开云体育

From: Jeff Urban <JURB6006@...>

Whatever happened to Jim Yanik. On Usenet he was the preeminent authority on Tek equipment. I guess he worked for them for about 100 years. I mean if you posed a question, once I did, 7063 with such and so symptom and he comes back with "I think you got the model wrong, sounds like a 7603. you are probably looking at C ___ (or whatever) and he was right quite a bit. maybe he didn't have to go to work, just phone it in.

He also used to sign his posts with "Jim Yanik NRA member". I like that, Put your views out there and fear nothing. The irrational fear of guns is ridiculous, would you rather I electrocute you, make a makeshift MASER out of the part from a microwave oven, use a hammer or a knife ? But he put it right out there.

And he never started any political shit, except for the "NRA member" in his sig line. I would have really liked to meet him. I mean, I have no real desire to meet the President, but Trump is so unusual I wouldn't mind it. People go for celebs n shit and that is all meaningless, I want to meet Yanik, but it is probably too late.

He is one of the people who would not be here to learn like I am, but he did freely share his gained knowledge quite a bit.

One day, there were simply no more posts by him on Usenet. I guess he died. We lost a good resource when that happened.

Mike Terrell I recognize from Usenet, so he remembers Yanik, and would probably concur with what I posted here. But I don't recognize anyone else here from there, but then I haven't ran into everyone either.

He shared his vast Tek scope knowledge for free. Obviously he wanted to keep this amazing technology out of the dumpsters. And it was amazing for the time it came out. Some of the best sources for Tek surplus are in Israel, and those people know what they're doing. Shipping is a bit of a problem to the US, but if you need it you need it.

I saw the technology, when companies were building table radios with series filaments and a 50C5 output tube, Tek had dual timebase, all kind of things. Yanik worked on most of it.

So, who all remembers him ?

On 26 June 2018 at 06:39 "Ed Breya via Groups.Io" <edbreya@...> wrote:


The integrating cube sounds good if sufficient. You can improve the uniformity and efficiency to arbitrary degrees by adding more surfaces, say starting in the corners, making it k-hedral, approaching a sphere as k goes up, but of course it quickly gets a lot more complicated and tedious. Just doing the eight corners should give a large improvement - beyond that it's diminishing returns, and lots and lots of pieces to deal with. Another option for larger sized ones that's occurred to me over the years, is to put a reasonably-accurate, suitably-sized sphere - like an over-inflated beach ball - inside a cardboard box, and fill the outer volume with polyurethane foam. After it all sets up, you can cut ports and other access to the inside, and roll the liquid coating. You could even slice it in half, and gain full access to the insides, then put the two pieces back together for use. This whole thing would be basically plastic and cardboard, so could melt or burn if you put a very hot source right in a port.

Your flat white paint should be pretty good. It may be worthwhile to see if there's any kind of super-reflective paints or coatings available, like maybe what's used on projection screens, if you want a slight improvement. The coating on my real 12" sphere looks like a flat white TiO2 DAG of some sort. I think when they make these, they pour in the DAG and roll it around to coat the insides, then dump out the excess. Also, as I recall, there's a baffle between the orthogonal ports to block any direct passage. This is more important as the ports get bigger, relative to the sphere size.

Ed

On 26 June 2018 at 00:50 "Daniel Koller via Groups.Io" <kaboomdk@...> wrote:


Of course, this is one of those subjects, like religion, sex, drugs, rock-and-roll and politics that I hesitate to respond to here as there are some fanatics about incandescent light bulbs in our ranks.? ?On the other hand, it's a topic near and dear to my heart as I have only a few incandescents left in my house.? ?I replaced all the PAR30 65 Watt flood lamps with CFLs at least 10 years ago, and started replacing them with LEDs starting 1/1/2014.? Out of 37 installed LEDs of all different types,? NONE have yet to fail.
A question I have that may be of relevance to others here is how does one measure the light output of an LED?? ?This is not at all trivial, and it wouldn't surprise me in the least if the stated output, in Lumens, on the box of many of the Chinese made LED bulbs is just a lie.? ?Lumens are not easy to determine because it's the light output of the bulb, multiplied by the response curve of the human eye (the so-called photopic response, for color daylight vision).? That means you need a sensor that is closely matched to the human eye, and then you have to integrate around the bulb.? ??
Most light meters have an extended response in the infra-red, which if properly filtered can give a better response, but they are often 10-20% off from the human eye's response.? ?You can't simply apply a correction factor because the spectral output of LEDs varies a lot and it's not a simple black-body light curve like an incandescent bulb.? You have to measure the spectrum, apply a curve to it, and then integrate around the bulb.? If I were ever so lucky as to have a 7J20 plug-in for my 7854 scope, this measurement is exactly what I would be doing with it!
Interestingly, I recently discovered a TI light sensor chip which has a very accurate photopic response.? It's the OPT3001.?? ?Even better, there are Chinese companies selling breakout boards (and probably knock-offs) of this chip for $5 and I have one on its way to me fro me-bay.? ?I'll just replace the chip with a free one sampled from TI....
So I am curious to play with this chip and see what kind of measurements I get from my LEDs.? ?Does anyone here have any direct experience with such light measurements of non-black body sources?
? Dan






