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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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#1
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Just Joined!
Hey everyone!
Just joined and wanted to let everyone know. I'm looking forward to hearing different ways to fix electronics. Have had some bad luck lately-with the xbox 360, my p2 and some cell phones!! |
#2
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On Mon, 20 Jul 2009 15:30:19 -0700, Mike wrote:
Hey everyone! Just joined and wanted to let everyone know. I'm looking forward to hearing different ways to fix electronics. Have had some bad luck lately-with the xbox 360, my p2 and some cell phones!! Welcome! Not sure what a P2 is, but the others are quite sophisticated. Please take a good look (longer is better) at the Repair FAQ: http://www.repairfaq.org/ How much technical knowledge do you have? (A trial question: How do you connect a better DMM to measure current?) It's also important to learn how not to damage what you're trying to fix. Having worked in industry, I'm almost fanatical about wrist ground straps. You seem to have the enthusiasm and desire, and that surely helps! -- Nicabod =+= Waltham, Mass. Who's been involved in electronics in some way since 1942 |
#3
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On Mon, 20 Jul 2009 15:30:19 -0700, Mike wrote: Hey everyone! Just joined and wanted to let everyone know. I'm looking forward to hearing different ways to fix electronics. Have had some bad luck lately-with the xbox 360, my p2 and some cell phones!! You don't really 'join' usenet newsgroups. They are not web-based moderated forums. You just access any group you fancy, and go ahead and post questions as a new thread, or append answers or comments to existing threads. It's usually a good idea to check a group's FAQs, to see what is and what isn't considered good practice and manners for that group. That said, sci.electronics.repair is pretty tolerant, and has a good collection of regular posters and contributors from a number of electronics related disciplines, as well as many amateurs from a wide range of backgrounds with skill levels from dabbler to accomplished tech. A degree of off-topic subject discussion is tolerated as 'bar room chatter', but usually only once a thread has been running for a while, and the central issues have been thrashed to death :-) Oh, and remember that contributions to newsgroups are world wide, so be careful how you phrase yourself. What might sound like a tongue in cheek comment to you, might sound very offensive to the person it's directed at .... Have fun, and don't be afraid to jump in. All (most !!) contributors are very welcome. Arfa |
#4
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In article ,
"Arfa Daily" wrote: You don't really 'join' usenet newsgroups. They are not web-based moderated forums. But they appear so to google groupers. Mike, use google to search out the word "usenet." Once you've figured out where the hell you are, find a way to get here other than through google's half-assed portal. Most regulars here block all google groupies. |
#5
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On Mon, 20 Jul 2009 15:30:19 -0700 (PDT), Mike
wrote: Hey everyone! What would you do if everyone responded? Just joined and wanted to let everyone know. I'm looking forward to hearing different ways to fix electronics. Have had some bad luck lately-with the xbox 360, my p2 and some cell phones!! Join? One does not join a Usenet newsgroup. Perhaps "enlist" might be a better term. Well, there are many ways to fix electonics. My motto is "Learn By Destroying". I've even registered the domain name. Basically, one doesn't really understand how something works until after they've destroyed it, and frantically attempted to repair it before the spouse, customer, or owner finds out. Any method of destruction is acceptable as real learning ocurrs only after the destruction. Blaming bad luck on lack of repair success would be acceptable is the repair industry operated like Las Vegas. This is not the case, so luck only plays a small part. Undertanding, dilligence, documentation, and knowing someone with a clue and a large parts collection is far more important than luck. The xbox 360 and some computah motherboards have problems with lousy BGA soldering. There are several videos on YouTube showing how to reflow the CPU. I use a hot air soldering iron and hot plate as shown he http://www.youtube.com/watch?v=ndeq6cAA8MY I also use an infra-red optical thermometer to monitor temperature. There are other videos showing using a bottle cap with burning cotton and alcohol. It works, but with with a very low batting average. I guess the P2 is a PS2 or Playstation 2. (11th commandment.... Thou shalt not abrev). There's plenty on the web on how to fix most anything. For example: http://www.ps2repair.com/PS2.htm Use Google find more. Cell phones are something I fix in my non-existent spare time. They're usually quite easy, especially when most of the damage is mechanical. If it moves, it breaks. However, the average life of a cell phone is 18 months and the cost of commodity cell phones is so low, that it's often not worth fixing. http://802.11junk.com/jeffl/pics/office/slides/radio-mess.html Hopefully, I've given you enough clues so that you can destroy electronics in a deliberate and organized manner. That should teach you enough so that you're able to avoid old mistakes on the next repair. |
