- Tascam digital recorder with defective display. - 5 Updates
- Before I break this connector... - 9 Updates
- Dead Tek 2235 - 4 Updates
- Hum from Cable - 4 Updates
- Repairing damaged ribbon connector slot - 3 Updates
| 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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