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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#41
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Recommendation for electronics forums?
Hi David,
On 3/20/2011 3:54 PM, David Nebenzahl wrote: On 3/19/2011 11:51 PM D Yuniskis spake thus: On 3/19/2011 6:39 PM, David Nebenzahl wrote: I'm looking for an online electronics forum (web-based) where I can post some questions. I think you have to refine your overall goals/interests. There are many places you can find out "how to use an op amp" (or, "how an op amp works", etc.). But, what you *want* to use that op amp for is probably where you will get far more pertinent information/advice if you can refine your needs better. Be that as it may, I went ahead and joined the first forum that was suggested here (Electro-Tech Online, http://www.electro-tech-online.com) and whaddya know, I got answers--pretty good ones--within an hour that allowed me to get parts of my project working. Maybe it's not the Great! Then you're set -- for now. definitive, be-all and end-all of understanding op amp operation that No, quite the contrary. If you know *everything* about op amps, then there is no difference between applications -- because you already know all the little details that differentiate one type of application from another. My point was, if you find a group that is dealing with the same types of applications that you are wanting to address, then they will have already tweaked the "oversimplification" of what an op amp is by appending "... except, you have to do ________ when you use it *this* way _______" to that description. I.e., they will have highlighted the details that are important in *that* type of application (e.g., if you are running with a single supply instead of balanced supplies, needing more voltage compliance in your output than the op amp can provide, etc.) Most of "design" is figuring out which details to *ignore* and which to *pursue*. A group of folks working on similar applications will have already sorted that out for you. [I recall designing (passive) speaker crossover networks with a friend at school. He always had "50 ..." as his expressions. I finally asked him where the heck he kept coming up with this "50"?? Ans: 2 * pi * 8 ohms (more or less) D'oh! you seem to be suggesting, but that isn't what I asked for anyhow. I'm just trying to muddle through at this point. Actually, I have a pretty good textbook which probably has all the answers I need, if I can only understand them: Albert Malvino's /Electronic Principles/ (actually fished out of a dumpster!). It's extremely well-written and explains all about op amp operation, including the four feedback configurations (SP/SS/PP/PS), calculating gain and impedance, and various op amp applications. Now if I can only get over having to deal with the math (ugh!) ... I started with Senturia & Wedlock's _Electronic Circuits and Applications_ (and, before that, just reading data sheets). It was one of those "good" books that predated the "sold by the pound" trend that seems to have infected "modern" writing : (though it was $20+ about 35 years ago!) There also were "Made Simple" books aeons ago (When Dinosaurs Walked the Earth). These were the precursors of the "For Dummies" books -- but infinitely more intense! Highly condensed but very good to get exposed to a lot in very few pages. (e.g., "Electronics Made Simple") |
#42
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Recommendation for electronics forums?
On Sun, 20 Mar 2011 11:03:15 -0700, D Yuniskis
wrote: On 3/20/2011 10:18 AM, Jeff Liebermann wrote: On Sun, 20 Mar 2011 05:09:04 +0000 (UTC), "Geoffrey S. Mendelson" wrote: David Nebenzahl wrote: I'm looking for an online electronics forum (web-based) where I can post some questions. Get a ham license. Then you can find people who actively design and build things, like to talk about them and would gladly help you. Locally, we have about 2800 licensed hams in the county, of which I would guess about 500 are at least semi-active, 100 regularly attend various club meetings, 50 bother to build things, and perhaps 4 are qualified to design anything useful. Expressed in your characteristic "dry" manner... : I try not to get excited about such things. But, illustrates the point, well. Yet, doesn't say how accessible those "4" are nor where their interests lie. Actually, very accessible, if they're interested. We have a local startup, Elecraft, that