Apple IIe Machine Hub

Unenhanced, Enhanced & Platinum Apple //e workbench reference — Astec PSU RIFA alert, 6502/65C02/65C816 architecture, Slot 1–7 & Aux 80-Column guide, self-test codes, and F6–F13 DRAM locator.

Astec / Dyna-Comp PSU RIFA Capacitor Alert & Quad-Rail Check

Inside the long silver/gold metal power supply brick of every Apple II, II Plus, and Apple IIe (most commonly the Astec AA11040 / AA11042 or Dyna-Comp switching supply) sit two amber epoxy RIFA PME 271 M mains filter capacitors (C1 = 0.1 μF and C20 = 0.01 μF / 0.047 μF) right behind the IEC mains switch. After 40+ years, their epoxy shells craze, absorb humidity, and detonate with a loud bang and clouds of foul white smoke within minutes of plugging into the wall. Drill out the PSU rivets (or remove the case screws) and replace the RIFA caps with modern 275 V–310 V AC X2 polypropylene safety film caps before powering on!

1 6-Pin Motherboard Power Plug Pinout

The Apple IIe PSU outputs four regulated DC voltages via its 6-pin Molex connector (J13):

Molex Pin	Signal	Target Spec	Primary Use
Pin 1	GND (0 V)	0.00 V Return	System Digital Ground
Pin 2	GND (0 V)	0.00 V Return	System Digital Ground
Pin 3	+5 V DC	4.85–5.15 V (2.5 A)	CPU, MMU, IOU, 4164 RAM, ROMs & regulation feedback!
Pin 4	+12 V DC	11.4–12.6 V (1.5 A)	Disk II drive stepper/motor & expansion cards
Pin 5	−12 V DC	−11.4 to −12.6 V (0.25 A)	Super Serial Card RS-232 & analog cards
Pin 6	−5 V DC	−4.75 to −5.25 V (0.25 A)	Expansion slots & Mockingboard/analog audio

2 Why the Astec PSU "Ticks" Unplugged

Never test an Astec AA11040 completely unloaded! Because the Astec flyback switching design regulates off the +5 V rail load, turning it on with the 6-pin motherboard plug disconnected causes it to enter an overvoltage hiccup loop — making a rhythmic "tick-tick-tick" chirp with wild voltage readings!
Bench Dummy Load: To test the PSU outside the Apple IIe, connect a 10 Ω 5 W power resistor (or old 12 V/5 V hard drive) across Pin 3 (+5 V) and Pin 1 (GND) so it draws ~500 mA minimum load.
Ticking While Plugged Into Motherboard: Indicates a dead short on one of the motherboard rails (most commonly a shorted radial tantalum decoupling capacitor on an expansion card or a shorted 4164 DRAM!). Unplug all Slot 1–7 cards first to isolate.

3 RIFA & Electrolytic Recap Values

C1 (Across Mains Line): 0.1 μF (100 nF) 275 V AC X2 safety film capacitor (15 mm lead pitch).
C20 (Mains Filter): 0.01 μF (10 nF) or 0.047 μF 275 V AC X2/Y2 safety capacitor.
Secondary Output Caps: Replace the 1000 μF / 2200 μF 16 V (+5 V filter) and 470 μF 25 V (+12 V filter) axial/radial caps with 105 °C low-ESR capacitors.
Drop-in Reactive PSU Upgrade: You can also swap the internal PCB inside the original Astec metal shell with a modern ReactiveMicro Universal PSU kit for 85–264 V auto-switching power.

Apple IIe Model Selector & CPU Evolution

Compare the 1983 Unenhanced Apple //e, the 1985 Enhanced Apple //e (65C02 + MouseText), the 1987 Platinum //e, and 65C816 16-bit upgrades.

Unenhanced Apple //e 1983–1985 • 820-0060-A / B • Boots with "Apple ]["

Introduced in January 1983, the Apple //e replaced over 70 discrete TTL chips from the Apple II Plus with two custom Apple LSI chips — the MMU (Memory Management Unit, 344-0010) and IOU (Input/Output Unit, 344-0020) — while adding native uppercase/lowercase keyboard support, 64 KB of single-rail 4164 DRAM on the motherboard, and the dedicated 60-pin Auxiliary Slot for 80-column display and 128 KB total bank-switched memory.

Key ICs & Identification

Boot Banner: Displays Apple ][ (NOT Apple //e) at the top of the screen!
CPU (B4): NMOS MOS / Synertek 6502 @ 1.023 MHz
MMU (C3): Apple Custom 344-0010 (DIP-40) — RAM bank switching, zero page, and slot address decoding
IOU (D5): Apple Custom 344-0020 (DIP-40) — video counters, soft-switches, keyboard strobe, speaker & cassette
HAL (B2): 341-0170 (16R8 PAL/HAL) — master timing generator
System ROMs (D8 & D10): CD ROM (342-0135-A, $C100–$DFFF) and EF ROM (342-0134-A, $E000–$FFFF)
Video ROM (D12): 342-0133-A (2732 4 KB) — lacks MouseText characters (inverse uppercase only)
Main RAM (F6–F13): 8× 4164 (64K×1, +5 V single-rail) DRAMs

Revision A vs Revision B Motherboard (Double Hi-Res!)

