Safety concerns repairing test equipment - Page 1
Forum section: electronics / repair

author: Bicurico
author_rank: Super Contributor
timestamp: January 01, 2018, 03:49:06 pm
content: Hi,Today I was doing some repair/cleaning of R&S modules for the CRTU.I took the RF frontend, opened it, cleaned it and only after some time did I notice a warning sticker: "BERILYMUM OXID - SICHERHEITSHINWEISE BEACHTEN - OBSERVE SAFETY INSTRUCTIONS".F*CK! I googled Beryliumoxide and indeed, toxic, hazardous, cancer inducing, ...I washed my hands and face, gurgled water through mouth and nose and cleaned everything. I know, I am paranoid.Why did I not notice this sticker before?What ARE the safty instructions?Where is the berylium oxide?This led me to think on how dangerous is can be, to purchase older second hand test equipment on ebay and then opening it for cleaning and repair.What are the most common dangerous substances found in eelctronic test equipment? I think i.e. about a rubidium time module, etc.How to deal with it? Should common people even be allowed to buy/sell these things?Interestingly, I did not see this topic being discussed here. I did not especifically search for it, but I wonder if it wouldn't make sense to put a sticker on top of this forum, alerting for these things...Regards,Vitor

author: stj
author_rank: Super Contributor
timestamp: January 01, 2018, 05:15:19 pm
content: it's used to make insulation, and looks like a ceramic.dont panic, it's a solid unless you break it.

author: Bicurico
author_rank: Super Contributor
timestamp: January 01, 2018, 05:27:08 pm
content: I freaked out a little, because when I opened the RXTX module, there was some white dust inside and I started cleaning it and blowing it out...I thought it was just aluminium oxide or something inoffensive.Only later did I notice the sticker on the RF frontend.What I am not sure about:1) There is no sticker on the RXTX module.2) I replaced the RF frontend with a second hand one bought on eBay - this one has the sticker, my previous one did not. I don't know if they changed any component or if they started to put these stickers. Perhaps it is because my unit is a CRTU and the new RF frontend comes from a CMU200. Also, I don't know if the RXTX modules are free from berylium oxide (it was this module that had the white powder).2) I did not see any ceramic inside the RF frontend.3) What was that white powder? It was especially accumulated close to the sponge pads.I guess that it won't harm me as a one time thing and probably the white powder was not the berylium oxide anyway.Yet I feel a bit alerted on how easily one can make significant mistakes!Regards,Vitor

author: stj
author_rank: Super Contributor
timestamp: January 01, 2018, 05:54:49 pm
content: the most common use for berylium oxide is to make ceramic insulator plates to put between power components and heatsinks.so in your case, it's probably under the final output transistors.

author: SMB784
author_rank: Frequent Contributor
timestamp: January 01, 2018, 05:56:16 pm
content: Yes, it is easy to make significant mistakes, but just remember that when it comes to carcinogenic substances, one brief exposure is generally not enough to give you cancer. It's the chronic, repeated exposures that are what get you in the end, not the "whoops that one time I got light headed painting my room" experience.

author: Bicurico
author_rank: Super Contributor
timestamp: January 01, 2018, 05:58:11 pm
content: Thanks for the information stj!I am still not sure what the white powder was, but as SMB784 correctly noted, a one time exposition is not the end of the world, either.But I did learn my lesson today: never ignore the stickers!Regards,Vtor

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 01, 2018, 06:08:20 pm
content: Quote from: Bicurico on January 01, 2018, 05:58:11 pmOne of the stupidest things is to come to forums to ask "opinions" of non professional people in connection to possible exposure to carcinogens radioactive materials or poisons.Call your national poison and exposure line they will be able to redirect you to right direction.A professional needs to assess your exposure in this case to Beryllium oxide.As note Beryllium oxide is non toxic in its solid form and is used in quite few places as posters have pointed out.Another hand is if you go blow or handle it in dust form what is not healthy at all.Be smart call your country's poison line they be able to tell what to do.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 01, 2018, 06:30:54 pm
content: And yes do not panic.If you develop skin lesion or respiratory problems (what can be delayed) go hospital and inform the substance you been exposed.Otherwise as i said best call your country's poison and exposure line where they can make assessment of your potential exposure and if doctor needs take urine test.

