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Cursitor Doom <curd@notformail.com>: Jan 19 06:18PM Gentlemen,   Would I be correct in thinking that if you have an item of test equipment with a CRT display and it's dim and when you try to turn up the brightness it actually gets dimmer for the last bit as you get towards maximum? And there's nothing you can do about it; it's only fit for spare parts?   tia --   No deal? No problem! :-D

Cursitor Doom <curd@notformail.com>: Jan 19 10:40PM On Sun, 19 Jan 2020 13:39:12 -0800 (PST), John-Del <ohger1s@gmail.com> wrote:   >Lots of circuit maladies will simulate a weak CRT. Start with voltage readings, move to waveforms. Low high voltage will cause the picture to dim as the drive to the tube is increased for instance.   I was given to understand elsewhere (which is why I'm double-checking here) that a CRT which has gone dim and reaches its peak brightness before dimming again towards the end of the intensity control sweep is irretrievably fucked and not worth further investment in time. It would be nice if that advice is indeed incorrect!   --   No deal? No problem! :-D

Cursitor Doom <curd@notformail.com>: Jan 20 09:56AM On Sun, 19 Jan 2020 15:02:37 -0800, Jeff Liebermann <jeffl@cruzio.com> wrote:   >provide the maker and model number of what you are working on? I'm >wondering if you have a pathological aversion towards numbers, or >perhaps you might be embarrassed by your choice of test equipment.   I didn't want to limit it to one specific item, Jeff; just wanted to make the question as general to CRO test equipment as possible. Someone opined thusly about the matter on some discussion forum and I thought it might be useful to keep it in mind for future eventualities, that's all! Anyway, it was bad advice, clearly.   --   No deal? No problem! :-D

Cursitor Doom <curd@notformail.com>: Jan 20 09:59AM On Sun, 19 Jan 2020 22:44:02 -0800, John Robertson <spam@flippers.com> wrote:   >usually a fault with the HV diode, especially in B&W CRTs.   >That might be considered to be cheating - actually providing useful >background information...   Since you didn't read the question in the first place I'll excuse myself on that one. The issue was *not* about the image shrinking/growing during intensity adjustment!! --   No deal? No problem! :-D

Cursitor Doom <curd@notformail.com>: Jan 18 09:11PM Gentlemen,   How reliable are the old 'tin-can' encapsulated op-amps from say 40 years ago? I'm talking about the ones that look like large transistors and have typically 8 leads in the TO5-8 package. I'm unable to provide a part number as these don't have one as such. Could be a 741 perhaps but I can't be certain. Are they known to fail?   thanks. --   No deal? No problem! :-D

Cursitor Doom <curd@notformail.com>: Jan 19 01:26AM On Sat, 18 Jan 2020 14:12:19 -0800, John Robertson <spam@flippers.com> wrote:   >damage (moisture working in via the leads) is one primary cause of >failure. If the leads look good then chances are fairly good the device >will work.   No sign of corrosion at all on the leads.   >I use lots of 30 to 40+ year old components all the time for servicing >our classic arcade games. Most are perfectly good. Other than >electrolytic capacitors.   So do I. The question wasn't about NOS components, but components that have been in service for decades.     --   No deal? No problem! :-D

Trevor Wilson <trevor@rageaudio.com.au>: Jan 19 12:32PM +1100 On 19/01/2020 8:11 am, Cursitor Doom wrote: > and have typically 8 leads in the TO5-8 package. I'm unable to provide > a part number as these don't have one as such. Could be a 741 perhaps > but I can't be certain. Are they known to fail?   **No. Provided supply Voltages remain within the limits set by the manufacturer, metal can OP amps, transistors, etc are phenomenally reliable. For a long time, all MIL-spec semiconductors were metal can only. They might still be, but I doubt it. In the early days of plastic encapsulation, some problems were notable. Mostly with power devices. Things have improved markedly over the years, but you will likely never approach the reliability of a metal can device by using plastic.     -- Trevor Wilson www.rageaudio.com.au

Trevor Wilson <trevor@rageaudio.com.au>: Jan 20 10:04AM +1100 On 20/01/2020 9:55 am, Jeff Liebermann wrote: > alternate sources for about $2.5 million/year of their components. > When I mentioned this to the sales rep, he acted like he didn't care > or it wasn't important.   **Oh, now that is interesting stuff.   -- Trevor Wilson www.rageaudio.com.au