makes ham radio kits and accessories. Most of the qualified hams in the area are now working for them. http://www.elecraft.com There's not much design work being done locally, but the engineers and techs certainly know how the radios operate. E.g., you would be hard-pressed to get me to help you design an audio amp out of discretes -- but, could probably keep me obsessed with trying to cut power consumption by half a milliwatt on a battery powered device! (and I'm a *helpful* soul ;-) I have a similar problem. When I was still designing electronics, the major obsession was reducing the cost. At that time, it meant reducing the component count. If you get my attention, I can waste enormous amounts of time, on futile exercises in component count reduction. Same with unusual ways to implement simple things. A lot also depends on how dense that population of "experts" is, as well. E.g., our county is 9,200 sq mi with a population of just over 1,000,000. So, 90 people / sq mile. *If* we have those 2800 hams, here (no idea), that would be one ham for every 4 sq mi. That can make accessing that "expert" a bit problematic (I find learning is usually faster "in person"). You can get a fair idea of the number of hams by diving into the FCC ULS database and searching for counts by your local zip codes. http://wireless2.fcc.gov/UlsApp/UlsSearch/searchAmateur.jsp For 95005 (Ben Lomond, CA), it shows 61 licenses. Unfortunately, the FCC updates the data perhaps every 10 years, so some hams that have moved out or died are still listed. And, if the hams (and population, in general) are not evenly distributed throughout the county, it only gets worse (potentially). Worse, most hams seem to live in post office boxes. E.g., there are *no* electronic suppliers, here, within driving distance. The closest possible (overpriced) retailer is clear across town (and would never have the types of components that I am interested in). We have one local supplier (other than Radio Shock). They're expensive, but not outrageous. http://www.santacruzelectronics.com This is the age of specialization. Exactly! The days of being able to keep a drawer full of transistors, diodes, resistors, etc. and hack together an amplifier -- or a logic gate (!) -- are long behind us. Yep. Just finding the part in my mess is difficult. However, I do have a fairly good collection of 1980's vintage discrete parts, which are useful for raising the dead and repairing the antiques. One problem with specialization is that it tends to create some rather bizarre implementations. I once reverse engineered a microprocessor design that could have been replaced by a quad op amp. Sure, you can still do it, but there is no point. I can recall building 8 digit counters out of discretes with nixie displays... would I bother wasting my time on that *now*?? (though I *have* been sorely tempted to build a Difference Engine). Hint: I never build or design anything that I can't sell or turn into a sellable product. When I do build something for myself, I usually build 3 to 5 extras, to sell to friends and recover my expenses. Expertise in PCB layout is a must. Note that it's still possible to have fun with electronics: "How to blow up a microwave" http://www.youtube.com/watch?v=V9Gn0auLFUA -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#43
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Recommendation for electronics forums?
On 3/20/2011 2:00 PM Meat Plow spake thus:
On Sun, 20 Mar 2011 14:47:36 -0800, David Nebenzahl wrote: On 3/20/2011 1:10 AM Michael A. Terrell spake thus: David Nebenzahl wrote: I'm looking for an online electronics forum (web-based) where I can post some questions. news:sci.electronics.basics or news:sci.electronics.design are both good. You get more hand holding in the .basic group, but you see the same people from the .design group. They have more patience on the .basic group which is intended to teach electronics, while the .design group is to trade ideas between professional designers. How did you miss that I specifically requested an online forum, not other Usenet newsgroups? It's right up there in the very first sentence I wrote, for chrissakes. Remember Dave, honey attracts more flies than vinegar I'll be sure to remember that next time I want to attract a bunch of flies! -- The phrase "jump the shark" itself jumped the shark about a decade ago. - Usenet |
#44
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Recommendation for electronics forums?
