Atari 8-Bit Family Machine Hub
400/800, 600XL/800XL & 65XE/130XE workbench reference — "Ingot" PSU danger alert, ANTIC/GTIA/POKEY/SALLY diagnostics, Micron DRAM locator, 800XL S-Video Chroma & UAV mods, and SIO/PBI/ECI pinouts.
Atari XL/XE "Ingot" Power Supply Danger — DO NOT USE EPOXY-POTTED BRICKS!
Just like the Commodore 64's "Brick of Death", Atari's 600XL, 800XL, 65XE, 130XE, and XEGS have NO internal voltage regulator — they rely entirely on the external 7-pin DIN power brick to supply regulated +5.0 V DC (at 1.5 A) straight to the SALLY, ANTIC, GTIA, POKEY, and 4164 DRAMs. One specific original Atari supply — universally known as the "Ingot" (Part CO61982 / CA017964, smooth bevelled brown/black wedge with NO ventilation slots, completely filled with solid epoxy resin) — overheats internally until its 7805 regulator fails short-circuit, dumping +9 V to +11 V DC straight into the computer and instantly killing all eight DRAM chips and custom VLSI chips!
1 Safe vs. Deadly XL/XE Power Bricks
- DEADLY — The "Ingot" (
CO61982/DV-515): Heavy, smooth, angled trapezoid block with no vents and no screws (potted in rock-hard epoxy). Cut the 7-pin DIN cord off to build a USB-C / MeanWell cable and throw the brick away immediately! - REPAIRABLE — "Black Beauty" (Finned / Vented) & "White Beauty" (
CA016804): Have screws/vents and aren't potted in epoxy, so their internal filter caps and 7805/LM317 can be serviced — though a modern switching PSU with overvoltage protection is still far safer. - Note on Atari 400 / 800 / 1200XL / 1050 Drive: Unlike the 600XL/800XL/XE, the Atari 400, 800, 1200XL, and 1050 Disk Drive use a simple 9 V AC (15–31 VA) transformer with a 3.5 mm or barrel plug (all DC regulation happens inside those machines!).
2 7-Pin DIN XL/XE Power Pinout (+5V DC)
Viewed looking at the rear female 7-pin DIN socket on the 600XL / 800XL / 65XE / 130XE / XEGS (or solder side of the male DIN plug):
| DIN-7 Pin | Signal | Target Spec |
|---|---|---|
| Pin 1, Pin 4, Pin 6 | +5.0 V DC (Bridged) | 4.95–5.15 V DC (@ 1.5–2.0 A) |
| Pin 2, Pin 3, Pin 5 | GND (0 V) (Bridged) | System Return Ground |
| Pin 7 (Center) | Shield / NC | Leave unconnected or shield |
Why 3 Pins Are Used in Parallel: A single DIN pin is only rated for ~1 A continuous without heating up. Always bridge Pins 1+4+6 for +5 V and Pins 2+3+5 for GND when soldering a new USB/5 V cable!
3 Atari 800 Power Board (+5V/+12V/-5V)
- Inside the classic Atari 800 (and 400), the 9 V AC input is rectified on the side power board into +5 V, +12 V, and −5 V because the 400/800 RAM cards use triple-rail 4116 DRAMs!
- Always replace the two big axial filter capacitors (
4700 μF 16V/2200 μF 25V) on the 400/800 power board and clean the gold card-edge fingers on the CPU, OS, and RAM cards with DeoxIT.
Model Selector & Custom Chipset Architecture
Explore Jay Miner's pioneering co-processor architecture (ANTIC, GTIA, POKEY, SALLY) across the 400/800, XL, and XE generations.
Atari 600XL / 800XL / 1200XL 1983–1985 • Brown & Brushed Aluminium • PBI Bus
The iconic Atari 800XL consolidated the multi-board Atari 800 into a single compact motherboard with 64 KB of RAM, built-in Atari BASIC (which can be disabled at boot by holding the silver OPTION key!), a built-in diagnostic self-test ROM, and the rear 50-pin Parallel Bus Interface (PBI). Its smaller sibling, the 600XL, shipped with 16 KB RAM (two 4416 chips) and can be upgraded to a full 64 KB 800XL in 10 minutes by swapping in two 4464 DRAMs and soldering 3 jumper wires!