Board Revision	Part Number	Key Hardware Difference
Revision A (Early 1983)	`820-0060-A`	Does NOT support Double Hi-Res (560×192 16-colour) graphics! Lacks the Pin 55 (`FRCTXT`) connection on the Auxiliary Slot. Also uses a 6-ROM socket configuration on very early prototypes.
Revision B (Mid 1983–1986)	`820-0060-B` / `820-0087-A`	Supports full Double Hi-Res graphics when paired with an Extended 80-Column 64K Card (with jumper/molex blocks connected). Can be upgraded to an Enhanced //e in 5 minutes by swapping 4 chips!

How to Upgrade Any Rev B //e to Enhanced //e: Simply swap out the 4 socketed chips in the official Apple Enhancement Kit: CPU (→ CMOS 65C02), CD ROM (→ 342-0304-A), EF ROM (→ 342-0303-A), and Video ROM (→ 342-0265-A with MouseText)!

Enhanced Apple //e & 65C816 16-Bit Upgrades 1985–1987 • Boots with "Apple //e"

Released in March 1985 for compatibility with the Apple IIc and ProDOS 8 GUI software (such as AppleWorks, MouseDesk, and GEOS). Upgrades the processor to the low-power CMOS WDC / NCR / Rockwell 65C02 (adding 27 new opcodes including BRA, PHX, PHY, STZ), adds the 32 MouseText graphical UI icons to the Video ROM, and improves the Monitor/80-column firmware (mini-assembler included at ! prompt!).

6502 vs 65C02 vs 65C816 CPU Breakdown

CPU	Architecture	Apple IIe Role & Compatibility
MOS 6502 (Unenhanced //e)	8-bit NMOS (1.023 MHz)	Original processor. Supports unofficial/undocumented NMOS opcodes used by a few early 1980–82 copy-protected games, but cannot run ProDOS 2.x or MouseDesk.
WDC 65C02 (Enhanced //e)	8-bit CMOS (1.023 MHz)	Required for Enhanced //e! Adds `STZ`, `BRA`, `PHX/PLX`, bit manipulation opcodes, and fixes the 6502 indirect `JMP ($xxFF)` page-boundary bug. Note: Modern WDC `W65C02S` (with `S` suffix) needs Pin 36 (`BE` Bus Enable) tied to +5 V!
WDC 65C816 / 65802 (16-Bit Upgrade / TransWarp / IIgs)	8/16-bit CMOS (1–14 MHz)	The 16-bit processor of the Apple IIgs (24-bit 16 MB addressing, 16-bit registers, hardware Emulation Mode `E=1` for 100% 65C02 compatibility). Fitted to Apple IIe systems via 40-pin 65802 drop-in CPU, Applied Engineering TransWarp, or Zip Chip / FASTChip accelerators!

80-Column vs Extended 80-Column (64K Aux) Card

The single 60-pin socket near the front-left of the motherboard (AUXILIARY SLOT, NOT Slot 3!) accepts one of two cards:

Standard 80-Column Text Card (1 KB RAM): Only holds 1 KB of static/dynamic RAM — enables 80-column text, but leaves the machine at 64 KB total RAM (no Double Hi-Res, no ProDOS /RAM drive).
Extended 80-Column Text Card (820-0067 — 64 KB RAM): Populated with eight 4164 DRAMs, bringing the Apple IIe to 128 KB total RAM, enabling 560×192 16-colour Double Hi-Res graphics, AppleWorks expanded desktop, and a 64 KB ProDOS /RAM disk!
Modern RAMWorks III / VGA Aux Cards: Plug into the 60-pin Aux slot to expand an Apple IIe up to 1 MB–8 MB of banked RAM or provide lag-free HDMI/VGA output (e.g. A2DVI / RGBtoHDMI).

Apple IIe Platinum 1987–1993 • 820-0188-A • Built-in Numeric Keypad

The final, longest-lived evolution of the Apple IIe, finished in Apple's late-1980s "Platinum" warm grey to match the Apple IIgs and Macintosh SE. Features a redesigned keyboard with a built-in numeric keypad, relocated RESET key at the top-center, and a heavily condensed motherboard that reduces the chip count from 31 ICs down to just 17 ICs!

