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Re: OT - Method of choice to sort and store assorted transistors (apart from having one bin for every part number)
Small plastic bags with a ziploc, widely available on fleabay. Many can then be put in a single component drawer. Choose bag size so it fits into drawer without folding. Put a paper label inside the bag, if that helps locating devices in the future.
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Care with static-sensitive devices, of course. On 03/12/18 19:59, Fabio Trevisan wrote:
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Re: Large lot of Tek equipment for sale
You and the rest of us!
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Jim F Sent from my Verizon, Samsung Galaxy smartphone -------- Original message --------From: "Robert Simpson via Groups.Io" <go_boating_fast@...> Date: 12/3/18 1:05 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Large lot of Tek equipment for sale
Sigh, It's a good thing I don't live near there if I want to keep my marriage working. Just a few weeks ago I picked yet another scope (two dozen and counting). A fully loaded 7704A with two extra plug-ins and a non Tek probe. I didn't need it but at $130, what does need matter? Bob |
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Re: Large lot of Tek equipment for sale
Sigh,
It's a good thing I don't live near there if I want to keep my marriage working. Just a few weeks ago I picked yet another scope (two dozen and counting). A fully loaded 7704A with two extra plug-ins and a non Tek probe. I didn't need it but at $130, what does need matter? Bob |
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TDS3032 does not boot. LCD backl-ight and fan working.
Hi guys,
I have a TDS 3032 that does not start. When powered on, the fan spins, and the LCD shows a white screen (i.e., back-light only). There is no beep, no floppy seek sound, and no relay clicks - the scope simply stays this way and does not attempt to boot. All power supply voltages are within spec. Pressing the calibration button in the back during power on has no effect. Any ideas as to what may be the cause of this would be most welcome! Can it be a dead battery in the Dallas NVRAM chip? I know this can cause weird problems at startup, but I do not know if this is one of them. Thanks in advance, Benjamin |
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OT - Method of choice to sort and store assorted transistors (apart from having one bin for every part number)
Hello Guys,
I come to ask your ideas (or how do you guys do) on the best way to separate and store assorted transistors. With the years, I came to scrap and possess quite a number of transistors of all kinds (maybe a few hundreds). I know that this amount is still few in comparison to what probably some of you guys have, but they're enough to annoy me quite much whenever I need to browse them, looking for a possible candidate for a new project or to use as a replacement of something that may have blown. The thing is, I can't afford the space to have separate drawers for each possible model, so I would like to separate them in some sort of matrix, that is easier to browse later on. Then, when I get to a given bin, I may need to look for the best part number only in that bin. But I can't seem to find a good way to sort them... I thought about four drawers, each with maybe a dozen or sixteen bins (4 x 3 or 4 x 4). The four drawers would be Small and Medium PNP (or P-channel) - Small and Medium NPN (or N-channel), Large PNP - Large NPN. Up 'til here, I think it's just common sense to have these 4 major separations and I can`t think of a better way to go about it. Now, within each drawer, I can't seem to make up my mind about the best way to sort them... By Vce (Vds) across one axis and by Ic (Ids) across the other? Which 2 major selection parameters are the most useful? I welcome your suggestion / wisdom... Rgrds, Fabio |
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Re: What is this soft metal, and is it toxic?
Hi,
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Indium is also used by the Vandervell Co. for their tri metal copper lead engine bearings as the overlay to the copper for the actual bearing surface. The US uses lead as the overlay but the English/Vandervell process used lead/indium and hold the patent for it. The lead/indium is a better bearing surface. Jim O On December 2, 2018 at 11:37 PM Roy Thistle <roy.thistle@... mailto:roy.thistle@... > wrote: |
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Re: 7T11 horizontal memory
Hi Chris,
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It's not so easy to interpret the graphs 26 and 27 the correct way. The shaded area in 26 actually consists of horizontal lines, the value of which are sampled when the memory gate conducts. In 27 something similar for the rest period between end of hold-off and next trigger event. When probe TP555 at a slow sweep speed, 5 ms/div, trigger from this signal and play with the SCAN rate of the 7T11, you can get a more or less stable display. You will recognize the 7T11 sweep as a rising envelope with an amplitude of 5 V. The output at TP564 is a nice 2X inverted, down going sweep signal with amplitude 10 V. TP556 shows about the same as TP564 but with small amplitude. Albert On Mon, Dec 3, 2018 at 01:06 PM, cmjones01 wrote:
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Re: What is this soft metal, and is it toxic?
