Macintosh Color Classic II Capacitor Replacement Guide

The Macintosh Color Classic II (also sold as the Macintosh Performa 275) 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 reports four leaky capacitors around the PLCC sound chip at the top left of the logic board, damaged traces in that area as a common find, and says any unrecapped Color Classic II "is living on borrowed time".

Safety

Discharge the CRT anode before working on the analogue board; see CRT Discharge Procedure. The analogue board is a mains-connected switch-mode supply with a universal 90–240 V AC input. On 240 V mains its primary reservoir, CP30 (330 µF 400 V), charges to about 340 V DC and holds it after the machine is unplugged. Measure across CP30 before touching the primary side.

The logic board comes out through the I/O door at the back without opening the case, so the logic board recap involves no high voltage.

Logic board

Low End Mac says the Color Classic II shares its logic board with the Performa/LC 550. powercc.org counts the same capacitors on the Performa/LC 550 board as on the original Color Classic board:

Color Classic II / LC 550 logic board capacitors

Capacitance	Voltage	Quantity	Recap-a-Mac replacement (tantalum)
47 µF	16 V	6	KEMET T491D476K016AT
100 µF	6.3 V	2	KEMET T491D107K006AT
10 µF	16 V	1	KEMET T491B106K016AT

Quantities from powercc.org; part numbers from Recap-a-Mac. Recap-a-Mac's Color Classic II guide photographs board 820-0368-A and marks the same count: six 47 µF 16 V, two 100 µF 6.3 V and one 10 µF 16 V. Recap-a-Mac warns that the plastic at the bottom of the board, near three of the capacitors, is easily melted with a soldering iron. A tantalum's stripe marks the positive terminal, the opposite of an aluminium electrolytic.

The original Color Classic logic board, 820-0367-C (Recap-a-Mac). The Color Classic II board, 820-0368-A, has the same count with the capacitors in different places; Recap-a-Mac's Color Classic II guide marks them.

Analogue board

Apple lists one Analog Board/Power Supply, 661-0732, for both the Color Classic and the Color Classic II. Apple publishes no component list for it. The board numbers its parts in function-prefixed blocks (CD, CF, CL, CP, CS, CV), with ratings from 6.3 V to 400 V.

Color Classic / Color Classic II 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	330 µF (powercc.org) or 3300 µF (Console5)	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 powercc.org's list, which agrees with Console5's list for board 630-0349 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 and ceramic capacitors (powercc.org marks them "poly capacitor", for example 0.22 µF 250 V parts) are not in the table. The same list, with the resistor and zener upgrades for the parts that burn on this board, is on the Macintosh Color Classic Capacitor Replacement Guide.

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 3300 µF 16 V capacitor near the middle of the board, which "can leak and play havoc with the display". CP30 must stay a 400 V part: 240 V mains rectifies to about 340 V DC across it.

Color Classic / Color Classic II analogue board capacitor locations (Recap-a-Mac)

Procedure

Logic board

1. Remove the logic board through the I/O door and take out the PRAM battery.
2. Remove each capacitor by heating one terminal while gently tilting the can, alternating terminals until it comes free, or with hot air, shielding the plastic parts.
3. Clean the electrolyte residue off with isopropyl alcohol and check continuity on the traces near each capacitor, especially round the sound chip. Repair broken traces with fine wire.
4. Tin one pad, place the new part with the correct polarity, tack it, solder the other terminal, then reflow the first.
5. On refitting, check that no bent chassis tab can touch the underside of the board.

Analogue board

1. Remove the rear housing, discharge the CRT and remove the anode cap.
2. Unhook the video board ground wire, pull the video board off the CRT neck, unplug the degauss, yoke and microphone cables, slide the board out and unplug the speaker cable beneath it.
3. Confirm with a meter that CP30 has discharged before working on the primary side.
4. Replace the through-hole capacitors like for like, at the same or a higher voltage rating, observing polarity.
5. On reassembly, reconnect the video board ground wire to the CRT strap; Apple warns that switching on without it can damage components. Perform the cutoff video adjustment after replacing the analogue board.

After the recap

Check all polarities and joints, and check each rail for shorts to ground before power is applied. Apple publishes no rail tolerances and no supply adjustment for this machine; its Adjustments chapter covers geometry, video, convergence, geometric distortion, yoke and light meter setup. Compare each rail with its nominal value at the logic board connector.

Related pages

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