I have on the workbench three RX8E PDP-8 RK05 controllers. The goal is to get all three sets 100% working. After doing some initial testing and swapping of boards, I have come to the disappointing conclusion that no combination of boards is fully functional. Repair Strategy Having three sets of

Following the repair of the timing card, it's time to give running the diagnostics a try. So I toggled in the RIM Loader and started it, and the system immediately malfunctioned. Symptoms After doing some basic testing I identified that "Memory Reference Instructions" were failing. For

The second timing card presented a basic fault. When trying to start any program, the timing chain never started. Looking at the logic analyser, the fault was particularly obvious. The system timing simply didn't start. Diagnosing The Fault Run flip-flop is latched High by the PRE input (pin

For this PDP-8/e system, I have two sets of boards; one set is mostly functional, while the other set is only capable of loading addresses. All other console functions don't work. This includes examine and deposit. Symptoms Pressing examine causes the wrong address to be loaded and

OmniProbe is a basic debugging tool for the PDP-8/e. Its main function is to provide a simple interface to connect up a logic analyser to the PDP-8e's bus. The OmniProbe also provides LEDs for each of the 96 signals that make up the Omnibus, allowing you to

I have been graciously given the opportunity to fix a PDP-8e as my next project. This system is currently configured in a minimal configuration, including only the CPU, UART, memory, and Memory Extension. Additionally, the system came with some spare CPU cards. Initial Hardware Configuration Slot Module 13 M837 – Memory