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A collection of 5 posts
PDP-11 DL-11 Repair (UART)
DEC

PDP-11 DL-11 Repair (UART)

I quickly ran into a separate problem: the UART wasn’t transmitting data reliably. That pointed me toward a likely issue with the UART card itself.
Apr 26, 2025 3 min read
PDP-11 Timing Repair
PDP-11

PDP-11 Timing Repair

The next part of my PDP-11 to fix is the M7234 - Timing card. It's responsible for the system clock and unibus bus operations. In this situation, the issue presented itself as a fault related bus operations. Symptoms Console Any operations involving the unibus did not work. Examine,
Mar 8, 2025 3 min read
PDP-11 uWord Repair
PDP-11

PDP-11 uWord Repair

In December of 2024, my PDP-11 developed a new fault in the uWord board. The system had gone from mostly functional to almost completely dead!
Mar 1, 2025 5 min read
PDP-11/40 Servicing
PDP-11

PDP-11/40 Servicing

On this page, I have documented all the things I have repaired on my PDP-11 and things to watch out for with your PDP-11 Power Supply Modules The first time I powered up the PDP-11 a full full bridge rectifier failed in one of the power supply modules. I have
Nov 3, 2024 4 min read
MicroVMS 4.7 Installation on a MicroVAX II
Emulation

MicroVMS 4.7 Installation on a MicroVAX II

This is a rough guide on installing VMS 4.7 into a MicroVAX II  running an MFM Emulator and GoTek floppy Emulator. Required Equipment * MicroVAX II * OpenSIMH v4.1 Simulator (Pre-built Simulator) * GoTek Emulator * MFM Emulator * VMS 4.6 and VMS 4.7 * MicroVAX-II Diagnostics (MDM) (Source) Overview Installing VMS
Nov 18, 2023 8 min read
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