Digest for sci.electronics.repair@googlegroups.com - 8 updates in 5 topics

JW <none@dev.null>: Aug 31 11:12AM -0400

On Mon, 29 Aug 2016 10:18:01 -0400 JW <none@dev.null> wrote in Message id:
>battery so I can't stray far from an outlet. I have an LG Escape2 phone
>and I found a free app to measure signal strength. Cool.
>I should have the router this week and I'll do the before and after test.
 
Got the new router and have it all set up. Previously with the old router,
I was able to stray about 150' from the house before the power level
dropped to -90dBm and speed to 1Mbps. I now get about 250' before the same
occurs. Typical power levels with the new router are about 12dBm higher
than with the old router from the same distances.
 
I'm currently running all the devices on the network at 2.4GHz. I'll
probably leave it that way as I think only my phone is capable of dual
band operation, and according to the Internet (so it must be true) 2.4Ghz
has better range and penetration through walls than 5GHz.
 
Seems to be working great so far. Thanks for your advice Jeff.
"pfjw@aol.com" <pfjw@aol.com>: Aug 31 08:10AM -0700

Mpfffff....
 
Now, exactly what is wrong with:
 
From each according to his abilities.
To each according to his needs.
 
Ignore the :his: vs. the more politically correct his/her, just look at the logic of the statement.
 
Warren Buffet, clearly, has abilities beyond the normal, yet lives quite modestly. He could be a good standard as to the "to each". He is also very, very productive, and so a decent example of the "from each".
 
Bill Gates is also exceedingly generous - but not so modest. Perhaps a case could be made that his "to" is in proportion to his needs and based on his abilities.
 
As to American politics - we get exactly the government we deserve, as we vote them in time after time after time, and every part and piece of our government devolves back to those elected "representatives" as by deliberate choice or by neglect, they permit all those parts and pieces to continue.
 
The difference between *your* politicians and *my* politicians is that mine tell me the lies that I want to hear, yours tell you the lies you want to hear. That they are lying is neither in doubt or a subject of debate.
 
Lastly, keep in mind that the Average American:
 
Does not have a college education.
Does not have a passport.
Speaks one language - badly.
Has never traveled voluntarily more than 200 miles from his/her birthplace.
Has never visited a foreign country, not even the Mexico or Canada.
Cannot name the Speaker of the House, even today.
Cannot name the three branches of government.
Does not believe in Evolution (42% creationism, 32% evolution, 26% no opinion).
Only 71.2% of eligible voters are registered.
Only 57.5% of registered voters voted in 2012.
Meaning that the average American eligible to vote does not vote (only 41.5% net).
 
And you think that our present government is anything other than exactly what we deserve, doing exactly what we should expect it to do based on what we tell it (and allow) it to do?
 
This has not one damned thing to do with party, democrat, republican, libertarian, communist, green, whatever. It has to do with massive, systemic and deliberate neglect, and industrial-grade stupidity mixed equally with mil.Spec. ignorance.
 
Like some few of you here, I have lived in another culture vastly different from here - and I have seen how Americans are perceived in other parts of the world. You might be surprised how easily it is for other cultures to separate Americans (whom they largely respect and admire) from American Culture (continuous amazement, mixed with a varying amounts of jealousy and horror) and the American Government (poorly understood, largely disliked - much as here).
 
Peter Wieck
Melrose Park, PA
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"pfjw@aol.com" <pfjw@aol.com>: Aug 31 05:17AM -0700

Next time I am in Bangalore, I will be sure to call. Perhaps with a bag of sugar...
 
Peter Wieck
Melrose Park, PA
"Ian Field" <gangprobing.alien@ntlworld.com>: Aug 30 07:14PM +0100

<jurb6006@gmail.com> wrote in message
news:b4c546df-5b9b-413d-b800-6fab1310ef66@googlegroups.com...
> and reverse the meter coil polarity that would work.
 
> However, a bridge rectifier would introduce error, and that error would be
> greater at lower voltages. Many meter movement barely need a volt
 
I remember meter shunts being available in 2 different types - one was 100mV
and the other might have been something like 70mV.
 
It was usually printed in a corner of the dial plate so you could order the
right shunt.
jurb6006@gmail.com: Aug 30 09:56PM -0700

>and the other might have been something like 70mV.
 
>It was usually printed in a corner of the dial plate so you could >order the
>right shunt. "
 
What Terrell say about the bridge rectifier only introducing about a volt of error only applies if there is no shunt. I am not sure. Now this Keithley we got has a shunt but will ot rui into 10 megs, so that leaves regular VTVMs out.
 
These totally passive HV probes must load more than a 1090 meg one, and certainly do for the Keithley probe which is way up in the gigohms. I forget the specs but the resistance is very high.
 
I am not so sure we need it that high. A CRT pulls current, some even do a bit on the focus electrode though I think i a perfect one it doesn't. But there is current from the cathode to anode so I think 1100 megs will be high enough to determine if it is i regulation and whatever. Most of the scope print I have seen seem to indicate it would be alright for the control grid or the blanking grid as well. That is what we need. We are not measuring the output of a Van De Graff generator here.
 
Still waiting to hear if all the low voltage supplies are there. Many of the older Tek CROs used the supply that fed the 15V regulator, unregulated and just regulated the HV directly.There could be fusibles to that supply. Sorry, but I am just about doe studying prints for people, let them download them and have a look, ad maybe learn something in the process. I am tired, half blind and my computer is quite full. I am tired of going to BAMA, electrotanya, hifiengie and that 401 whatever for nothing, I don't even do that for work anymore since my computer there disappeared. I couldn't stand the thing anyway with Win 10 on it. Can't up the font so I can see the damn thing, can't change the homepage to Google, fukit. I get paid by the hour and if they slow me down it costs me NOTHING. It costs them. I am tired of fucking around. I got a stack of 53 amplifiers that need a modification, go ahead and drag your feet. Take some more tools away, I don't give a fuck. I used to but now I will sit on the head, do my nails or who fucking knows.
 
I said what I said, check the low voltage supplies first. Not having a trace can be caused by 100 different things, not just lack of HV.
"Michael A. Terrell" <mike.terrell@earthlink.net>: Aug 31 06:47AM -0400

>> right shunt. "
 
> What Terrell say about the bridge rectifier only introducing about a volt of error only applies if there is no shunt. I am not sure. Now this Keithley we got has a shunt but will ot rui into 10 megs, so that leaves regular VTVMs out.
 
> These totally passive HV probes must load more than a 1090 meg one, and certainly do for the Keithley probe which is way up in the gigohms. I forget the specs but the resistance is very high.
 
 
What is the model of that probe? You should be able to find out what
Keithley meters it was made to work with.
 
The 1600A probe looks to be made for a 1 Meg input impedance meter.
 
The manual says the resistor is ~ 1000Meg, and it it a 1000:1 probe, so
it would be used on the 50V range.
 
 
<http://www.libertytest.com/assetmanager/uploaded/pdf-2011721-141719-kei_1600a-ug.pdf>
Micky <NONONObobbyburns1111@gmail.com>: Aug 31 01:36AM -0400


>if speaker ohms doahn match amp ohms then the mismatch will blow the amps output circuit ....
 