Core Custom Silicon Quartet
- SALLY 6502C (
CO14806— U8): Custom Atari 6502 @ 1.79 MHz (NTSC) / 1.77 MHz (PAL) adding Pin 35 (/HALT) so ANTIC can pause the CPU cleanly during display list DMA without external tri-state bus buffers! - ANTIC (
CO12296NTSC /CO21697PAL — U7): Direct Memory Access display processor executing its own programmable Display Lists, fine scrolling, Display List Interrupts (DLIs), and DRAM refresh. - GTIA (
CO14805NTSC /CO14889PAL — U17): Graphic Television Interface Adapter — 256-colour palette (16 hues × 16 luminances), 4 hardware Player/Missile sprites, collision detection, andSTART/SELECT/OPTIONconsole key reading + internal keyclick speaker output. - POKEY (
CO12294— U20): Potentiometer & Keyboard Integrated Circuit — 4-channel audio synthesizer + polynomial noise/random number generator + 64-key matrix scanner + 8 paddle ADCs + high-speed SIO Serial UART! - PIA (
6520/6821— U23): Port A reads the two DE-9 joystick ports; Port B ($D301) controls ROM/RAM bank switching and Self-Test ROM enable! - MMU (
CO61618— U3, PAL16L8): 20-pin memory management PAL decoding RAM, OS ROM (U5), BASIC ROM (U4), and$D000–$D7FFhardware registers.
600XL Easy 16K → 64K Upgrade & 800XL Keyboard Types
| Topic | Bench Procedure & Identification |
|---|---|
| 600XL 2-Chip 64KB RAM Upgrade | Replace the two socketed 18-pin 4416 (16K×4) chips at U11 & U12 with two 4464 (64K×4) DRAMs, lift Pin 6 of U6 (74LS158) and Pin 3 of U5, and run 3 jumper wires for A14 and A15 — instant 64 KB 800XL with zero expansion box needed! |
| 5 Different 800XL Keyboard Mechanisms! | Atari sourced 800XL keyboards from 5 vendors: (1) ALPS (discrete mechanical switches — gold standard!), (2) Stackpole (white square plungers), (3) Mitsumi (Mylar membrane), (4) AWI (foam-and-foil/Mylar), and (5) Hi-Tek. On Mitsumi Mylar keyboards, clean the oxidised 24-pin ribbon tail with a soft white eraser or install a new Mylar sheet. |
Atari 65XE / 130XE / 800XE & XEGS 1985–1992 • ST-Style Case • FREDDIE & 128KB Banked RAM
Styled in cool grey with angled function keys to match the 16-bit Atari 520ST, the 65XE (64 KB) and 130XE (128 KB) introduce the 40-pin FREDDIE (CO61922 / CO61991) RAM controller IC (replacing the discrete 74LS158 DRAM multiplexers and dividing the 14.318 MHz clock) and replace the rear 50-pin PBI slot with the dual Cartridge + ECI (Enhanced Cartridge Interface) connector.
130XE 128KB Bank-Switched Architecture
- FREDDIE (
CO61991— U20): 40-pin DIP integrating the 14 MHz/3.58 MHz/1.79 MHz clock dividers and DRAM/RAS+/CASrow/column address multiplexing. - EMMU (
CO25953— U22 on 130XE): 16-pin Extended Memory Management PAL decoding PIA Port B ($D301bits 2–5) to bank four 16 KB extended RAM banks into the$4000–$7FFFwindow (independently selectable for the CPU and for ANTIC!). - RAM Population: Early 130XEs use 16× 4164 DRAMs (
U26–U33= Base 64K;U9–U16= Extended 64K — almost always failure-prone MicronMT4264chips!). Late 65XE/130XE boards condense RAM to two or four4464(64K×4) chips. - Single 16KB OS ROM (
U4—CO61598B): 28-pin JEDEC pinout + 8 KB Atari BASIC Rev C (CO24947A) inU5!
