Recap guide

Recap the Macintosh Classic and Classic II

Both boards leak: the logic board has SMD electrolytics, and the analog board's through-hole electrolytics need attention too.

Open the interactive checklist Tick off each capacitor as you replace it. It saves in your browser.

Worth a recap. Reports say it is a common and useful fix on this machine.

Which board do I have?

Boards changed during production. These notes come from the linked sources, and many are only partly documented, so check the board in front of you.

• Classic logic (digital) board (Medium confidence). How to tell: One article says there is only one production variant of the Classic digital board. Capacitors: 1x 1uF 50V SMD and 7x 47uF 16V SMD. Capacitor list differs from other revisions: no. Source
• Classic analog board 630-0395, early with 1000uF 35V at CP2 (Medium confidence). How to tell: Assembly number 630-0395; the unit shown is dated February 1991. Capacitors: A Tinker Different reply says the commonest US version has a 470uF 50V cap at CP2 instead of 1000uF 35V; this board has the 1000uF 35V part. Capacitor list differs from other revisions: yes. Source
• Classic analog board, common US version with 470uF 50V at CP2 (Low confidence). How to tell: Check the cap fitted at CP2. Capacitors: Same set otherwise; analog board set in one article: 4x 1uF 50V, 1x 4.7uF 250V, 1x 10uF 25V, 3x 47uF 25V, 2x 220uF 50V, 5x 470uF 50V, 4x 1000uF 25V, 3x 2200uF 16V. Capacitor list differs from other revisions: yes. Source

Where to start

Clues from write-ups and forum threads, not a diagnosis. Low confidence means one thread or one repair; high means several write-ups agree.

• Logic board SMD caps (High confidence). One restoration replaces the Classic's 8 logic board SMD electrolytics and lists parts for both boards, with photos of the damage. A second walkthrough also covers the 8 caps and a tantalum swap. Source
• Polarity warning (Low confidence). A cautionary analog board thread reports a polarity mistake that popped a 470 uF cap, and also suggests replacing two diodes and the opto. Source

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us. Check part references and values against your own board.

• Watch out: Kits differ by board revision (Medium confidence). A Classic owner got a kit built for board 630-0560 while his board was 630-0395. The thread says CP2 needed 1000uF 35V rather than the kit's 470uF 50V, and CL1 differs by revision too (10uF 50V on the 630-0395). After fitting the right caps and a new TEA2037A the vertical collapse remained. Source
• Watch out: Polarity and pop-after-recap on the analog board (Medium confidence). A thread on a Classic with no chime and glitching video lists backwards electrolytics as a frequent mistake, and says the 470uF 50V cap often fails, sometimes popping at power-up after a recap. Replies advise scrubbing residue with a toothbrush and swabs and checking the 5V rail stays above about 4.75V. Source
• Maybe: Diodes and opto near the regulation loop (Low confidence). In the same thread replies suggest, when voltage regulation is flaky, also replacing the 1N4148 diodes DP3 and DP4 and the opto-isolator OP1 (a CNY17G), and checking the PP1 pot. These are repair suggestions from posters, not confirmed fixes. Source
• Tip: Burnt TDA4605-3 usually follows dead caps (Medium confidence). A Classic repair page says to recap the analog board first because failed capacitors often burn the TDA4605-3 control IC, and suggests an LTV702 for the CNY17-3 opto and a diode-check on QP2 when the fuse blows. It also notes the board is very prone to battery leak damage. Source

Before you start

• Boards changed during production. Check your board number against the guides before you order parts.
• A tube and its high-voltage circuit can hold a lethal charge. Do not open the tube, and leave the analog board to a professional.

Manuals and technical documents

Service manuals, schematics and datasheets for this machine, kept in our own library. Check your own board and part numbers against them.

• Apple Macintosh Service Guide - Classic II (Service manual)

All 1 documents for Macintosh Classic and Classic II in the library

Guides we used

This page and the interactive bench are built from these. They have the photos and the full detail, so please read them and support their authors.

