sci.electronics.repair@googlegroups.com

Google Groups

tabbypurr@gmail.com: Jul 10 06:12AM -0700 On Tuesday, 9 July 2019 09:10:55 UTC+1, Jeff Urban wrote:   > On a certain unit if you are really dumbfuddled, think "I have to do this, how do I do it ?". Approach it from the beginning.   the only problem with that approach is that with a battery charger you could use maybe 10% the parts they did. Too many things have junk they don't need nowadays.   I once replaced a whole large psu pcb in a Sony tv with a rectifier & lightbulb. Yep, it worked. Wonder if that's where the fashion for surround lighting came from with TVs.     NT

"pfjw@aol.com" <peterwieck33@gmail.com>: Jul 11 11:19AM -0700 > the only problem with that approach is that with a battery charger you could use maybe 10% the parts they did. Too many things have junk they don't need nowadays.   Mad Man Muntz had this minimalism down to a science. That being written, please consider:   Any device sold to the great unwashed is a balancing act between first-cost, utility, warranty and longevity. Add into that a significant measure of product safety, and you would have a very basic formula for the design of a consumer item.   What do battery chargers (as discussed) do? They interact with a very large, highly energetic devices called 'lead-acid' batteries in a way that *can* lead to spectacular results. A charger that creates such results on a regular basis will not do its manufacturer any favors.   It is takes no power of imagination whatsoever to figure out that a manufacturer will add nothing more than what is absolutely necessary to any device per the basic formula already described.   Peter Wieck Melrose Park, PA

tabbypurr@gmail.com: Jul 11 12:47PM -0700 > It is takes no power of imagination whatsoever to figure out that a manufacturer will add nothing more than what is absolutely necessary to any device per the basic formula already described.   > Peter Wieck > Melrose Park, PA     Consumer devices are a slowly moving target on the various performance points you mentioned. In the 60s you got no charging control & were lucky if you got a fuse. Today most chargers are 'smart', which is to say too dumb to charge a flat battery. Most battery chargers have a lot more features than they need so they can boast & sell more. To the average consumer more crap is better, though it often isn't.   Avoiding fireworks is a low barrier for chargers, except for lithium cells.     NT

makolber@yahoo.com: Jul 08 01:22PM -0700 > --- > Questa email è stata esaminata alla ricerca di virus da AVG. > http://www.avg.com   what type of display LED?   can you use standard signal tracing to determine which audio stage is picking up the noise, does the volume control effect it, tone controls etc. ? m

tabbypurr@gmail.com: Jul 10 06:18AM -0700 On Monday, 1 July 2019 16:36:27 UTC+1, blisca wrote: > I would like to know your opinion. > Thanks for your time > Diego   The simple way to find out if replacing a cap will help is to bridge it with another cap. If the original is ok, it makes no difference. If the original is bad, it solves the problem. Sometimes you can just hold the 2nd cap & touch it onto other caps one after another to dx a fault.     NT

Fox's Mercantile <jdangus@att.net>: Jul 10 08:24AM -0500 > The simple way to find out if replacing a cap will help is > to bridge it with another cap.   That only works if the cap has gone open.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jul 10 10:40AM -0400 >> noise gate called "H.U.S.H." This is a good pic of the board ,found >> on a website >> https://images.reverb.com/image/upload/s--oH5vkrFt--/a_exif,c_limit,e_unsharp_mask:80,f_auto,fl_progressive,g_south,h_620,q_90,w_620/v1497562015/pq4p7tei1daqvapl3ygx.jpg   I'm finding it a bit too noisy,and this noise sounds as "digital > If the original is bad, it solves the problem. Sometimes you can just > hold the 2nd cap & touch it onto other caps one after another to dx a > fault.   That's a great way to blow stuff up, too.   Cheers   Phil Hobbs     -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510   http://electrooptical.net http://hobbs-eo.com

tabbypurr@gmail.com: Jul 11 12:34PM -0700 On Wednesday, 10 July 2019 15:40:24 UTC+1, Phil Hobbs wrote:   > That's a great way to blow stuff up, too.   > Cheers   > Phil Hobbs   how? I never have that way. Obviously some clue is required, not applying a 400v charged cap to a base somewhere.     NT

OGY <X@NOWHERE.COM>: Jul 04 06:08PM -0700 I still cannot find a bubbler.   I am sucking the air out of epoxy or molding compound and similar.   I have seen them at a factory. Just a large bottle with water in the bottom. One long pipe into the water and one short pipe.   Are these custom or commercially available ?       Jeff Liebermann wrote:

Jeff Liebermann <jeffl@cruzio.com>: Jul 05 06:38PM -0700 >I still cannot find a bubbler.   If Google can't find it, it doesn't exist. (Liebermann's Law)   >I am sucking the air out of epoxy or molding compound and similar.   No problem. I've done that for epoxy potting compound. All we had was a inlet filter. No water.   >I have seen them at a factory.   Which factory? What were they making? Can you contact them and ask?   >Just a large bottle with water in the bottom. One long pipe into the >water and one short pipe.   I'll try one more time. If you draw down more the 30 mbar absolute pressure (where atmospheric pressure equals the vapor pressure), the water will boil at room temperature. Plug 30 mbara into the calculator below and notice that the calculated temperature is room temperature: <https://www.engineeringtoolbox.com/water-evacuation-pressure-temperature-d_1686.html> If you don't believe me, just evacuate a bottle with some water in it and watch it boil. Or, watch a few YouTube videos demonstrating how water boils in a vacuum at room temperature: <https://www.youtube.com/results?search_query=boiling+water+at+room+temperature> In other words, an inlet bubbler is not going to work.   >Are these custom or commercially available ?   I have no idea. Maybe if you disclose what manner of "epoxy or molding compound" you're using, I could lookup the required vacuum? If it's not much of a vacuum, you might be able to use water without having it boil. Search for "vacuum inlet or intake filter" and you might find something: <https://www.google.com/search?q=vacuum+inlet+filter&tbm=isch> Extra credit for disclosing the maker and model number of the pump you're using so the flow rate (and size) of the filter can be calculated or estimated.   I have an Edwards E2M1 two stage vacuum pump with plastic intake filter: <http://www.learnbydestroying.com/jeffl/crud/Vaccum%20Pump.jpg> On Pg 29 of the service manual: <https://shop.edwardsvacuum.com/Viewers/Document.ashx?id=1335&lcid=2057> You'll find a drawing showing 8 different inlet filter types.   Also, you might want to look into resin degassing equipment such as: <https://www.amazon.com/Gallon-Vacuum-Degassing-Chamber-Pump/dp/B01N11WMX2/> <https://www.amazon.com/Gallon-Vacuum-Chamber-Degassing-Kit/dp/B07HM646VS/>       -- 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

Ralph Mowery <rmowery28146@earthlink.net>: Jul 05 11:34PM -0400 In article <svqvhe5gg0fbceeb1mojc8767v1m7q4bvn@4ax.com>, jeffl@cruzio.com says... > water boils in a vacuum at room temperature: > <https://www.youtube.com/results?search_query=boiling+water+at+room+temperature> > In other words, an inlet bubbler is not going to work.   High vacuum does strange things to water. At work I have seen a 6 inch diameter pipe that is in about 100 deg F area and steam traced with a 1/4 inch pipe and insulated form a ball of ice and clog the pipe. The device making the vacuum was a hollow tube with steam blowing into it through a hole about 1/8 of an inch in diameter. There are seveal of thease in series to make the vacuum.

Jeff Liebermann <jeffl@cruzio.com>: Jul 05 09:30PM -0700 On Fri, 5 Jul 2019 23:34:03 -0400, Ralph Mowery >device making the vacuum was a hollow tube with steam blowing into it >through a hole about 1/8 of an inch in diameter. There are seveal of >thease in series to make the vacuum.   Yep. Put a bubbler in the vacuum intake and it will also produce ice.   "It's Scientifically Possible to Boil Water Until It Freezes Solid" <https://www.sciencealert.com/you-can-actually-boil-water-so-hard-it-freezes> If you watch the video, notice at the beginning, the effort put into preventing water vapor from enter the vacuum pump.   The water boils when the vapor pressure equals atmospheric pressure. If the vacuum is lowered to less than this point, the water starts to evaporate, taking the higher energy water molecules with it, which is also the residual heat in the water. Eventually, all the "hot" water molecules end up in the water vapor, the water temperature drops to freezing, and remaining low energy water molecules form ice crystals.   -- 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

Bob Engelhardt <BobEngelhardt@comcast.net>: Jul 06 09:32AM -0400 On 7/5/2019 9:38 PM, Jeff Liebermann wrote: > ... > I'll try one more time. ...   You've so much more patience than me. When they ignore my advice the 1st time, they don't deserve any more help.

etpm@whidbey.com: Jul 06 09:33AM -0700 Probably the reason you can't find what you want is because the water boiling at low temp from the vacuum would dump water into the vacuum pump. The vacuum drawn during the typical epoxy degassing operation is plenty low enough to cause water to boil at room temp. Maybe what you need is some type of system where oil, not water, is used. Actually though I think what you really need is a standard filter available from many sources, even Harbor Freight. If you can't find a filter online to do what you want then I think you are probably not competent enough be degassing epoxies. Eric

Fox's Mercantile <jdangus@att.net>: Jul 06 12:05PM -0500 > If you can't find a filter online to do what you want then I > think you are probably not competent enough be degassing epoxies.   Being cheap, I use an old pressure cooker as a vacuum chamber. That and a vacuum pump I acquired surplus from Hughes Aircraft.   The only problem I've had is the "safe time" before materials start to cook off. I've used it with silicon, Tru-Cast resins and Epoxies.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

