Macintosh Color Classic Capacitor Replacement Guide

The Macintosh Color Classic has surface-mount electrolytic capacitors on its logic board and through-hole electrolytics on its analogue board, which is also the power supply. Recap-a-Mac, which calls the Color Classic the second most popular board for recapping after the SE/30, reports four leaky capacitors around the sound chip at the top left of the logic board and trace damage around that chip on the boards it repairs. The same machine was sold as the Macintosh Performa 250.

Safety

The logic board comes out without opening the case or touching the CRT: open the I/O door at the back and pull the board straight out. On refitting, check that no bent metal tab on the chassis can touch the underside of the board.

Battery first

Apple's procedure is to remove the logic board, measure the cell on the 10 V DC range, and replace it if it reads below 3.0 V. Take an old cell out before recapping. Low End Mac reports that most Color Classics use a 3.6 V half-AA lithium cell but some use a 4.5 V Rayovac 840, so check what is fitted. Clean lithium-cell residue with bicarbonate of soda, then water and isopropyl alcohol, not vinegar. See Battery Explosion, Capacitor or Corrosion Damage.

Capacitor inspection

Recap-a-Mac's finding on this board is leakage, with trace damage round the sound chip. Look for dark haloes or dried crust at the base of the cans, green or dull solder on nearby IC pins, and broken traces, especially around the sound chip. On the analogue board, look for domed tops, crust at the leads and staining under the cans. See Capacitor Failure Symptoms.

Logic board

Color Classic logic board (820-0367-C)

Reference	Capacitance	Voltage
C2	100 µF	6.3 V
C3	100 µF	6.3 V
C4	47 µF	16 V
C5	47 µF	16 V
C6	47 µF	16 V
C8	10 µF	16 V
C9	47 µF	16 V
C10	47 µF	16 V
C11	47 µF	16 V

Designators from Console5's list for board 820-0367-C. Recap-a-Mac and powercc.org both count six 47 µF 16 V, two 100 µF 6.3 V and one 10 µF 16 V, which agrees, and Recap-a-Mac's photograph of an 820-0367-C board shows them at these positions. BOMARC's schematic of the earlier 820-0367-B board draws the same values at the same nine positions: 100 µF 6.3 V at C2 and C3 on the sound chip's supply, 47 µF 16 V at C4, C5, C6, C9, C10 and C11, and 10 µF 16 V at C8.

Recap-a-Mac fits KEMET solid tantalum parts: T491D476K016AT (47 µF 16 V), T491D107K006AT (100 µF 6.3 V) and T491B106K016AT (10 µF 16 V). A tantalum's stripe marks the positive terminal, the opposite of an aluminium electrolytic. Recap-a-Mac warns that the plastic at the bottom edge of the board, near three of the capacitors, is easily melted with a soldering iron.

Color Classic logic board recapping guide (Recap-a-Mac)

Analogue board

Apple's service part is the "Analog Board/Power Supply", 661-0732. Apple publishes no component list for it. The bare board is 630-0349; Console5 notes that the Macintosh TV's 630-0355 is nearly identical, with an extra 47 µF and 1 µF capacitor.

This board numbers its parts in function-prefixed blocks (CD, CF, CL, CP, CS, CV), not in a single Cn run.

Color Classic analogue board (630-0349), electrolytic capacitors

Reference	Capacitance	Voltage
CD3	10 µF	16 V
CF2	4.7 µF	50 V
CF7	100 µF	25 V
CF8	3300 µF	16 V
CF9	220 µF	25 V
CF10	220 µF	35 V
CF11	470 µF	35 V
CL4	100 µF	25 V
CL11	1 µF	50 V
CL13	2.2 µF	200 V
CL14	47 µF	100 V
CL19	10 µF	250 V
CL21	100 µF	100 V
CL23	100 µF	6.3 V
CL24, CL31	1 µF	50 V
CL33, CL34	2.2 µF	100 V
CL35	0.47 µF	100 V
CP9, CP15, CP34	100 µF	25 V
CP10	1 µF	50 V
CP12	100 µF	100 V
CP13	1000 µF	35 V
CP14, CP41	1000 µF	16 V
CP30	330 µF	400 V
CP35, CP47, CP54, CP55	1 µF	50 V
CP39	3300 µF	16 V
CP40, CP42	5600 µF	10 V
CP43, CP44	470 µF	25 V
CP46	1000 µF	10 V
CP56	3300 µF (Console5) or 330 µF (powercc.org)	16 V
CS4	1 µF	50 V
CV13	10 µF	100 V
CV17, CV21	100 µF	25 V
CV18, CV19, CV20	2.2 µF	200 V
CV39, CV40	1 µF	50 V

