- Component Damage - 17 Updates
- Is there A New Thing That can Interfere With My WIFI ? - 8 Updates
| Cursitor Doom <curd@notformail.com>: Jun 13 08:21PM One of the books I picked up on faultfinding and troubleshooting whilst in London the other day (title escapes me but I can find it if anyone cares) states that: a) A bipolar transitor may be permanently damaged by dropping it on a concrete floor from a height of over 4'. (I'm paraphrasing but that's the gist of it). Elsewhere it states that: b) static sensitive components can be damaged by careless use of air dusters, which can build up a static charge, in their vicinity. Whilst I'm prepared to place some faith in assertion b) I'm reluctant to do so in the case of a). However, I'm more concerned with b) because I recently purchased a fair sized air compressor for blowing dust out of the insides of test equipment which is of course considerably more powerful than the aerosol cans the author was thinking about when he asserted b). Has anyone ever caused damage to static-sensitive components through the use of compressed air? Is this something we really need to be mindful of? |
| tabbypurr@gmail.com: Jun 13 01:45PM -0700 On Tuesday, 13 June 2017 21:24:50 UTC+1, Cursitor Doom wrote: > asserted b). > Has anyone ever caused damage to static-sensitive components through the > use of compressed air? Is this something we really need to be mindful of? I'd first be mindful of mechanical damage from doing that. When was the book written? Germanium? NT |
| Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Jun 14 06:50AM +1000 On 14/06/2017 6:21 AM, Cursitor Doom wrote: > asserted b). > Has anyone ever caused damage to static-sensitive components through the > use of compressed air? Is this something we really need to be mindful of? **a) is possible (barely). Rip the top off a TO3 transistor and examine the construction. You'll get the idea. As for b), I have no idea why any sane person would use compressed air on any product, unless required by very specific circumstances. It is a daft idea. A soft brush and a vacuum cleaner is a far superior and gentler way to do things. Even better, there is far less chance that the dust will end up inside pots, switches and other mechanical components. -- Trevor Wilson www.rageaudio.com.au |
| Cursitor Doom <curd@notformail.com>: Jun 13 08:59PM On Tue, 13 Jun 2017 13:45:40 -0700, tabbypurr wrote: > I'd first be mindful of mechanical damage from doing that. When was the > book written? Germanium? > NT Haha! I think even those old germanium diodes would easily cope with a four foot fall! |
| Jon Elson <jmelson@wustl.edu>: Jun 13 04:16PM -0500 Cursitor Doom wrote: > asserted b). > Has anyone ever caused damage to static-sensitive components through the > use of compressed air? Is this something we really need to be mindful of? The original, point-contact trasnsistors from the 1950's were quite fragile devices, basically a pair of etched hair whiskers on a Germanium speck. Supposedly, it is the tiny dust particles in an air stream that create the triboelectric charge. So, clean air should be better. I live in Missouri, so we have enough humidity that ESD is a fairly rare phenomenon. I have used vacuum cleaners to clean old computer gear, and never had damage, although I was concerned about the possibility. I have seen a fat spark produced when firing off a CO2 fire extinguisher, which seemed like a pretty big design defect. They should have made the hose and nozzle with a static dissipative material. Jon |
| tabbypurr@gmail.com: Jun 13 02:38PM -0700 On Tuesday, 13 June 2017 22:03:32 UTC+1, Cursitor Doom wrote: > > book written? Germanium? > Haha! I think even those old germanium diodes would easily cope with a > four foot fall! I think those would be some of the more fragile items. Many have an extremely thin filament stretching a few mm with no support at all. NT |
| Chris <cbx@noreply.com>: Jun 13 09:39PM On Wed, 14 Jun 2017 06:50:59 +1000, Trevor Wilson wrote: > I have no idea why any > sane person would use compressed air on any product, unless required by > very specific circumstances. It is a daft idea. I beg to differ. Air compressors totally *rock*! Having used one now for 7 years I could not imagine going back to *any* other method. Nothing else comes close. |