• 1991 Apple Macintosh Classic I Repair & Restoration (Write-up) by Adam's Vintage Computer Restorations. Has a capacitor list. Lists replacement parts for both the digital and analog boards with photos of the damage
• Macintosh Classic logic board recap (Write-up) by Matt Sephton (gingerbeardman). Clear logic board walkthrough (8 caps, tantalum swap); no value list
• Mac Classic Analog Board repair help (Forum) by TinkerDifferent forum. Useful cautionary thread: polarity mistakes popped a 470 uF cap; also suggests replacing two diodes and the opto
• Macintosh Classic II (Write-up) by Retro.Engineer. Classic II project page, shows leaked logic board and points at C49; photos only

Macintosh Classic logic board 630-0390 / 820-0390

Eight capacitors, mostly 47 uF 16 V.

Classic analog board 630-0395 (early, 1000 uF at CP2)

Twenty-five capacitors. Console5 says the 630-0420 (240 V) version uses 220 uF 400 V at CP1 and CP13. This board holds mains and tube voltage: discharge it properly, and leave it to a professional if you are not trained.

Classic analog board 630-0560 (470 uF 50 V at CP2)

Console5 shares one list with the 630-0395 and notes two changes for the 630-0560: CP2 is 470 uF 50 V and CP11 is 220 uF 50 V. This board holds mains and tube voltage: discharge it properly, and leave it to a professional if you are not trained.

Classic analog board 630-0525

Console5 gives this board its own list of twenty-five capacitors. This board holds mains and tube voltage: discharge it properly, and leave it to a professional if you are not trained.

Classic II boards, one combined list (39 parts)

oldcrap.org lists the whole Classic II in one table. The C-numbers are SMD parts on the logic board (the 10 uF and 47 uF parts), and the CF, CL, CP and CV parts belong to the analog board.

Classic analog board, oldcrap.org's list (25 parts)

oldcrap.org's list for the Classic analog board, noted from the original parts. Compare it with the Console5 lists above, which are for specific board numbers. Check your board before you order.

Shopping list

147 capacitors in all, grouped by value. Buy a few spares.

• 26 x 1 µF, 50 V (check your board): Amazon · eBay
• 15 x 470 µF, 25 V (check your board): Amazon · eBay
• 12 x 47 µF, 16 V (check your board): Amazon · eBay
• 10 x 47 µF, 25 V (check your board): Amazon · eBay
• 10 x 1000 µF, 16 V (check your board): Amazon · eBay
• 10 x 2200 µF, 10 V (check your board): Amazon · eBay
• 8 x 10 µF, 16 V (check your board): Amazon · eBay
• 6 x 220 µF, 250 V (check your board): Amazon · eBay
• 5 x 4.7 µF, 250 V (check your board): Amazon · eBay
• 5 x 10 µF, 25 V (check your board): Amazon · eBay
• 5 x 220 µF, 16 V (check your board): Amazon · eBay
• 5 x 1000 µF, 10 V (check your board): Amazon · eBay
• 5 x 2200 µF, 16 V (check your board): Amazon · eBay
• 3 x 10 µF, 50 V (check your board): Amazon · eBay
• 3 x 220 µF, 50 V (check your board): Amazon · eBay
• 3 x 220 µF, 400 V (check your board): Amazon · eBay
• 3 x 470 µF, 50 V (check your board): Amazon · eBay
• 3 x 1000 µF, 6.3 V (check your board): Amazon · eBay
• 2 x 0.01 µF, 250 V (check your board): Amazon · eBay
• 2 x 220 µF, 25 V (check your board): Amazon · eBay
• 2 x 470 µF, 10 V (check your board): Amazon · eBay
• 2 x 1000 µF, 35 V (check your board): Amazon · eBay
• 2 x 1000 µF, 25 V (check your board): Amazon · eBay

Console5 capacitor kits for this machine

Console5 sells ready-made capacitor kits. Kits come in different versions, so match the board number in the kit name to yours and check the listing before you buy.

