A replacement for beeswax that has similar properties is microcrystalline wax. It is derived from petroleum. I’ve used it to pot transformers, although not HV ones. It can be purchased from online sho

What is described here was found while fixing an HP 180A scope mainframe, but is applicable to Tek scopes as well. I wanted to test an old HP 180A mainframe (rackmount type). I didn't have a working v

The upside-down black and aluminum cylinders look like British 9-pin loctal tubes, or more correctly, valves. The shorter aluminum ones are likely the famous EF50 <https://www.dos4ever.com/EF50/EF50.h

Microcrystalline wax, derived from petroleum, is similar in consistency to beeswax: sticky and non-brittle. Its melting point is below that of boiling water, so can be safely melted using a double-boi

Scope Usage at chez Atwood: Main work bench: 561A with 3A6 or 3A74 and 3B4 plug-ins. I do mainly audio or low HF work here. No fan! Second bench: 502A - again, mostly audio work. I like the sensitivit

FWI: Antique Electronic Supply (tubesandmore.com <http://tubesandmore.com/>) sells new manufacture twist-lock electrolytics under their “CE Manufacturing" brand. They bought the tooling and equipment

Since you mention compactrons, it should be remembered that Tektronix did use them - in the 556 scope: three 6M11 and two 6GF5. Did any other Tek equipment use compactrons? - John Atwood

In virtually all CRTs, the cathode is made up of a metal cup with one end coated with a mixture of barium and strontium carbonates. While the tube is being evacuated, the cathode is heated much hotter

A friend of mine just purchased an old Tek 570 Vacuum Tube Curve Tracer that hadn't been used in decades. He is a competent technical guy, but wasn't too familiar with old tube scopes. I made up a lis

Both the GeigerCounterEnthusiasts group and the GammaSpectroscopy group were shut down by the owner, George Dowell, in September. In their places, new groups were started on Yahoo. I'm not a member of

I'm a member of the GeigerCounters Yahoo group, and it went silent from Nov. 19 to Nov. 24. A post I made around Nov. 22 showed up as one of the first posts on Nov. 24. So, something is going on at Ya

I've also got a 570. I'm also involved in vacuum tube audio design. I bought it from a retired engineer in Silicon Valley in the mid-1980s. I think I paid $220 for it. These are quite scarce now, sinc

The 556 dual-beam scope uses several 6M11 tubes (dual triode + pentode) as well as two 6GF5 tubes (beam power tube). As far as I know, this is the only Tek scope that uses compactrons. I've got a 556,