| Cursitor Doom <curd@notformail.com>: Jun 13 10:03PM On Tue, 13 Jun 2017 16:16:01 -0500, Jon Elson wrote: > so we have enough humidity that ESD is a fairly rare phenomenon. I have > used vacuum cleaners to clean old computer gear, and never had damage, > although I was concerned about the possibility. I'd be more worried about the action of brushing itself giving rise to static charges. It's hard to know for sure what > I have seen a fat spark produced when firing off a CO2 fire > extinguisher, which seemed like a pretty big design defect. Yes, been there; done that. In fact a gave a co-worker a pretty nasty shock by using a CO2 extinguisher which must have charged me up to 10s of thousands of volts whilst I put out a fire with it. It was a very noisy situation so I needed to shout into his ear to make myself heard and this terrific blue spark shot straight from my nose to his ear! Had no effect on me but sent him reeling. You should have seen the look on his face! :-> |
| Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Jun 14 08:49AM +1000 On 14/06/2017 7:39 AM, Chris wrote: > I beg to differ. Air compressors totally *rock*! Having used one now for > 7 years I could not imagine going back to *any* other method. Nothing > else comes close. **OK. I'll trade your 7 years with my 40 years professionally servicing electronic equipment. And yes, I have a (filtered) air line into my workshop. However, a vac is vastly more preferable and much safer. I do use air, very sparingly, when required. -- Trevor Wilson www.rageaudio.com.au |
| whit3rd <whit3rd@gmail.com>: Jun 13 03:58PM -0700 On Tuesday, June 13, 2017 at 2:03:32 PM UTC-7, Cursitor Doom wrote: > > book written? Germanium? > Haha! I think even those old germanium diodes would easily cope with a > four foot fall! Oh, no; a point contact diode can easily jar out of spec. There was even an old device (the 'coherer') which reformed a rectifying contact by motorized shaking during normal operation. |
| Chris <cbx@noreply.com>: Jun 13 11:02PM On Wed, 14 Jun 2017 08:49:40 +1000, Trevor Wilson wrote: > electronic equipment. And yes, I have a (filtered) air line into my > workshop. However, a vac is vastly more preferable and much safer. I do > use air, very sparingly, when required. Yeah, air is so expensive you gotta use it sparingly hehehe! The one caveat I would add about blasting boards with (clean) compressed air is that you *gotta* do it outdoors for all sorts of reasons I can't be assed to go into here. |
| Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Jun 14 09:12AM +1000 On 14/06/2017 9:02 AM, Chris wrote: >> workshop. However, a vac is vastly more preferable and much safer. I do >> use air, very sparingly, when required. > Yeah, air is so expensive you gotta use it sparingly hehehe! **Read what I wrote, moron. Using air spreads dust to places inside the equipment where you don't want it to go. Like pots and switches for instance. How do you prevent that from occurring? > The one caveat I would add about blasting boards with (clean) compressed > air is that you *gotta* do it outdoors for all sorts of reasons I can't > be assed to go into here. **And yet another good reason to use a vac. -- Trevor Wilson www.rageaudio.com.au |
| dplatt@coop.radagast.org (Dave Platt): Jun 13 04:32PM -0700 In article <frCdnbCAQueXy93EnZ2dnUU7-XvNnZ2d@giganews.com>, >I have seen a fat spark produced when firing off a CO2 fire extinguisher, >which seemed like a pretty big design defect. You're certainly right - if you had used it around any sort of flammable vapors, the spark might have started a fire. ;-) > They should have made the >hose and nozzle with a static dissipative material. I'm not sure that would have helped. Where would the charge have gone, during the second or three that one was blasting away with CO2? There'd be only a very limited amount of charge flow back into the CO2 cloud (neither the CO2 nor the ice crystals which were triboelectrically active, will be particularly conductive), or dissipate into the air nearby. The major charge-sink would still be the body of the person wielding the extinguisher. http://www.ece.rochester.edu/~jones/demos/charging.html is interesting. Apparently, even aluminum can generate a charge via triboelectric effect, and it's about as static-conductive as you could ask for. |