Cost-Reduced Platinum Motherboard Changes

Main RAM (2 Chips Instead of 8): Replaces the eight 4164 DRAMs with just two 4464 (64K×4, DIP-18) DRAMs (UA5 & UA6)
Single 16 KB Combined System ROM: Combines the CD and EF ROMs into a single 28-pin 27C128 (342-0349-A) (CF ROM)
8-Bit Video ROM: Uses a 28-pin 2764 (342-0265-A / 341-0160)
Onboard 64K Aux Card Included: Shipped from the factory with a compact 2-chip (4464) 64 KB Extended 80-Column Card already installed in the Aux slot

Keyboard Switch Types Across Apple IIe Models

Keyboard Type	Switch Mechanism	Bench Repair Notes
Alps SKCC Tall Stem (Most 1983–85 //e)	Mechanical gold/silver leaf contact	Very reliable; flush stuck switches with DeoxIT D5 and compressed air.
SMK Vintage Linear	Mechanical metal leaf switch	Crispy linear feel; check for cracked solder joints on the 26-pin keyboard ribbon header.
Mitsumi / Alps SKCL (Platinum //e)	Tactile/linear mechanical	Uses a different 26-pin keyboard encoder matrix ROM (`341-0348-A`) to map the numeric keypad!

Expansion Slot 1–7 Conventions & 50-Pin Bus Pinout

Standard Apple IIe peripheral card slot assignments, memory-mapped I/O decoding, and 50-pin edge connector pinout.

Standard Apple IIe Slot 1–7 Card Map

While the seven 50-pin peripheral slots on the back of the motherboard are electrically nearly identical (except Slot 3 and Slot 7), Apple DOS 3.3, ProDOS, and games expect cards in specific standard slots:

Slot	Device I/O (`$C0n0`)	Slot ROM (`$Cn00`)	Standard Card Assignment
AUX SLOT (60-Pin, Front-Left)	Soft-switches `$C000–$C00F`	Shares internal `$C300` / `$C800`	Extended 80-Column 64K Text Card (or RAMWorks III / RGB video card). Never plug a 50-pin card here!
Slot 1	`$C090–$C09F`	`$C100–$C1FF`	Parallel Printer Card (Grappler+ / Apple Parallel Printer Interface)
Slot 2	`$C0A0–$C0AF`	`$C200–$C2FF`	Super Serial Card (SSC) — RS-232 modem, ADTPro disk transfer, or serial printer
Slot 3	`$C0B0–$C0BF`	`$C300–$C3FF` (Internal 80-Col ROM)	Leave EMPTY when using an Aux 80-Column Card! (Or used for No-Slot Clock / Uthernet II in I/O-only mode)
Slot 4	`$C0C0–$C0CF`	`$C400–$C4FF`	Mockingboard Sound Card (dual 6522 VIA + dual AY-3-8910 PSG) or AppleMouse II Card
Slot 5	`$C0D0–$C0DF`	`$C500–$C5FF`	3.5″ SmartPort / Liron Drive Controller, CP/M Z80 SoftCard, or second Disk II card
Slot 6	`$C0E0–$C0EF`	`$C600–$C6FF`	Primary Disk II / 19-Pin Floppy Controller! Auto-boot scans down from Slot 7 → Slot 6 (`PR#6`).
Slot 7	`$C0F0–$C0FF`	`$C700–$C7FF`	CFFA3000 / BOOTi / FujiNet / ProDOS Hard Drive / Accelerator Card. (Also carries unique `SYNC` and `COLOR REF` video pins on Pins 35 & 19!).

CRITICAL EDGE CONNECTOR RULE: Every Apple II expansion card has an arrow or component-side marking that MUST point toward the front keyboard (Pin 1 = Front Left, Pin 25 = Rear Left, Pin 26 = Rear Right, Pin 50 = Front Right). Inserting a Disk II or Mockingboard backwards will instantly short +12 V/−12 V into the 6502 address bus and destroy the MMU!

50-Pin Peripheral Expansion Slot Pinout Slots 1–7 • 0.1″ Pitch

Pins 1–25 run Front-to-Back along the Left (Component) side; Pins 26–50 run Back-to-Front along the Right (Solder) side:

Left Pin	Signal	Right Pin	Signal
1	/IOSEL (`$Cn00–$CnFF` ROM Select)	50	−12 V DC
2 – 17	A0 – A15 (Address Bus)	49 – 42	D0 – D7 (Data Bus: 49=D0 … 42=D7)
18	R/W (Read = High, Write = Low)	41	/DEVSEL (`$C0n0–$C0nF` I/O Strobe)
19	NC (Slot 7 only: `SYNC`)	40	Φ0 (1.023 MHz CPU Phase 0 Clock)
20	/IOSTB (`$C800–$CFFF` Shared ROM)	39	μPSYNC (6502 Opcode Fetch Sync)
21	RDY (CPU Ready / Wait)	38	Φ1 (Phase 1 Clock)
22	/DMA (Direct Memory Access Request)	37	Q3 (2.046 MHz Asymmetric Clock)
23	INT OUT (Daisy-chain Interrupt Out)	36	7M (7.159 MHz Clock)
24	DMA OUT (Daisy-chain DMA Out)	35	NC (Slot 7 only: `3.58MHz COLOR REF`)
25	+5 V DC	34	−5 V DC
— Rear of Slot —		33	+12 V DC
26	GND (0 V)	32	/INH (Pull low to disable motherboard RAM/ROM)
27	DMA IN (Daisy-chain DMA In)	31	/RES (System Reset, active-low)
28	INT IN (Daisy-chain Interrupt In)	30	/IRQ (Maskable Interrupt Request)
29	/NMI (Non-Maskable Interrupt)	—	—

Built-in Self-Test & 4164 DRAM Fault Locator

Running the onboard Apple IIe diagnostic routine and decoding RAM: bit errors or boot screen character corruption directly to chips F6–F13.

