I went to Houston Vintage Radio Association (http://hvra.org) meeting this past weekend and picked up two used oscilloscopes during the auction.
The first of the two is a Textronix TAS465 100 Mhz, dual-trace oscilloscope. Built in 1993, this scope was used in a school until it was put in storage in 1999. There it stayed until the seller brought it in.
The seller was forthright about the fact that the traces worked but that several buttons were wonky or didn't work at all. There were two scopes. I bid on the first but lost. On the second I bid it up to USD$36.00 (I know, right!) and took it home.
I cleaned the outside and then performed a quick test. The seller was right, several button dead to use. The scope itself displayed a beautiful trace.
I found the manual at the Tektronix website and called the kids into my electronics "lab" to help/watch.
Taking the front panel off was pretty easy. The buttons under the CRT were immediately accessible. We cleaned the pads and the elastomer with a bit of isopropyl alcohol.
The other buttons required a second disassembly step but on the whole were pretty easy to get to. This time I was more cautious about cleaning the pads. They were covered in a black, conductive paint that is soluble in alcohol so I only cleaned the elastomer.
I put everything back together, restarted it and tried the dead buttons. They all worked! For $36 and less than an hour of work we now have a fantastic analog, dual trace scope with digital sampling (cursors for measurement) with less than 6 years of use!
Heathkit IO-12 "Laboratory Oscilloscope"
The second is a Heathkit IO-12 "Laboratory Oscilloscope". See my blog post at Heathkit IO-12 "Laboratory Oscilloscope" Restoration.