The University of Iowa's DEC PDP-8 Restoration Log Part of the UI-8 pages by Douglas W. Jones THE UNIVERSITY OF IOWA Department of Computer Science

Contents

• Introduction
• Log entires for 2013
• Log entires for January-March 2014
• Log entires for April-June 2014
• Log entires for July-December 2014
• Log entries for January-February 2015
• Log entries for March-June 2015
• Log entries for July 2015-December 2016
• Log entries for 2017
• Log entries for 2018
• Log entries for 2019

• Jan 31, 2023, More R-Series logic probes

Introduction

This is a chronological log of the progress restoring the University of Iowa's PDP-8 computer. Entries are added at the end as work progresses. Click on any thumbnail image to see full-sized image.

Jan 31, 2023, More R-Series logic probes

Bug 64: After a long hiatus forced on us by the COVID-19 epidemic, the retrocomputer lab was reopened during the fall of 2022. We went over many of the same ssues covered in previous years, verifying that memory didn't seem to be working and renewing our suspicion that there might be a problem with the memory strobe signal.

Three probes

Bug 65: In doing that, we realized that we really needed more logic probes, so we set out to manufacture two more, using the design documented on Dec. 6, 2018. As with our previous probes, we packaged them in dry-erase marker bodies. The new probes all behave just like the Dec. 2018 one, differing only in the color of the caps on the markers.

In the photo

• The probe with the green cap is viewing a clock, the signal is mostly positive low pulses.
• The probe with the yellow cap is viewing a steady high signal.
• The probe with the pink cap is viewing a steady low signal.

Doug Jones built one probe while Elle Goodrich and Samuel Nicklaus built the other, learning to solder and doing some logic debugging in the process, locating inadvertent cold solder joints, forgotten connections and solder bridges.