I'm sure I posted NeverMind to my first crisis post, but I don't see
it coming back to me. I posted a couple hours after the first one to
say that I installed it anyhow, Tuesday morning. Then Tuesday
evening I went for a drive and the speaker is great. It booms like
crazy. When I get the seatback back in place, it will be muffled a
little bit, so it will be more balanced with the other rear speakers.
 
 
>speakers are cheap.
 
I don't know how you mean that. They don't last long; they're cheap
to make; cheap to buy, they break easy? If you made the voice coil
heavier, the speaker would not be as responsive, I think. This
speaker is not cheap, lists at $260, sells for about $200.
 
>read:
 
>https://www.google.com/#q=bcae+speaker+wriring
 
There are 18,000 hits there. I wouldn't know which one to read.
 
>glue is not glue....glue is ADHESIVES search: adhesives...there's a sheet.
 
I'm sure there are more than 18,000 hits on adhesives. Even harder
to know which one to read. Everyone knows what is meant when
someone says glue. And why do you think glue is not glue? How does
it differ from adhesives?
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Digest for sci.electronics.repair@googlegroups.com - 11 updates in 6 topics

avagadro7@gmail.com: Aug 30 06:40AM -0700

On Monday, August 29, 2016 at 12:30:22 AM UTC-4, whit3rd wrote:
 
> Most auto manufacturers wire power and speakers to a proprietary connector.
> Different for Ford, Chrysler, etc... but auto sound shops can get a
> harness for any make or model.
 
I'm burned out on harnessing: direct wire to batt n ground. the connectors are for removing the unit for parking in high crime areas eg trailheads, boat ramps, suburban Chicago, California, Oregon .....
Micky <NONONObobbyburns1111@gmail.com>: Aug 29 02:23PM -0400

On Mon, 29 Aug 2016 09:48:54 -0400, Micky
 
>What should I do now? I measured again and both sides had 31.2
 
Mostly never mind. Dave, you weren't here in my crisis, so I went
ahead without you.
 
;-)
 
That is, I installed it anyhow. I tried to do it before it got sun
got bright and hot, but I'd forgotten to glue the 'gasket' to the
front**.
 
And I had to let the glue dry and it took a few minutes to solder the
cut wire.
 
I only played it a couple minutes with talk and it sounded okay. Too
hot to go for a drive; this evening.
 
Could it have read low ohms because the voice coil moved from the
center and touched something on the side the hole? It's been decades
since I tore apart a speaker, but I think it was metal on both sides
of the coil.
 
Or if the ohms are high, 31 instead of 7 or 4, how come they're both
the same amount of high, now?
 
** (It doesn't do anything much, because the speaker doesn't touch
anything in front of it, but maybe it will help keep the foam from
detaching, and I don't know where else to put the gasket ring.)
 
 
avagadro7@gmail.com: Aug 30 06:37AM -0700

if speaker ohms doahn match amp ohms then the mismatch will blow the amps output circuit ....
 
speakers are cheap.
 
read:
 
https://www.google.com/#q=bcae+speaker+wriring
 
glue is not glue....glue is ADHESIVES search: adhesives...there's a sheet.
"Ron D." <Ron.Dozier@gmail.com>: Aug 29 10:23PM -0700

On Monday, August 29, 2016 at 12:13:42 AM UTC-4, Micky wrote:
 
> My mother had a '65 Plymouth Fury II with an aftermarket AC. I think
> it worked pretty well. Not all the vents of factory AC, I think, but
> it wasn't so hot back then.
 
That too.
 
Sorry about the ice expansion thing: Yep the volume of ice is larger than the volume of water used to create the ice.
avagadro7@gmail.com: Aug 30 06:30AM -0700

On Tuesday, August 30, 2016 at 1:23:27 AM UTC-4, Ron D. wrote:
> > it wasn't so hot back then.
 
> That too.
 
> Sorry about the ice expansion thing: Yep the volume of ice is larger than the volume of water used to create the ice.
 
water volume changes, weak bonding are foundations of life on earth ....
"Michael A. Terrell" <mike.terrell@earthlink.net>: Aug 29 08:43PM -0400

> sorta in the market for one of those 1090 ohm jobs but the ones
> I see are a little to high for something that might get used once
> a year.
 
 
The self contain HV probes are easy to change polarity. Either
reverse the meter leads, or connect a small bridge rectifier between the
meter and the probe and ground lead.
 
 
--
Subject: Spelling Lesson
 
The last four letters in American.........I Can
The last four letters in Republican.......I Can
The last four letters in Democrats.........Rats
 
End of lesson. Test to follow in November, 2016
 
Remember, November is to be set aside as rodent extermination month.
jurb6006@gmail.com: Aug 29 08:01PM -0700

>"The self contain HV probes are easy to change polarity. Either
>reverse the meter leads, or connect a small bridge rectifier between >the
>meter and the probe and ground lead. "
 
Not so fast. These things had a current detect function for the horizontal output TUBE (vale for those overseas). Now if you put a DPDT switch there and reverse the meter coil polarity that would work.
 
However, a bridge rectifier would introduce error, and that error would be greater at lower voltages. Many meter movement barely need a volt but a standard diode drops .6 of that. At scope cathode voltages which might only be like 2 KV or less, this is significant.
 
We now have a Keithley HV probe but acn't really use it. Dude found a good deal on it, but it has a 350 meg output resistance which means you need an electrometer to use it. A regular VTVM will not work without alot of math, and even then... We do have one meter is would work on and it is seriously aged. (two syllables there, really) Actually it agrees with the best of the Flukes we got, but nobody is going to do the NIST routine on it and certify it.
 
I have seriously considered building one, but not with 1090 megs. The meter is 10 megohm, so 90 megs gives it enough range to measure scope CRT voltages. We are sort of committeds to repairing and restoring CROs. I do not like DSOs, let alone LCD based scopes. I believe that every electronics class in highschool should have a CRO for the kids to play with, once they know enough to not fuck it up of course. I also think they should not graduate without certain other knowledge, like the different types of firearms ad how to at least unload them and make sure there is not one in the chamber. If we are going to have guns here, dammit, make sure people know how to be safe with them.
 
They should know how to change a tire on the care, some at least simple mechanics. How many times has someone called on a neighbor or whatever to do one of the simplest of tasks claiming that are "not mechanically inclined" ? We put a Man on the moon and now we are down to this ? No wonder conspiracy theorists think it was fake.
 
But I can tell you the moonshot was real. Not that I was there but it is not hard to figure out. This was a milestone in human history, a worldwide event. There were Russian kids with telescopes all over the place and it was during the cold war. If ANY ONE of them caught even one little piece of evidence that it was faked they would be rich and the USSR would have never let us live it down. And if you really think about it, and I mean really, it would have cost more to fake it than to actually do it. Plus they really did want to do it.
 
But I have digressed quite a bit. As I look at my old 561A Tek that was built before I was born with dual trace and dual time base, sometimes I wonder just how far we have come. They have minuturized things and packed more transistor and other devices into one case, but what have they really done ?
 
When I was young my Uncle gave me the basic books from the air force. Whatever branch of the US military you serve(d) in, if it was the air force you usually had the least risk and got the best jobs when you got out. At least back then.
 
But those books said there are only three electronic circuits, rectifier, amplifier and oscillator. And every circuit to this day you see can be described as one of those. It might be gated or controlled, fancied up in all kinds of ways but it is still the same thing. Consider the function, a computer gate can be considered rectifiers feeding an amplifier.
 