| dplatt@coop.radagast.org (Dave Platt): Jun 13 04:43PM -0700 In article <eqb9r2F4pmkU1@mid.individual.net>, >> air is that you *gotta* do it outdoors for all sorts of reasons I can't >> be assed to go into here. >**And yet another good reason to use a vac. In particular: I'd be cautious about using compressed air to clean out electronic equipment that's been stored in sheds, barns, or other locations where there might be rodent activity. I've seen some pretty grotty equipment donated to our ham club, which I thought might well have been peed or pooped upon by rats and/or mice. Hantavirus is no joke. A vacuum, particularly one with a HEPA filter, would be safer than compressed air (either indoors or outdoors). |
| Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au>: Jun 14 10:02AM +1000 On 14/06/2017 9:43 AM, Dave Platt wrote: > grotty equipment donated to our ham club, which I thought might well > have been peed or pooped upon by rats and/or mice. > Hantavirus is no joke. **I confess that I had not thought of that, but certainly, spreading any dust around can be injurious to many people. > A vacuum, particularly one with a HEPA filter, would be safer than > compressed air (either indoors or outdoors). **Of course. And MUCH safer for the equipment. -- Trevor Wilson www.rageaudio.com.au |
| mike <ham789@netzero.net>: Jun 13 06:58PM -0700 On 6/13/2017 5:02 PM, Trevor Wilson wrote: >> A vacuum, particularly one with a HEPA filter, would be safer than >> compressed air (either indoors or outdoors). > **Of course. And MUCH safer for the equipment. How do you get the cat hair out of the CPU heat sink underneath the fan? |
| Jeff Liebermann <jeffl@cruzio.com>: Jun 13 08:52PM -0700 On Wed, 14 Jun 2017 06:50:59 +1000, Trevor Wilson >vacuum cleaner is a far superior and gentler way to do things. Even >better, there is far less chance that the dust will end up inside pots, >switches and other mechanical components. I have an air compressor at home, in my palatial office, and a small one in my car. It was one of the best purchases I ever made. Lots of benefits: 1. It totally eliminated black nose disease, where the dust found inside computahs, test equipment, and flea market junk does not end up being inhaled and producing a disgusting black goo when ejected by sneezing. 2. I blow out EVERYTHING that arrives in the office that has even the possibility of containing dust. The result is that I only have to vacuum the office perhaps every 2 months. 3. I don't worry much about static electricity, but I do watch the relative humidity. If it drops below about 20%, I start throwing lighting bolts of static electricity. At that point, I take precautions, like discharging myself, wearing anti-static shoe coverings, and generally avoiding anything risky. So far, I've only blown up a few things in 30+ years, none of which involved an air compressor. 4. I have an electrostatic voltmeter for measuring static buildup. Something like these but home made: <https://www.google.com/search?tbm=isch&q=electrostatic+voltmeter> I don't guess, I measure. 5. I frequently wash PCB's and equipment. Getting them dry takes some time. So, I speed things up by blowing the water out from under components and in inaccessible locations. Without compressed air, a keyboard wash takes about a week to dry completely. With compressed air, 24 hrs will usually do the trick. However, there are disadvantages: 1. Everyone in the building asks me to put air in their tires, especially the bicycle riders. I have 100ft of air hose so that I don't need to drag the compressor outside. 2. An air compressor and air tools are noisy but I'm good at ignoring complaints from the neighbors. 3. I have to remember to drain the condensed water out of the tank or I end up spraying rusty water on everything. I could get a filter/dryer, but don't want to spend my life cleaning them. Incidentally, I've convinced some friends and competitors to buy air compressors for their office or shop. All have been very successful. -- 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 |
