4 layers223.5 × 129.8 mm
4 layers223.5 × 129.8 mm
ClassicIIRevB
btb/ClassicII16Reproduction of Macintosh Classic II
- Size
- 223.5 × 129.8 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 447
- Nets
- 440
- Pads
- 1,868
- Tracks, vias
- 10,001, 1,306
- Pours
- 41
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 25 May 2025
- Updated
- 12 Oct 2026
Overview
ClassicIIRevB is an open-source printed circuit board by btb, from the btb/ClassicII repository on GitHub. It is a 4-layer board of 223.5 × 129.8 mm with 447 parts on 440 nets, routed with 10,001 tracks and 1,306 vias.
It is built around the 74LS245SC, AM26LS30JC and AM26LV32ID, with the 78L08 among its other parts. Its parts include 111 capacitors, 97 resistors, 15 ICs, 11 inductors and 2 connectors.
Main components
474LS245SC
-0℃~+70℃ 12ns@5V,45pF 15mA 24mA 4.75V~5.25V 74LS 8 Bidirectional Output enable Schmitt trigger Tri-State - Buffers, Drivers, Receivers, Transceivers ROHSTexas InstrumentsBuffers, Drivers, Receivers, Transceivers
AM26LS30JC
PLCC-20(9x9)0℃~+70℃ 4.75V~5.25V Driver Low-power mode PLCC-20(9x9) Ethernet TransceiversAMDEthernet Transceivers
AM26LV32ID
SOP-16-40℃~+85℃ 0 3.3V~3.6V 32Mbps 4 8mA Receiver ±5kV SOIC-16 RS-485 / RS-422 ICs ROHSTexas InstrumentsRS-485 / RS-422 ICs
78L08
SOT-89-3-40℃~+85℃ 1 1.7V 150mA 23V 45dB@(120Hz) 6.5mA 8V Fixed Positive SOT-89-3 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSShikuesVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
README
ClassicIIReloaded/README.mdClassic II Reloaded
Started with my reverse-engineered later-revision Classic II, and made some changes for convenience:
- Can use ROM chips from the earlier or later revisions.
- Should be able to use more "modern" 12mm right-angle pushbuttons.
- Can use a 2032 battery.
- Late revision jumper block made no sense, use separate jumpers like the earlier revision.
- Electrolytic capacitor pads wide enough to safely accomodate tantalum capacitors.
Parts
447| Qty | Value | Footprint | References |
|---|---|---|---|
| 119 | ~ | MyPackage:TestPoint_THTPad_D1.0mm_Drill0.5mm | TP1, TP10, TP11, TP100, TP101, TP109, TP110, TP111, TP112, TP113, TP114, TP115, TP116, TP117, TP118, TP119 +103 |
| 41 | 100nF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C28, C38, C42, C44, C45, C46, C47, C49, C51, C53, C55, C57, C100, C101, C104, C113 +25 |
| 36 | ~ | MyPackage:TestPoint_Pad_D1.0mm | TP13, TP14, TP15, TP17, TP135, TP136, TP149, TP150, TP152, TP157, TP158, TP160, TP161, TP162, TP163, TP165 +20 |
| 31 | 4.7K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R2, R13, R16, R18, R36, R38, R41, R43, R45, R47, R50, R51, R53, R54, R57, R59 +15 |
| 22 | 22R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R4, R12, R20, R52, R56, R58, R61, R62, R63, R67, R68, R73, R74, R75, R78, R79 +6 |
| 15 | 10nF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C23, C27, C31, C34, C37, C50, C64, C88, C95, C96, C102, C103, C105, C107, C114 |
| 13 | 560pF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C1, C2, C16, C17, C18, C19, C20, C22, C24, C25, C26, C29, C30 |
| 12 | 10uF 16V | MyPackage:CP_Elec_4x5.8 | C5, C6, C7, C8, C10, C11, C12, C14, C21, C74, C79, C106 |
| 11 | Ferrite | MyPackage:L_2010_5025Metric_Pad2.0x2.2mm_HandSolder | L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11 |
| 6 | NetTie_2 | MyPackage:NetTie-2_THT_Pad0.43mm | NT1, NT2, NT3, NT4, NT5, NT6 |
| 5 | 3.3uF 16V | MyPackage:CP_EIA-3528-21_Kemet-B_Pad3.0x2.35mm_HandSolder | C36, C48, C76, C84, C93 |
| 5 | 47R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R10, R11, R21, R49, R76 |
| 4 | 1Mx4 | MyPackage:SOJ-26-20_7.62x17.145mm_P1.27mm | U13, U14, U17, U19 |
| 4 | 1nF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C32, C33, C40, C54 |
| 4 | Fiducial | Fiducial:Fiducial_1mm_Mask3mm | FD2, FD3, FD4, FD5 |
| 4 | MountingHole | MyPackage:MountingHole_3.2mm_M3_ISO14580 | ZH1, ZH2, ZH3, ZH4 |
| 3 | 220R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R17, R33, R86 |
| 3 | 47uF 16V | MyPackage:CP_Elec_6.3x5.4 | C3, C4, C13 |
| 2 | 1.6K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R7, R15 |
| 2 | 100K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R26, R95 |
| 2 | 100nF | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | C111, C112 |
| 2 | 100pF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C35, C115 |
| 2 | 10M | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R48, R55 |
| 2 | 19.1K 1% | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R42, R46 |