But anyway, I am probably boring the OP (et al) so it is time to stop.
 
To the OP, do you got 15 volts ? Do you got 130 volts ? Before tearing into the HV shit that doesn't like to be touched, make sure you got everything else.
"Michael A. Terrell" <mike.terrell@earthlink.net>: Aug 30 07:56AM -0400

>> meter and the probe and ground lead. "
 
> Not so fast. These things had a current detect function for the horizontal output TUBE (valve for those overseas). Now if you put a DPDT switch there and reverse the meter coil polarity that would work.
 
> However, a bridge rectifier would introduce error, and that error would be greater at lower voltages. Many meter movement barely need a volt but a standard diode drops .6 of that. At scope cathode voltages which might only be like 2 KV or less, this is significant.
 
Not all of them have a current function. The bridge rectifier would
introduce a little over 1 volt error. There is a shunt in the ones that
monitor cathode current for the horizontal output. You have no need for
hat in a scope repair. The reason I wouldn't use the switch is that
there isn't enough wetting current, so after a few years it can start
arcing. Even at low current, you don't want to create plasma. Calculate
the current, through the resistor for the full scale range. It is quite
low to keep from loading the HV supply and affecting the reading.
 
 
--
Subject: Spelling Lesson
 
The last four letters in American.........I Can
The last four letters in Republican.......I Can
The last four letters in Democrats.........Rats
 
End of lesson. Test to follow in November, 2016
 
Remember, November is to be set aside as rodent extermination month.
"Michael A. Terrell" <mike.terrell@earthlink.net>: Aug 29 07:28PM -0400

>> " Do you really think that the spammer comes back to look for >replies?"
 
> He even said he doesn't. Some people are so stupid, how do they even live ? Someone must be there to remind them to breathe.
 
 
 
Far left Liberals! What else can you expect from them? :(
 
 
--
Subject: Spelling Lesson
 
The last four letters in American.........I Can
The last four letters in Republican.......I Can
The last four letters in Democrats.........Rats
 
End of lesson. Test to follow in November, 2016
 
Remember, November is to be set aside as rodent extermination month.
jurb6006@gmail.com: Aug 29 05:55PM -0700

Don't tell me actually found some common ground.
 
Really, some liberals did some good things, but they are out of hand, and I am thinking possibly out of touch with reality. I think in the old days if you asked them "How are you going to pay for that ?" they might say "Tax and borrow". Now I think you'll just get a blank stare, like a deer being spotlighted.
 
I actually liked Bernie Sanders, he is a socialist liberal but he is a non-interventionist and plus he is not an Israel firster unlike Clinton, despite the fact that he is Jewish. But the party didn't like him and it really looks like there is going to be a President Trump next year.
 
But what people do not understand is that we are not electing a dictator. The President can do two things other than sign or veto what congress sends him. One is to start a war. The other is to issue executive orders and while they are rarely challenged they can be struck down by the judiciary branch of the government. If I remember correctly it has only happened a couple of times but I think of the choices we have now it might just start happening more. The other problem is the appointments to the supreme court, but they have to be confirmed by congress which means neither Alan Sharpton or David Duke is getting in.
 
People better pay attention to this congressional race. Many seats up for grabs. Those people are what keeps the President from being a dictator. I think if you have a republican President you need a democrat congress, and vice versa. But if Trump gets in it doesn't matter because neither party wants him in. Actually, that is a big part of the reason I want to see him get in. It would be like a kick in the balls to both parties. Teach them who's boss. The people who ruin the political parties were not elected, and the ones who run the media are not elected. They have no business having so much power.
 
I fuck with the Brits sometimes like - give up your guns and pay your telly tax, and that is a point. But the telly tax in Britain goes to fund a Citizen's oversight committee which evaluates the quality of their news outlets. As such the BBS is one of the most respected and trusted news outlets in the world. Meantime, Fuck Snooze goes to court to get the right to outright lie on the air with impunity, AND WINS.
 
What does that mean ? That means if they know a severe thunderstorm is coming and decide to lie and you go out and get a cookout started and ten people get hit by lightning they have zero legal culpability. Even if it kills someone. How the court could ever issue that judgement in good conscience is beyond me. How do they sleep at night ?
 
If we are going to change this country for the better we need Citizens oversight groups for the government, the cops and the media. No more cop shoots n____r and gets a paid vacation, he goes to jail under investigation. We needed that with Carl Stokes, one of the biggest crooks in Cleveland history, but it is politically incorrect to say that because he is Black. We The People need the right to call them on the carpet for the shit they do.
 
It is ridiculous,they allow the sale of prescription drugs (even for smoking cessation) that make people suicidal and some to shoot up schools and even army bases, while putting people in prison for selling pot that grows in the ground ? What is wrong with this picture ?
 
I have thought about it and the answer is because to those MFs it is all about money. We got judges who invest in companies that run private prisons. We got industry insiders on the boards of the USDA and FDA, and look at all the class action lawsuits.
 
Do other countries have that ? they do not have a Constitution like ours but they do get a response when they petition or get out and demonstrate. Britains got Brexit on the ballot, China changed some plans because people demonstrated in the streets. Now what was their response to OWS here ? Free country my fucking ass. That was pretty big and not a fucking thing changed.
 
I am sorry you fought for this country because they are wrecking it as fast as they can. If your physical maladies are due to your service I am even sorrier. I don't know your age, but if you are old now you pretty much fought for a different country than it is today.
mhooker32@gmail.com: Aug 29 10:03AM -0700

> > whatever signals it outputs, rather than looking at EDID data the way a
> > PC would.
 
> will that affect what i'm trying to do?
 
i made up the cable as per jeff's chart, and the lcd monitor displayed a very nice image. now i can go thru the machine and test all its functions. with the image on the original monitor as described above, do you think a cap kit will do the trick?
 
thanks
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Digest for sci.electronics.repair@googlegroups.com - 25 updates in 5 topics

Jeff Layman <JMLayman@invalid.invalid>: Aug 26 07:21PM +0100

On 25/08/16 23:17, David Farber wrote:
 
> It's amazing a movie could be so loud that it caused structural damage to a
> building but not cause hearing damage to the moviegoers!
 
> Thanks for your reply.
 
In 1980 I saw Pink Floyd perform "The Wall"
(https://en.wikipedia.org/wiki/The_Wall#Tour) live at London's Earl's
Court. At the end, when the Wall came down, the whole building
shook.You couldn't hear it, but you could sure feel it. As Earl's Court
could hold an audience of 20,000, that required some serious amplifiers.
 
Although it's a little hazy now, I believe I remember reading that Pink
Floyd used 55kW of amplification for the concert, of which 18kW was used
subsonically only at the end when the wall came down. I have no idea
what frequency they used or what sort of loudspeakers generated it.
 
--
 
Jeff
"David Farber" <farberbear.unspam@aol.com>: Aug 26 11:50AM -0700

N_Cook wrote:
>> months old. Thanks for your replies.
 
> Before replacing new display, look for grit/swarf etc maybe from
> manufacture, then stressing of the case caused point stress crack
 
Thanks for the pointers. I'll check it out.
--
David Farber
Los Osos, CA
Sjouke Burry <burrynulnulfour@ppllaanneett.nnll>: Aug 27 03:35AM +0200

On 25.08.16 22:11, David Farber wrote:
> display? If I replace the display, is it likely to happen again? The
> recorder has only been used a few times and it's about 18 months old.
 
