Tektronix 453 Oscilloscope & Beryllium Oxide Block - Page 1
Forum section: electronics / repair

author: RCL
author_rank: Newbie
timestamp: May 27, 2022, 01:58:49 am
content: Gentlemen:I am scrapping-out an old Tektronix 453 oscilloscope. When I got to the high voltage section, a white block of something fell out. By it's position, in the power supply, it appears to be there to transfer heat, from the HV section, to the chassis. Could this possibly be a dangerous block of Beryllium oxide? It has not been broken.Thanks-in-advance,rlong@ivytech.edu

author: tggzzz
author_rank: Super Contributor
timestamp: May 27, 2022, 07:08:57 am
content: Berillium oxide heatsinks will feel like stone and surprisingly cool to the touch, since they reaily conduct heat away from your fingertips.Don't break them, don't breath in any dust.

author: BrokenYugo
author_rank: Super Contributor
timestamp: May 27, 2022, 03:22:51 pm
content: If it's a plain block, measure it, calculate the volume, weigh it, and calculate the density. BeO ceramic is about 3.0g/cm3, aluminum oxide ceramic (most common) is around 3.7.

author: factory
author_rank: Super Contributor
timestamp: May 27, 2022, 06:30:21 pm
content: Well according to the first manual on Tekwiki, there are 5 heatsink insulator discs, part #214-0317-00, these are BeO according to the NSN part reseller website:https://www.parttarget.com/5970-00-104-7899_5970001047899_214-0317-00.htmlDavid

author: TimFox
author_rank: Super Contributor
timestamp: May 27, 2022, 07:09:07 pm
content: I knew a modern victim of berylliosis: Prof. H. L. Anderson, who had been a junior member of the Manhattan Project.I believe he contracted it by polishing a window made from metallic beryllium, and lost a lung.He survived for another 45 years, but his official cause of death was berylliosis.Beryllium oxide can also cause it.Note that this is usually considered to be an inhalation hazard, especially from breathing dust, although there is some evidence that it can be caused by skin reaction.

author: free_electron
author_rank: Super Contributor
timestamp: May 27, 2022, 07:11:07 pm
content: it's the BeO dust that gets you. handle it with gloves, put in a sealed plastic bag and dispose iof it at a hazardous waste facility. .

author: CaptDon
author_rank: Super Contributor
timestamp: May 27, 2022, 07:19:58 pm
content: We handled power vacuum tubes with BeO seals almost daily. The dust or small particules when inhaled are the bad actors. As long as you don't break the block or try to 'sand it down' to fit a different application you will be fine. In one particular R.F. amplifier for VHF we had the weird version of a 4CX250 Eimac tube that used BeO links to the large heatsink to cool the external anode plate structure. These links were about 2" tall, 8" long and nearly .5" thick with liberal amounts of that silicone heat sink grease getting all over everything with heat and age. We handled BeO as if it were a cathode ray tube being careful not to drop it or nick it!!

author: RCL
author_rank: Newbie
timestamp: May 29, 2022, 08:20:24 pm
content: Density Calculation:Length (mm): 50.28Width (mm): 17.32Height (mm): 13.38Mass (grams): 39.75Volume (mm3): 11650.968Density (g/cm3): 3.41rlong@ivytech.edu29/May/2022

author: factory
author_rank: Super Contributor
timestamp: May 30, 2022, 07:23:05 pm
content: Quote from: factory on May 27, 2022, 06:30:21 pmThese are four of the BeO discs, in the 453 I acquired earlier this year, not sure where the fifth is.Can't see the block you described in the HV section of mine, unless it's under the polycarbonate box.David