XL vs XE Hardware & Bench Comparison
| Feature | Atari 800XL | Atari 130XE |
|---|---|---|
| RAM Capacity | 64 KB (8× 4164) | 128 KB (16× 4164 or 4× 4464) |
| DRAM Multiplexer | 2× 74LS158 (U26 / U27) | FREDDIE (CO61991) + EMMU (CO25953) |
| Built-in BASIC Version | Rev B (buggy!) or Rev C | Rev C (CO24947A — bug-fixed!) |
| S-Video Chroma on DIN-5 | Missing on stock 800XL (easy 1-wire mod!) | Connected on Pin 5 from factory! |
| Expansion Bus | 50-Pin Rear PBI Edge | 15-Pin Cart + 14-Pin ECI Rear Edge |
Atari 400 & Atari 800 1979–1983 • Cast-Aluminium RF Cage • 4 Joystick Ports
To pass strict FCC Class B RF emission rules in 1979, Atari encased the 400 and 800 motherboards inside heavy die-cast aluminium Faraday shields. The Atari 800 features a removable top hatch housing a 10 KB Personality (OS) ROM card and up to three 16 KB RAM cards (48 KB total), two cartridge slots (Left and Right), and four front DB9 joystick ports (driven by the 6520 PIA!). The Atari 400 features a spill-proof flat membrane keyboard and a single internal RAM card slot (upgradeable to 48 KB).
CTIA vs GTIA Upgrade & CPU Card Notes
- CPU Card: Early 400/800 CPU cards use a standard MOS 6502B plus three 74LS logic chips to implement
/HALTbus disconnect; late 400/800 CPU cards use the single-chip SALLY 6502C (CO14806). - CTIA (
CO10745) vs GTIA (CO14805/CO14889): Very early 1979–81 400/800s shipped with the CTIA chip (128 colours, lacks GTIA modes 9, 10, 11). A 40-pin GTIA is a 100% direct drop-in replacement on the CPU card!
Atari 800 Modular Card Edge Cleaning
Whenever an Atari 800 boots to a black/brown screen or reports less than 48 KB in PRINT FRE(0) (37902 bytes free with BASIC Cartridge in Left Slot = healthy 48K):
- Pop open the top RAM/ROM bay and pull out the 10K OS Card and all three 16K RAM Cards.
- Buff the gold PCB edge fingers on every card (AND on the hidden CPU Card inside the rear cast-aluminium cage!) with a soft white eraser and 99% IPA.
Diagnostic Checklist, Micron DRAM Locator & Mylar Repair
Decoding the "Red/Rust Screen of Death", using the built-in Self-Test ROM/RAM bars, and replacing Micron MT4264 DRAMs.
"Solid Red / Rust-Brown Screen" & 800XL / 130XE 4164 DRAM Chip Locator
On an 800XL, 65XE, or 130XE, booting to a solid Red, Brick-Brown, or Maroon screen (or immediately dropping into the built-in SELF TEST screen with red RAM blocks!) is the classic Atari 8-bit failure signature. Good news: a solid red/brown raster proves your GTIA, ANTIC video sync, and master clock are alive — the CPU crashed during initial Zero-Page RAM or OS ROM verification!
4164 DRAM Bit-to-IC Map (800XL vs 130XE)
If your 800XL or 130XE contains Micron Technology MT4264 DRAM chips (with the stylized M logo), expect them to fail in batches!
| Data Bit | 800XL IC (64K Main) |
130XE Base 64K (Main RAM) |
130XE Ext 64K (4×16K Banks) |
|---|---|---|---|
| Bit 0 (D0) | U9 | U26 | U9 |
| Bit 1 (D1) | U10 | U27 | U10 |
| Bit 2 (D2) | U11 | U28 | U11 |
| Bit 3 (D3) | U12 | U29 | U12 |
| Bit 4 (D4) | U13 | U30 | U13 |
| Bit 5 (D5) | U14 | U31 | U14 |
| Bit 6 (D6) | U15 | U32 | U15 |
| Bit 7 (D7) | U16 | U33 | U16 |
Using the Built-in Self-Test & Star Raiders Cart Trick
- Boot While Holding OPTION: Holding OPTION during power-on disables built-in BASIC (
U4) and jumps straight to the Built-in Self-Test (if no disk drive responds). In theMEMORYtest:- 2 Rows of
ROMBars: Green = OS ROM checksum OK; Red = bad OS ROM (U5) or MMU (CO61618). - 48
RAMSquares (1KB each) + 4 Extended Banks (on 130XE): A red square + error tone indicates a bad 4164 DRAM! (Note: if Low RAM$0000–$07FFis dead, the Self-Test cannot even start and shows a solid Red/Black screen).