#6
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"Smitty Two" wrote in message news In article , "Arfa Daily" wrote: You don't really 'join' usenet newsgroups. They are not web-based moderated forums. But they appear so to google groupers. Mike, use google to search out the word "usenet." Once you've figured out where the hell you are, find a way to get here other than through google's half-assed portal. Most regulars here block all google groupies. Hi Smitty ! How's it going ? Yeah, you're right - I'd forgotton that and was lazy enough not to check ... I've come across quite a few web-based forums now, that 'tap into' usenet, without the members being aware that's what's happening. Still, if a few of these replies find their way back, at least some of the people might get the idea that there are much better ways to access newsgroups ... Arfa |
#7
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In article ,
"Arfa Daily" wrote: "Smitty Two" wrote in message news In article , "Arfa Daily" wrote: You don't really 'join' usenet newsgroups. They are not web-based moderated forums. But they appear so to google groupers. Mike, use google to search out the word "usenet." Once you've figured out where the hell you are, find a way to get here other than through google's half-assed portal. Most regulars here block all google groupies. Hi Smitty ! How's it going ? Yeah, you're right - I'd forgotton that and was lazy enough not to check ... I've come across quite a few web-based forums now, that 'tap into' usenet, without the members being aware that's what's happening. Still, if a few of these replies find their way back, at least some of the people might get the idea that there are much better ways to access newsgroups ... Arfa I'm waging a profane campaign against the web forums on another n.g. It's not a "service" to their readers, it's just viral advertising. Many of the posts are shills put up by the site's operator. |
#8
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Jeff Liebermann wrote:
Well, there are many ways to fix electonics. My motto is "Learn By Destroying". I've even registered the domain name. Basically, one doesn't really understand how something works until after they've destroyed it, and frantically attempted to repair it before the spouse, customer, or owner finds out. grin I blew up my mother's TV when I was about 14 (I'd run a tap into it for composite video, but it was a live-chassis unit - I'm sure you can guess the failure mode...), & managed to fix it before she got home. (Only a transistor & a few resistors, thank god.) Boy, was that educational! Mind you, that was back in the days when TV's came with a schematic. Any method of destruction is acceptable as real learning ocurrs only after the destruction. Too true. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#9
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On Sat, 25 Jul 2009 23:32:00 +1000, Bob Larter
wrote: Jeff Liebermann wrote: Well, there are many ways to fix electonics. My motto is "Learn By Destroying". I've even registered the domain name. Basically, one doesn't really understand how something works until after they've destroyed it, and frantically attempted to repair it before the spouse, customer, or owner finds out. grin I blew up my mother's TV when I was about 14 (I'd run a tap into it for composite video, but it was a live-chassis unit - I'm sure you can guess the failure mode...), & managed to fix it before she got home. (Only a transistor & a few resistors, thank god.) Boy, was that educational! Mind you, that was back in the days when TV's came with a schematic. Huh? Transistors in a TV with an AC-DC power supply? I doubt it. That was the case with some tube type TV's and of course, the classic 5 tube radio, but not xsitorized TV's. Any method of destruction is acceptable as real learning ocurrs only after the destruction. Too true. My first experience was not electronic in nature. I was about 12 years old. We had a wind up mechanical clock on the mantle which caught my attention. I wanted to know what made it tick, literally. When the main spring went "sprong!", I knew that I had seriously erred. I attempted to repair the damage, with no useful results. The best I could do was cram all the parts and screws back into the case, and hope that nobody noticed. Unfortunately, the lack of clock hands and the lack of ticking made it all too obvious that something was amiss. I was duly interrogated by the parents, and after the usual improbable lies failed badly, I confessed. Prior to this incident, every time I destroyed something, my father would do his best to repair the damage. Broken windows, broken toys, broken furniture, etc. This time was different. He demanded that I repair the clock, while he watched. Every evening for perhaps 30 minutes (the limit of my attention span), I would sit with the guts of the clock on the kitchen table, while my father introduced me to the art of using small tools, deducing function, puzzle theory, search for parts on the floor, and how a clock should work. Invaluable advice was offered such as "if you don't know how it