Recap guide

Recap the Mac 128K, 512K, Plus and SE analog board

The analog board's electrolytics and the line-filter caps are the standard recap on compact Macs.

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.

• Analog board 630-0102 (120V) (Medium confidence). How to tell: Assembly number on the top front edge opposite 820-0082-B. Capacitors: Console5 kit has 21 caps from 0.1uF to 4700uF, 10 to 275V; Console5 sells one US and one international kit for 128K through Plus. Capacitor list differs from other revisions: not known. Source
• Analog board 630-0108 (240V) (Medium confidence). How to tell: Assembly number for the 240V analog board; the PCB itself is the same 820-0082 style board marking. Capacitors: Recap list has 25 positions, 3.9uF to 4700uF, 10 to 250V; wire W12 selects 120V or 240V. Capacitor list differs from other revisions: not known. 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.

• 630-0108 board list (Medium confidence). A forum thread gives a full list for the 630-0108 board with Mouser part numbers. Board revisions differ, so match your board number. Source
• 630-0102 board list (Medium confidence). A 21-cap list covers the 630-0102 board (Mac 128K analog board 820-0082-B) and mentions a pre-built kit option. Source
• Line-filter caps (Low confidence). One recent full restoration explains its ESR choices and swapped the line-filter caps for X1-rated ones. It gives no part list. 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.

• Tip: Ticking analog board is often not a capacitor (Medium confidence). On a Mac Plus whose analog board just ticks, posters list a failing flyback, the BU406 output transistor (Q3), the U3 regulator and diodes CR15, CR17, CR20 and CR21 ahead of capacitors, with a full recap as a later step. The owner's board stayed dead after replacing Q3 and the flyback. Source
• Watch out: Fading optocoupler can run the 5V rail away (Medium confidence). A 128K restoration diary says the analog board optocoupler LED fades with age, which can make the supply run away to overvoltage and kill the digital board. The author replaced it with a 4N35 and recalibrated the 5V feedback, and also swapped the Rifa line caps for X-rated modern parts. Source
• Story: Drifted resistors and tired flyback (Low confidence). The same diary found large 1W resistors that had drifted badly (one 33K reading over 45K), degraded flyback potting, and chose regular-ESR caps on the supply secondary to limit inrush. These are one author's choices rather than a standard recipe. Source
• Story: Wrong kit voltage and C3 failing after a new flyback (Medium confidence). A Mac Plus owner with a whining board used a 240V parts list because the first kit was for 120V models. After fitting a new flyback, C3 (between +12V and the flyback) failed violently, and the BU406 and diodes CR1 and CR5 were also replaced. Source

Before you start

• Boards changed during production. Check your board number against the guides before you order parts.
• A mains power supply can hold a dangerous charge. If you are not trained to work on one, have a professional do it.
• 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 - Macintosh and Macintosh Plus (Service manual)
• Apple Macintosh Service Guide - Macintosh SE (Service manual)
• Apple Technical Procedures - Macintosh and Macintosh Plus (Service manual)
• Apple Technical Procedures - Macintosh SE (Service manual)

All 4 documents for Mac 128K, 512K, Plus and SE analog board 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.

• Macintosh 128k/512k/Plus 240V Analog Board Recap List (List) by TinkerDifferent forum. Has a capacitor list. Full list for the 630-0108 board with Mouser part numbers; board revisions differ so match your board number
• Mac 128k Analog Board 820-0082-B from 1983 (List) by TinkerDifferent forum. Has a capacitor list. 21-cap list for the 630-0102 board; mentions a pre-built kit option
• Compact Mac Caps List (List) by TinkerDifferent forum. Has a capacitor list. Short value summary for compact Macs with sourcing pointers; less board-specific than the others
• The immortal 1984 Macintosh (restoration diary) (Write-up) by The Byte Attic. Recent full restoration; explains ESR choices and swapping the line-filter caps for X1-rated ones, no part list

Macintosh SE analog board 630-0147

Twelve capacitors. C15 is a bipolar low-ESR part. The 128K, 512K and Plus boards (630-0102 and 630-0108) are a different design, so use the forum lists in the guides above for those.

Macintosh SE logic board 820-0176 / 820-0250

Eleven capacitors, nearly all 33 uF 16 V.

Macintosh 512K analog board (21 parts)

From oldcrap.org's list, noted from the original parts removed from the board. C11 is blank on the list except for the "uF" and its 16 V rating; the grid on the same list counts two 33 uF 16 V parts, and C13 is the other, so C11 is read as 33 uF. C1 is bipolar. C7 sits on the keyboard, not on the analog board, and the list's grid leaves it out.

Macintosh Plus analog board (21 parts)

From oldcrap.org's list, noted from the original parts removed from the board. C1 is bipolar.

Shopping list

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

• 15 x 33 µF, 16 V (check your board): Amazon · eBay
• 6 x 100 µF, 200 V (check your board): Amazon · eBay
• 6 x 220 µF, 16 V (check your board): Amazon · eBay
• 6 x 2200 µF, 16 V (check your board): Amazon · eBay
• 5 x 22 µF, 50 V (check your board): Amazon · eBay
• 5 x 1000 µF, 16 V (check your board): Amazon · eBay
• 4 x 100 µF, 16 V (check your board): Amazon · eBay
• 4 x 470 µF, 10 V (check your board): Amazon · eBay
• 3 x 10 µF, 160 V (check your board): Amazon · eBay
• 3 x 4700 µF, 16 V (check your board): Amazon · eBay
• 2 x 3.9 µF, 25 V (check your board): Amazon · eBay
• 2 x 47 µF, 10 V (check your board): Amazon · eBay
• 1 x 0.1 µF, 250 V (check your board): Amazon · eBay
• 1 x 1 µF, 50 V (check your board): Amazon · eBay
• 1 x 1 µF, 63 V (check your board): Amazon · eBay
• 1 x 3.9 µF, 35 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 SE SE FDHD Nichicon VX Axial Electrolytic Cap Kit
• Macintosh SE 30 SMD Tantalum Axial Capacitor Main PCB Cap Kit
• Macintosh SE 30 Power Supply Sony Cr 44 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
• Apple Macintosh on the timeline
• Macintosh 512K on the timeline
• Macintosh Plus on the timeline
• Apple Macintosh SE on the timeline