Vintage Computer Workshops

This Web page last updated June 18 2009, links updated June 29 2023.

Introduction

This Web page talks about a vintage computer restoration workshop held by in June 2009; as an example for others to follow. A number of photos on this page were taken by Mike Loewen, and used with his permission. Thank you. The others were taken by me, Herb Johnson.

My "active restoration" Web page describes activities for the repairing and restoring computers of the 1970's and earlier. In addition, my home Web page for computer restoration provides background information about all this. I welcome corrections, comments and contacts from organizations with these interests. - Herb Johnson

Why restore and repair?

I think local restoration and display events are important and even critical for the preservation of "vintage" computing - stuff from the '60's and 70's, often poorly and inaccurately described as "hobby" computing. There's nothing hobby or amateur about many of the computing devices of the 1970's. All that will be lost, if "old guys" like us don't get together to preserve knowledge, and make it all work again.

A Vintage Computer Workshop by Mike Loewen

In June 2009, Mike Loewen held a weekend "Vintage Computer Workshop" in State College PA. On his Web site, he shows several people and himself at work in his garage, on computers ranging from a 1960's vacuum tube analog computer, to several Heath/Zenith H-89's. Bill Degnan also describes the event in his blog.

Mike says Bill Degnan gave him the idea to have a workshop: "Bill Degnan actually had [a number] of these at his place in Landenberg PA before he suggested my place as midway for he and Dan. I just provided the venue and put out the word." Like a few others, I got the word and participated in this workshop. We shared knowlege of repair and debugging methods, swapped parts. A number of computers or devices were restored to operation, or problems identified, as a result. Mike Loewen said afterward, "I'm happy to see things like my keypunches work again, partially because I have fond memories of using them back in the day, and [also] because I like to see old things that still function."

I consider these workshops as a template for how to gather locally and perform restorations. Mike's invitation said everything about how to organize one. "We'll be meeting on both Saturday and Sunday at my place, and the weather is supposed to be good for both days. Drop in for as long as you like, and stay the night if you want (bring a sleeping bag). There's no set schedule, except we'll have sandwich fixins available for lunch and I anticipate we'll head out to a local restaurant for dinner."

tools, parts:
We all brought tools and parts, extra systems for comparisons and part-swapping. The local Radio Shack was of marginal help for parts.

skills learned and practiced:
operate a vacuum tube tester
soldering and desoldering
cleaning contacts, IC pins
selecting tantalum capacitors to bypass voltage regulators

discoveries:
corroded contacts make poor connections; even oxidized IC pins
voltage regulators can look like transistors
poorly mounted circuit boards can short and damage components
old DRAM chips can work poorly with age

exchanges:
64K DRAMS for voltage regulators
8-inch floppy drives
Commodore computer

Results:
Two Heath/Zenith H-89's were restored to operation as CP/M machines.
One Heath H-19 terminal was restored to operation.
a Donner 3500 analog portable computer was examined, its vacuum tubes tested
an 029 IBM keypunch was largely restored to operation
a MITS 680's problems were due to bad voltage regulators

open issues
Mike: info on Dynabyte "naked terminal" S-100 card
Bill: clean up poor soldering on MITS 680; better mounting of CPU board

links to participants:
Mike Loewen
Bill Degnan's 2008 workshop
2009 Bill Degnan workshop: check his blog for additional events
Herb Johnson's site
Alex Bodnar is active in the SEBHC Heathkit 8-bit computer group.

Copyright © 2023 Herb Johnson