> Thanks for your replies.
 
Looks like air intrusion from a leak in the edge of the LCD.
No known cure, except replacement.
"David Farber" <farberbear.unspam@aol.com>: Aug 26 09:18PM -0700

Sjouke Burry wrote:
>> months old. Thanks for your replies.
 
> Looks like air intrusion from a leak in the edge of the LCD.
> No known cure, except replacement.
 
I ordered a repalcement dispaly today. Hopefully it will all go back
together as easily as it came apart.
 
Thanks for your reply.
--
David Farber
Los Osos, CA
jurb6006@gmail.com: Aug 26 10:20PM -0700

">In 1980 I saw Pink Floyd perform "The Wall"
>(https://en.wikipedia.org/wiki/The_Wall#Tour) live at London's Earl's
>Court."
 
You would probably like "Dogs Of War". I have a really good copy of it on VHS Hifi but not the means to put it on the PC or the web. It was always in the Friday night playlist.
 
Actually I might not still have it, I haven't looked. I looked for a copy of the same performance on gnutella and youtube and neither has this version, and I DO know how to search. I got shit youtube doesn't got, and I mean popular shit, not some obscure assholes in their in the garage. But then Buddy Holly stasrted out on a garage...
"David Farber" <farberbear.unspam@aol.com>: Aug 26 11:56AM -0700

I'd like to know if there is way to tell ahead of time how to remove this
cable. I've found that trial and error can lead to unrecoverable errors! By
the way, this is (I think) the display connector to the Tascam DL-44WL that
I posted about yesterday. I would like to remove it before turning the board
upside down to get to the display.
 
http://webpages.charter.net/mrfixiter/images/Electronics/Tascam/DR-44WL-connector.jpg
 
Thanks for your replies.
--
David Farber
Los Osos, CA
Andy Burns <usenet@andyburns.uk>: Aug 26 08:39PM +0100

David Farber wrote:
> I'd like to know if there is way to tell ahead of time how to remove this
> cable.
 
> http://webpages.charter.net/mrfixiter/images/Electronics/Tascam/DR-44WL-connector.jpg
 
Just a guess, but it looks like the black "comb" would tilt upwards and
stop pinching the flat flex ... possibly FPC type connector.
"David Farber" <farberbear.unspam@aol.com>: Aug 26 12:57PM -0700

Andy Burns wrote:
 
>> http://webpages.charter.net/mrfixiter/images/Electronics/Tascam/DR-44WL-connector.jpg
 
> Just a guess, but it looks like the black "comb" would tilt upwards
> and stop pinching the flat flex ... possibly FPC type connector.
 
We have a winner! Thanks Andy. I gently lifted that "comb" and it easily
came up.
 
--
David Farber
Los Osos, CA
Chuck <chuck@mydeja.net>: Aug 26 03:06PM -0500

On Fri, 26 Aug 2016 11:56:47 -0700, "David Farber"
>upside down to get to the display.
 
>http://webpages.charter.net/mrfixiter/images/Electronics/Tascam/DR-44WL-connector.jpg
 
>Thanks for your replies.
 
With your finger nail , lift up the gray plastic tab. It is hinged on
the back.
 
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
"David Farber" <farberbear.unspam@aol.com>: Aug 26 01:13PM -0700

Chuck wrote:
 
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
 
That worked!
 
Thanks.
--
David Farber
Los Osos, CA
"Ian Field" <gangprobing.alien@ntlworld.com>: Aug 26 09:25PM +0100

"David Farber" <farberbear.unspam@aol.com> wrote in message
news:npq806$sn9$1@dont-email.me...
>> This email has been checked for viruses by Avast antivirus software.
>> https://www.avast.com/antivirus
 
> That worked!
 
There's also the "wedge" type that jams the cable in - they just slide out
slightly instead of flipping up.
"David Farber" <farberbear.unspam@aol.com>: Aug 26 01:31PM -0700

Ian Field wrote:
 
>> That worked!
 
> There's also the "wedge" type that jams the cable in - they just
> slide out slightly instead of flipping up.
 
Hi Ian,
 
Yes, wouldn't it be nice if there were some type of universal marking on the
connector so we'd know ahead of time where to pull? I thought I'd make sure
this time by asking first. (-:
 
Thanks for your reply.
--
David Farber
Los Osos, CA
avagadro7@gmail.com: Aug 26 03:00PM -0700

http://www.clamming.com/mm5/graphics/00000001/clamrake_2_500x500.png
 
https://images-na.ssl-images-amazon.com/images/I/31JEEB5rCrL._SX425_.jpg
 
http://www.google.com/search?site=imghp&tbm=isch&source=hp&biw=1522&bih=765&q=bosch+mini+tools&oq=mini+tools+&gs_l=img.1.4.0i30k1l3j0i5i30k1l3j0i8i30k1l4.2019.6098.0.9831.11.11.0.0.0.0.371.1479.0j8j0j1.9.0....0...1ac.1.64.img..2.9.1469...0j0i10k1.deeECQihMNg#tbm=isch&q=electronic+connector+pick+tool+set
 
unlike written in English computer directions, connectors usually appear rational and concise. But always use a tool …. And 3 hands.
 
CRC electronics cleaner followed with CRC silicone from Wal are useful thru dusty coverings.
"David Farber" <farberbear.unspam@aol.com>: Aug 26 09:12PM -0700

> appear rational and concise. But always use a tool .. And 3 hands.
 
> CRC electronics cleaner followed with CRC silicone from Wal are
> useful thru dusty coverings.
 
That clamrake will let you do four connectors at once!
 
--
David Farber
Los Osos, CA
isw <isw@witzend.com>: Aug 26 09:44AM -0700

In article <npojvq$dnb$1@dont-email.me>,
 
> http://w140.com/tekwiki/wiki/2235
 
> Also you might join the tek yahoo group and describe your findings there.
 
> https://groups.yahoo.com/neo/groups/TekScopes/info
 
Thanks.
 
Isaac
dplatt@coop.radagast.org (Dave Platt): Aug 26 11:50AM -0700

>Green pilot lights up, but the screen does not, even in a darkened room.
 
>Are there well-known failure points in these? Where to find a schematic
>and/or service manual?
 
One known weak point in this family is a chain of high-value
carbon-composition resistors which divide down the high voltage to
provide the focus voltage. They run fairly hot, and tend to drift
over time, resulting in a fuzzy image which can't be focused properly.
 
If one of these were to fail "open" I suspect it might disrupt the
operation of the CRT badly enough that you wouldn't see a trace.
 
Repair costs a few dollars in parts (either some old-stock carbon
comp resistors selected for the right value, or more modern leaded
resistors of a type rated for high voltage) and an hour or two of
work (a few of the resistors in the chain are tucked into slightly
tricky places on the board). It's not a bad job, though: I picked up
a 2235 at a flea market for $60, found it had this problem, and had it
repaired by the end of the afternoon.
 
Failure-to-light-up might mean a more serious problem in the high
voltage supply - if I recall correctly it's a switcher. Dried-out
(high-ESR) or leaky caps would be another common suspect.
"Ian Field" <gangprobing.alien@ntlworld.com>: Aug 26 09:28PM +0100

"isw" <isw@witzend.com> wrote in message
news:isw-2D3B4E.09442026082016@news-roam.garlic.com...
 