⚙

Built-in Apple IIe Hardware Self-Test Routine

Every Apple IIe (with CD and EF ROMs) contains a built-in hardware diagnostic suite in ROM that tests the MMU, IOU, Zero Page, and all 64 KB of main RAM (plus 64 KB of Aux RAM if installed)!

How to Launch the Self-Test

Keyboard Shortcut: Hold down CONTROL + OPEN-APPLE ( outline) + CLOSED-APPLE ( solid) simultaneously, then press and release RESET before releasing the Apple keys.
No-Keyboard Trick: Simply remove the 26-pin keyboard ribbon cable (or remove the Aux 80-column card if the diagnostic jumper is set) and turn on the power — with both Apple-key sense lines floating high (same as holding both Apple keys down!), the Apple IIe automatically launches the self-test!

Decoding Self-Test Results

Screen Message	Meaning & Faulty Component
`KERNEL OK` (or `SYSTEM OK` on Enhanced //e)	100% Pass! Main 64K RAM, Aux 64K RAM, MMU, and IOU soft-switches all passed.
*` RAM ZP 0 0 1 0 0 0 0 0`** (8 binary digits: Bit 7 → Bit 0)	Mainboard 4164 DRAM Failure! A `1` in any of the 8 positions indicates which data bit (`D7` on left down to `D0` on right) failed during the Zero-Page / Main RAM test. See the F6–F13 locator table opposite!
*` RAM AUX 0 0 0 0 1 0 0 0`**	Faulty 4164 DRAM on the Extended 80-Column Aux Card! Unplug the Aux card and re-run the test to confirm the motherboard passes `KERNEL OK`.
`MMU <code>` / `IOU <code>`	Failed soft-switch or bank-latch inside the custom MMU (`344-0010` at C3) or IOU (`344-0020` at D5). Clean and reseat their 40-pin sockets first!

▦

Garbled Text & 4164 DRAM Chip Locator (F6–F13)

Because the 40-column text screen ($0400–$07FF) is stored directly in Main RAM and constantly refreshed by the IOU/MMU, a single dead 4164 DRAM (F6–F13) turns the blank screen ($A0 = normal space, 1010 0000 binary) into a grid of repeating characters even if the CPU can't boot!

Data Bit	IIe Board IC (8-Chip Board)	Platinum IC (2-Chip 4464)	Self-Test Bit Position (Left → Right)	Screen Character If Stuck
Bit 0 (D0)	F6 (Leftmost)	UA5 (Pin 2)	`0 0 0 0 0 0 0 1`	`!` (`$A1` if stuck HIGH)
Bit 1 (D1)	F7	UA5 (Pin 3)	`0 0 0 0 0 0 1 0`	`"` (`$A2` if stuck HIGH)
Bit 2 (D2)	F8	UA5 (Pin 15)	`0 0 0 0 0 1 0 0`	`$` (`$A4` if stuck HIGH)
Bit 3 (D3)	F9	UA5 (Pin 17)	`0 0 0 0 1 0 0 0`	`(` (`$A8` if stuck HIGH)
Bit 4 (D4)	F10	UA6 (Pin 2)	`0 0 0 1 0 0 0 0`	`0` (`$B0` if stuck HIGH)
Bit 5 (D5)	F11	UA6 (Pin 3)	`0 0 1 0 0 0 0 0`	`@` (`$80` if stuck LOW)
Bit 6 (D6)	F12	UA6 (Pin 15)	`0 1 0 0 0 0 0 0`	Flashing characters (`$60` if stuck LOW)
Bit 7 (D7)	F13 (Rightmost)	UA6 (Pin 17)	`1 0 0 0 0 0 0 0`	Inverse white blocks (`$20` if stuck LOW)

Bench Tip — Micron MT4264 Warning: If your Apple IIe motherboard or Aux 80-Column card has Micron MT4264 DRAMs soldered in row F, expect multiple failures — socket the entire F6–F13 row and install reliable NEC, Hitachi, or TI 4164-15 chips!

Composite Video, Game I/O & Cassette Pinouts

RCA Composite NTSC/PAL video output tips, rear DE-9 Joystick port, and internal 16-pin DIP Game I/O socket.

RCA Composite Video Out & NTSC Artifact Colour 1 V p-p 75 Ω

The Apple IIe outputs baseband composite video directly on its rear yellow/metal RCA phono jack (J15). Unlike the C64 or Atari, the Apple II generates colour entirely in the digital domain using 3.579545 MHz NTSC phase-shifted pixel patterns (Wozniak Artifact Colour)!