works, you probably can't fix it". While I fumbled, my father patiently watched, while sitting on his hands. When I later asked why he was sitting on his hands, he replied to was to keep from strangling me to relieve the frustration of watching my inept fumbling. I don't recall if I ever really fixed the clock. It was returned to the mantle, but only ran erratically. We usually let it run down so it wouldn't make so much noise. After my first experience in "Learn by Destroying", as long as I put it back together, it was perfectly acceptable to destroy things for no better reason than to see how it worked. At one point, I applied the process to rebuilding a 1960 Ford Falcon engine, in the driveway. It took 4 months. This was also where I decided RTFM is a futile exercise as the shop manual was nearly useless. Such destruction and resurrection exercises are a basic requirement to later obtaining expertise and proficiency in the repair and engineering biz. I've met people that failed to has such childhood experiences, that have 5 thumbs on each hand, and are unable to use tools other than a hammer. Those that failed the "Learn by Destroying" test, can become attorneys, programmers, and decision manufacturers. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#10
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Jeff Liebermann wrote:
On Sat, 25 Jul 2009 23:32:00 +1000, Bob Larter wrote: Jeff Liebermann wrote: Well, there are many ways to fix electonics. My motto is "Learn By Destroying". I've even registered the domain name. Basically, one doesn't really understand how something works until after they've destroyed it, and frantically attempted to repair it before the spouse, customer, or owner finds out. grin I blew up my mother's TV when I was about 14 (I'd run a tap into it for composite video, but it was a live-chassis unit - I'm sure you can guess the failure mode...), & managed to fix it before she got home. (Only a transistor & a few resistors, thank god.) Boy, was that educational! Mind you, that was back in the days when TV's came with a schematic. Huh? Transistors in a TV with an AC-DC power supply? I doubt it. That was the case with some tube type TV's and of course, the classic 5 tube radio, but not xsitorized TV's. Any method of destruction is acceptable as real learning ocurrs only after the destruction. Too true. My first experience was not electronic in nature. I was about 12 years old. We had a wind up mechanical clock on the mantle which caught my attention. I wanted to know what made it tick, literally. When the main spring went "sprong!", I knew that I had seriously erred. I attempted to repair the damage, with no useful results. The best I could do was cram all the parts and screws back into the case, and hope that nobody noticed. Unfortunately, the lack of clock hands and the lack of ticking made it all too obvious that something was amiss. I was duly interrogated by the parents, and after the usual improbable lies failed badly, I confessed. Prior to this incident, every time I destroyed something, my father would do his best to repair the damage. Broken windows, broken toys, broken furniture, etc. This time was different. He demanded that I repair the clock, while he watched. Every evening for perhaps 30 minutes (the limit of my attention span), I would sit with the guts of the clock on the kitchen table, while my father introduced me to the art of using small tools, deducing function, puzzle theory, search for parts on the floor, and how a clock should work. Invaluable advice was offered such as "if you don't know how it works, you probably can't fix it". While I fumbled, my father patiently watched, while sitting on his hands. When I later asked why he was sitting on his hands, he replied to was to keep from strangling me to relieve the frustration of watching my inept fumbling. I don't recall if I ever really fixed the clock. It was returned to the mantle, but only ran erratically. We usually let it run down so it wouldn't make so much noise. After my first experience in "Learn by Destroying", as long as I put it back together, it was perfectly acceptable to destroy things for no better reason than to see how it worked. At one point, I applied the process to rebuilding a 1960 Ford Falcon engine, in the driveway. It took 4 months. This was also where I decided RTFM is a futile exercise as the shop manual was nearly useless. Such destruction and resurrection exercises are a basic requirement to later obtaining expertise and proficiency in the repair and engineering biz. I've met people that failed to has such childhood experiences, that have 5 thumbs on each hand, and are unable to use tools other than a hammer. Those that failed the "Learn by Destroying" test, can become attorneys, programmers, and decision manufacturers. The first lesson is: "Don't take anything apart that you cannot put back together". which is a subset of "Don't do what you cannot undo". This lesson requires a good deal of "lab time". Most of humanity seldom, if ever, learns this lesson. |
#11
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On Sat, 25 Jul 2009 23:32:00 +1000, Bob Larter
