Description
Genuine Texas Instruments TMS4116-15NL – The Heart of the ZX Spectrum Lower RAM
Essential for Sinclair Restoration
The “Lower RAM” in a Sinclair ZX Spectrum consists of eight 4116 DRAM chips. These chips provide the first 16k of memory, which includes the vital screen buffer. When these chips fail, the machine often displays a characteristic screen of coloured blocks or patterns and fails to reach the copyright screen. This Texas Instruments TMS4116-15NL is the premium choice for replacing these failing components and bringing your 8-bit machine back to life.
Why Choose Texas Instruments?
While various manufacturers produced 4116 chips, Texas Instruments versions are highly regarded by the retro-repair community for their timing accuracy and reliability. These are the 15NL variant, offering a 150ns access time that perfectly matches the requirements of the Spectrum’s ULA and Z80 processor.
Key Features & Technical Specs:
- Manufacturer: Texas Instruments.
- Part Number: TMS4116-15NL.
- Capacity: 16k x 1 Bit Dynamic RAM.
- Speed: 150ns access time.
- Package: 16-pin DIL (Dual In-Line).
- Compatibility: Direct replacement for all Sinclair ZX Spectrum 16k/48k “Lower RAM” positions (IC6 to IC13).
Installation Notes:
The 4116 is a triple-rail chip, requiring -5V, +5V, and +12V to operate correctly. If your Spectrum has suffered a power rail failure (often caused by the TR4 or TR5 transistors), it is highly likely that one or more of these Lower RAM chips has been damaged. We strongly recommend installing these chips into high-quality 16-pin DIL sockets during your repair to protect the motherboard and allow for easier troubleshooting in the future.