Monochrome vs Colour in 80 Columns: In 80-column text mode, pixel transitions occur at 14.318 MHz, which a colour NTSC TV interprets as rainbow colour fringes! On real CRT monitors (like the AppleColor Composite Monitor IIe), press the monitor's front Monochrome / Color button (or use a green-phosphor Apple Monitor II) for razor-sharp 80-column text.
European PAL Apple IIe Boards (820-0073): PAL Apple IIe motherboards include an extra PAL colour encoder circuit and 14.25 MHz crystal. Ensure the onboard 50/60 Hz and Monochrome/Colour links are set appropriately.
Modern Upscalers (RetroTINK 5X / 4K vs HDMI Cards):
- For the RCA composite jack, the RetroTINK 5X-Pro or 4K includes a dedicated comb-filter decoder that cleanly renders Apple II NTSC artifact colours.
- For pixel-perfect digital HDMI, install an A2DVI / RGBtoHDMI card in Slot 3 or an Aux-slot RGB adapter.

Rear DE-9 Joystick Port, Internal 16-Pin Game I/O & 50-Pin Expansion Slots

See also our dedicated 50-Pin Apple II Peripheral Slot and Super Serial Card DB25 RS-232 pinout pages. Apple IIe joysticks use 150 kΩ linear potentiometers wired between +5 V and the four PDL0–PDL3 inputs of a 558 Quad Timer IC (NE558 at C13). Note: The rear 9-pin D-Sub is NOT Atari-compatible!

DE-9 Pin	16-Pin DIP Socket	Signal	Function
Pin 1	Pin 3	PB1 (Closed-Apple)	Pushbutton 1 / Solid-Apple key (active-high, internal pull-down)
Pin 2	Pin 1	+5 V DC	+5 V supply for joystick pots & buttons
Pin 3	Pin 8	GND (0 V)	System ground
Pin 4	Pin 10	PDL2 (X2 Axis)	Second joystick X-axis pot (150 kΩ to +5 V)
Pin 5	Pin 6	PDL0 (X1 Axis)	Primary joystick X-axis pot (150 kΩ to +5 V)
Pin 6	Pin 4	PB2	Pushbutton 2 (`$C063` bit 7)
Pin 7	Pin 2	PB0 (Open-Apple)	Primary Fire Button 0 / Open-Apple key (`$C061` bit 7)
Pin 8	Pin 7	PDL1 (Y1 Axis)	Primary joystick Y-axis pot (150 kΩ to +5 V)
Pin 9	Pin 11	PDL3 (Y2 Axis)	Second joystick Y-axis pot (150 kΩ to +5 V)

Joystick Centering Drift Fix: If the joystick pulls hard to one side or jitters in games, replace the four 0.022 μF (22 nF) timing capacitors (C4–C7) and the socketed 16-pin NE558 Quad Timer (C13) on the motherboard!

Chip & EPROM Reference

Interactive IC Pinout Finder links plus Apple custom silicon (MMU, IOU, HAL) and ROM/EPROM substitution guide.

DIP-40

MOS / Synertek 6502

B4 (Unenhanced //e) — Original 1.023 MHz NMOS 8-bit microprocessor.

View Pinout →

DIP-40

65C02 (CMOS)

B4 (Enhanced & Platinum //e) — Low-power CMOS 65C02 with 27 additional instructions required by Enhanced ROMs.

View Pinout →

DIP-16

4164 DRAM (×8)

F6–F13 (Main) & Aux Card — Single-rail +5 V 64K×1 dynamic RAM chips.

View Pinout →

DIP-40

MOS 6522 VIA

Used in pairs on the Mockingboard sound card, Mouse Interface Card, and Z80/6809 co-processor cards.

View Pinout →

DIP-40 / DIP-28

AY-3-8910 / 8913 PSG

Dual 3-voice stereo sound generators fitted to Apple II Mockingboard and Phasor audio expansion cards.

View Pinout →

Apple Custom LSI & Keyboard Encoder Reference

Chip	Apple Part #	Function & Bench Notes
MMU (C3)	`344-0010-A / B` (NTSC & PAL)	40-pin DIP Memory Management Unit. Generates `RAS`/`CAS`, manages `$C000–$FFFF` language card RAM banking, and Aux RAM switching.
IOU (D5)	`344-0020-A` (NTSC) `344-0021-A` (PAL)	40-pin DIP Input/Output Unit. Generates video display addresses, sync, speaker toggle (`$C030`), and graphics soft-switches (`$C050–$C057`).
HAL (B2)	`341-0170-A` (16R8 PAL)	20-pin High-speed Array Logic dividing the 14.318 MHz master crystal into `Φ0`, `Φ1`, `7M`, `Q3`, and `RAS`/`CAS` timing edges.
Keyboard Encoder (E13)	AY-5-3600-PRO (`341-0150`)	40-pin DIP matrix scanner reading the keyboard via a 2K/4K Keyboard ROM (`341-0132-B` / `D`) at E12. If all keys are dead except Reset & Apple keys, check AY-5-3600-PRO!