>> Also you might join the tek yahoo group and describe your findings there.
 
>> https://groups.yahoo.com/neo/groups/TekScopes/info
 
> Thanks.
 
The simplest and easiest thing to do is check the CRT heater lights - a dry
joint somewhere would probably be more likely than an OC heater.
jurb6006@gmail.com: Aug 26 04:09PM -0700

This is where an old VTVM and 1090 meg HV probe come in handy. The self contained ones most people used for TV work could not measure negative voltages and it is a hell of alot easier to get to the cathode than the anode on a scope.
 
Those voltages are usually on the print, so you can tell if it is in regulation or not. If I am not mistaken, the dividing resistors for the focus are part of the HV regulation feedback loop, so a fairly accurate measurement of the cathode voltage can be quite useful. Also, turn it off and let it all discharge, then turn it on with the probe connected and see if you get HV for a split second and then goes away. If so it is going into shutdown, dead giveaway.
 
Most of the scopes we bought/buy we get a chance to plug them in and tend to get the ones that at least produce a trace. We are sorta in the market for one of those 1090 ohm jobs but the ones I see are a little to high for something that might get used once a year. Also that the market for them is so limited. So that means I get to wrestle with the fun ones, like B sweep not starting on a 465B. You REALLY want B sweep to work on a 465B because it has the split function where you can see the whole trace and the expanded trace at the same time. Even though it is not something you would use everyday, it is still a feature and it should work.
 
And don't overlook the possibility of a failure in the main power supply. Check everywhere it says 15V, 5V, 8V -5V, -15V, 130V, 50V, -50V and so forth. Those seem to be the supply voltages Tek used to like to use.
whit3rd <whit3rd@gmail.com>: Aug 26 11:41AM -0700

On Thursday, August 25, 2016 at 7:24:18 PM UTC-7, Bob Simon wrote:
> I recently moved and connected my new Cox Contour DVR to an audio receiver and TV. (A Blu-ray player is also connected to the receiver and TV; this may or may not have any relevance to my issues.) There was a pretty bad hum so I inserted an isolation transformer between the cable feed and the DVR, which eliminated the hum. I measured the voltage between the outside of the cable connector and safety ground ..
 
Good; measurement is the right thing to do.
 
> Is this voltage difference the cause of the hum?
 
Probably.
> Was my measurement approach appropriate?
Yes!
 
> Do the measured voltages indicate that the cable is improperly grounded?
 
Not necessarily; the grounding of the cable is intended to protect you
from lightning, and isn't supposed to pass a 'hum' test.
 
> If the cable were to be bonded to the house neutral with 3/0AWG, would this likely eliminate the need for the isolation transformer?
 
Hopefully, you mean bonded to the house GROUND, since the only neutral
bonding allowed by code is inside the circuit breaker box. No, confusing
the matter with multiple straps won't help. Any cable with multiple
connections to ground is a ground loop, and those CREATE hum.
 
If your audio path can be replaced with digital or TOSlink, that would
be another solution (and would simplify the wiring instead of adding
to it). RCA-plug stereo connection is common, and commonly causes
problems, in part because (unless one is clever) it creates ground
loops.
dplatt@coop.radagast.org (Dave Platt): Aug 26 11:44AM -0700

>eliminated the hum. I measured the voltage between the outside of the cable connector and safety ground with a cheap VOM and found 0.2VAC and 1-9 mVDC.
>I have a number of questions that I hope someone can answer for me.
 
>Is this voltage difference the cause of the hum?
 
It seems entirely possible and likely. It could easily result in 200
millivolts of AC ripple appearing on the audio signal. Since audio
these days is usually 2 volts or so, peak-to-peak, you'd end up with a
serious hum.
 
Common problem with cable installs, and the solution you've used is a
common one.
 
>Was my measurement approach appropriate?
 
What I'd suggest doing, is disconnect the DVR from all of your other
A/V equipment, and reconnect it directly to the cable. Then, measure
the AC voltage between its A/V ground (e.g. the shell of the RCA
connectors for the audio-out) and the corresponding AC ground on
something else in your A/V setup.
 
I strongly suspect you'll get roughly the same voltage rating.
 
 
>Do the measured voltages indicate that the cable is improperly grounded?
 
>If the cable were to be bonded to the house neutral with 3/0AWG, would this likely eliminate the need for the isolation transformer?
 
DO NOT BOND IT TO NEUTRAL. Neutral, by definition, is a
current-carrying wire, and it can be pulled several volts away from
ground by voltage-drop in the wiring. The only place this isn't the
case is back at the service panel, where neutral and ground are bonded
together.
 
The only place you should bond grounds to, is other grounds (and
ideally do so at a single point).
 
You don't need 3/0 to comply with NEC - 14/0 or heavier is apparently
adequate.
 
>Whether it would eliminate the hum or not, should I have it done?
 
There's no harm to doing so, it's a common solution, and since it
fixed your problem, Be Happy!
 
Grounding the coax at the point of entry (per NEC) would provide you a
bit of additional protection against something like a near-strike by
lightning onto the cable wiring.
 
>Does the cable company have any obligation to do it in order to comply with regulations?
 
My recollection is that in most jurisdictions, cable-TV drops are
supposed to have their braids bonded to building ground at the point
of entry. A lot of installers skip this step, as there's often no
"good" ground at the point of entry, and they don't want to run a
heavy ground wire back to the panel and do a proper job of bonding at
both ends.
 
National Electric Code, article 820, seems to be the relevant one.
I don't have the full text here (my old salvaged copy of the NEC is at
home) but the summary I see on-line does indicate that this is
necessary:
 
http://ecmweb.com/code-basics/article-820-community-antenna-tv-and-radio-distribution-systems
 
Sidebar: 820 Tips
 
Determine point of entrance.
 
Ground the incoming cable as close as practicable to the point of
entrance.
 
If you run cables above a suspended ceiling, route and support them to
allow access via ceiling panel removal.
 
If you use a separate grounding electrode, bond it to the power
grounding system.
 
Use the correct cable type and raceway for application the general,
plenum, or riser.
jurb6006@gmail.com: Aug 26 03:55PM -0700

Unless you are using an indoor antenna, somewhere the cable from wherever is grounded. It is obviously not grounded at the same place as the electrical ground.
 
While newer electrical installs will have a ground rod stuck ten feet in the ground, I think in most areas cable and phone installers can still use a cold water pipe because those are more for lightning than ground faults in appliances, like if an internal hot wire gets shaved and touches the metal body.
 
The cable or antenna ground is so that if lightning strikes it does not arc across your house and kill you from ten feet away. It doesn't really protect the equipment much either.
 
There are ground gradients, I had a similar problem with an electician's house. He has a large house, so large that he decided to use two ground rids. We sold himm a video projectot which at the time was the only piece of his system that had a three prog grounded plug. He comes back and says that as soon as he plugs in the cable he gets a bar running up the screen. This is called a hum bar and had the exact same cause as your audio hum, but when the video gets the hum you get a bar. Our solution was to find an antenna isolator from an old hot chassis type TV and adapt it to be F to F rather than F to modified RCA. Finding such an isolator these days might not be so easy since TVs all when to SMPS type supplies and thus need no isolation.
 
