Description
Sinclair ZX Spectrum 48K DC-DC Power Circuit Refresh Kit (Issue 3 / 3B)
The “inverter” circuit in the 48K Spectrum is responsible for generating the various voltages needed by the memory and video chips. In the Issue 3 and 3B revisions, these components are under significant stress. Our DC-DC mod kit replaces ageing, out-of-spec parts with modern, high-quality alternatives to keep your 5V, 12V, and -5V rails rock-solid.
Why This Kit is Essential:
- RAM Protection: A faulty DC-DC circuit is the leading cause of “dead” lower RAM (4116 chips). Replacing these components proactively can save you a much larger repair bill later.
- Stable Video Output: Clean power leads to a cleaner video signal, reducing vertical bars and interference in your display.
- Modern Specifications: We use high-quality, branded transistors and diodes that meet or exceed the original Sinclair specifications for better thermal management.
- Comprehensive Spares: Includes the critical transistors (often TR4 and TR5) and diodes known to fail in the Issue 3/3B power rail.
Installation & Technical Support:
Fitting this kit requires soldering skills. To ensure a successful installation, please refer to the linked technical document provided below. This guide covers the component placement and the necessary checks to ensure your power rails are safe before you power up your precious Sinclair hardware.
NOTE: this kit can be purchased as an add-on to the full capacitor kit – if you need the full kit then purchase from HERE.
See notes here on performing the mod: DC-DC Mod notes PDF