wrote: snip grin I blew up my mother's TV when I was about 14 (I'd run a tap into it for composite video, but it was a live-chassis unit - I'm sure you can guess the failure mode...), & managed to fix it before she got home. (Only a transistor & a few resistors, thank god.) Boy, was that educational! Mind you, that was back in the days when TV's came with a schematic. Jeff Liebermann wrote: Huh? Transistors in a TV with an AC-DC power supply? I doubt it. That was the case with some tube type TV's and of course, the classic 5 tube radio, but not xsitorized TV's. Au contraire, mon ami; in 1979 I added a 75 video input connection (BNC) to a Ward's branded 13 inch color set which did not have a power transformer and I need to use an isolation transformer with it when it was connected to a video source. Michael |
#12
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On Sat, 25 Jul 2009 23:32:00 +1000, Bob Larter
wrote: snip grin I blew up my mother's TV when I was about 14 (I'd run a tap into it for composite video, but it was a live-chassis unit - I'm sure you can guess the failure mode...), & managed to fix it before she got home. (Only a transistor & a few resistors, thank god.) Boy, was that educational! Mind you, that was back in the days when TV's came with a schematic. Jeff Liebermann wrote: Huh? Transistors in a TV with an AC-DC power supply? I doubt it. That was the case with some tube type TV's and of course, the classic 5 tube radio, but not xsitorized TV's. Au contraire, mon ami; in 1979 I added a 75 video input connection (BNC) to a Ward's branded 13 inch color set which did not have a power transformer and I needed to use an isolation transformer with it when it was connected to a video source (IIRC, it had a full wave and not bridge rectifier, with one lead from the AC mains connected to the chassis (through a filter)). I made the mistake of failing to check AC plug polarity one time (without using the isolation transformer) and got a nasty current loop through the video source that fortunately only blew a fuse. Michael |
#13
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On Sat, 25 Jul 2009 10:10:30 -0700, none ""karls\"@(none)" wrote:
The first lesson is: "Don't take anything apart that you cannot put back together". which is a subset of "Don't do what you cannot undo". The phrase "Learn by Destroying" implies that one learns something from the exercise. Apparently, you haven't learned much. Fear of disassembly is what prevents ordinary mortals from becoming competent service personnel. I've dived into many contrivances, where I had no clue as to what I was getting into, much less any clue what I was doing. Sometimes, an astute customer will ask me "Have you ever done this before"? Usually, my answer is no. Lack of expertise and prior experience doesn't bother me. If I understand how it works, or is suppose to work, I can usually figure out what's broken. I learn as I go along. Lack of experience has never stopped me. However, I were worried about reassembly, I probably wouldn't try to fix anything. These days, I take digital photos of the disassembly, and organize the screws so that I can replace them in the original location. I will admit to having some difficulties putting Humpty Dumpty back together again, but it's rare. I recent near disaster was replacing the batter on an Apple iPod Touch 1G. Getting it apart is hell. Putting it back together is worse. I eventually had to clamp the case together between two pieces of wood, and apply excessive force with a pair of vice grips. The risk of breaking the glass was rather high. If I had known what was involved, I'm not sure if I would have attempted the job. However, now that I know how it works, it's no big deal. Anyway, at age 12, one would not expect anyone to know their own limitations. After watching Superman on TV, I tried flying. This lesson requires a good deal of "lab time". Sure. Experience is a good teacher. However, reading the manual, looking at the schematic, and understanding how it works, will dramatically reduce the "lab time". Most of humanity seldom, if ever, learns this lesson. That's why I'm still in business. If the GUM (great unwashed masses) had any interest in getting their hands dirty by tearing into their toys, I would be looking for something else to do. I suspect this is because of the ancient patrician attitude that the upper classes should not have to deal with manual labor. Incidentally, one the secrets to staying in business is the ability to fix anything. Customers call me with computah problems. However, when I arrive, it's not unusual to get involved in other electronic failures. Phone, various audio/visual devices, cell phones, appliances, garage door openers, and such are common repairs. For a while, I was making more money dealing with printer problems than computah. However, last week, I hit the undo button. The customer called with a problem with their ancient Konica copier. 500,000 pages and just about everything is worn out. I've kept it alive by just keeping it clean for about 15 years. So, I made a big show of tearing it apart, proclaiming unsolvable difficulties, overestimating the damage, and then hitting the undo button by returning it to its original malfunctional state. Also, I was seriously considering starting a "black list" of manufacturers and products that are unusually difficult to disassemble and/or repair, or are otherwise designed to discourage repair. It probably won't help make things repairable, but it will highlight the problem. Top of the list are the iPhone and iPod Touch followed by laptop manufacturers that use snap together plastic cases the literally require breaking tabs to disassemble. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#14