| 2 | 1A | MyPackage:Fuse_2512_6332Metric_Pad2.54x2.54mm_HandSolder | F1, F2 |
| 2 | 1K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R19, R44 |
| 2 | 1uF 50V | MyPackage:CP_Elec_4x5.8 | C9, C15 |
| 2 | 200K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R5, R34 |
| 2 | 25R 150pF | MyPackage:SOIC-20W_7.5x12.8mm_P1.27mm_RC | RC1, RC2 |
| 2 | 27C322 | MyPackage:DIP-42_W15.24mm_Socket | ZU22, ZU23 |
| 2 | 27C400 | MyPackage:DIP-40_W15.24mm_Socket | U22, U23 |
| 2 | 27K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R29, R40 |
| 2 | 33R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R71, R72 |
| 2 | 4.7nF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C72, C108 |
| 2 | 74LS245 | MyPackage:SOIC-20W_7.5x12.8mm_P1.27mm_oval | U20, U21 |
| 2 | 820R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R32, R35 |
| 2 | AM26LS30 | MyPackage:PLCC-20_rounded | U6, U7 |
| 2 | AM26LV32 | MyPackage:SOIC-16_4.55x10.3mm_P1.27mm_oval | U3, U5 |
| 2 | Ferrite | MyPackage:L_Pack03_P2.54mm | LP1, LP3 |
| 2 | Fiducial | MyPackage:Fiducial_1mm_Mask3mm_square | FD1, FD6 |
| 1 | 0R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R97 |
| 1 | 1.2K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R85 |
| 1 | 1.5nF | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | C69 |
| 1 | 100R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R83 |
| 1 | 10K 1% | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R96 |
| 1 | 10pF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C66 |
| 1 | 11.3K 1% | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R31 |
| 1 | 16K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R37 |
| 1 | 180R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R14 |
| 1 | 1N5817 | MyPackage:D_SMA | D3 |
| 1 | 220pF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C39 |
| 1 | 23.2K 1% | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R25 |
| 1 | 25R 150pF | MyPackage:SOIC-20W_7.5x12.8mm_P1.27mm_oval | RC3 |
| 1 | 2N3904 | MyPackage:SOT-23_Handsoldering | Q1 |
| 1 | 3.3K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R1 |
| 1 | 3.3uF 16V | MyPackage:CP_EIA-3528-12_Kemet-T_Pad1.98x2.35mm_HandSolder | C71 |
| 1 | 3.9nF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C41 |
| 1 | 300pF | MyPackage:SMD_1206_3216Metric_Pad1.65x1.27mm | C61 |
| 1 | 31.3344MHz | MyPackage:Oscillator_SMD_Abracon_ABLNO | ZG1 |
| 1 | 31.3344MHz | MyPackage:Oscillator_DIP-14 | G1 |
| 1 | 32.768K | Crystal:Crystal_AT310_D3.0mm_L10.0mm_Vertical | Y1 |
| 1 | 330K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R39 |
| 1 | 33pF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C70 |
| 1 | 34.8K 1% | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R22 |
| 1 | 39R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R23 |
| 1 | 3V | MyPackage:BatteryHolder_Keystone_108_1_2xAA | BT1 |
| 1 | 470R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R3 |
| 1 | 470pF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C52 |
| 1 | 6.2K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R28 |
| 1 | 6.8K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R27 |
| 1 | 60.4K 1% | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R30 |
| 1 | 68030 | MyPackage:PQFP-132_24x24mm_P0.635mm_alt | U16 |
| 1 | 680R | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R8 |
| 1 | 680pF | MyPackage:SMD_1206_3216Metric_Pad1.65x1.27mm | C97 |
| 1 | 68pF | MyPackage:SMD_0603_1608Metric_Pad1.52x1.02mm | C90 |
| 1 | 75K | MyPackage:SMD_0805_2012Metric_Pad1.25x1.65mm | R24 |
| 1 | 78L08 | MyPackage:SOIC-8_3.9x4.9mm_P1.27mm_oval | U2 |
| 1 | ADB | Connector_Imports:TE_5749263-1_MINI_DIN_4_RA_Shield | J6 |
| 1 | AM85C80 | MyPackage:PLCC-68_24.2x24.2mm_P1.27mm_oval | U8 |
| 1 | BURN-IN | Connector_Mine:Mac_Burn_In | J15 |
The 422 most common of 447 parts.
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Questions
How big is the ClassicIIRevB PCB?
It measures 223.5 × 129.8 mm and has 4 copper layers, 1.6 mm thick.
What parts does the ClassicIIRevB use?
447 parts, built around the 74LS245SC, AM26LS30JC, AM26LV32ID and 78L08. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the ClassicIIRevB KiCad files?
From the btb/ClassicII repository on GitHub, at the commit this page was made from: the board is ClassicIIRevB/ClassicIIRevB.kicad_pcb and its schematic ClassicIIReloaded/ClassicIIReloaded.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the ClassicIIRevB design in my own project?
Its repository states no licence, so its author keeps all rights: ask btb before reusing the design.