- 2 Rows of
- The
Star Raiders/Sys-Check V2.2Cartridge Trick: A diagnostic cartridge (like Sys-Check II on the rear PBI/ECI bus) or an early 8 KB game cart (Star Raidersrequires only the bottom 8 KB of RAM!) immediately tells you whetherSALLY,ANTIC,GTIA, andMMUare healthy when the OS ROM or upper RAM is dead!
POKEY (CO12294) Failure Symptoms & Replacements
Because POKEY handles four different subsystems on one 40-pin chip, a damaged POKEY causes a distinctive combination of symptoms:
- 1. Keyboard Completely Dead (OR Repeating Phantom Keys on Boot): POKEY Pins 10–15 (
K0–K5) and Pin 16 (KR1) / Pin 24 (KR2— Shift/Ctrl/Break) scan the entire 64-key matrix via two4051CMOS analog multiplexers (U18&U19on 800XL)! Before blaming POKEY for a dead keyboard, swap or test the two cheap 16-pinCD4051BEmultiplexers (U18/U19) first — static electricity from fingers frequently kills the 4051s while sparing POKEY! - 2. SIO Disk/FujiNet Transfers Fail (
BOOT ERRORor No SIO Beep): POKEY pins 31, 32, 34, 38 handle serial SIO Data In/Out and Clock. Check the protection diodes/capacitor arrays (CA3086/ discrete diodes) behind the 13-pin SIO port if hot-plugging an SIO device killed serial I/O. - 3. Missing Sound Channels (While GTIA Keyclick Still Works!): Remember that the 800XL/XE mixes the GTIA
CONSOLkeyclick into the audio path separately from POKEY Pin 37 (AUDIO)! - Modern POKEY Replacements: Original
CO12294chips are expensive, but modern FPGA/CPLD drop-ins like PokeyMAX (which supports full Keyboard, Paddle pots, SIO, and Stereo/Quad POKEY + Covox!) work in every 400/800/XL/XE!
MMU (CO61618), FREDDIE & XL/XE Mylar Restoration
Checking custom glue logic and restoring oxidised Mitsumi Mylar keyboard ribbons.
- Replacing a Dead XL/XE MMU (
CO61618— 20-Pin DIP): The original PAL16L8 MMU (U3on 800XL,U21on XE) runs warm and occasionally fails, causing a solid black or red screen. You can program a standard LatticeGAL16V8B(15ns) with the official AtariCO61618JEDEC file as a 100% drop-in replacement! (On a 130XE, the 16-pinCO25953EMMU can also be replaced with aGAL16V8using a 20-to-16 pin adapter orUltimate 1MBupgrade). - 800XL / 65XE / 130XE Mylar Keyboard Ribbon Fix:
- Never use harsh acetone on the flexible green/clear Mylar ribbon tail — it dissolves the conductive silver ink!
- Lightly buff the dark oxidised silver fingers at the tip of the Mylar tail with a soft white vinyl pencil eraser until bright silver returns, wipe dust away with a dry cloth, and clean inside the 24-pin PCB connector with DeoxIT D5.
- If traces have cracked at the fold, drop-in newly manufactured replacement Mylar membranes are readily available for both Mitsumi 800XLs and 65XE/130XEs.
5-Pin DIN Monitor (800XL Chroma Fix & UAV), 13-Pin SIO & PBI/ECI Pinouts
Why a stock Atari 800XL outputs Black & White on an S-Video cable (and the 1-wire fix!), plus SIO FujiNet/SDrive wiring.
5-Pin DIN Monitor Port & The 800XL Missing Chroma Fix DIN 180° • C64 S-Video Compatible!