author: Bicurico
author_rank: Super Contributor
timestamp: January 01, 2018, 06:38:13 pm
content: The thing is that I don't even know IF the white powder was berylium oxide.The only component that had the sticker was the RF frontend (one of two). Inide those, there was NO white powder, actually I did not see anything that could be berilyum oxide at all.The white powder was on the casing of the RXTX module, which seems to be machined from a block of some aluminum alloy. There was some white powder in the corners and I troed to swipe it out with a brush, toothbruth and blowing it. I know, stupid, as I see now. I don't think it was berylium oxide, as it wouldn't make sense nor was there any warning sticker - the TXTX module came from the same CMU200 donor.We don't have a poison and exposure line, I think, and what should I tell them? That I MAY have blown on some berylium oxide powder, because I opened a device which has another module with a warning sticker?

author: Tomorokoshi
author_rank: Super Contributor
timestamp: January 01, 2018, 06:48:07 pm
content: It seems like there is a relatively small window between when stickers like that were put in, and when materials like that were phased out.I wonder about the things inside some of the really old equipment. That "old equipment" smell is volatile chemicals being released. Older phenolic circuit boards, weird capacitor chemistries and whatever they break down into, various beryllium alloys, parts with mercury, cadmium, PCBs, etc.I have something from around 1975 with a mercury battery in it. Last time I looked perhaps 10 years ago it had something that looked like tin whiskers growing out of it. What to do? How do I get rid of it? Can it even be cleaned? The equipment certainly isn't worth any cost to clean properly, so proper disposal is probably the best route.

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 01, 2018, 06:55:50 pm
content: BeO is used in some RF power transistors. The datasheet in these warn the need to properly recycle them and thats why there is a sticker in the module

author: PartialDischarge
author_rank: Super Contributor
timestamp: January 01, 2018, 06:57:52 pm
content: https://materion.com/-/media/files/pdfs/ceramics/articles/beo-still-a-force-in-rf-power-transistor-packaging.pdf

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 01, 2018, 07:03:15 pm
content: Quote from: Bicurico on January 01, 2018, 06:38:13 pmI am saying what you should do .You are totally free to ignore my suggestion.

author: Bicurico
author_rank: Super Contributor
timestamp: January 01, 2018, 07:04:07 pm
content: Hi,I just called the health line and they did pass me on to the toxic/poison emergency - I didn't know this existed and they were very professional.They asked me a few questions and as I did not have any reaction and it being a single occurrence, no further action required, unless I get some sympthoms like rash, coughing, etc.Right now I believe the white powder was NOT berylium, but rather aluminium oxide from the casing itself.Thanks for all your input.I find it important to alert people messing with old test equipment (and other equipment) of possible hazzards.Regards,Vitor

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 01, 2018, 07:07:27 pm
content: Quote from: Bicurico on January 01, 2018, 07:04:07 pmThat is good.You always want professional opinion in these things and now you do not need to worry.Cheers.

author: stj
author_rank: Super Contributor
timestamp: January 01, 2018, 07:40:46 pm
content: i also think it was aluminium oxide - i see it all the time.

author: richnormand
author_rank: Unknown
timestamp: January 01, 2018, 09:32:21 pm
content: Came across BeO several times in Ar laser tubes, heat transfer devices and electronics heat transfer for cooled CCDs and thermal pads.It is ceramic like and quite stable. The small pads I have did not generate any powder over the years as you described. The real issues are machining it or any other process that generate powder/mist that you could breathe in. Guidelines were to machine it under water or oil flow to contain any airborne stuff. Handling whole pieces were not viewed as an issue. If you broke one by clamping it or dropping or hitting with a tool you used copious amounts of water or oil to get any fine particles. Cutting it with a slow speed diamond saw that was cooled with water you had to make sure it did not go dry.I tend to agree with the comments above.

