en

# Conflicts:
#	Mod 128k/README.md

Mod 128k/README.en.md

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+> [English](README.en.md) | [Русский](README.md)  
+  
+# Leningrad-2 128K Modification Guide (Classic Piggyback Method)
+
+
+This modification allows the stock Leningrad-2 computer to run any official software and games designed for both the \*\*Spectrum 128K\*\* and \*\*Spectrum 48K\*\* models.
+
+
+
+## Required Components
+
+
+
+In addition to the components specified in the main schematic, you will need:
+
+*   \*\*8x KR565RU5 (КР565РУ5 / 4164)\*\* DRAM chips. \*Crucial:\* They must have the exact same speed/letter suffix rating as the chips already installed on your motherboard.
+
+*   \*\*1x 27256\*\* EPROM chip flashed with the official Spectrum 128K firmware.
+
+
+
+---
+
+
+
+## Step-by-Step Assembly
+
+
+
+1\.  \*\*RAM Stacking (Piggybacking):\*\* Solder the second set of 8x RU5 DRAM chips directly on top of the original motherboard RAM chips, pin-for-pin. 
+
+    \*   \*\*Do not solder pin 15\*\* of the upper chips. Instead, bend pin 15 of all upper chips upward, tie them together with a jumper wire, and connect this line to the \*\*`CAS1`\*\* signal.
+
+    \*   Locate pin 15 of the lower (original) RAM row. Cut the original trace feeding them and connect this row to the \*\*`CAS0`\*\* signal.
+
+2\.  \*\*Address Lines:\*\* Disconnect lines `A14` and `A15` from the `D21` multiplexer chip (KR555KP11 / 74ALS257) on the motherboard. Connect the new \*\*`A14+`\*\* and \*\*`A15+`\*\* signals to those freed multiplexer pins respectively.
+
+3\.  \*\*ROM Switch Signal:\*\* Connect the \*\*`CHSR`\*\* signal to pin 13 of the `D24` multiplexer chip (KP11), replacing its original connection to Ground (GND).
+
+4\.  \*\*EPROM Installation:\*\* Replace the stock `D18` ROM chip with your newly flashed 27256 EPROM. Connect the \*\*`A14R`\*\* signal to pin 27 of this EPROM socket.
+
+5\.  \*\*Decoder Modification:\*\* Locate the `D15` decoder chip (KR555ID7 / 74ALS138). Isolate/cut pin 1 from the `A13` address line. Then, pull pin 1 up to \*\*`+5V`\*\* through a \*\*2 kOhm\*\* resistor.
+
+
+
+---
+
+
+
+## Tuning \& Calibration
+
+
+
+Tuning must be performed using a diagnostic \*\*Test ROM\*\* chip. 
+
+
+
+The calibration process involves adjusting the propagation delay of the \*\*`RAS`\*\* signal. To achieve full system stability and eliminate RAM artifacts, find the optimal capacitance value by temporarily placing a small ceramic capacitor (typically between 10pF and 100pF) between pin 4 of any RU5 RAM chip and Ground (GND).
+
+
+

Mod 128k/README.md

@@ -1,6 +1,8 @@
+> [English](README.en.md) | [Русский](README.md)  
+  
+  
 Доработка позволяет пользоваться любыми фирменными программами как для "Spectrum 128k", так и для "Spectrum 48k".  
   
-  
 Кроме указанных на схеме элементов необходимо 8 565РУ5 с той же буквой, что и уже установленных.
 И ПЗУ 27256 с фирменной прошивкой "128к"
 

README.en.md

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+# Leningrad2-Upgrade-Kit  
+
+## Memory Expansions and AY/TS for Leningrad-2.  
+  
+> [English](README.en.md) | [Русский](README.md)  
+  
+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 (`#7FFD` for memory paging and `#BFFD`/`#FFFD` for 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](https://github.com/Alex-2-Graf/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)
+*   [Schematics](Ext%20AY%20128k/Leningrad%202%20Ext%20AY%20128k.pdf) | [Placement](Ext%20AY%20128k/Leningrad%202%20Ext%20AY%20128k.html) | [Gerber Files](Ext%20AY%20128k/Leningrad%202%20Ext%20AY%20128k%20gerber.zip)
+
+### 2. Leningrad 2 Expansion 128k & Turbo Sound 2x YM2149F (AY-3-8910)
+*   [Schematics](Ext%20TS%20128k/Leningrad%202%20Ext%20TS%20128k.pdf) | [Placement](Ext%20TS%20128k/Leningrad%202%20Ext%20TS%20128k.html) | [Gerber Files](Ext%20TS%20128k/Leningrad%202%20Ext%20TS%20128k%20Gerber.zip)
+
+### 3. Leningrad 2 Expansion 256k & Turbo Sound 2x YM2149F (AY-3-8910)
+*   [Schematics](Ext%20TS%20256k/Leningrad%202%20Ext%20TS%20256k.pdf) | [Placement](Ext%20TS%20256k/Leningrad%202%20Ext%20TS%20256k.html) | [Gerber Files](Ext%20TS%20256k/Leningrad%202%20Ext%20TS%20256k%20Gerber.zip)
+
+### 4. RAM Plug-in Board 2x64
+*   [Schematics](RAM%202x64/Leningrad%202%20RAM%202x64.pdf) | [Placement](RAM%202x64/Leningrad%202%20RAM%202x64.html) | [Gerber Files](RAM%202x64/L2\_RAM\_128k\_gerber.zip)
+
+---
+
+## 🔧 Mainboard Preparation
+
+*   **For my custom [Leningrad-2-48k](https://github.com/Alex-2-Graf/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](Mod%20128k/README.md)
+
+---
+
+## 💾 Memory Testing Software
+
+To verify your new memory configuration, you can use the following diagnostic tools included in the repository:  
+  
+*   [GTEST](Mod%20128k/GTEST1_0.ZIP)  
+*   [HFT](Mod%20128k/HFT1_02.ZIP) 

README.md

@@ -2,6 +2,8 @@
   
 Memory Expansions and AY/TS  
   
+> [English](README.en.md) | [Русский](README.md)  
+  
 ## 🧠 Контроллер расширения памяти и звука (128K/256K + AY/TurboSound)  
   
 Данный репозиторий содержит проекты плат расширения оперативной памяти для компьютера Leningrad-2.