Make It With Matty

BBC Model B Repair I love collecting and repairing retro computers, but prices can get high so I usually buy faulty ones and try to fix them. Recently I picked up a BBC Model B listed as “powers on, light comes on, nothing else working.” That sounded like a potential easy fix, so I made a cheeky low offer and it was accepted! In this post, I’ll walk through how I diagnosed and repaired the fault. Unfortunately, my camera corrupted most of the footage but I managed to save some photos from the process and the final video of it powered up and working. Please note that this is a hobby for me and you should not do this if you do not know what you are doing as you could risk electrocution!!! First off opening up the case, there was no obvious damage, which is a good sign. These computers are now over 40 years old, and the electrolytic capacitors in the PSU tend to dry out or leak, causing start-up failures or blown components. Since the previous owned powered this on, no doubt one of the...

 Installing NVIDIA Tesla M60's on my servers In this post, I’ll go through how I upgraded my HP Gen8 servers to use NVIDIA Tesla M60 GPUs , including replacing the PCIe riser cards, verifying detection in BIOS, and preparing for driver installation on openSUSE Leap 15.6 . My servers 🖥️ Node 1 – HP DL385p Gen8 Component Spec CPU 2 × AMD Opteron 6380 Threads 64 RAM 128   GB DDR3 ECC GPU NVIDIA Tesla M60 (16   GB GDDR5 – dual GPU card, 2 × 8 GB) Storage 11.7   TB total     🖥️ Node 2 – HP DL380p Gen8 Component Spec CPU 2 × Intel Xeon E5 ‑ 2665 Threads 32 RAM 256   GB DDR3 ECC GPU NVIDIA Tesla M60 (16   GB GDDR5 – dual GPU card, 2 × 8 GB) Storage 512   GB SSD   🖥️ Node 3 – HP DL380 Gen8 ...

 Understanding Boolean Logic Before we can build logic gates or design digital systems, we need to understand the language that describes how they work,  Boolean logic . What Is Boolean Logic? Boolean logic is a type of algebra that deals with true or false values. Represented as 1 (true/high) and 0 (false/low) . It’s the foundation of all digital electronics , from simple gates to full CPUs. Every digital circuit you’ll ever build using 74LS chips, microcontrollers, or even a 6502 ultimately follows Boolean rules. Think of Boolean logic as mathematics for truth,  where instead of adding numbers, we combine logical conditions. The Basic Boolean Operators These three operators form the basis of Boolean algebra . Every logic gate, circuit, and even program condition can be expressed using these symbols. Truth Tables A truth table lists all possible combinations of inputs and the resulting output. They’re one of the most useful tools when designing or testing...

Build a Tiny Command-Line Virtual Assistant in Python (Step-by-Step) Want a lightweight virtual assistant you can run in the terminal and extend with your own commands? In this post we’ll build a clean, single-file assistant called va.py . We’ll start from a bare read a command, evaluate the comment, print the response and the loop. then layer on a command system, persistence (notes & todos), helpful built-ins, and a tiny intent guesser. You’ll end up with: a va> prompt (the loop) a decorator-based command registry (easy to add commands) persistent notes & todos stored at ~/.va_state.json help , history , clear , exit , and more a simple keyword-based intent fallback Requires: Python 3.9+ (tested on 3.10/3.11). Run with: python va.py 1) Start We begin with a loop that reads a line, splits it into a command and arguments, and exits cleanly on Ctrl+C / Ctrl+D. #!/usr/bin/env python3 import shlex, sys BANNER = """\ Command-line Virtua...

6502 Retro Console Part 2 Add a Reset and Clock Circuit In Part 1 we powered up the 6502 and watched it running a NOP test with just the CPU and LEDs on the address bus. Now we’ll give it a clock and a clean start every time you power on, rather than relying on a function generator. In this post we will cover a simple 555 Timer Clock circuit and reset circuit. 555 Timer The 6502 needs a steady pulse on its Φ0 (pin 37) to step through instructions. A NE555 timer is perfect for low-speed testing reliable, simple, and easy to wire. Parts List NE555 timer 1 kΩ resistor 10 kΩ resistor 100 nF capacitor (timing) 0.1 µF capacitor (decoupling) Breadboard + jumper wires Circuit Diagram How to Wire It Add a 0.1 µF decoupling cap across the +5V and GND rails stability. Typical speed: ≈ 7–10 kHz perfect for a visible NOP test. Use larger resistors or capacitors to slow it down. Tip: Swap the timing capacitor for 1 µF and the 10 kΩ for 100 kΩ to step slowly enough ...

 The Simplest Working 8-bit CPU Circuit Before we start building a full retro console, let’s do something beautifully simple get a 6502 CPU to run,  no RAM, no ROM, no glue logic, just the chip, a few LEDs, and a clock. This is called a NOP test (No Operation). It’s the digital equivalent of “does it breathe?” What You’ll Need Part Purpose MOS 6502 CPU The heart of our system Bench power supply (5 V) Power for the CPU Function generator Clock source 8 × LEDs To watch address lines change 8 × 470 Ω resistors Current-limiters for the LEDs 1 × 0.1 µF capacitor Decoupling between VCC and GND Breadboard and jumper wires For connections MOS 6502 Cpu Pin Out Check your IC and its datasheet to ensure that you have the correct pin out map as the steps below may vary slightly. Step 1 — Power and Decoupling Give the 6502 a clean 5 V supply: VCC (pin 8) → +5 V VSS (pins 1 and 21) → Ground Place the 0.1 µF capacitor between VCC and VSS close to the chip. That tiny capacitor...