Cursitor Doom <curd@notformail.com>: Jan 19 01:23AM >> but I can't be certain. Are they known to fail?   >> thanks.   >The problem components from that era are lytics of course and glob-top transistors.   OK, I have to know.. "Glob-top"?? --   No deal? No problem! :-D

Cursitor Doom <curd@notformail.com>: Jan 19 10:10AM >http://www.ichom.org/Overig-499982/Connectoren-schakelaars-kabels-FAIRCHILD-Glob-Top/   >The round top is an epoxy glob covering the die, which sits on the flat thick sheet material that holds the leads. 2 tone ones make this easy to see, all black ones not so much.   Ah. Ok. I have a few hundred of those but some obscure part numbers and all PNP so are unlikely to be called into service here. :) --   No deal? No problem! :-D

KC JONES <kcharlie@nowhere.net>: Jan 18 04:11PM -0500 I've had a germicidal lamp more or less in storage for a number of years, but recently brought it out to sterilize a room where a person had been sick. However, I don't know if it still emits the germ killing UVC spectrum. What's a quick way I could tell for sure? Thanks.

Allodoxaphobia <trepidation@example.net>: Jan 19 06:09PM On Sun, 19 Jan 2020 10:08:04 -0500, Ralph Mowery wrote: > that some buttons are sewen on with will work.   > Where I worked making polyester sandoze was added to the material to > make the whites even whiter. That glows under UV light.   Cat piss. Cat piss shows up quite bright under UV light.   Glad to help, Jonesy -- Marvin L Jones | Marvin | W3DHJ.net | linux 38.238N 104.547W | @ jonz.net | Jonesy | FreeBSD * Killfiling google & XXXXbanter.com: jonz.net/ng.htm

amdx <nojunk@knology.net>: Jan 19 09:01AM -0600 On 1/19/2020 8:59 AM, amdx wrote: > senses any UVC. OR buy a UVC sensor and flip flop covering and > uncovering the sensor and see if you get a square wave output.   >                                       Mikek   I should have posted the sensor. > https://cdn-shop.adafruit.com/datasheets/1918guva.pdf   and the adafruit pcb.

amdx <nojunk@knology.net>: Jan 20 08:23PM -0600 On 1/19/2020 9:01 AM, amdx wrote:   >  and the adafruit pcb.   >> https://www.adafruit.com/product/1918?gclid=Cj0KCQiAmZDxBRDIARIsABnkbYTW4uwwxg5rvIcjY6z2MlUDvmN4QcL5PgAGeBvgHixbOqSlqbiXfFMaAn90EALw_wcB   No one has responded to my post. Is there anything fundamentally wrong other than the cost of filters is high and the sensor has it weakest response in the UVC wavelength. I don't mind the idea getting shot down, I'd learn something.   Mikek

Stephen Wolstenholme <steve@easynn.com>: Jan 20 03:18PM On Sat, 18 Jan 2020 16:11:01 -0500, KC JONES <kcharlie@nowhere.net> wrote:   >years, but recently brought it out to sterilize a room where a person >had been sick. However, I don't know if it still emits the germ killing >UVC spectrum. What's a quick way I could tell for sure? Thanks.   All the UVC lights I have ever used have some part of the visible spectrum. See if white items "glow".   Steve   -- http://www.npsnn.com

Lucifer <LuciferMorningstar@bigpond.com>: Jan 18 12:10PM +1100 >in a spare telephone at that jack, and used my Tracfone to call >my landline number. The first time, the telephone rang. A little >while later, I tried it again, and by golly, it did not ring.   Is your phone connected to your modem or are you still on ADSL?

jaugustine@verizon.net: Jan 21 07:25AM -0500 On Mon, 20 Jan 2020 09:34:17 -0800 (PST), "pfjw@aol.com"   >The internet is your friend.   >Peter Wieck >Melrose Park, PA   Hi, I saw that "sandman", and other places on the web, but it did NOT say anything about the ringing voltages from red to ground or green to ground.   That is why I made this post.   John

jaugustine@verizon.net: Jan 20 12:23PM -0500 Hi,   I have used a Fluke DMM with a Max/Min capture feature to measure the ringing voltage, not only red to green, but also red to ground (and green to ground).   To my surprise, the red wire to ground ringing voltage (some telephone equipment on line) was 93.2 VAC !! The green wire to ground ringing voltage was 36.4VAC. Note: Telephones are ringing.   Is this normal?   Thank You in advance, John