System & Video ROM EPROM Substitution Guide

All four ROM sockets on the standard 1983–86 Apple IIe motherboard (D8, D10, D12, E12) use standard 28-pin or 24-pin JEDEC EPROM pinouts — no custom adapters required!

Socket	Unenhanced Part #	Enhanced Part #	Direct EPROM Drop-In
D8 (CD ROM — 8 KB) (`$C100–$DFFF`)	`342-0135-A / B`	`342-0304-A`	27C64 (8 KB, 28-pin) direct drop-in! (Or 27C128 with image burned in upper or both 8K halves).
D10 (EF ROM — 8 KB) (`$E000–$FFFF`)	`342-0134-A`	`342-0303-A`	27C64 (8 KB, 28-pin) direct drop-in!
D12 (Video ROM — 4K/8K)	`342-0133-A` (4 KB)	`342-0265-A` (US) `342-0273-A` (UK/PAL)	2732A (4 KB, 24-pin) or 27C64 (8 KB, 28-pin) depending on motherboard jumper `X6` (`2732` vs `2764` socket).
E12 (Keyboard ROM — 2 KB)	`341-0132-B`	`341-0132-D`	2716 (2 KB, 24-pin) or 2732A (with 2K image duplicated in both halves).

Important Note When Fitting a Modern WDC W65C02S6TPG-14 CPU: Brand-new Western Design Center W65C02S chips assign Pin 36 as BE (Bus Enable, active-high) and Pin 1 as /VPB (Vector Pull Output), whereas the Apple IIe motherboard ties Pin 1 directly to GND! To use a modern W65C02S in an Apple IIe: bend out Pin 1 (leave unconnected) and bend out Pin 36 and bridge it to Pin 8 (+5 V V_DD) via a 3.3 kΩ resistor (Vintage 1980s R65C02P2 / NCR 65C02 chips drop straight in with no pin bending).

Resources & Further Reading

Blog posts, interactive bench tools, and essential Apple II hardware archives.

Smiggy's Apple II & 6502 Posts

Bench Tools & Machine Hubs

Retro File Utilities (Rust/Wasm) — 6502/65C02 disassembler & Apple II .BIN ROM CRC32 verifier/patcher
IC Pinout Finder — 6502, 65C02, 4164, 6522, AY-3-8910 & more
Connector Pinout Directory — 50-Pin Apple II Slot Bus, DB25 RS-232 Serial, RJ45 Ethernet
Recap & Repair Reference — capacitor replacement guide
Ohm's Law Calculator
C64 Machine Hub — Commodore 64 reference
C128 Machine Hub — C128, C128D & DCR reference
SX-64 Machine Hub — Executive Portable C64 reference
Amiga Machine Hub — A500/A600/A1200 reference
Atari ST Hub — 520ST, 1040STFM & STE reference
BBC Micro Hub — Model B, B+ & Master 128 reference
ZX Spectrum Hub — 16K/48K & +2/+3 reference
Dragon 32/64 Hub — Dragon 32 & 64 reference
Amstrad CPC 464 Hub — CPC 464 & Datacorder reference
Sinclair QL Hub — 68008, Microdrive & ULA reference
Acorn Atom & Electron Hub — Atom & Electron reference
Osborne 1 & Kaypro II Hub — CP/M luggable reference
Oric-1 & Atmos Hub — Oric 6502A & ULA reference
Amstrad CPC 6128 Hub — 128K & 3″ disc reference
MSX Machine Hub — MSX1, MSX2, MSX2+ & Turbo R reference
Big-Box Amiga Hub — A1000, A2000, A3000 & A4000 reference
Atari 8-Bit Hub — 400/800, 800XL & 130XE reference
VIC-20 Machine Hub — Commodore VIC-20 reference
Commodore PET Hub — PET 2001, 4000 & 8000 reference
Plus/4 & C16 (TED) Hub — C16, C116 & Plus/4 reference
TRS-80 & CoCo Hub — Model I/III/4 & CoCo 1/2/3 reference
TI-99/4A Machine Hub — 16-bit TMS9900 & PEB reference

External Apple IIe Resources

Asimov Apple II Archive — schematics, ROM dumps, disk images, and SAMS manuals
ADTPro (Apple Disk Transfer ProDOS) — bootstrap & transfer disks over audio or serial from PC/Mac
Applefritter Apple II Forum — hardware repair and restoration community
Understanding the Apple IIe (Jim Sather) — the definitive cycle-by-cycle MMU/IOU hardware bible

Apple II Series 1983–1993 · 8-Bit Computers

Apple IIe (Standard / Enhanced / Platinum) — Unified Workbench Reference

Astec AA11040 PSU RIFA capacitor replacement, Slot 1–7 & Aux 80-Col bus guide, built-in Kernel self-test, and F6–F13 4164 DRAM bit locator.