Jeff Liebermann <jeffl@cruzio.com>: Jul 06 10:31AM -0700 On Sat, 6 Jul 2019 09:32:53 -0400, Bob Engelhardt >> I'll try one more time. ...   >You've so much more patience than me. When they ignore my advice the >1st time, they don't deserve any more help.   Well, I have a rather different approach. I spend far too much time answering questions on Usenet, mailing lists, and forums. I try to be helpful, but in most cases, it's more for my personal benefit than for any benefit to the person asking the question.   In order to produce a useful answer, I first needed to do some research. I already knew that sucking water into a vacuum pump was a really bad idea, but I didn't really understand why or what alternatives were available. Some Goggling and fast reading provided the necessary details, which I provided in my reply. While my answer was probably beneficial to the person asking the question, it was equally beneficial to me by adding yet another item of trivial knowledge to my vast collection.   Reading between the lines, it would seem that the person asking the question does not understand what happens in a vacuum. He seems to be lacking in experience at asking questions on Usenet or in forums. Tracing his IP address shows him on Road Runner Cable somewhere in southern California. He's using: User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:49.0) Gecko/20100101 Firefox/49.0 SeaMonkey/2.46 which seems rather old. I'm not sure what's happening there, but offhand, it looks like an older machine and operating system. The style of his question seems to be rather jumbled, terse, lacking in technical terms, but where all the words are correctly spelled. That suggests a smartphone user, using speed to text software. By the sentence structure and apparent frustration, I would guess a fairly young person, possibly a teenager.   So, after reading my analysis and guesswork, do you still think that they don't deserve any more help?   -- 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

Bob Engelhardt <BobEngelhardt@comcast.net>: Jul 08 10:38AM -0400 On 7/6/2019 1:31 PM, Jeff Liebermann wrote: ... > So, after reading my analysis and guesswork, do you still think that > they don't deserve any more help?   First I'd like to say that I appreciate the effort that you put into your replies, even when I'm not the OP. You have a great deal of credibility and when there's a long thread that has sidetracks of the "Yes it is" "No it isn't" variety I often skip most of it and read your replies.   But, to the point here: your 1st reply brought up the boiling-under-vacuum problem. Which he totally ignored in his reply to you and repeated his original request for finding the device he thought he needed. If they're not going to listen, I'm not going to waste my time. If he won't listen, he probably can't be helped anyhow.

bruce2bowser@gmail.com: Jul 07 08:24AM -0700 On Tuesday, June 11, 2019 at 6:23:13 PM UTC-4, Jon Elson wrote: > > handled properly, causing things to run too hot. Don't know if it rose > > to the level of hardware failure though.   > Yeah, we're talking about 1996, maybe?   Even now. Putting a laptop on the bed on top of the covers for example, versus on top of an airy permeated surface that allows plenty of air circulation. That's why data centers have so much refrigeration, right?

Fox's Mercantile <jdangus@att.net>: Jul 07 10:52AM -0500 > Putting a laptop on the bed on top of the covers for example   It's still a problem. A friend got the top of his legs burned by a laptop.     -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com

~misfit~ <shaun.at.pukekohe@gmail.com>: Jul 08 11:53AM +1200 On 8/07/2019 3:52 AM, Fox's Mercantile wrote: >> Putting a laptop on the bed on top of the covers for example   > It's still a problem. A friend got the top of his legs burned by > a laptop.   I keep a piece of 2mm hardboard the same size as my laptop in my laptop bag and always use it under my laptop if it's not being used on a hard surface. It maintains clearances for air gaps. Common sense really... -- Shaun.   "Humans will have advanced a long, long way when religious belief has a cozy little classification in the DSM" David Melville   This is not an email and hasn't been checked for viruses by any half-arsed self-promoting software.

"Percival P. Cassidy" <Nobody@NotMyISP.net>: Jul 07 08:55PM -0400 On 6/5/19 11:37 AM, bitrex wrote:     >> be the last machine I buy from this company just avoid these shit heads.   > It's too bad ThinkPad used to be a quality product when IBM made them > but it's just bargain basement zombie-brand China junk, now.   I have bought still-in-warranty used Lenovo T-series ThinkPads and found them excellent in quality and excellent value for money.   Perce

OGX <X@NOWHERE.COM>: Jul 04 06:13PM -0700 My weather station went down after years of service.   Changed out the THREE rechargeble alkaline batteries and it ran for a week but now dead again.   Probably the solar panel not recharging the batteries.   Pain to get down.   Need suggestion on finding a replacement solar panel.   I can just stick on the outside of the weather station rather than tearing into the unit.   Need an all weather (Southern California, no snow or ice) solar panel.   What might the open circuit voltage of the solar panel be ?   Links please.

OGX <X@NOWHERE.COM>: Jul 04 08:15PM -0700 Model is: Ambient Weather WS-1200-IP

Lucifer <LuciferMorningstar@bigpond.com>: Jul 05 09:43PM +1000 >Need an all weather (Southern California, no snow or ice) solar panel.   >What might the open circuit voltage of the solar panel be ?   >Links please.   I have a weather station that uses three AA rechargeable alkalines. It stopped working but a reset of the indoor unit fixed it.

OGX <X@NOWHERE.COM>: Jul 05 12:38PM -0700 It started working and worked for about a week after just replacing the batteries. No reset was necessary.   Resetting "Outdoor Reset" does nothing to fix the current situation.   I am pretty sure it is the solar panel.

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.