PCB for ZX Spectrum Harlequin 128 Clone ver. 3H

Lineage: This is a ZX Spectrum clone based on the Harlequin project by Chris Smith, maintaining the original physical format — fits in a standard 48K/48K+ case.

Specifications (common for the entire Superfo-Harlequin line, including 3H):

• Flash ROM memory 29F040/39SF040, supporting up to 8 banks of 64K, switchable via a toggle,
• Configurable video timing for 48K or 128K,
• AY-3-8910 sound chip,
• Kempston Joystick port,
• Composite output (PAL and NTSC),
• Powered by standard ZX Spectrum 9V power supply (positive outer pin, negative middle pin),
• ALL RAM mode allowing CP/M operation when connected to a disk drive interface,
• Support for ROM configurations 48K, 128K, and 128K +2A/+3/+3E.

Design:

https://github.com/DonSuperfo/Superfo-Harlequin-128