The Tektronix 585A Oscilloscope, manufactured from 1963-71 was at the top of Tektronix's tube scope line. The 585A was initially rated to 100 MHz, but eventually it was downrated to 85 MHz. It contains 73 electron tubes and weighs 30 kilograms.
Source: TekWiki, Radiomuseum
The 585A I have was given to me by the president of our local antique radio club, and this page covers the repairs I have made to it.
This is the oscilloscope shortly after I picked it up.
Here are some pictures taken after cleaning it up a few years later.
The first issue I had to fix was some arcing in the high voltage cage. The insulating coating had worn off of a resistor's lead and it was acing to the case. I fixed this by gluing a strip of plastic to the case to serve as insulation.
After I fixed the arc, I was able to get a trace on the scope, but it had a large amount of ripple. The first thing I did was to use a different oscilloscope to check the various low voltage supplies for ripple.
I discovered that the -150 V reference supply had the largest amount of ripple. It turned out that one of the filter capacitors on the -150 V supply was bad, so after replacing it I had a clean trace.
September 2024 Update: I've been using this scope pretty regularly since I've repaired it (when I'm at home of course). I've done some housekeeping on it, such as acquiring a manual, original probes, installing vinyl Tek handles,
and acquiring a Type 82 plugin which allows me to use the full bandwith of the scope. I'm still hunting for the other 80-series plugins, and I'd like to give the instrument a full calibration in the future.
Ripple on the traces. They should be flat.
First test after putting everything back together
Testing the Type 82 Plugin
