| Ext AY 128k | ||
| Ext TS 128k | ||
| Ext TS 256k | ||
| Mod 128k | ||
| RAM 2x64 | ||
| LICENSE | ||
| README.en.md | ||
| README.md | ||
Leningrad2-Upgrade-Kit
Memory Expansions and AY/TS for Leningrad-2.
This repository contains hardware expansion board projects designed for the RAM and sound upgrade of the "Leningrad-2" home computer.
These modules allow you to upgrade the stock 48K base model to a full 128KB or 256KB system. This expansion is essential for running modern homebrew games, advanced demos, and heavy software.
The boards are designed with a primary goal: minimizing messy wire-wrap modifications ("spaghetti wiring"). They connect directly to the system expansion slot, transforming the basic Leningrad-2 48K into a powerhouse 128K+ class machine.
🎸 All-in-One Module Features
- Memory: Upgrade to 128KB (Standard Spectrum 128 mapping) or 256KB using classic DRAM chips.
- Sound: Integrated AY-3-8910 sound chip (or YM2149F equivalent).
- Turbo Sound (Optional): Supports dual AY/YM chips to achieve full 6-channel Turbo Sound capabilities.
- Beep Mixer: The standard motherboard Beeper signal is mixed directly into the main audio channel output.
- Circuitry: Standard port decoding logic (
#7FFDfor memory paging and#BFFD/#FFFDfor sound chip registers). - Compatibility: Full support for games and demos requiring official memory bank switching.
🧩 Hardware Construction & Connection (Bus Through-Port)
The upgrade boards feature a Bus Through-port design. They plug directly into the main system connector of the Leningrad-2, while providing an identical expansion slot connector on top.
- Plug-and-Play: This allows you to stack other peripherals—like BDI (TR-DOS) or DivMMC controllers—directly on top of this expansion board without using flat ribbon cables.
- Motherboard Integration: Optimized for seamless operation with my custom version of the Leningrad-2-48k.
- Universal Compatibility: The board can also be wired to any standard vintage or third-party version of the Leningrad-2. In this case, you will only need to manually route a few core control signals according to the provided schematic.
📦 Modular RAM Replacement (RAM Plug-in Board)
As an alternative to chip stacking ("piggybacking"), this project includes a specialized adapter PCB that holds 16x KR565RU5 (КР565РУ5 / 4164) DRAM chips to replace the stock computer memory.
- Installation: The adapter plugs directly into the original RAM IC sockets (or footprints) on the Leningrad-2 motherboard.
- Universal Fit: The pin group layout completely matches the original RU5 memory chip placement found across all known Leningrad-2 PCB revisions.
- Key Advantage: No messy chip stacking. It provides a clean install, a reliable contact interface, and superior cooling/ventilation for the RAM chips.
- Solderless Upgrade: Equipped with thin male pin headers (PLS-type) that slide perfectly into standard round-hole machined IC sockets on the mainboard. It preserves the clean, aesthetics and long-term hardware reliability.
🛠️ Project Modules
1. Leningrad 2 Expansion 128k & AY-3-8910 (YM2149F)
2. Leningrad 2 Expansion 128k & Turbo Sound 2x YM2149F (AY-3-8910)
3. Leningrad 2 Expansion 256k & Turbo Sound 2x YM2149F (AY-3-8910)
4. RAM Plug-in Board 2x64
🔧 Mainboard Preparation
- For my custom Leningrad-2-48k revision: Preparation is as simple as configuring the onboard jumpers JP5 to JP11 (clearly labeled on the PCB silkscreen).
- For stock/vintage motherboards: Please consult the descriptive documentation and schematics provided in this repository to properly tap the missing address lines. here
💾 Memory Testing Software
To verify your new memory configuration, you can use the following diagnostic tools included in the repository: