE/30 down to individual components, with exact replacement specifications. It is hosted on this wiki.

Symptom	Component	Specification
No chime, dark display, a dreadful hissing or sizzling noise	CR2 shorted (0.00–0.01 Ω)	Barrel rectifier GI854, R-51, 600 V 3 A. Pina suggests an MR824 (R-51, 400 V, 5 A) as a heavier-duty replacement.
No chime, dark display, apparently completely dead, no hissing noise	CR3 shorted; then Q2 burned; then flyback T2	CR3 is the same GI854 barrel rectifier. Q2 is the BU4060 horizontal output transistor.
Right side of the picture shakes in and out during disk access or when a window opens	CR2, then Q2	As above
Chimes, fan turns, hard disk spins, but the display stays dark and the brightness control does nothing	R22 open	470 kΩ, ½ W, 5 %
Chimes, then a relatively dim vertical line	R19 burned	220 Ω, ½ W, 5 %. Vacuum-desolder and resolder linearity coil L3 with fresh solder, or it will recur.
Poor horizontal linearity, then a bright vertical line and smoke	C15, and yoke plug P1	3.9 µF NP 25/35 V HF; fit 3.9 µF NP 100 V HF

A single vertical line is a horizontal sweep collapse — C15, R19, L3 or the yoke plug. A single horizontal line is a vertical sweep collapse, a different circuit built around the TDA1170 vertical deflection IC. In either case switch off at once; a concentrated line burns the phosphor within minutes.

Capacitor Replacement 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 gently tilting the can, or use hot air with the surrounding plastic shielded. Twisting a can off cold will take the pads with it.
3. Clean thoroughly. Isopropyl alcohol and a soft brush over the whole area, repeatedly, until no residue transfers to a clean swab.
4. Inspect and test. Check continuity across every trace that ran under or beside a capacitor. Repair breaks with fine wire before fitting anything new.
5. Fit the new parts the right way round. On a tantalum the stripe marks positive; on an aluminium electrolytic it marks negative. This catches people out.
6. Check for shorts across each rail before applying power.
7. Discharge the CRT before starting on the analogue board, if you are going that far.

Tools are listed on Recommended Tools.

Module Part Numbers

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

• Analogue board — 661-0371 (shared with the SE)
• Power supply — 661-0370 (shared with the SE)
• Video board — 982-0024 (shared with the SE)
• Logic board — 661-0527
• CRT and yoke assembly — 076-0103
• Front bezel — 630-5499

Related Pages

• Macintosh SE/30
• Macintosh SE/30 General Maintenance
• Macintosh SE/30 Troubleshooting
• Macintosh SE Capacitor Replacement Guide
• Macintosh SE/30 Logic Board Schematic
• Battery Explosion, Capacitor or Corrosion Damage
• Capacitor Failure Symptoms
• CRT Discharge Procedure
• Recommended Tools
• Sad Mac Error Codes