I really liked this repair video from CuriousMarc (aka AJ6JV). This counter pre-dates the use of integrated circuits -- it is all discrete transistors. Near the end, Marc mentions how this made this repair "like debugging a big integrated circuit, but with access to each transistor -- this made it quite satisfying." I hear ya Marc -- with big ICs maybe all you would get to do would be to swap out a single IC. There would not be much of a challenge there.
With the older, discrete circuitry you get a good view of how Marc troubleshoots -- how he finds the precise points where the device is failing. Note his use of the old HP paper manuals. I know this is an old guy thing, but I think the paper manuals (as opposed to the online versions) just make the process easier. Note too that Marc at one point had to go back to microfiche.
The transistor tester Mark used was very cool.
The whole physical structure of the HP device is very similar to my NYC HP8640B. Thanks again Steve Silverman and Dave Bamford.
I will look at Parts II and III of this series soon.
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I haven't watched any of Marc's vids before (though they show up in my suggested feed), but now I've subscribed. A little test-gear porn among consenting adults doesn't hurt anybody.
ReplyDeleteYour preference for paper manuals isn't just an old-guy thing. The reason they're better (especially with fold-outs) than screens is that the paper versions can be used *synoptically*, particularly when several papers are spread in front of you. Even in book form, any page can be accessed and compared with any other paper or sheet. This was the great innovation of the Latin *codex* (ca. 500CE)--a book as a bound stack of sheets ("pages") that replaced the older books on scrolls that could be accessed only serially and couldn't really be indexed.
1500 years later, with computer screens we're back to scrolling. Computers connected to the network are great for *distributing* technical information, but for actually using it they suck big time. It's like trying to read a roadmap (another synoptic device) through a paper-towel tube.
I see Honeysuckle Creek gets a mention in this video,f having a row of these frequency counters. Honeysuckle Creek in Australia received and relayed television footage of the moon landing. In the film "The Dish" Parkes Observatory got most of the credit. Parkes only received the landing footage. Six hours later the first steps on the moon were received by Honeysuckle Creek. Honeysuckle signals were sent to OTC Sydney via Williamdale and Red Hill. Charlie Goodman from NASA then selected the feeds from Honeysuckle and Parkes for worldwide broadcast.
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