As noted by other posts, it may be indium. If so, it¡¯s melting point is 313F (easily reached in an oven). It has a very low vapor pressure (also noted) so it is suitable to high vac systems. Typically used for soft metal seals and thermal transfer joints. It¡¯s Young¡¯s modulus is 11GPa (similar to wood!) so it deforms easily, fills voids and contours even at low temperatures. It will wet many metals, so maybe it is there as a thermal conductive layer.
If it is indium, it will talk to you (squeak) if bent by the ear. Something to do with crystal migration. Kjo |
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Re: 7T11 horizontal memory
On Sat, Dec 1, 2018 at 10:49 AM, Albert Otten wrote:
The memory gate is open when Q546 conducts, so when its base is pulledI've now had another look at this and found at least one fault with my plugin. I see the multivibrator behaving as you describe, and outputs B and D do indeed spend a couple of microseconds low together. The reason that Q546 was never turning on was that R542 and R541 have drifted in value. R542 should be 30k but measures 26.2, and R541 should be 27k but measures 28.5. That meant that Q542 was stuck on and thus clamping the base drive to Q546. I've desoldered R541 and R542 for now. Now I have healthy gate pulses at the collector of Q546. However, I don't have any sweep at TP555 in equivalent time mode. Need to look in to this next. Chris |
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Re: Large lot of Tek equipment for sale
Craig Sawyers
I have no affiliation with the seller, but he has a lot of equipment (Tek) for sale via Craigslist,Wow - what a haul. The big mainframe on the cart is a 7904A, and has a 7CT1N curve tracer in the second bay. That in itself is a nice and exceptionally useful thing. Craig |
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Re: What is this soft metal, and is it toxic?
Yes...according to the above Website, Indium wets class...it should leave a silvery streak when rubbed across glass. As for Indium being putty like... I remember it as being plastic; but more like very stiff taffy then putty... so I guess... putty like. Maybe the really pure stuff is softer?
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Re: What is this soft metal, and is it toxic?
hi:
Indium... at least mostly pure Indium (not an allow) is very shiny...it doesn't tarnish in air... they used to use it for the reflectors in headlights. At room temperature, it is soft, and it cuts¡ but, it isn't sticky. It also cries when you bend it. There are Indium/lead solders, for soldering to gold...and alternative to tin/lead that leeches the gold plating. Also, I seem to recall, Indium...or Indium/Gallium alloys wet glass, and leave a mirror like surface. They use Indium in vacuum gaskets; but, usually those are shaped like O rings, or like copper gasket on spark plugs... the Indium flattens and seals under pressure. Anyway, Indium won't melt in boiling water. You can do a flame test... usually its a paste of the metal sample and hydrochloric acid, dipped onto a platinum wire, in a non-luminous flame...like a propane torch flame... natural gas in the lab. Pure Indium isn't known to be toxic; but, the solder alloys (with lead) probably are. I've seen rubber (Buna), fluoropolymers, silicone rubber, Teflon, gold, copper, and Indium gaskets, in vacuum systems. |
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Re: What is this soft metal, and is it toxic?
in the implant refurbish business we used an elastomer for the platens. Under some conditions it turned hard, some other materials were indium. depends on who made the platen and when. contaminated- most likely not, although depends on the ion being spewed......just use gloves and do not breath the stuff. masks not necessary.
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¸é±ð²Ô¨¦±ð On 2018-12-02 3:20 p.m., Chuck Harris wrote:
Why do you think it is metal? Is it shiny in a way |
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Re: What is this soft metal, and is it toxic?
hi
you could try to dissolve, or soften at least, a little bit of it in kerosene, WD-40, or contact cleaner¡ some kind of organic solvent. If it softens but doesn't all dissolve, it is some kind non-metallic material, with maybe a metal filler...like heatsink compound. If it is Wood's metal, or Gallium, it is going to melt pretty quickly in boiling water...or near boiling water. Basically, it will look like a little blob of mercury, at those temperatures. (Don't heat it directly...see below!) Different amalgams of mercury, have different physical properties. Mercury lead can form a brittle solid.. about the composition of a cookie. Mercury cadmium is similar. But in plastic, or pasty form (lots of liquid mercury in the mix)¡ I don't recall them being sticky. If it is an amalgam... as long as you have ventilation, don't smear it on your skin... or especially don't eat it or heat it strongly so the metal boils... then you should be fine. The solid or liquid forms of these metals/amalgams have low vapor pressures, unless you strongly heat and boil them. The vapor/gas is very dangerous, when inhaled. If its an amalgam, sweep up, or shovel up any contaminated areas, without raising dust...into a doubled up clear plastic bag(s)¡ and dispose of it as you would batteries (how every you do that locally.) If its organic...like thermal paste...it could have a metal filler like aluminum, or silver; but, I don't think they use cadmium, or mercury amalgams for fillers. I'm not sure how to dispose of thermal paste... other than to dispose of it the way you do solvents and paint. I guess, if one doesn't want a toxic surprise, and is scrapping, or recovering parts from scientific, medical, or industrial equipment, it might pay to know what to expect. My neighbor smashes microwave oven magnetrons, for the aluminum, even though I told him berylliosis is very serious. |
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Re: What is this soft metal, and is it toxic?