On Monday, June 25, 2018, 12:11:29 AM EDT, Ed Breya via Groups.Io <edbreya@...> wrote:

This is OT, but I just have to say I happened to stop by the Fremont Costco today, and stumbled upon some amazing deals on certain types of LED bulbs, like six-packs of PAR-xx/xxW equivalent spots for two dollars, and other stuff. They are mostly in the good warm-white 2700K/3000K range. PGE has some promotional subsidy pricing going on in some California markets, so anyone in the right areas can pick up some great deals. This is reminiscent of what they did in the CCFL era a decade or more ago. I've been an early adopter of LED illumination, and have all kinds of them collected over the years, so of course, I had to get a bunch of different ones to try out, and some more of ones that I paid five to ten times as much for only months ago. These are even cheaper than various questionable ones I've picked up at flea markets recently - and are brand new. Only certain ones (maybe slow-sellers) are priced in closeout ranges, like six-packs or two-packs for two or three bucks, depending on the particulars, but it may be worth a look. I don't know how long the deals and stock will last, but I'll be back looking for more. Usual disclaimer - no, I don't own a Costco store.

Ed

Thank you all for suggestions - it worked! Indeed, after rotating both the
outside (A) and the inside (B) timebase knobs a few times, and cranking up the
intensity control, I did get something that resembles the sample trace:
/g/TekScopes/photo/60634/0?p=Name,,,20,1,0,0

It seems though that the trace is bit blurry, jittery/jumpy, and with a
significant amount of ghosting... The same symptoms (blurry, unstable and
ghosting) are present on a simple trace as well:
/g/TekScopes/photo/60634/1?p=Name,,,20,1,0,0

I suppose that I will start by trying to clean both A and B Volts/Div
Attenuator Switch contacts...

Dan, I think you can find the sensor pieces to make a reasonably-priced setup with good spectral matching, but the tricky part is the integration of the total bulb output, on a "hobby" budget. Commercial measurements would use an optical integrating sphere or a purpose-built structure, which can get very spendy in sizes big enough to say, stick a whole PAR LED lamp into its port. I'd recommend looking at commercial setups for ideas, and maybe you can come up with a home-made thing that will be "good enough" for your needs.

Ed

On Fri, Jun 22, 2018 at 10:56 am, Mike Merigliano wrote:

The Tek 475 is analog, with a CRT screen, so the tools for LCD screens will
probably not work.

I meant Bob's computer monitor. If LCD which most are these days, some are not quite perfect. My 23" on my good old PC, I think it is an Acer has great viewing angle, about like a CRT. But my laptop which has an edge (bottom) lit LCD is not so good.

There were people on here recently looking for donations for the cost of
scanning a bunch of manuals and making PDFs out if them. I would have
kicked in a few bucks but I do not have a credit card, so someone told me
to just spread the word about this site...OK.

Look back a couple of pages of posts and you'll probably find it, if not
maybe they'll find you. If you got something they don't, and are willing,
let them have it. In fact they probably only need to borrow it. Get them
back and actual paper manuals still have intrinsic value, and I have worked
with them and liked it. Sometimes I print sections and tape them together
into the bedsheet they resemble.

It's up to you, I would at least scan them or let others scan them. I have
a couple of old ones which don't seem to be on the net, once they get it
together I will send them what I have, either scans or the paper itself.

I will do everything in my power (which ain't much really) to keep good
technology out of the dumpster.