On Sun, 20 Mar 2011 11:42:01 -0700, mike wrote:
Locally, we have about 2800 licensed hams in the county, of which I would guess about 500 are at least semi-active, 100 regularly attend various club meetings, 50 bother to build things, and perhaps 4 are qualified to design anything useful. While it's possible to get some help with design and construction from ham radio, it really depends on whom you contact. Valid point, although I think you exaggerate a bit. I'm fairly sure about the 2800 hams in Santa Cruz County. The other numbers are from many years of experience dealing with exactly the issues that were mentioned. For example, the local electronics dealer (Santa Cruz Electronics) often sends me customers who need some expertise beyond what could be provided by the counter sales person, but not so much that it would require a consulting contract. Much of the stuff people want designed already exists. Other time, I end up building some abomination for yet another get rich quick scheme. Sometimes, I have to ask for help (i.e. I'm a lousy programmer), so I have a clue as to how many locals are available and able to help. Of course, since I'm a member of both SCZ County radio clubs, I know how many of those are hams. My numbers might be off perhaps +/- 25%, but not much more. Now, give those same numbers for the denizens of sci.electronics.repair. Maybe two numbers, with and without the profuse few who insist on pushing the SNR toward zero. Well, if you mean topic drift, you're discussing the problem with the chief culprit. If the original question is boring or of little interest, I simply change the topic. If the OP wants his question answered, he can simply rephrase it so that it's more interesting and less boring. I'd also like to hear your estimate of the percentage that even attempt to add USEFUL new information that helps answer the original question. That's easy. Just grep through the answers and see how many answers supply calculations, numbers, references, and specifics. It won't be many, but if you look hard, you may find some specific answers. URL's don't count because most people don't explain why the URL should be read. In my case, I always try to add something useful to my answers. It may not answer the original question, but it should be at least interesting. Percentages by post will be different than percentage by author. True. Quantity is a bad substitute for quality. Just ignore the quantity of my words and postings. And the percentage that just want to argue for the sake of arguing, name calling, backstabbing, "hey look how smart I think I am", etc. That would be 100%. I doubt that everyone is interested in helping the OP as much as grandstanding, ego inflation, or some kind of power trip. It's a futile effort, but it's still commonly practiced. My motivation varies radically by the day. For example, todays endless drivel is justified by my procrastinating on working on my income taxes. Other days, I'm don't have a clue about the original question, but am sufficiently interested in the topic to do the necessary research on the topic, and present a passable summary of what I've found. In rare cases, I may have some experience or knowledge about the topic, and deign to pontificate about it. Whatever works. On any subject, it's important to ask someone who knows what he's talking about. Not really. I ask very few questions. My last attempt resulted in demonstrating how I can ignore the obvious by installing several polarized capacitors backwards. http://802.11junk.com/jeffl/crud/GX520-bad-caps.jpg Even so, there were plenty of wrong answers supplied by various people trying to be helpful. In most cases, I can eliminate the clueless by simply looking at the writing style. No numbers means no clue. One line answers means no thinking was involved in crafting the answer. Pontifications without substantiation means that they're not really certain about their answer or their abilities. I don't even bother with RTFM type answers. However, I'm perfectly willing to grovel through the garbage for an answer and NEVER pass judgment on the author. The reason dates back to my introduction to usenet, where I managed to accidentally insult a well known expert, who didn't have the time or interest to offer more than a general clue. Incidentally, I've seen more wrong answers by established experts, who are either too much in a hurry to supply a complete answer, or make assumptions that the reader may not be able to catch. Unfortunately, there are precious few of them. On the contrary. Everyone is an expert on something. Where the problems start are when they go out of their area of expertise. The recent discussions on nuclear reactors in various forums is a great example. Most of those posting are perfectly competent in their areas of expertise, but rather marginal when discussing nuclear power. Similarly, the amazing number of climate experts in the global warming discussion should make one wonder how there can possibly be so many climate experts in a field that didn't really exist more than perhaps 10 years ago. Incidentally, ever notice that the more insignificant the question, the more answers are supplied. Really well written and important questions, rarely get any attention. Most get drowned out by the multitude. At the bottom of every dumpster is a diamond. It's yours if you're willing to dig through the muck. Some of them ARE hams. Sure. However, the typical 10 minute monologue on 80 meters doesn't offer much of an endorsement. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#45
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Recommendation for electronics forums?
On Sun, 20 Mar 2011 19:39:12 +0000 (UTC), "Geoffrey S. Mendelson"
wrote: BTW, did Don Lancaster ever update his "OP Amp Cookbook"? Geoff. As far as I can determine from Googling, the 3rd and last edition was published in 1986. Hmmm... that's odd. It's not listed: http://www.tinaja.com/books/bkdons.asp -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#46
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Recommendation for electronics forums?