See also our dedicated 13-Pin Atari SIO Bus, 7-Pin DIN XL/XE Power, and DB9 Joystick/Paddle pinout pages. The Atari 800, 800XL, 65XE, and 130XE use a 5-pin 180° DIN MONITOR socket with the exact same pinout as the 5-pin/8-pin Commodore 64 S-Video/Composite cable! However, on the Atari 800XL ONLY, Atari left Pin 5 (CHROMA) disconnected at the factory — meaning a C64 S-Video cable gives a razor-sharp Black & White picture on an un-modified 800XL!
| DIN-5 Pin | Atari Signal | RCA / S-Video Target | 800XL vs 130XE Status |
|---|---|---|---|
| Pin 1 | Luminance + Sync (Y) | S-Video Y (Pin 3) | Connected on 800, 800XL, 65XE, 130XE |
| Pin 2 | GND (0 V Shield) | Video & Audio Ground | Connected on all models |
| Pin 3 | Audio Out (Mono) | White/Red RCA Audio | Connected on all models (POKEY + GTIA Click) |
| Pin 4 | Composite Video Out | Yellow RCA Video | Connected on all models |
| Pin 5 | Chrominance (C) | S-Video C (Pin 4) | Connected on 800 & XE; DISCONNECTED on stock 800XL! (Note: absent on un-modded 600XL/1200XL) |
How to Enable S-Video Chroma on an Atari 800XL (10-Minute Mod!):
1. Locate the junction of resistor R67 and R68 (or inductor L7 / capacitor C54) in the chroma path on the left side of the 800XL PCB.
2. Solder a 75 Ω–100 Ω resistor in series with a 470 pF–10 nF ceramic capacitor (or direct wire through the empty R67/chroma pad on late revisions) to Pin 5 of the 5-pin Monitor DIN socket (J2)!
3. Also clip out capacitor C56 (an excessive low-pass filter cap on the Luma line) for an instant jump in 800XL S-Video sharpness — or drop a UAV (Ultimate Atari Video) board straight into the CD4050 (U16/U14) hex-buffer socket for studio-grade S-Video and Composite!
13-Pin SIO (Serial I/O) Bus Pinout FujiNet / SDrive-MAX / 1050
Joe Decuir's daisy-chained 19,200–125,000 baud intelligent serial bus (the direct ancestor of USB!). Viewed looking at the rear female 13-pin trapezoidal SIO socket on the Atari (Top row = Odd pins 1, 3, 5, 7, 9, 11, 13 left-to-right; Bottom row = Even pins 2, 4, 6, 8, 10, 12 left-to-right):
| Top Odd Pin | SIO Signal | Bottom Even Pin | SIO Signal |
|---|---|---|---|
| Pin 1 | CLOCK IN (to Atari) | Pin 2 | CLOCK OUT (from Atari) |
| Pin 3 | DATA IN (to Atari, Pin 38 POKEY) | Pin 4 | GND (0 V Digital Ground) |
| Pin 5 | DATA OUT (from Atari, Pin 32 POKEY) | Pin 6 | GND (0 V Shield Ground) |
| Pin 7 | /COMMAND (from PIA CB2 Pin 19!) | Pin 8 | MOTOR CONTROL (Cassette 410/1010) |
| Pin 9 | /PROCEED (to PIA CA1 Pin 40) | Pin 10 | +5 V DC / READY (~50–300 mA max!) |
| Pin 11 | AUDIO IN (External Tape Audio to TV) | Pin 12 | +12 V DC (400/800 ONLY! NC on XL/XE!) |
| Pin 13 | /INTERRUPT (to PIA CB1 Pin 18) | — | — |
SIO /COMMAND (Pin 7) Troubleshooting: While DATA IN (Pin 3) and DATA OUT (Pin 5) go to POKEY, the /COMMAND frame strobe on Pin 7 comes from the 6520 PIA (CB2, Pin 19)! If keyboards and sound work (POKEY OK) and joysticks work, but a 1050 drive or FujiNet never responds to disk requests at all, check PIA Pin 19 (CB2)!