author: Bicurico
author_rank: Super Contributor
timestamp: January 01, 2018, 10:20:07 pm
content: OK, feeling much less stressed now, so here a few comments:1) I really think that the powder was just aluminium oxide. The whole block was oxidized and that was the reason why I decided to clean it.2) It makes sense that the sticker refers to some components having berylium oxide and not (as I thought initially) to some kind of coating.3) Some modules have the sticker, others not. This may be due to the fact that they changed components between production series or because those stickers were mandatory from a given date onwards.4) I think I learned my lesson, to take MUCH greater care handling exotic equipment - unfortunately there is not always a warning sticker on the device.5) This particular components (the CMU200/CRTU RF frontend and RXTX module) have been discussed plenty of times in this forum. There are lots of pictures of these open modules and different repair instructions, i.e. to replace the input amplifiers on the RF frontend board: none of these threads mention any safety considerations!6) Even if I made a fool out of myself here: if this thread helps preventing anyone from doing a silly mistake with huge consequences, then it was a helpfull thread!@Bashstreet: Thank you for your replies. In my defense I have to say that I did not "come to this forum to get health tips", but to rather understand where the berylium oxide is supposed to be and what the white powder could have been. Your concerns however were valid and in the end got me even more paranoid to call the health line.@stj: I think so, too. Probably just aluminium oxide.@MasterTech: Thanks! Interesting read. Yesterday I did not know anything about berylium oxide...@Dave: Perhaps you are in for a video about safety in repairing test equipment?@ All: Have a great 2018!Regards,VitorPS: BTW, the exchange of the RXTX and RF frontend were a success!

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 01, 2018, 10:54:05 pm
content: Quote from: Bicurico on January 01, 2018, 10:20:07 pmI did not wish to mention this earlier but i was somewhat concerned that the molding was made out of beryllium composite and could had rubbed against the casing (would been very daft design but known to happen) (white powder)Any case my comments were aimed to your well being nothing else.I might be sometimes quite direct but it is not my intention to appear discourteous.Cheers

author: Bicurico
author_rank: Super Contributor
timestamp: January 01, 2018, 10:56:10 pm
content: Don't worry - I appreciated your comments.Thanks!Regards,Vitor

author: tggzzz
author_rank: Super Contributor
timestamp: January 02, 2018, 12:15:01 am
content: You didn't make a fool of yourself. A fool would have not thought there might be a problem. a fool would not have asked questions.There are slabs of beryllium oxide in some old Tek scopes, connecting the PSU power transistors to the case. Since it is a good heat conductor, it feels cold to the touch.In other news, I probably have some Hg in my mouth, have asbestos steering for my garage/shed, formaldehyde in the house's cavity wall insulation, and Pb water pipes; I probably don't have Radon coming up into the house from the bedrock.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 02, 2018, 01:11:54 am
content: Quote from: tggzzz on January 02, 2018, 12:15:01 amMight be good idea get rid of the asbestos if the insulation is starting to disintegrate.

author: tggzzz
author_rank: Super Contributor
timestamp: January 02, 2018, 07:17:32 am
content: Quote from: Bashstreet on January 02, 2018, 01:11:54 amIt isn't insulation, it is asbestos cement sheeting. That is benign when damp and not machined. In the UK simple precautions have to be taken during removal only. OTOH some asbestos work requires extremely care and planning.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 02, 2018, 08:54:14 am
content: The beryllium oxide in many devices is actuallyinsidethe device, whereas the ceramic you can see & touch does not include that material.As others have said, unless for some weird reason you file, grind, cut, or otherwise abrade the actual beryllium oxide carrying material, you are OK.The "heatsink compound" used between some early devices & their heat sinks allegedly contains BeO, so if it dries there may be a problem.Heat sink compound from the 1970s on does not contain such material.The white dust in your case is almost certainly aluminium oxide.There seems to be a trend to portray Electronics work as a very hazardous activity, somewhere between Lion taming & trapeze work.In truth, injuries are very rare, compared to many other everyday activities.