David Nebenzahl wrote: On 3/20/2011 1:10 AM Michael A. Terrell spake thus: David Nebenzahl wrote: I'm looking for an online electronics forum (web-based) where I can post some questions. Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying to educate myself here, am working on a project, and a web forum that allows one to post pictures would be better for my purposes. At least I'd like to try it. (The subject of my current research is the ins and outs of op amps.) news:sci.electronics.basics or news:sci.electronics.design are both good. You get more hand holding in the .basic group, but you see the same people from the .design group. They have more patience on the .basic group which is intended to teach electronics, while the .design group is to trade ideas between professional designers. How did you miss that I specifically requested an online forum, not other Usenet newsgroups? It's right up there in the very first sentence I wrote, for chrissakes. My suggestion still stands. Online forums drop like flies, so I've stopped even trying to find one that's useful. Do whatever you like. -- You can't fix stupid. You can't even put a Band-Aid™ on it, because it's Teflon coated. |
#47
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Recommendation for electronics forums?
On Sun, 20 Mar 2011 00:16:07 -0400 "Michael A. Terrell"
wrote in Message id: : Smitty Two wrote: In article , David Nebenzahl wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. |
#48
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Recommendation for electronics forums?
JW wrote: On Sun, 20 Mar 2011 00:16:07 -0400 "Michael A. Terrell" wrote in Message id: : Smitty Two wrote: In article , David Nebenzahl wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. -- You can't fix stupid. You can't even put a Band-Aid™ on it, because it's Teflon coated. |
#49
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Recommendation for electronics forums?
On Sat, 19 Mar 2011 17:39:54 -0800, David Nebenzahl
put finger to keyboard and composed: I'm looking for an online electronics forum (web-based) where I can post some questions. Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying to educate myself here, am working on a project, and a web forum that allows one to post pictures would be better for my purposes. Here in Australia most ISPs offer free web space to their users. I use my web space to post pictures and other binary data. Is that an option for you? - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#50
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Recommendation for electronics forums?
On 3/21/2011 1:10 PM Franc Zabkar spake thus:
On Sat, 19 Mar 2011 17:39:54 -0800, David Nebenzahl put finger to keyboard and composed: I'm looking for an online electronics forum (web-based) where I can post some questions. Don't get me wrong: I love, and usually prefer, Usenet. But I'm trying to educate myself here, am working on a project, and a web forum that allows one to post pictures would be better for my purposes. Here in Australia most ISPs offer free web space to their users. I use my web space to post pictures and other binary data. Is that an option for you? It's an option I'm already using. Well, not through my ISP, but using one of the dozens of free photo hosting sites out there. In fact, the forum I'm using (see below) doesn't let me post pictures directly, so I have to first post them to a hosting site, then give a link to the picture in the forum posting. A little cumbersome, but not too bad. The thing I like about the web forums (I'm using Electro-Tech now, as suggested above) is that you can post pictures *in your message*. What a concept! So rather than dicking around with "binary" newsgroups (which I don't use anymore since I stopped downloading pron), I can post schematics, etc., right in the message. As I said, I still prefer Usenet for most online communication. But these newfangled Web thingies sure have their good points. -- The current state of literacy in our advanced civilization: yo wassup nuttin wan2 hang k where here k l8tr by - from Usenet (what's *that*?) |
#51
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Recommendation for electronics forums?
In article ,
Jeff Liebermann wrote: On Sun, 20 Mar 2011 19:39:12 +0000 (UTC), "Geoffrey S. Mendelson" wrote: BTW, did Don Lancaster ever update his "OP Amp Cookbook"? Geoff. As far as I can determine from Googling, the 3rd and last edition was published in 1986. Hmmm... that's odd. It's not listed: http://www.tinaja.com/books/bkdons.asp That's because Walter Jung wrote it. Mark Zenier Googleproofaddress(account:mzenier provider:eskimo domain:com) |
#52
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Recommendation for electronics forums?
On 3/21/2011 5:31 PM, David Nebenzahl wrote:
On 3/21/2011 1:10 PM Franc Zabkar spake thus: On Sat, 19 Mar 2011 17:39:54 -0800, David Nebenzahl put finger to keyboard and composed: I'm looking for an online electronics forum (web-based) where I can post some questions. Snipped DutchForce is a good one: http://www.dutchforce.com/~eforum/index.php? |
#53
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Recommendation for electronics forums?