PBI (50-Pin XL) & ECI (14-Pin + Cart XE) Expansion Buses
Both the 600XL/800XL's 50-pin rear PBI edge and the 130XE/late-65XE's 14-pin ECI port (adjacent to the 30-pin cartridge slot) expose the full unbuffered 6502C address/data bus, /EXTSEL (to override internal RAM), /MPD (Math Pack Disable), and /RST — used today by plug-in AVGCart, SIDE3, Sys-Check V2.2, and 1MB RAM320XL expansions!
Custom Silicon & ROM / EPROM Reference
Interactive IC Pinout Finder cards plus Atari CO-number cross-references and 28-pin JEDEC OS/BASIC Rev C upgrades.
SALLY 6502C (CO14806)
1.79 MHz (NTSC) / 1.77 MHz (PAL) 6502 processor modified with Pin 35 (/HALT) tri-state DMA pause input.
6520 / 6821 PIA
Mapped at $D300–$D303: Port A = Joystick Ports 1 & 2; Port B = XL/XE ROM/RAM Banking ($D301); CB2 = SIO /COMMAND.
Atari ANTIC (CO12296/21697)
Display List processor — fetches screen & sprite DMA via /HALT, generates DLIs, and streams AN0–AN2 to GTIA.
Atari GTIA (CO14805/14889)
256-colour graphics chip — outputs LUM0–3 + COLOR, renders Players/Missiles, and reads START/SELECT/OPTION.
Atari POKEY (CO12294)
4-channel audio synthesizer, 64-key matrix scanner, 8 paddle ADCs, and high-speed SIO serial UART.
View Pinout →4164 / 4464 DRAM
Single-rail +5 V DRAMs in the 800XL (8× 4164) and 65XE/130XE (8/16× 4164 or 2/4× 4464).
View Pinout →4116 DRAM (16K×1)
Triple-rail (−5 V, +12 V, +5 V) DRAMs used on Atari 400 and Atari 800 16 KB RAM boards.
View Pinout →Atari Custom Silicon CO Part Number Cross-Reference
| Chip | NTSC Part Number | PAL Part Number | Key Pins & Notes |
|---|---|---|---|
| SALLY (6502C) | CO14806 / CO14806-12 (Both NTSC & PAL) |
Differs from standard 6502 on Pin 35 (/HALT input) and Pin 3 (Φ1 out), Pin 37 (Φ0 in), Pin 39 (Φ2 out). |
|
| ANTIC (Display DMA) | CO12296 (1979)CO21697 (XL/XE, 7-bit refresh) |
CO14887 (Early)CO21698 (XL/XE PAL, 50Hz) |
Generates 240/262 (NTSC) vs 312 (PAL) scanlines. CO21697 / CO21698 adds bit RNMI / 8th refresh line for 64K DRAMs. |
| GTIA (Graphics/Colour) | CO14805 |
CO14889 (PAL)CO20120 (SECAM) |
Outputs Luminance bits LUM0–LUM3 (Pins 22–25), Color phase COL (Pin 21), CSYNC (Pin 27), and Console speaker (Pin 15). |
| POKEY (Sound/I-O) | CO12294 / CO12294B (Both NTSC & PAL) |
Pin 37 = AUDIO OUT, Pins 10–15 = K0–K5, Pins 31/32/34/38 = SIO. |
|
| FREDDIE (XE / Late XL) | CO61922 / CO61991 (DIP-40) |
DRAM multiplexer & clock divider on 65XE, 130XE, and XEGS. | |
XL / XE OS (16KB) & Atari BASIC Rev C (8KB) EPROM Guide
Unlike the 24-pin 1200XL, the 600XL, 800XL, 65XE, and 130XE use standard 28-pin JEDEC sockets for the 16 KB OS ROM (and a 24-pin 2364 socket for the 8 KB BASIC ROM):
| Socket | Original Part # | Direct EPROM Drop-In & Upgrade Advice |
|---|---|---|
XL/XE OS ROM (16KB)( U5 on 800XL; U4 on XE) |
CO61598B (Rev 2) |
27C128 (16 KB, 28-Pin) is a 100% Direct Drop-In! Or use a 27C256 / 27C512 with toggle switches on Pin 27 (A14) and Pin 1 (A15) to switch between stock XL/XE OS, QMEG OS, Omnimon!, and a High-Speed SIO / 800-Translator OS! |
Atari BASIC ROM (8KB)( U4 on 800XL; U5 on XE) |
CO60302A (Rev B — Buggy!)CO24947A (Rev C — Fixed!) |
Most 800XLs shipped with BASIC Rev B (CO60302A), which has a notorious memory-corruption bug that adds 16 bytes to your program every time you SAVE and locks up the machine! Check with PRINT PEEK(43234) (96 = buggy Rev B; 234 = clean Rev C!). Replace U4 with an original CO24947A, a 24-pin MCM68766, or a 2364-to-27C64 adapter burned with BASIC Rev C (or Altirra BASIC)! |
Resources & Further Reading
Blog posts, interactive bench tools, and essential Atari 8-bit hardware communities.
