2 layers100 × 100 mm
2 layers43.7 × 34 mm
Tick circuit
nmelnick/cbm-ii1Odds and ends to support the Commodore CBM-ii or B128 machine
- Size
- 43.7 × 34 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 15
- Nets
- 20
- Pads
- 52
- Tracks, vias
- 48, 0
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 12 Nov 2023
- Updated
- 1 Jul 2025
Overview
Tick circuit is an open-source printed circuit board by nmelnick, from the nmelnick/cbm-ii repository on GitHub. It is a 2-layer board of 43.7 × 34 mm with 15 parts on 20 nets, routed with 48 tracks and 0 vias.
It is built around the 74HCT4060D. Its parts include 4 capacitors, 2 resistors, 2 ICs, 1 connector and 1 crystal.
Main components
1README
tick-circuit/README.mdtick-circuit
This is a work in progress, largely copied from the Mix and Tick by Michael Schulz.
This will take a +5V and GND input from a power supply and output a 50 or 60 Hz square wave from J2, depending on the quartz crystal placed at X1. This circuit has been prototyped with the 3.93216 MHz crystal, providing 60 Hz. The V1 and V2 circuits have been ordered and used successfully in a Commodore B128.
BOM
| Part | Quantity | Location |
|---|---|---|
| 74HCT4060 | 1 | U1 |
| 74HCT73 | 1 | U2 |
| 10M Resistor | 1 | R1 |
| 100K Resistor | 1 | R2 |
| 6.8pF Capacitor | 2 | C1, C2 |
| 100nF Capacitor | 2 | C3, C4 |
| Bournier 2p Block | 1 | J1 |
| Metz 360272 1p Block | 1 | J2 |
| 3.93216 MHz Xtal | 1 | X1 |
3.93216 MHz Xtal can be replaced with a 3.2768 MHz for 50 Hz output.
The terminal block pads can be directly soldered to if you're feeling wild.
Resources
This uses the logic-4000 libraries from https://github.com/alexisvl/kicad-schlib
Parts
15| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 100nF | Capacitor_THT:C_Disc_D4.7mm_W2.5mm_P5.00mm | C3, C4 |
| 2 | 6.8pF | Capacitor_THT:C_Disc_D4.7mm_W2.5mm_P5.00mm | C1, C2 |
| 1 | 100K | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R2 |
| 1 | 10M | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | R1 |
| 1 | 3.93216 MHz | Crystal:Crystal_HC49-4H_Vertical | X1 |
| 1 | 50/60Hz | TerminalBlock_MetzConnect:TerminalBlock_MetzConnect_360272_1x01_Horizontal_ScrewM2.6 | 50/60Hz |
| 1 | 74HCT4060 | Package_DIP:DIP-16_W7.62mm_Socket | U1 |
| 1 | 74HCT73 | Package_DIP:DIP-14_W7.62mm_Socket | U2 |
| 1 | Power | TerminalBlock:TerminalBlock_bornier-2_P5.08mm | J1 |
The 11 most common of 15 parts.
Questions
How big is the Tick circuit PCB?
It measures 43.7 × 34 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Tick circuit use?
15 parts, built around the 74HCT4060D. 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 Tick circuit KiCad files?
From the nmelnick/cbm-ii repository on GitHub, at the commit this page was made from: the board is tick-circuit/tick-circuit.kicad_pcb and its schematic tick-circuit/tick-circuit.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Tick circuit design in my own project?
Its repository states no licence, so its author keeps all rights: ask nmelnick before reusing the design.
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