Michael A. Terrell wrote:
Smitty Two wrote: In article , David Nebenzahl wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback |
#54
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Recommendation for electronics forums?
Wiebe Cazemier wrote: Michael A. Terrell wrote: Smitty Two wrote: In article , David Nebenzahl wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback Not if you're at unity gain... -- You can't fix stupid. You can't even put a Band-Aid™ on it, because it's Teflon coated. |
#55
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Recommendation for electronics forums?
Michael A. Terrell wrote:
The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback Not if you're at unity gain... But then you'll run into oscillation |
#56
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Recommendation for electronics forums?
Wiebe Cazemier wrote: Michael A. Terrell wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback Not if you're at unity gain... But then you'll run into oscillation Everyone needs to exercise. -- You can't fix stupid. You can't even put a Band-Aid™ on it, because it's Teflon coated. |
#57
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Recommendation for electronics forums?
Michael A. Terrell wrote:
Wiebe Cazemier wrote: Michael A. Terrell wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback Not if you're at unity gain... But then you'll run into oscillation Everyone needs to exercise. To obtain a higher slew-rate? |
#58
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Recommendation for electronics forums?
Wiebe Cazemier wrote: Michael A. Terrell wrote: Wiebe Cazemier wrote: Michael A. Terrell wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback Not if you're at unity gain... But then you'll run into oscillation Everyone needs to exercise. To obtain a higher slew-rate? Or just to keep from rusting, in place. -- You can't fix stupid. You can't even put a Band-Aid™ on it, because it's Teflon coated. |
#59
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Recommendation for electronics forums?
Michael A. Terrell wrote:
Wiebe Cazemier wrote: Michael A. Terrell wrote: Wiebe Cazemier wrote: Michael A. Terrell wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback Not if you're at unity gain... But then you'll run into oscillation Everyone needs to exercise. To obtain a higher slew-rate? Or just to keep from rusting, in place. I've run out of bandwidth... |
#60
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Recommendation for electronics forums?
Wiebe Cazemier wrote: Michael A. Terrell wrote: Wiebe Cazemier wrote: Michael A. Terrell wrote: Wiebe Cazemier wrote: Michael A. Terrell wrote: The subject of my current research is the ins and outs of op amps. A little pun, there? A bit bipolar, if you ask me... I dunno, but then again I may be biased. I figured that you were a little off center. Now that's unfair feedback Not if you're at unity gain... But then you'll run into oscillation Everyone needs to exercise. To obtain a higher slew-rate? Or just to keep from rusting, in place. I've run out of bandwidth... You need a wider pipe... -- You can't fix stupid. You can't even put a Band-Aid™ on it, because it's Teflon coated. |
#61
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Recommendation for electronics forums?
Michael A. Terrell wrote:
I've run out of bandwidth... You need a wider pipe... That's what the plumber said... |
#62
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Recommendation for electronics forums?
Wiebe Cazemier wrote: Michael A. Terrell wrote: I've run out of bandwidth... You need a wider pipe... That's what the plumber said... The 'Watergate plumbers' used tape. -- You can't fix stupid. You can't even put a Band-Aid™ on it, because it's Teflon coated. |
#63
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Recommendation for electronics forums?
The Virtual Electronics Club Is established to support Engineers with creative and innovative ideas and build a unique electronics culture among their members to build and design electrical circuits. Virtual Electronics Club is the world's #1 source for sharing ideas on electronics, get news on electronics, interviews, electronics projects, videos, tool reviews and more!
http://www.virtualelectronicsclub.com/ |
#65
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Recommendation for electronics forums?
"learn electronics" wrote in message ... The Virtual Electronics Club Is established to support Engineers with creative and innovative ideas and build a unique electronics culture among their members to build and design electrical circuits. Virtual Electronics Club is the world's #1 source for sharing ideas on electronics, get news on electronics, interviews, electronics projects, videos, tool reviews and more! http://www.virtualelectronicsclub.com/ YEAH, BUT CAN I GO THERE AND TALK ABOUT RAEANNE BEING A MUDSHARK? |
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