Smiggy's Atari & 6502 Posts
Bench Tools & Machine Hubs
- Retro File Utilities (Rust/Wasm) — 6502 disassembler & XL/XE OS
.BINROM CRC32 verifier/patcher - IC Pinout Finder — 6502, 6520/6821, 4164, 4116 & more
- Connector Pinout Directory — 5-Pin DIN Monitor, 13-Pin SIO Bus, 7-Pin DIN XL/XE Power, DB9 Joystick/Paddle
- 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
- Big-Box Amiga Hub — A1000, A2000, A3000 & A4000 reference
- Atari ST Hub — 520ST, 1040STFM & STE reference
- Apple IIe Hub — Unenhanced, Enhanced & Platinum reference
- BBC Micro Hub — Model B, B+ & Master 128 reference
- Acorn Atom & Electron Hub — Atom & Electron reference
- ZX Spectrum Hub — 16K/48K & +2/+3 reference
- Sinclair QL Hub — 68008, Microdrive & ULA reference
- Dragon 32/64 Hub — Dragon 32 & 64 reference
- Oric-1 & Atmos Hub — Oric 6502A & ULA reference
- Amstrad CPC 464 Hub — CPC 464 & Datacorder reference
- Amstrad CPC 6128 Hub — 128K & 3″ disc reference
- MSX Machine Hub — MSX1, MSX2, MSX2+ & Turbo R reference
- Osborne 1 & Kaypro II Hub — CP/M luggable 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 Atari 8-Bit Resources
- AtariAge 8-Bit Forum — the world's largest active Atari 400/800/XL/XE hardware and repair community
- AtariMania — comprehensive software, ROM, and hardware documentation database
- FujiNet Project — open-source Wi-Fi SIO network & disk/printer adapter for Atari 8-bit
- Atari 800XL / 130XE Field Service Manuals — official Atari diagnostic flowcharts and schematics
Atari 8-Bit (800XL / 130XE) — Capacitor & Recap Reference
Board revisions, electrolytic capacitor lists, voltage/farad ratings, and Through-Hole servicing notes.
Atari 800XL & 130XE — Atari 800XL (CO61598) & 130XE (CO24947)
6502C SALLY + ANTIC + GTIA + POKEY mainboards • Mount: Through-hole • Difficulty: Beginner friendly
Atari 800XL / 130XE Mainboard (6 Capacitors)
| Ref | Capacitance | Voltage | Package / Type | Circuit Location & Bench Notes |
|---|---|---|---|---|
C1 |
470 uF | 16 V | Axial / Radial | |
C2 |
100 uF | 16 V | Radial | |
C18 |
10 uF | 25 V | Radial | |
C54 |
10 uF | 25 V | Radial | |
C56 |
220 uF | 16 V | Radial | |
C78 |
47 uF | 16 V | Radial |
Complete Diagnostic Flowchart: Capacitive Load, ESR & Power Rail Ripple Diagnostic Tree (Universal Retro Mainboards (C64, Amiga, ZX Spectrum, Game Gear, Consoles))
Atari 8-Bit (800XL / 130XE) — 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.
74LS08
SN74LS08N / DM74LS08N
Quad 2-input AND gate — same 14-pin pinout as the 74LS00, with outputs high only when both inputs are high.