You can actually build one, in case you would rather have that isolation transformer for other uses. If so, I'll look into the best/easiest way to do it, but if you are happy now and this is all academic you can just leave it as it is. However, your equipment is no longer grounded, which should not be a problem.
dplatt@coop.radagast.org (Dave Platt): Aug 26 04:08PM -0700

>Unless you are using an indoor antenna, somewhere the cable from
>wherever is grounded. It is obviously not grounded at the same place
>as the electrical ground.
 
In cases like this, chances are that the cable's nearest ground is
either out at a street-side service pole, or a curb-side vault, or a
neighbor's house. There's all kinds of opportunity for current loops
between the cable ground, house ground, and neutral.

>You can actually build one, in case you would rather have that isolation transformer for other uses. If so, I'll look into the best/easiest way to do
>it, but if you are happy now and this is all academic you can just leave it as it is. However, your equipment is no longer grounded, which should not be
>a problem.
 
http://flynwill.rosshay.com/Electronics/antIso/ shows a nice way to
rebuild a standard cheap 75-to-300-ohm balun, to turn it into an
isolated 75-to-75-ohm unun. The result is probably rather similar to
what you'd find in a commercial 75-ohm coaxial groundbreaker.
 
(This very problem was the source of a discussion on the FMTuners
mailing list last week, and that's where I cribbed the reference to
this particular DIY project.)
Micky <NONONObobbyburns1111@gmail.com>: Aug 26 12:09PM -0400

On Thu, 25 Aug 2016 02:00:32 +0100, "Gareth Magennis"
 
>I've been on this planet a few years now, and have yet to find a situation
>where Superglue is a good idea.
 
It's never worked for me, either.
 
I've tried using less and less, and more.
 
>It pretty much just does not work, except for sticking your fingers
>together.
 
It doesn't do that either, for me.
 
Is it just a big scam, propelled by the enormous advertising campaign
years ago, or are there people it works for?
 
My mother had some Duco Cement, and that never worked for me either.
 
>Hot melt glue sometimes works, but does not adhere well to many surfaces.
 
>Silicone glue/sealant pretty much sticks to everything, is flexible and
 
You're talking about GE silicone sealant that comes in white, black**,
clear, and iirc silver??? **Black is only sold at autoparts
stores.
 
>shockproof, and can be peeled off without damaging anything if you need to
>have another go.
>Win, win, win, in my book, I rarely use anything else now.
 
I use it too, but I also use:
 
Contact cement is good for cloth etc. because it bends, even after
drying. It used to be Weldwood in the red tube and not Weldwood in
the white tube, but that was decades ago and has probably changed.
 
Android cement is good for almost everything, not as strong as epoxy
but strong, and yet can be broken apart if you want later. Dries
quickly, smells good. Only sold in hobby stores. Tube never dries
out if you keep it sealed. I used one big tube for 20 years. (I
only learned about it because the hardware store at Myrtle Ave. in
downtown Brookly had two cartons of them on sale cheap because they
were all beat up, each tube had been squeezed and bent, but that's the
tube that lasted 20 years.
 
Five-minute epoxee in the syringe is very good for many many things.
 
PC-7 and PC-11, very very strong, sticks to almost anything including
glass (at least the demo showed that. I've never needed to glue
anything to glass.) Moldable, space filler. Can be applied to a
dripping drain (because the drain had a hole in it and the faucet
washer was no good) and still dries and stops the leak. I lost the
cap to a wine sack, put vaseline on the threads, molded some PC-7
around it, put a hole through for a string, and when it tried, I
unscrewed it and now it's a cap. I patched a leaking pot and then
forgot and boiled all the water out, but it still didn't leak. I
even made replacement teeth on the gear of a commercial "egg" mixer,
but that only worked for a couple minutes. (I should have roughed up
the glossy area where most of the glue went, but I was only 19 y.o.)
I've never used PC-11 iirc, and I don't understand the difference. The
label says PC-11 is for water areas -- well I guess that's the
difference but 7 seemed to work well there too. 7 is dark grey and 11
is white.
 
Micky <NONONObobbyburns1111@gmail.com>: Aug 26 12:11PM -0400

On Thu, 25 Aug 2016 10:26:34 +1000, Clifford Heath
 
>China Post (aka the Chinese government) provides free shipping
>for small parcels. So "big box" here means "shipping container"
>and "pro-rate" is at zero cost...
 
Well that would account for it. So who gets the 80 cents?
 
>except to the postal services
>in the destination countries.
 
So the US etc. have to handle their part for free, because that's the
system for all but the originating country, right?
"jfeng@my-deja.com" <jfeng@my-deja.com>: Aug 26 09:17AM -0700

On Friday, August 26, 2016 at 9:11:32 AM UTC-7, Micky wrote:
> So the US etc. have to handle their part for free, because that's the
> system for all but the originating country, right?
By international treaty. Google "Universal Postal Union". The recipient country agrees to complete the delivery. It works both in both directions.
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Digest for sci.electronics.repair@googlegroups.com - 25 updates in 6 topics

JW <none@dev.null>: Aug 25 11:12AM -0400

On Wed, 24 Aug 2016 13:05:43 -0700 (PDT) whit3rd <whit3rd@gmail.com> wrote
>WiFi user (or other device in the 2.4 GHz band) its broadcast could swamp
>yours, except for pauses between transfers.
 
>Signal strength might be excellent, but the road is crowded.
 
Thanks, I don't think it's that given the symptoms (requires power cycle)
JW <none@dev.null>: Aug 25 11:11AM -0400

On Thu, 25 Aug 2016 06:07:24 -0700 (PDT) jack4747@gmail.com wrote in
>> http://www.linksys.com/us/support-article?articleNum=148629
 
>there are firmware update, just not from Linksys:
 
>http://www.dd-wrt.com/site/index
 
Thanks. Looks like I have already have the last version ever released by
Linksys.
http://dd-wrt.com/wiki/index.php/Linksys_WRT54GS_v2.0
Jeff Liebermann <jeffl@cruzio.com>: Aug 25 03:27PM -0700


>Happens once a day or so, but sometimes not for several days or more.
>Wired connections work fine.
 
>Firmware version: v4.71.4
 
Current firmware is:
WRT54GS_4.71.4.001_fw,2.bin
<http://www.dd-wrt.com/phpBB2/viewtopic.php?p=643052>
<http://www.dd-wrt.com/phpBB2/download.php?id=20701&sid=e2141ada1089e4d9835e4103538b2801>
 
>to be... Maybe they pulled the plug on this model?
>http://www.linksys.com/us/support-article?articleNum=148629
 
>Thanks.
 
It's been many years since I've seen that phenomenon and it's quite
real. It's a bug in the firmware that runs the radio section. The
problem is that the easily replaceable firmware such as DD-WRT
operates mostly on layer 3, while the wireless card operates on layer
2. For alternative firmware, the layer 2 stuff is supplied by Linksys
in the form of a linkable library that can't be tweaked. This might
be why firmware transplants haven't done anything to fix the problem
and why only some WRT54G and GS v2 boxes have the problem.
 
It's been many years since the WRT54GS was in fashion. There has been
considerable progress in wireless chips, antennas, router features,
acronyms, and aerodynamic packaging. You might want to consider a
newer wireless router.
 