"Paul Hovnanian P.E." <paul@hovnanian.com>: Jan 25 05:43PM -0800 Jeff Liebermann wrote:   > On Fri, 24 Jan 2020 15:40:47 -0800, "Paul Hovnanian P.E." > <paul@hovnanian.com> wrote:   >>https://www.cnet.com/reviews/ambient-devices-7-day-weather-forecaster- review/ >>any ideas?   > Please post the FCC ID number from the serial number sticker and I'll > see what I can find out about the receiver section.   No model or FCC ID number anywhere on this thing (it's Chinese). Either on the outside, it the battery compartment or internally. What appears to be the receiver section has a sticker on it that reads '929.6125'. Taking a wild gues that this is MHz, that puts it in a pager band.     > Hmmm... <http://map.myambient.com> is suppose to produce a coverage > map for the weather service. Instead, it produces a text page > suggesting you call Ambient Support.   Ambient support is pretty much defunct. Although they do seem to be broadcasting updates.   > For troubleshooting, see:   <http://myambient.com/productDetail/XDayForecasterSupportPage/serialPrefix/140/> > Check the signal strength indicator in the upper right corner of the > screen. Zero or 1 bar isn't good enough.   Yeah. One bar most of the time. Although I did try an interesting experiment. I took the thing with me in my car and drove to the neighborhood grocery store. One bar pretty much everywhere except for one location about a block from my house. The signal strength meter pegs in front of one house.   I'm toying with the idea of putting together a spectrum analyzer app for my SDR dongle and sniffing around for spurious sources around that frequency.   -- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ The large print giveth and the small print taketh away. -- Tom Waits

Jeff Liebermann <jeffl@cruzio.com>: Jan 25 09:50PM -0800 On Sat, 25 Jan 2020 17:43:42 -0800, "Paul Hovnanian P.E."   >No model or FCC ID number anywhere on this thing (it's Chinese).   Lovely. So much for FCC type certification. Probably arrived in the US by the back door.   >Either on >the outside, it the battery compartment or internally.   The label is suppose to be plainly visible on the outside of the unit.   >What appears to be >the receiver section has a sticker on it that reads '929.6125'. Taking a >wild gues that this is MHz, that puts it in a pager band.   Yep, that's a pager frequency. Probably USA Mobility running Flex, not POCSAG: <https://wiki.radioreference.com/index.php/Paging> Are you near one of these cities? If so, I might be able to find the location of the local paging transmiters using 929.6125 Mhz.   >Ambient support is pretty much defunct. Although they do seem to be >broadcasting updates.   Yep. Over the years, I've bought quite a bit of weather station related stuff from them.   The weather updates are not coming from Ambient. They're coming from some service that uses the paging frequencies for distribution. Pager users are usually (not always) expected to pay for such added services. My guess(tm) is that data originates from the NOAA "Weather Wire" or EMWIN satellite feed: <https://www.weather.gov/nwws/> <https://www.weather.gov/emwin/> Probably not EMWIN as it was suppose to roll over and die on December 2, 2019.   >experiment. I took the thing with me in my car and drove to the neighborhood >grocery store. One bar pretty much everywhere except for one location about >a block from my house. The signal strength meter pegs in front of one house.   I suspect the reason it pegs is the house has a 900 MHz wireless headset or telephone in use. The receiver in your 7 day forecaster box is probably fairly crude and might have a rather wide band front end. If you have anything handy that will belch 900 MHz, see if it registers on the bar graph.   >I'm toying with the idea of putting together a spectrum analyzer app for my >SDR dongle and sniffing around for spurious sources around that frequency.   That should work. You can also decode the FLEX 3200(?) data: <https://www.rtl-sdr.com/tag/flex/> I use my modified Radio Shock scanner and Linux laptop running Mulimon-NG: <https://www.rtl-sdr.com/tag/multimon-ng/> <https://github.com/EliasOenal/multimon-ng> I have a pile of RTL-SDR dongles that I use mostly for monitoring aircraft ADS-B transmissions: <https://flightaware.com/adsb/stats/user/JeffLiebermann>   I'm wondering about the difference in performance between your friends unit and yours. My guess(tm) is that there's something wrong with your receiver section. Open it up and look for a disconnected antenna connection. If you have a service monitor, try tuning the receiver for best performance. Maybe replace the antenna with a length of coax and RF connector so that you can attach an external antenna.     -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