Open Interactive Pinout →74LS138
SN74LS138N / DM74LS138
3-to-8 line decoder with three enable inputs and eight active-low outputs — the classic memory-address decoder.
Open Interactive Pinout →74LS14
SN74LS14N / DM74LS14N
Hex Schmitt-trigger inverter — six NOT gates with hysteresis, the standard cure for slow or noisy input edges.
Open Interactive Pinout →74LS74
SN74LS74AN / DM74LS74A
Dual D flip-flop with asynchronous preset and clear (both active low) — the standard edge-triggered latch and divider of the 74-series.
Open Interactive Pinout →MOS 6502
MOS 6502 / R6502 / UM6502
The 8-bit CPU at the heart of the Apple II, PET, VIC-20, BBC Micro and Atari 2600.
Open Interactive Pinout →Motorola MC6821 PIA
MC6821 / EF6821 / MC6820 / MOS 6520
Two 8-bit I/O ports with two interrupt lines each — the 6800-family peripheral chip, half-shared with the 6522 and 6526.
Open Interactive Pinout →Atari ANTIC (CO12296 / CO21697)
CO12296 (NTSC) / CO21697 (PAL) / CO14887
Atari's programmable Display List processor — fetches its own Display List programs via 6502 /HALT DMA, generates Display List Interrupts (DLIs), and streams AN0-AN2 pixel data to GTIA.
Open Interactive Pinout →Atari GTIA (CO14805 / CO14889)
CO14805 (NTSC) / CO14889 (PAL) / CTIA CO10745
Atari's Graphics Television Interface Adaptor — converts ANTIC AN0-AN2 streams into 256 colours (LUM0-3 + COLOR), renders 4 Players & 4 Missiles, and reads START/SELECT/OPTION.
Open Interactive Pinout →Atari POKEY (CO12294)
CO12294 / CO12294B
Atari's Potentiometer and Keyboard Integrated Circuit — 4-channel audio synthesizer, 64-key scanner, 8 paddle ADCs, hardware PRNG, and high-speed SIO serial UART.
Open Interactive Pinout →2764 8K x 8 EPROM
2764 / 2764A / 27C64 / M2764A / HN482764
8K x 8 UV-erasable EPROM, the JEDEC 28-pin byte-wide standard. Same pinout as the 6264 SRAM except for four pins.
Open Interactive Pinout →4116 16K x 1 DRAM
4116 / MK4116 / TMS4116 / MCM4116 / uPD416
16K x 1 DRAM with FOUR supply pins and THREE rails. A 4164 fitted here receives +12 V on its 5 V pin and will not survive.
Open Interactive Pinout →4164 64K x 1 DRAM
4164 / MT4264 / TMS4164 / MB8264 / KM4164 / 41464 (x4)
64K x 1 DRAM, single +5 V. VCC is pin 8 and GND is pin 16 — the reverse of almost every other 16-pin DIP. Apply 5 V to pin 16 and it dies.
Open Interactive Pinout →4416 / 4464 (16K/64K x 4) DRAM
TMS4416 / MB81416 / TMS4464 / MT4067 / KM41464
The 18-pin nibble-wide (x4) DRAM family — just TWO chips replace eight 4116/4164 DRAMs! Upgrading 4416 to 4464 unlocks 64KB on the C16, C128 VDC, CoCo 2 and Atari 600XL.
Open Interactive Pinout →Signal & Trace Visualizer (Scope)
Compare healthy vs. faulty CPU clocks, reset ramps, PLA strobes, and 5V PSU ripple waveforms.
Disassembler & ROM LabRetro File Utilities (Rust/Wasm)
6502/6510 disassembler with IC register links, C64 .D64 parser, and EPROM CRC32 verifier/patcher.
Logic & PinoutsConnector & Port Pinout Reference
59 interactive RGB SCART, DIN A/V, PSU polarity, joystick, floppy, and expansion bus pinouts.
Logic & PinoutsLogic & RAM Substitution Guide
Cross-reference 4116→4164 DRAM mods, 2364→27C256 EPROM adapters, and 74LS/74HCT swaps.