From Console5's list for 630-0349; powercc.org's list gives the same electrolytics and values except at CP56. Recap-a-Mac's photograph of a 630-0349 board marks three 3300 µF 16 V capacitors, the same number as Console5 lists (CF8, CP39 and CP56); powercc.org gives 330 µF at CP56. Read CP56 off your own board. Film, ceramic and safety capacitors on this board (for example CP16, a 10 nF Y-class part) are not in the table.

Recap-a-Mac does not think every capacitor on this board needs replacing; its guide marks the ones most prone to leakage, and it singles out the short, fat 3300 µF 16 V capacitor near the middle of the board, which "can leak and play havoc with the display".

Color Classic analogue board recapping guide (Recap-a-Mac)

Parts that burn besides the capacitors

TinkerDifferent members found the two 18 V zener diodes DL21 and DL22, which are wired in parallel, scorching the board beneath them; one member reported scorch marks under them on every analogue board he had seen. The 47 Ω resistor RL62 burned open on one board and smoked again when its replacement was a 1 W part. Console5 lists uprated replacements drawn from that thread: a single 5 W 1N5355B zener in place of DL21 and DL22, a 5 W 1N5344B at DF2, and 5 W resistors at RF11 (390 Ω), RL22 (100 Ω) and RL62 (47 Ω).

Replacement procedure

1. Remove the logic board through the I/O door and take the battery out.
2. Remove the rear housing (four case screws, and the two I/O door security screws if fitted), discharge the CRT and remove the anode cap.
3. Take out the analogue board: unhook the video board ground wire from the CRT strap, pull the video board off the CRT neck, unplug the degauss cable (BP2), the yoke cable (BD1) and the microphone cable, slide the board out about two inches, lift it, and unplug the speaker cable beneath it.
4. Confirm with a meter that CP30 has discharged before working on the primary side.
5. Replace the capacitors, observing polarity.
6. Clean the boards with isopropyl alcohol and check the traces round every surface-mount position, especially near the sound chip, before fitting new parts.
7. On reassembly, reconnect the video board ground wire to the CRT strap. Apple warns that switching on without it can damage components.
8. After replacing the analogue board, Apple's procedure is to perform the cutoff video adjustment.

After the recap

Apple publishes no rail tolerance and no power-supply adjustment for the Color Classic. Its Adjustments chapter covers geometry, video, convergence, geometric distortion, yoke and light meter setup. The "+5 V 4.85–5.15 V / +12 V 11.90–12.75 V" pair quoted for compact Macs is Apple's Macintosh Plus procedure and does not apply; the Color Classic has no 3.3 V rail. Compare each rail with its nominal value at the logic board connector.

Apple's first steps for the display symptoms most often blamed on the supply are worth following before reaching for the meter.

Symptom	Apple's first steps
Screen jitters or flashes	Check that nearby equipment is grounded, move electrical devices away and switch off fluorescent lights; check the ground cables; disconnect the internal hard and floppy drives; then the analogue board
Raster tilted, distorted or off-centre	Move the machine to rule out its surroundings; geometry adjustments; then the analogue board
Flashing or wavy screen, or a high-pitched noise	Analogue board

Related pages

• Macintosh Color Classic
• Macintosh Color Classic General Maintenance
• Macintosh Color Classic Troubleshooting
• Macintosh Color Classic II Capacitor Replacement Guide
• CRT Discharge Procedure
• Capacitor Failure Symptoms