author: Gyro
author_rank: Super Contributor
timestamp: January 02, 2018, 11:13:03 am
content: Radium is the one that scares me now - as a kid I played around with so many ex-MOD 'treasures' - meters with white dial markings, toggle switches with little white glass capsules in the end etc. These thing had long since burned out the Zinc Sulphide that had originally made them glow! You only need to look at WW2 era luminous watches with burn marks on the dial where the hands have been stopped.P.S. I have a tiny glass 'no longer luminous' phial from an old WW2 Astrocompass, that I have safely embedded in epoxy inside a drilled block of steel, that I keep as a test source for my Geiger counter. Not even a hint of a glow.

author: bd139
author_rank: Super Contributor
timestamp: January 02, 2018, 11:21:45 am
content: I had a colleague once who proceeded to drill one of the tabs out on a rather large and dead beryllium oxide filled RF power transistor to use as a keyring. He got a quick education in not being stupid from his superior.... As long as you don't do that sort of stuff, you'll be fine.Disposal is difficult for beryllium compounds; you can't just take them to your normal commercial waste "tip", here in the UK at least. You have to pay someone to take it away.I got given an old Harris PA a while ago. It was made in the 1960s. That was nasty. Had asbestos, beryllium and a mercuryin it! Someone really went to town on the hazardous shit there.

author: Bicurico
author_rank: Super Contributor
timestamp: January 02, 2018, 11:23:59 am
content: Well, a day has passed and so far no signs of any reaction, so I do assume I did not have any contact with BeO.Also, I now understand that the BeO is used INSIDE power resistors and power transistors and not as a coating.Here are some links on how people on this forum have been repairing the exact same modules:https://www.eevblog.com/forum/repair/rohde-schwarz-cmu200-repair-(analyzer-levels)/https://www.eevblog.com/forum/repair/rohde-and-schwartz-cmu200-rxtx-module-issues/https://www.eevblog.com/forum/repair/rohde-schwarz-cmu200-repair-of-analyzer-level-dips/msg1160112/#msg1160112-> on this thread is a picture: the attachment ex1.jpg shows some of the white powderhttps://www.eevblog.com/forum/testgear/sca-14-(c4)-mmic-amplifier-replacement-for-cmu200/-> this thread shows a picture of the inside of the RF frontendA forum member was kind and took many pictures of the RF Frontmodule:http://wunderkis.de/cmu200/rawpicex2.jpg shows where there is some dry white thermal pads. I would think this is NOT BeO.In none of these threads is there a discussion on the BeO. Am I just paranoid now?I still think that there should be a sticking post listing common problematic components and devices (YIG, Rubidium reference, stuff containing toxic materials, etc.). It is very easy for amateurs, noobs and beginners to commit a fatal mistake.Regards,Vitor

author: vk6zgo
author_rank: Super Contributor
timestamp: January 03, 2018, 02:13:45 am
content: The white stuff in ex1 looks like quite severe corrosion of the aluminium part, but is harmless.The white stuff in ex2 is heat sink compound which tends to dry up with age & heat.Heat sink compound hasn't used BeO for many years, so you should be OK.If you are still worried, you can probably take samples & get some local Technical authority to test it.(University Chemistry Dept, for instance).

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 03, 2018, 06:25:03 pm
content: Quote from: Bicurico on January 02, 2018, 11:23:59 amEx2 I just dried up thermal compound and is "safe" Just wash hands after handling stuff like that.Long as BeO is in it's intended form (solid) it is quite safe to handle you can use latex gloves if you are concerned about skin irritation.I personally would not be concerned just use common sense(the worry was the powder that turned out to be likely aluminum oxide.)vk6zgo Also made sensible suggestion .