Switch System Hub (36):

CPU / Architecture MOS 6502 / WDC 65C02 @ 1.023 MHz

Memory (RAM / VRAM) 64 KB Main + 64 KB Aux 80-Col

Capacitor Mount Through-Hole

Custom Chipset & Key ICs

6502 / 65C02 MMU 344-0010 IOU 344-0020 HAL / PAL AY-3-3600 Keyboard 4164 DRAM

Capacitor & Power Stage Reference

Apple IIe / Platinum — Capacitor & Recap Reference

Board revisions, electrolytic capacitor lists, voltage/farad ratings, and Through-Hole servicing notes.

Apple IIe / Platinum — Printable Board Recap & Capacitor BOM ReferenceFormat this system's capacitor replacement list, diagnostic flowchart, and IC pinouts into a high-contrast bench PDF.

Apple IIe — Apple IIe Mainboard (820-0064 / 820-0087) & Astec AA11040 PSU

Standard, Enhanced & Platinum Apple IIe • Mount: Through-hole • Difficulty: Beginner friendly

Full Printable Recap Sheet →

Astec AA11040 Switched-Mode Power Supply (7 Capacitors)

Ref	Capacitance	Voltage	Package / Type	Circuit Location & Bench Notes
`C1`	0.47 uF (470 nF)	275 V AC	Class X2 Film	Replaces large RIFA PME271M smoke bomb.
`C2`	0.1 uF (100 nF)	275 V AC	Class X2 Film
`C11`	2200 uF	16 V	Radial (Low-ESR)
`C12`	1000 uF	16 V	Radial (Low-ESR)
`C13`	1000 uF	25 V	Radial (Low-ESR)
`C15`	220 uF	25 V	Radial
`C16`	220 uF	16 V	Radial

Apple IIe Mainboard (820-0064 / 820-0087) (3 Capacitors)

Ref	Capacitance	Voltage	Package / Type
`C1`	47 uF	16 V	Axial
`C18`	22 uF	25 V	Axial
`C27`	10 uF	25 V	Axial

Printable Diagnostic Flowchart & Voltage CheckpointsFormat this step-by-step fault isolation tree into a high-contrast bench reference sheet.

Apple IIe / Platinum — Interactive Diagnostic Flowchart & Voltage Checkpoints

Enable JavaScript to run the client-side interactive fault-isolation flowchart engine.

Complete Diagnostic Flowchart: Capacitive Load, ESR & Power Rail Ripple Diagnostic Tree (Universal Retro Mainboards (C64, Amiga, ZX Spectrum, Game Gear, Consoles))

STEP 1: Measure 100Hz/120Hz Peak-to-Peak AC Ripple on the +5V / +12V Bulk Filter Cap [node-1]

Set your oscilloscope to AC Coupling, 200 mV/div, and 2.5 ms/div (20 MHz bandwidth limit ON). Probe directly across the main bulk filter capacitor (e.g. C19 2200µF / C88 1000µF on C64, or C303/C304 on Amiga) under full system load. Measure the peak-to-peak sawtooth ripple amplitude (mVpp).

Expected Reading: < 50 mVpp clean regulated rail (post-regulator) or < 350 mVpp on raw unregulated bulk DC before the 7805/7812.

STEP 2: Check Linear Regulator (7805 / 7812) Input-to-Output Dropout Margin [node-2]

Switch oscilloscope or multimeter to DC Volts and measure Pin 1 (Input) of the 7805 (+5V) or 7812 (+12V) regulator at the bottom of the ripple trough. Verify that Input Voltage remains at least 2.0V above the regulated output (e.g. ≥7.2V into a 7805, ≥14.2V into a 7812).

Expected Reading: 7805 Input ≥ 7.2V DC; 7812 Input ≥ 14.2V DC. Below this dropout threshold, ripple punches straight through to the logic rail.

STEP 3: Check Local IC Decoupling & Audio/Video AC Coupling Capacitors [node-3]

Probe audio output coupling caps (e.g. C91 100µF on C64 SID Pin 27, or C324/C334 22µF SMD on Amiga Paula) — compare upstream vs. downstream signal amplitude. Inspect SMD electrolytic pads (Amiga 600/1200, Game Gear, DMG-01) under magnification for fishy odor, dull grey solder corrosion, or lifted copper traces.

Expected Reading: Full audio/video swing across the coupling capacitor with zero DC leakage on the output side and clean, shiny solder pads.

[ISOLATED FAULT: RES-BULK-CAP] Fault Isolated: High-ESR Bulk Filter Capacitor (>100 mVpp Rail Ripple) VERDICT

Excessive 100/120Hz sawtooth ripple on the DC rail confirms that the primary reservoir/filter electrolytics have dried out and lost effective capacitance.