--
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
JW <none@dev.null>: Aug 26 05:23AM -0400

On Thu, 25 Aug 2016 15:27:30 -0700 Jeff Liebermann <jeffl@cruzio.com>
>considerable progress in wireless chips, antennas, router features,
>acronyms, and aerodynamic packaging. You might want to consider a
>newer wireless router.
 
Thank you for that Jeff. I think you may be right. Have any good
reasonably priced recommendations?
"ScottWW" <spamtrap@dcorp.com>: Aug 26 08:31AM -0400


>Thanks. Looks like I have already have the last version ever released by
>Linksys.
>http://dd-wrt.com/wiki/index.php/Linksys_WRT54GS_v2.0
 
I had a WRT54G that required frequent resets right out of the box. The
firmware was up-to-date. Reverting back one version made it much more
stable. Ultimately though, I had to replace it.
Scott
Jeff Liebermann <jeffl@cruzio.com>: Aug 26 08:19AM -0700


>Thank you for that Jeff. I think you may be right. Have any good
>reasonably priced recommendations?
 
Maybe, but I need to know what you're doing with it, the speed of the
internet connection, number of simultaneous connections, and whether
you plan to use alternative firmware. Some clue as to the environment
(business, coffee shop, outdoors, home, industrial, doorstop, etc). Do
you need gigabit ethernet or will 10/100Mbits/sec suffice? USB 2.0,
3.0, or none? What you consider reasonably priced?
 
If you want really cheap, I've been buying refurbished Linksys EA2700
wireless routers from the Belkin (they own Linksys) eBay store:
<http://stores.ebay.com/linksysofficialstore/Wireless-Routers-/_i.html?_sacat=44995>
<http://www.ebay.com/itm/Linksys-N600-Dual-Band-Wi-Fi-Router-Manfacturer-Refurbished-/301761478977>
for $25 including shipping. Can't get much cheaper than that for a
dual band router with gigabit ethernet interface. However, the router
has a few odd problem.
1. The wireless range is lousy.
2. The wall warts blow up after about 2 years of service.
3. I can't stack anything on top of it due to the rounded top.
4. No flashing lights for user diagnostics.
However, wireless speed is good, measured up to 60 Mbits/sec.
<http://802.11junk.com/jeffl/FLUG-talk-2015-02-28/802.11gn%20direct.jpg>
I use these for lighting up small areas that do NOT require going
through walls or covering long distances. I also stock spare power
supplies.
 
For home users, the other end of the scale is an Asus RT-AC68Uv2.
<https://www.asus.com/us/Networking/RTAC68U/>
About $130. I don't care much about the AC speeds, but the range is
much better thanks to three 2.4GHz and three 4GHz power amps inside.
However, I've only installed one of these, and haven't had time to do
any kind of performance analysis. My seat of the pants evaluation is
that I like what I see (except for the price).
<http://www.smallnetbuilder.com/wireless/wireless-reviews/32609-asus-rt-ac68p-dual-band-wireless-ac1900-gigabit-router-reviewed>
<http://www.smallnetbuilder.com/wireless/wireless-reviews/32239-ac1900-first-look-netgear-r7000-a-asus-rt-ac68u>
<http://www.smallnetbuilder.com/tools/router-chooser/detail/1235/asus-rtac68u>
<http://www.smallnetbuilder.com/tools/rankers/router/result/1235-asus-rtac68u>
It's on the DD-WRT supported list:
<http://www.dd-wrt.com/wiki/index.php/Supported_Devices#Asus>
but I haven't tried it yet.
 
Note: I'm a big fan of having the wireless access point(s) seperate
from the router, but cost and complexity prevent me from selling that
to home users.
 
 
--
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>: Aug 26 08:45AM -0700

On Fri, 26 Aug 2016 08:19:08 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:
 
>For home users, the other end of the scale is an Asus RT-AC68Uv2.
><https://www.asus.com/us/Networking/RTAC68U/>
 
Oops. I goofed. That should be for an RT-AC68P, not U.
<http://www.asus.com/Networking/RTAC68P/>
The FCC site has it listed as RT-AC68V2.
<http://www.smallnetbuilder.com/wireless/wireless-reviews/32609-asus-rt-ac68p-dual-band-wireless-ac1900-gigabit-router-reviewed>
 
The links I previously mentioned are all for the V1 router RT-AC68U.
There are some substantial hardware differences between v1 and v2. V1
is an RT-AC68U, while V2 is an RT-AC68P.
<https://wikidevi.com/wiki/ASUS_RT-AC68P>
Some sales web sites are mixing these two with little control over
which one will arrive. Anyway, look for the "P", not "U". This one
worked for me:
<http://www.newegg.com/Product/Product.aspx?Item=N82E16833320228>
Sorry(tm) and caveat emptor.
 
There is also Asus specific alternative firmware available:
<http://asuswrt.lostrealm.ca/about>
I haven't tried it yet.
 
--
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
avagadro7@gmail.com: Aug 25 05:22PM -0700


> want to separate connectors n pull receiver out during sensitive parking.
 
> several dc and 4 stereo connectors if possible with no distortion/loss .
 
> broadcast quality .....
 
no suggestions ?
mike <ham789@netzero.net>: Aug 25 06:47PM -0700


>> several dc and 4 stereo connectors if possible with no distortion/loss .
 
>> broadcast quality .....
 
> no suggestions ?
 
yep,
Go to any car stereo installation store and ask them.
avagadro7@gmail.com: Aug 26 06:09AM -0700

local shop
 
 
goo.gl/b7pC5g
"David Farber" <farberbear.unspam@aol.com>: Aug 25 01:11PM -0700

This Tascam DR-44WL digital recorder was given to me for repair. I asked how
the screen got damaged. The user, a friend of mine, said that it wasn't
dropped or mishandled. It was placed on the floor in an out of a way place
before his band played and 45 minutes later he went to retrieve it and the
screen looked like this:
http://webpages.charter.net/mrfixiter/images/Electronics/Tascam/DR-44WL-screen.jpg
The rest of the unit looks very clean. There are no scratches anywhere.
 
A new screen costs around $40 + shipping but I was curious what kind of
defect would cause an image like this without some severe impact to the
display? If I replace the display, is it likely to happen again? The
recorder has only been used a few times and it's about 18 months old.
 
Thanks for your replies.
--
David Farber
Los Osos, CA
"Gareth Magennis" <soundserviceleeds@outlook.com>: Aug 25 09:29PM +0100

"David Farber" wrote in message news:npnje4$n86$1@dont-email.me...
 
This Tascam DR-44WL digital recorder was given to me for repair. I asked how
the screen got damaged. The user, a friend of mine, said that it wasn't
dropped or mishandled. It was placed on the floor in an out of a way place
before his band played and 45 minutes later he went to retrieve it and the
screen looked like this:
http://webpages.charter.net/mrfixiter/images/Electronics/Tascam/DR-44WL-screen.jpg
The rest of the unit looks very clean. There are no scratches anywhere.
 
A new screen costs around $40 + shipping but I was curious what kind of
defect would cause an image like this without some severe impact to the
display? If I replace the display, is it likely to happen again? The
recorder has only been used a few times and it's about 18 months old.
 
Thanks for your replies.
--
David Farber
Los Osos, CA
 
 
 
 
 
 
Hmm, I suspect a severe impact.
 