| Jeff Liebermann <jeffl@cruzio.com>: Jun 13 10:11AM -0700 >You don't have to delete anything. But we got it all and >were taught not to use certain words in school n shit. >The adults also never talked down to us. I missed the standard American education in applied profanity. So I found other ways to be insulting, denigrating, tactless, insulting, etc. It is quite possible to accomplish these things without reference to sex practices and body waste elimination practices. For example, if I were to indicate that you might be mistaken, I would merely suggest that your cranium is firmly embedded in your posterior rectal outflow orifice. >But now I see my mistake. It is not a 4110 it is a 4111n, >and Pace is the make. Sorry, but sometimes I have trouble >remembering my name. <https://www.amazon.com/Modem-4111n-Broadband-Gateway-Packaging/dp/B009WEZ1BS> <https://www.att.com/accessories/specialty-items/pace-dsl-gateway-model-4111n.html> Customer comments at: <https://www.amazon.com/Modem-4111n-Broadband-Gateway-Packaging/dp/B009WEZ1BS> are evenly divided between "it's great" and "it sucks". Most of the complaints seem to revolve around the wireless section. Hmmm... I see a few of these in the area on AT&T DSL. I don't see much of a problem with them. I did have one with wireless disconnect problems, but that was solved by installing a 2nd wireless router, configured as an access point, to handle the wireless. >This is the second one of these they sent us, the other >one which was a different model always seemed to have >good RF but it was losing the DSL carrier on the line. Ever consider using a seperate modem and wireless router? That's what I like, but customers consider the extra boxes and wires rather messy. For DSL, I use: <https://www.netgear.com/home/products/networking/dsl-modems-routers/DM111PSP.aspx> For U-verse (IPDSL), I'm stuck with whatever AT&T offers. For routers, whatever I happen to like. This week it's Asus RT-AC66U. Better to switch (hardware) than to continue the battle with the 4111n. >Actually now I am trying to get a fax on the tomes of >these outages. It almost seems like cellphone peak >time but not quite. Do you have U-Verse (IPDSL) service? -- 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 |
| "pfjw@aol.com" <pfjw@aol.com>: Jun 13 11:58AM -0700 On Tuesday, June 13, 2017 at 1:11:40 PM UTC-4, Jeff Liebermann wrote: > example, if I were to indicate that you might be mistaken, I would > merely suggest that your cranium is firmly embedded in your posterior > rectal outflow orifice. I find that invective is most fun when clean. However, with some individuals, even the most massive clue-sticks are wasted. One of my favorite applicable expressions is one used by the "Car-Talk" guys - unencumbered by the thought process. Which goes well over the head of most to whom it applies. Or, "You do have a point. However, if you comb your hair just right, perhaps no one will notice." "So, a thought crossed your mind? Must have been a long and lonely journey." Peter Wieck Melrose Park, PA |
| jurb6006@gmail.com: Jun 13 03:03PM -0700 >"Do you have U-Verse (IPDSL) service? " Nope, just simple DSL and a land line which doesn't even have long distance, we use cellphones for that. |
| Gunther Heiko Hagen <guntherxxx@quantserve.de>: Jun 13 10:28PM On Mon, 12 Jun 2017 16:47:37 -0700, mike wrote: > When you badmouth someone, you should be sure your advice is absolutely > correct and stated clearly. Otherwise, you just look... ...like Phil Allison. >;-} |
| Mike Tomlinson <mike@jasper.org.uk>: Jun 14 03:13AM +0100 En el artículo <ohn935$lpn$1@dont-email.me>, mike <ham789@netzero.net> escribió: >Not clear from that sentence, but methinks you might have it backwards. No. The line pair is connected straight through to the router (modem). A low-pass filter is used to present the voice frequencies to a POTS device and prevents it interfering with the DSL signal. http://tinyurl.com/yafocw6s >When you badmouth someone, you should be sure your advice >is absolutely correct and stated clearly. Otherwise, you just look... You need to take your own advice. I shan't wait for your apology. -- (\_/) (='.'=) "Between two evils, I always pick (")_(") the one I never tried before." - Mae West |