[ISOLATED FAULT: RES-REG-DROPOUT] Fault Isolated: Linear Regulator Dropout / Bridge Rectifier Diode Open VERDICT

The pre-regulator DC rail is sagging below the minimum 2V dropout headroom required by the 7805/7812 regulator.

[ISOLATED FAULT: RES-COUPLING-CAP] Fault Isolated: Open/Leaky Audio or Video Coupling Capacitor & Trace Corrosion VERDICT

Signal attenuation, muffled audio, or DC offset hum across the coupling stage indicates dried-out or leaking coupling capacitors.

[ISOLATED FAULT: RES-RAILS-HEALTHY] Verification Passed: Power Rails, Ripple & Coupling Capacitors Within Spec VERDICT

All measured DC supply rails, AC ripple levels (<50 mVpp), and coupling stages pass bench specification. If performing a preventive recap, use the verified board BOM below.

Interactive Pinouts, Visualizers & Disassemblers

Apple IIe / Platinum — System Bench Tools & IC Pinouts

Click any chip below to open its interactive DIP/PLCC pinout diagram, pin-by-pin signal table, and oscilloscope test waveforms.

Apple IIe / Platinum — Printable IC Pinout & Chipset SummaryPrint this system's custom IC pinout summary or open any chip card below for its full DIP/PLCC pinout sheet.

DIP-14 74-Series Gates

74LS00

SN74LS00N / DM74LS00N

Quad 2-input NAND gate — the most common glue-logic part in retro computers.

Apple IIe Machine Hub

Astec / Dyna-Comp PSU RIFA Capacitor Alert & Quad-Rail Check

1 6-Pin Motherboard Power Plug Pinout

2 Why the Astec PSU "Ticks" Unplugged

3 RIFA & Electrolytic Recap Values

Apple IIe Model Selector & CPU Evolution

Unenhanced Apple //e 1983–1985 • 820-0060-A / B • Boots with "Apple ]["

Key ICs & Identification

Revision A vs Revision B Motherboard (Double Hi-Res!)

Enhanced Apple //e & 65C816 16-Bit Upgrades 1985–1987 • Boots with "Apple //e"

6502 vs 65C02 vs 65C816 CPU Breakdown

80-Column vs Extended 80-Column (64K Aux) Card

Apple IIe Platinum 1987–1993 • 820-0188-A • Built-in Numeric Keypad

Cost-Reduced Platinum Motherboard Changes

Keyboard Switch Types Across Apple IIe Models

Expansion Slot 1–7 Conventions & 50-Pin Bus Pinout

Standard Apple IIe Slot 1–7 Card Map

50-Pin Peripheral Expansion Slot Pinout Slots 1–7 • 0.1″ Pitch

Built-in Self-Test & 4164 DRAM Fault Locator

Built-in Apple IIe Hardware Self-Test Routine

How to Launch the Self-Test

Decoding Self-Test Results

Garbled Text & 4164 DRAM Chip Locator (F6–F13)

Composite Video, Game I/O & Cassette Pinouts

RCA Composite Video Out & NTSC Artifact Colour 1 V p-p 75 Ω

Rear DE-9 Joystick Port, Internal 16-Pin Game I/O & 50-Pin Expansion Slots

Chip & EPROM Reference

MOS / Synertek 6502

65C02 (CMOS)

4164 DRAM (×8)

MOS 6522 VIA

AY-3-8910 / 8913 PSG

Apple Custom LSI & Keyboard Encoder Reference

System & Video ROM EPROM Substitution Guide

Resources & Further Reading

Smiggy's Apple II & 6502 Posts

Bench Tools & Machine Hubs

External Apple IIe Resources

Apple IIe (Standard / Enhanced / Platinum) — Unified Workbench Reference

Apple IIe / Platinum — Capacitor & Recap Reference

Apple IIe — Apple IIe Mainboard (820-0064 / 820-0087) & Astec AA11040 PSU

Astec AA11040 Switched-Mode Power Supply (7 Capacitors)

Apple IIe Mainboard (820-0064 / 820-0087) (3 Capacitors)

Complete Diagnostic Flowchart: Capacitive Load, ESR & Power Rail Ripple Diagnostic Tree (Universal Retro Mainboards (C64, Amiga, ZX Spectrum, Game Gear, Consoles))

Apple IIe / Platinum — System Bench Tools & IC Pinouts

74LS00

74LS02

74LS04

74LS08

74LS138

74LS244

74LS245

74LS374

74LS74

74LS86

MOS 6502

WDC W65C02S

MOS 6522 VIA

Motorola MC6821 PIA

TI TMS5220 / TMC0285 Speech

2764 8K x 8 EPROM

27128 / 27256 EPROM & CPC 40009 System ROM

4116 16K x 1 DRAM

4164 64K x 1 DRAM

NE555

Signal & Trace Visualizer (Scope)

Retro File Utilities (Rust/Wasm)

Connector & Port Pinout Reference

Logic & RAM Substitution Guide

Theme Palette

Audio & Display

System Info