• Macintosh Classic SMD Tantalum Main PCB Cap Kit

Skip the sourcing

• Ready-made kit: Amazon · eBay
• Already recapped: Amazon · eBay

While you are in there

• Need the machine itself?: Amazon · eBay
• A box of spare capacitors: Amazon · eBay

Affiliate links. As an Amazon Associate I earn from qualifying purchases. These links only search by name. Disclosure

Step by step

1. Photograph both sides of the board before you touch anything. Zoom in on every capacitor. The photo is your map when you are three hours in.
2. Unplug it, take out the batteries and let it sit. Old power supplies and CRT parts can hold a charge. If your machine has a tube, leave the tube and its board to a professional.
3. Open it up and keep the screws sorted. A muffin tin or an egg carton works. Different screws go in different holes, and the holes never forgive you.
4. Look for leaks. Clean any sticky residue off with isopropyl alcohol and a soft brush. A leaked capacitor leaves brown crust and can eat copper traces. Look at the traces under it, not only the part itself.
5. Mark the polarity of every capacitor on the photo before it comes off. On an electrolytic, the stripe marks the negative leg. The board usually shows a half-shaded circle or a bar for the same spot.
6. Remove the old capacitors one at a time. Surface mount: add fresh solder to both ends and rock the part off, or use flux and a low-melt alloy. Through-hole: heat one leg at a time and clear the hole with wick or a pump.
7. Clean the pads and check for lifted pads or damaged traces. Clean flux off with isopropyl. A bad pad needs a jumper wire, not hope.
8. Fit and solder the new capacitor, matching polarity. Same capacity, same or higher voltage, and it has to physically fit. Work from the smallest parts up.
9. Clean the flux off and look at every joint. A good joint is shiny and shaped like a tiny volcano. A dull blob or a ball is a cold joint: reflow it.
10. With a multimeter, check for shorts across the power rails before you power it on. Use the continuity or resistance setting. A reading near zero means stop and look for a solder bridge.
11. Power it up and test everything: video, sound, controls, the lot. If something is wrong, check polarity first. It is the most common mistake and the easiest fix.

Tools

• Temperature-controlled soldering station. Steady heat so you do not cook pads. Most recaps are done between 320 and 350 C. Top: Hakko FX-951 · Mid: Hakko FX-888D · Budget: Pinecil
• Good solder. Rosin-core 63/37 flows and looks right. It is cheap and it matters. Kester 44 63/37
• Flux. Flux is what makes old joints let go and new joints flow. MG Chemicals flux pen · Chip Quik flux syringe
• Low-melt alloy (for surface mount). Melts old solder on both ends of a surface mount part at once, so it lifts off cleanly. Chip Quik SMD1
• Desoldering tool. Clears the old solder out of through-hole pads. Top: Hakko FR-301 · Mid: Engineer SS-02 pump · Budget: Solder wick
• Fine tweezers. For holding small surface mount parts exactly where you want them. ESD-safe tweezers
• Board holder. A third hand for the board, so both of yours are free. PanaVise circuit board holder
• Magnification. You cannot fix what you cannot see. Surface mount parts are tiny. Top: Stereo microscope · Mid: Head visor · Budget: Lighted magnifier
• Multimeter. Continuity, shorts and rail voltages. The one test that saves boards. Top: Fluke 117 · Mid: Fluke 101 · Budget: AstroAI
• ESR and capacitor tester. Checks old capacitors and your new ones before they go in. Top: Peak Atlas ESR70 · Budget: LCR-T7
• Isopropyl alcohol (99%) and a brush. For cleaning leaked goo and flux. Use the high-percentage kind. MG Chemicals 99.9% isopropyl
• Brass tip cleaner. A clean tip transfers heat. A dirty one does not. Hakko 599B
• Fume extractor. Pulls the smoke away from your face. Hakko FA-400 · Budget: Small bench fan
• Precision screwdrivers. Most old gear uses a mix of Phillips, Torx and security bits. iFixit Pro Tech Toolkit
• Kapton tape. Heat-proof tape to protect parts that sit close to the one you are changing. Kapton tape

Safety

• Good airflow, or a fume fan. Solder smoke is not for breathing.
• Safety glasses on. Solder spits and clipped legs fly.
• Iron in its stand when you are not holding it. Know where the cord is.
• Touch bare metal first, or use a wrist strap. Static kills old chips.
• No tube, no mains power supply. Leave those to a professional.
• Wash your hands after, especially if you used leaded solder.

Values are shown as published in the guides above, and boards changed during production. Check the board in front of you. A recap involves hot tools and, on some machines, dangerous voltages. You do it at your own risk.

More

• All recap guides
• The interactive Recap Bench
• Fix a dead vintage computer
• Macintosh Classic on the timeline
• Macintosh Classic II on the timeline