SixtyClone Bare-Board Project
| |
| Caption | Green-solder-mask SixtyClone 250407 replica PCB (rev b) |
|---|---|
| Type | Drop-in replica Commodore 64 mainboard (bare PCB only) |
| Designer | “Bob’s Bits” community project (lead: Rob Taylor) contributors incl. Jim Drew, Leif Bloomquist & C64 enthusiasts world-wide |
| Manufacturer | Unknown |
| First released | late 2016 (initial 250407 gerbers uploaded) |
| Latest revision | rev E gerber set (2022) – 250407, 250466 & 250469 variants |
| Operating voltage | — |
| Layers / PCB | 4-layer FR-4, ENIG finish, gold fingers |
| Compatibility | 100 % electrical* with original C64 ICs & shields (*one bodge wire on early rev A to route VIC /Φ0) |
| Features | • modern 4-layer impedance control • enlarged silkscreen legends & test-pads • optional dual-kernal footprints + JiffyDOS jumper • consolidated decoupling network & “silk-BOM” printing |
| Model No. | SixtyClone-250407 / -250466 / -250469 |
The SixtyClone bare-board project is an open-hardware effort to recreate every major revision of the Commodore 64 logic board as brand-new, professionally-fabricated PCBs. Designed so that hobbyists can transplant the original MOS/CSG chips from a corroded or broken donor machine into a fresh board, SixtyClone provides a legal, royalty-free alternative to scavenging vintage hardware. The gerbers (and KiCad sources for recent revisions) are released under a permissive licence; commercial runs are sold via Bob’s Bits on Tindie and by several regional group-buys.
Project goals
[edit | edit source]- One-to-one electrical compatibility – keep every trace, pad and via placement true to Commodore’s own artwork so that RF shields, heatsinks and cartridges still fit.
- Manufacturability upgrades – convert the 1980s 2-layer stack-up into a modern 4-layer with internal ground/power planes which greatly reduce crosstalk and audible VIC “jail-bars”.
- Usability improvements – large white silkscreen labels (including capacitor values) double as a printed Bill-of-Materials; mounting hole diameters match today’s metric M3 hardware.
- Educational licence – gerbers are free for personal use, encouraging new builders to learn through-hole soldering while preserving classic computers.
Supported C64 revisions
[edit | edit source]| SixtyClone variant | Original Commodore PCB | Key differences / notes |
|---|---|---|
| SC-250407 | “long-board” breadbin (1983-85) | Most common donor; retains separate 6581 SID & 12 V rail |
| SC-250466 | late breadbin (1986) | Two 4464 DRAMs, 8562/8565 VIC, color RAM integrated in PLA |
| SC-250469 | short-board / 64C (1987-92) | HMOS chips, 9 V SID supply; optional pads for dual-kernal switch |
Early SixtyClone rev A boards required a bodge wire between VIC pin 38 and the CPU ϕ0 trace; this was fixed in rev B and later.
Bill-of-materials overview
[edit | edit source]Because SixtyClone is just the PCB, builders must source every through-hole component:
- 21× logic ICs (74LSxx), 16× passives, crystal & can oscillator
- PLA, CPU 6510/8500, VIC-II, SID, two CIAs – taken from a donor or aftermarket replacements
- three linear regulators & heat-sinks (250407 only)
- 4700 µF + 1000 µF axial electrolytics (footprints accept radial if leads are bent)
- DIN keyboard, cassette & power connectors – modern CUI / Cliff equivalents fit the footprint
A colour-coded silk-screen value is printed beside every capacitor and resistor to speed hand assembly. Detailed spreadsheets, Digikey/Mouser links and pick-lists are maintained in the project GitHub wiki.
Assembly tips
[edit | edit source]- Wash & dry the PCB to remove fabrication flux; ENIG finish is already tinned.
- Install low-profile parts first (res-networks, jumpers, resistors) followed by sockets and electrolytics.
- Tin the stitched-via grounds under each TO-220 regulator (250407) before mounting the heatsink to guarantee low-impedance bonding.
- Perform continuity checks on the 5 V and ground planes *before* inserting irreplaceable MOS chips.
- Recommended to pair the build with a modern “C64 Saver” PSU protector when first power-up.
Known issues
[edit | edit source]- SID audio hum – greatly reduced versus original boards but still audible on high-gain amplifiers; adding a ground-lift plane under the audio path (rev E experimental) lowers the noise a further 3 dB.
- Keyboard bracket height – certain aftermarket metal keyboard braces foul the cassette port shield; trimming 1 mm from the bracket front edge resolves the clash.
- Case LEDs – early silkscreen marked +/- backwards; always verify polarity before soldering.
Licensing
[edit | edit source]Gerber and schematic files are released under Creative Commons BY-SA 4.0. Commercial resale of finished boards is permitted provided attribution remains on the silk-screen and in accompanying documentation.
Availability
[edit | edit source]- Tindie storefront “Bob’s Bits – Commodore 64 replica PCBs” – sells 250407 & 250469 boards in green, blue and black solder-mask, typically US $29 – $35 each.
- Group-buys on r/c64 and Amibay several times per year, often bundled with complete BOM kits.
External links
[edit | edit source]- Retrohax build-log & high-resolution photos
- Official GitHub repository – gerbers, KiCad source & BOM
- Tindie product page
Related pages
[edit | edit source]- C64 Reloaded MK2 – a professionally-re-engineered C64 logic board with CPLD PLA
- Ultimate 64 Motherboard – FPGA-based SoC replacement
- Commodore 64 Capacitor Replacement Guide – recommended before transferring ICs to SixtyClone
- PLA Replacement Options – modern substitutes for the 906114-01 in long-board builds