Chuck Harris
Indium solders just about anything that can stand the
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temperature. It is commonly used to solder glass to glass, in lasers. It also solders glass to ceramic, and ceramic to a variety of metals. Because it is soft, putty like, it gives a little, and accounts for variations in expansion rates of different metals. AFAIK, it is not poisonous, as it is commonly used in the alloys used in dental crowns. Its vapor pressure is very low, with its boiling point being over 2000C. -Chuck Harris Daniel Koller via Groups.Io wrote: Yeah, and now I eat crow because I didn't actually fully *read* the original post before I answered it and tried to be helpful. I bet Chuck is right - Indium is commonly used in vacuum environments. It's a good gasket material (RF and vacuum gaskets in a pinch). |
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Re: What is this soft metal, and is it toxic?
Yeah, and now I eat crow because I didn't actually fully *read* the original post before I answered it and tried to be helpful.? ?I bet Chuck is right - Indium is commonly used in vacuum environments.? ?It's a good gasket material (RF and vacuum gaskets in a pinch).
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? There's an awareness about Cadmium that is likely to have prevented its use in anything more modern (last 20 years of so?).? Lead is a no-no in high-vacuum systems.? I has a high vapor pressure.? You don't even use brass since the lead will outgass at temperature.? ? ? How was the indium (or whatever it is) bonded to the ceramic?? ?Try melting it on a hot plate to determine its melting point and maybe scrape up enough to measure specific gravity.?? ? Don't rule out bismuth or tin either.? Try a flame test.? I just googled Indium (Flame Tests) and found this: | | | | | | | | | | | Flame Tests Dave Barthelmy Listing of Flame coloration which can be used to identify elements in minerals. | | | | In | The element?Indium?is named for the prominent blue lines in its spectrum. | On Sunday, December 2, 2018, 10:57:55 PM EST, Chuck Harris <cfharris@...> wrote:
<> -Chuck Harris John Griessen wrote:
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Re: What is this soft metal, and is it toxic?
Chuck Harris
<>
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-Chuck Harris John Griessen wrote:
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Re: What is this soft metal, and is it toxic?
Oh, sorry.? I missed this message which provides the context I was looking for.? ?I can't think of any reason one would build a plasma etcher out of something that is particularly toxic, BUT, I would be more concerned about what someone could etch in a plasma etcher.? Gallium Arsenide comes to mind.? But looking that up now on Wikipedia, it's debateably carcinogenic.? ?Just the same, I wouldn't play scratch and sniff with the stuff.? ?Wash your hands really well, and try not to inhale anything as you chip away or grind or sand.? Better yet, wear a mask.? ?
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None of the soft heavy metals and going to kill you instantaneously.? ?You'll just have to get them recycled properly.? ?You can burn a chip of the stuff to see if it melts or burns at a low temperature to try to identify it.? Definietly don't breath those vapors. First guess, without knowing more about this system is that it's some sort of a protective alumina/ceramic plate glued onto the aluminum cover plate of the etcher, to protect if from etching.? ?Just a guess.? You can measure the density of the metal plate once you clean it up. ? Dan On Sunday, December 2, 2018, 3:17:09 PM EST, John Griessen <john@...> wrote:
It's parts of a plasma etcher that are in the high vacuum area.? The ceramic plate had wafer lifting pins and was bonded to a thick aluminum plate with low temp metal brazing. I can gouge it easily at a temperature of 60 deg F and the tool feels sticky.? A push and twist captures the tool and holds its cantilevered weight. Could this be Woods metal?? Gallium?? Toxic Mercury Cadmium Lead amalgam? I am thinking it must have been stable in vacuum with some warm temperatures when the etcher was running... |
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Re: What is this soft metal, and is it toxic? OT
Context needed.? ?What is the larger view of the part?? Where did it come from???Any date information, lab stickers, anything that might indicated what its function was?
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? Dan On Sunday, December 2, 2018, 7:26:14 PM EST, John Griessen <john@...> wrote:
On 12/2/18 5:20 PM, Chuck Harris wrote: Why do you think it is metal?? Is it shiny in a wayI guess the photos seemed more like reality right after I took them, but now that I review, they do look flat and like epoxy or caulk... I annotated the same photos, which were done in bright sun. -- John |
Fabio Trevisan
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