 
Gareth.
Adrian Caspersz <email@here.invalid>: Aug 25 09:44PM +0100

On 25/08/16 21:11, David Farber wrote:
> defect would cause an image like this without some severe impact to the
> display? If I replace the display, is it likely to happen again? The
> recorder has only been used a few times and it's about 18 months old.
 
A neighbour gave me their Lenovo laptop to fix that had a cracked
screen. Their kid was pretty insistant it wasn't dropped, but I couldn't
entertain the warranty company with that statement; I don't have a lie
detector that can be plugged into her and ethernet - so we fitted a new
display ourselves.
 
An idea. Extreme heat? Humidity? Electroluminescent panel flashover?
 
--
Adrian C
AL <noemail@none.com>: Aug 25 02:05PM -0700

On 8/25/2016 1:11 PM, David Farber wrote:
> display? If I replace the display, is it likely to happen again? The
> recorder has only been used a few times and it's about 18 months old.
 
> Thanks for your replies.
 
How close was it to the band's woofer? Some of the bands I've heard can
really shake things up. Could the vibration have caused the screen damage?
 
As an aside, years ago when the movie Earthquake first came out the
local theater put large woofers in the rear. So when the earthquake
scene came on the whole place really shook. After several weeks they
actually discovered structural damage to the building and the place had
to close for the repairs.
"David Farber" <farberbear.unspam@aol.com>: Aug 25 03:17PM -0700

AL wrote:
> scene came on the whole place really shook. After several weeks they
> actually discovered structural damage to the building and the place
> had to close for the repairs.
 
This is a rather low key band that plays traditional jazz music.
 
It's amazing a movie could be so loud that it caused structural damage to a
building but not cause hearing damage to the moviegoers!
 
Thanks for your reply.
--
David Farber
Los Osos, CA
dplatt@coop.radagast.org (Dave Platt): Aug 25 03:21PM -0700

>defect would cause an image like this without some severe impact to the
>display? If I replace the display, is it likely to happen again? The
>recorder has only been used a few times and it's about 18 months old.
 
It looks to me as if the edge of the LCD panel was compromised,
allowing an air leak into the panel.
 
This might be due to a manufacturing defect, but the radiating pattern
of lines, and the thin little hairline I see at the tip of the
leftmost radiating spike of blue-ness, suggests that the panel was
actually fractured or chipped at its edge... either by impact or by
excessive non-impact pressure. The whitish spots/rings near the top
of the display area suggest that something has pushed or scraped the
protective cover enough to damage the plastic film.
 
If the recorder was sitting on the floor, is there a possibility that
the place wasn't "out of the way" enough, and somebody accidentally
stepped on it? That might easily flex the plastic cover and put
pressure onto the LCD and crack it. Direct downward pressure by a
shoe might not have left scratches, other than perhaps those small
scrapes/defects just below the top.
"David Farber" <farberbear.unspam@aol.com>: Aug 25 04:12PM -0700

Dave Platt wrote:
> pressure onto the LCD and crack it. Direct downward pressure by a
> shoe might not have left scratches, other than perhaps those small
> scrapes/defects just below the top.
 
Hi Dave,
 
Yes, it is possible that someone or something came in contact with it as it
was out of view for a while. There were quite a few people milling about the
area and who knows what the real story is. Your explanation seems quite
plausible.
 
Thanks for your reply.
--
David Farber
Los Osos, CA
Phil Allison <pallison49@gmail.com>: Aug 25 07:05PM -0700

David Farber wrote:
 
 
> It's amazing a movie could be so loud that it caused structural damage to a
> building but not cause hearing damage to the moviegoers!
 
** The sound was all very low frequency so excited standing waves in the room.
 
The system was developed by speaker maker Cerwin-Vega and called "Sensurround":
 
https://en.wikipedia.org/wiki/Sensurround
 
Cerwin-Vega also supplied high powered amplifiers for the system, mostly models A3000 and A1800 which later turned up on the second hand market and were bought for use in PA systems for live music in the 1980s.
 
One of my customers acquired a number of them and they were constantly coming in for repair. They were never built well enough to go touring in the back of a truck.
 
 
.... Phil
N_Cook <diverse@tcp.co.uk>: Aug 26 08:01AM +0100

On 25/08/2016 21:11, David Farber wrote:
> display? If I replace the display, is it likely to happen again? The
> recorder has only been used a few times and it's about 18 months old.
 
> Thanks for your replies.
 
Before replacing new display, look for grit/swarf etc maybe from
manufacture, then stressing of the case caused point stress crack
isw <isw@witzend.com>: Aug 25 09:45PM -0700

A friend came across one of these, a bit dirty but otherwise looking OK.
Green pilot lights up, but the screen does not, even in a darkened room.
 
Are there well-known failure points in these? Where to find a schematic
and/or service manual?
 
Isaac
"tom" <tmiller11147@verizon.net>: Aug 26 01:28AM -0400

"isw" <isw@witzend.com> wrote in message
news:isw-A34D3E.21452125082016@news-roam.garlic.com...
 
> Are there well-known failure points in these? Where to find a schematic
> and/or service manual?
 
> Isaac
 
Service manual and Operators manual here:
 
http://w140.com/tekwiki/wiki/2235
 
Also you might join the tek yahoo group and describe your findings there.
 
https://groups.yahoo.com/neo/groups/TekScopes/info
 
 
Good luck.
 
--
Bob Simon <bobneworleans@gmail.com>: Aug 25 07:24PM -0700

I recently moved and connected my new Cox Contour DVR to an audio receiver and TV. (A Blu-ray player is also connected to the receiver and TV; this may or may not have any relevance to my issues.) There was a pretty bad hum so I inserted an isolation transformer between the cable feed and the DVR, which eliminated the hum. I measured the voltage between the outside of the cable connector and safety ground with a cheap VOM and found 0.2VAC and 1-9 mVDC. I have a number of questions that I hope someone can answer for me.
 
Is this voltage difference the cause of the hum?
 
Was my measurement approach appropriate?
 
Do the measured voltages indicate that the cable is improperly grounded?
 
If the cable were to be bonded to the house neutral with 3/0AWG, would this likely eliminate the need for the isolation transformer?
 
Whether it would eliminate the hum or not, should I have it done?
 
Does the cable company have any obligation to do it in order to comply with regulations?
 
Bob Simon
New Orleans
stratus46@yahoo.com: Aug 25 10:01PM -0700

On Thursday, August 25, 2016 at 7:24:18 PM UTC-7, Bob Simon wrote:
 
> Does the cable company have any obligation to do it in order to comply with regulations?
 
> Bob Simon
> New Orleans
 
Since the iso transformer got rid of the hum it's a real good bet that the 200mV is your problem. I had a similar problem with tuners in the computers and antenna / cable feeds and hum. A 'galvanic isolator' from these folks cleaned everything up.
 
http://www.rmscommunications.net/mi2120v_n.htm
 
The Voltage in my system is similar to yours so safety really isn't an issue. The isolator solved the problem and as far as I'm concerned, it's a permanent solution.
 

bscs-fa15-080@tuf.edu.pk: Aug 25 02:29PM -0700

dear sir am looking for solutions of this book
would you like to provide me
i'll be very thankfull to you
jurb6006@gmail.com: Aug 25 05:03PM -0700

>" Do you really think that the spammer comes back to look for >replies? "
 
He even said he doesn't. Some people are so stupid, how do they even live ? Someone must be there to remind them to breathe.
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