| Jeff Liebermann <jeffl@cruzio.com>: Jun 13 08:06PM -0700 >>"Do you have U-Verse (IPDSL) service? " >Nope, just simple DSL and a land line which doesn't even have long distance, we use cellphones for that. Fine. Throw everything out and start over. Buy a DSL modem (not router) that supports ADSL2+. I like Netgear DM111PSPv2: <https://www.netgear.com/home/products/networking/dsl-modems-routers/DM111PSP.aspx> <http://www.ebay.com/sch/i.html?_nkw=DM111PSP+v2> Make sure you get the PSPv2 mutation, not v1 or earlier models. Say goodbye to about $20 total. Then go shopping for a wireless router that actually works. Lots to choose from. I suggest Asus RT-AC66U. <http://www.ebay.com/sch/i.html?_nkw=RT-AC66U> You probably don't need 802.11ac support. However, there's a problem with the RT-N66U, which does everything except 802.11ac. It overheats. I got it to work by mounting it vertically (it comes with a plastic stand for vertical mounting) but would prefer to pay a few dollars more so I can mount is anywhere. Say goodbye to about $70. If you're cheap and or like to complain some more, I've been using Linksys EA-2700 routers. They do everything right except that the wireless range is not so great. However, they're cheap: <http://www.ebay.com/sch/i.html?_nkw=linksys+ea2700> at about $20 total. Be sure to upgrade the firmware to the latest in both boxes before complaining again on this newsgroup. The time you save will probably be mine. If you decide to go this route, I have some other suggestions and comments. Please remember that RF is magic and that if you're not a magician, you don't stand a chance. -- 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 |
| Jeff Liebermann <jeffl@cruzio.com>: Jun 13 08:20PM -0700 On Tue, 13 Jun 2017 20:06:55 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote: (blah-blah-blah) I forgot one item. My guess(tm) is that you have microfilters scattered around the house to isolate the POTS audio from the DSL tones. That's fine if you use decent filters and have decent inside wiring, which are problematic. So, to avoid the problems caused by plugging the filters in backwards, ratty wiring, missing filters, and noise pickup for light dimmers, AM radio stations, and similar EMI, I suggest you get a whole house DSL filter. I like the Siecor style xDSL outdoor splitters: <http://www.ebay.com/itm/Siecor-DSL-Outdoor-Pots-Splitter-Housing-/361886025837> <http://802.11junk.com/jeffl/pics/dsl/slides/splitter.html> <http://www.ebay.com/itm/SUTTLE-OUTDOOR-XDSL-POTS-SPLITTER/201944066409> Install the box near the MPOE (minimum point of entry) to the POTS line. Run a dedicated pair or CAT5 from this DSL splitter to your DSL modem. Remove all your DSL microfilters. Live happily ever after. -- 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 |
| Foxs Mercantile <jdangus@att.net>: Jun 13 10:42PM -0500 On 6/13/2017 10:20 PM, Jeff Liebermann wrote: > backwards, ratty wiring, missing filters, and noise pickup > for light dimmers, AM radio stations, and similar EMI, I > suggest you get a whole house DSL filter. I had a similar problem with a friend's house in Culver City, CA. You could listen to KHJ at one end of the house and KNX at the other end of the house. Proper wiring solved that. Or if you have a relatively NOT ancient MPOE box, install one of these: <http://www.ebay.com/itm/352026490188> When I moved to Texas, I moved into a 75 year old house. The phone wiring was a mixture of "anything that pours" so to speak, and was a combination of star and daisy chain wiring. I abandoned all of it and ran new Cat5e to a punch down block in a closet. When I switched from cable to AT&T U-Verse, I added the above mentioned MPOE filter. I put the AT&T Modem in a central location so that the WiFi signal was good through the entire house. I used my obsolete stash of Cat3 for the phone lines and Cat5e for the network lines. I did the same thing with my shop down the street. I have zero problems with either the phones or the network. "Life is tough. It's even tougher when you're stupid." Sgt. Stryker -- Jeff-1.0 wa6fwi http://www.foxsmercantile.com --- This email has been checked for viruses by AVG. http://www.avg.com |
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