James Reaper <jreap6678@aoldot.net>: Jan 25 12:22PM -0500 Not really a circuit board, but still an electronic item of trouble. My wireless keyboard space bar seems to want to stick, not completely but sometimes it just doesn't want to release. I have blown out the area all around the space bar with compressed air followed by 91% iso cleaning around it with cotton swabs, getting as deep as possible by thinning the swabs. Still wants to stick. Any other suggestions welcome. Thanks in advance.

tabbypurr@gmail.com: Jan 25 12:38PM -0800 On Saturday, 25 January 2020 17:22:08 UTC, James Reaper wrote: > cleaning around it with cotton swabs, getting as deep as possible by > thinning the swabs. Still wants to stick. Any other suggestions > welcome. Thanks in advance.   half a drop of mineral oil     NT

Jeff Liebermann <jeffl@cruzio.com>: Jan 25 09:15PM -0800 On Sat, 25 Jan 2020 12:22:04 -0500, James Reaper >cleaning around it with cotton swabs, getting as deep as possible by >thinning the swabs. Still wants to stick. Any other suggestions >welcome. Thanks in advance.   Any hints as to the maker of the keyboard and model number? If unavailable, a description of the type of keyboard, or a photo of something similar as found on Google image search.   My random guess(tm) is that it's an older Dell keyboard, such as one of these: <https://www.google.com/search?q=dell+sk-8135+sk-8115+sk-8125&tbm=isch> The SK-8135 happens to be my favorite keyboard. I'm therefore familiar with its benefits and its bad habits. A sticky space bar is one of them. The usual problem is one end of the stiff balance wire, that goes the length of the space bar, which allows the use of a single well for the key switch, has come loose at one end, causing the space bar to slide un-evenly into the square well with the switch at the bottom. This creates roughness and burrs around the square key well. It's difficult to see the burrs, but you can feel them with a finger or view them with a decent illuminated magnifier.   You'll need to remove the space bar in order to clean and deburr the plastic well. Remove the two Alt keys on either side of the space bar. Use the proper keycap removal tool, or you'll break something: <https://www.google.com/search?q=keycap+removal+tool&tbm=isch> Then, remove the space bar by pulling up evenly on both ends. Take a photo of how the stiff wire thing is mounted or you may have problems putting it back together.   My fix is to run a pocket knife over the mating surfaces and across the edges of the plastic box to remove any gouges and burrs. It doesn't take much of a burr to cause problems. Do NOT use a razor, sharp knife, Xacto knife, or anything sharp enough to add additional gouges in the plastic. Plastic razor scrapers also will work: <https://www.acehardware.com/departments/paint-and-supplies/painting-tools-and-supplies/paint-scrapers/1380971>   Please do NOT lubricate the plastic square well area with anything. All that does is attract dirt and dust, which will eventually turn to tar. Alcohol cleaning (70% or 91%) is fine as it removes any gunk and leaves no residue.   -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558

J-J <none@none.non>: Jan 25 08:52PM -0500 Now let me start off by saying that I have no intention of operating a 175W MV lamp with the envelope smashed as the guy does in the video you're about to see, but....   What fascinates me is that he seems to ignite and operate the MV lamp without a ballast using a standard incandescent and capacitor. The incandescent looks like it is wired in series with the bulb and the capacitor in parallel. Here is where he explains it in the video:   https://youtu.be/WjKkgkbRSgY?t=73   The question is, I don't have a ballast either and I would like to try out a standard 175 W MV lamp in my backyard briefly before investing in a standard ballast. How would I go about calculating incandescent size and capacitance? In the video, he is using 20 uF, but I think that's for a much larger bulb if I'm not mistaken. Thanks.

amdx <nojunk@knology.net>: Jan 25 11:58AM -0600 >> other cookers. I was melting pennies making the teacher very nervous! >> Mikek   > Did you try a nickel or a dime?   I'm to frugal for that! No, not that I recall, just Zinc pennies.   Mikek

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