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Jeff Liebermann wrote:
On Sat, 25 Jul 2009 10:10:30 -0700, none ""karls\"@(none)" wrote: The first lesson is: "Don't take anything apart that you cannot put back together". which is a subset of "Don't do what you cannot undo". The phrase "Learn by Destroying" implies that one learns something from the exercise. Apparently, you haven't learned much. Fear of disassembly is what prevents ordinary mortals from becoming competent service personnel. I've dived into many contrivances, where I had no clue as to what I was getting into, much less any clue what I was doing. Sometimes, an astute customer will ask me "Have you ever done this before"? Usually, my answer is no. Lack of expertise and prior experience doesn't bother me. If I understand how it works, or is suppose to work, I can usually figure out what's broken. I learn as I go along. Lack of experience has never stopped me. However, I were worried about reassembly, I probably wouldn't try to fix anything. These days, I take digital photos of the disassembly, and organize the screws so that I can replace them in the original location. I will admit to having some difficulties putting Humpty Dumpty back together again, but it's rare. I recent near disaster was replacing the batter on an Apple iPod Touch 1G. Getting it apart is hell. Putting it back together is worse. I eventually had to clamp the case together between two pieces of wood, and apply excessive force with a pair of vice grips. The risk of breaking the glass was rather high. If I had known what was involved, I'm not sure if I would have attempted the job. However, now that I know how it works, it's no big deal. Anyway, at age 12, one would not expect anyone to know their own limitations. After watching Superman on TV, I tried flying. This lesson requires a good deal of "lab time". Sure. Experience is a good teacher. However, reading the manual, looking at the schematic, and understanding how it works, will dramatically reduce the "lab time". Most of humanity seldom, if ever, learns this lesson. That's why I'm still in business. If the GUM (great unwashed masses) had any interest in getting their hands dirty by tearing into their toys, I would be looking for something else to do. I suspect this is because of the ancient patrician attitude that the upper classes should not have to deal with manual labor. Incidentally, one the secrets to staying in business is the ability to fix anything. Customers call me with computah problems. However, when I arrive, it's not unusual to get involved in other electronic failures. Phone, various audio/visual devices, cell phones, appliances, garage door openers, and such are common repairs. For a while, I was making more money dealing with printer problems than computah. However, last week, I hit the undo button. The customer called with a problem with their ancient Konica copier. 500,000 pages and just about everything is worn out. I've kept it alive by just keeping it clean for about 15 years. So, I made a big show of tearing it apart, proclaiming unsolvable difficulties, overestimating the damage, and then hitting the undo button by returning it to its original malfunctional state. Also, I was seriously considering starting a "black list" of manufacturers and products that are unusually difficult to disassemble and/or repair, or are otherwise designed to discourage repair. It probably won't help make things repairable, but it will highlight the problem. Top of the list are the iPhone and iPod Touch followed by laptop manufacturers that use snap together plastic cases the literally require breaking tabs to disassemble. I'm glad to see that you agree with everything I said. |
#15
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The first lesson is: "Don't take anything apart that you cannot put back together". which is a subset of "Don't do what you cannot undo". This lesson requires a good deal of "lab time". Most of humanity seldom, if ever, learns this lesson. However, taking it apart before you *know* that you can put it back together, is an important part of Jeff's 'learn by destruction' method, and a daily part of anyone in the repair business's routine. I've been professionally engaged in repairs for getting on for 40 years, and I still find myself regularly taking apart things that I only *think* that I will be able to reassemble by experience ... Arfa |
#16
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Bob Larter wrote:
grin I blew up my mother's TV when I was about 14 Did you burn your lips? ;-) -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida http://www.flickr.com/photos/materrell/ |
#17
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Arfa Daily wrote:
The first lesson is: "Don't take anything apart that you cannot put back together". which is a subset of "Don't do what you cannot undo". This lesson requires a good deal of "lab time". Most of humanity seldom, if ever, learns this lesson. However, taking it apart before you *know* that you can put it back together, is an important part of Jeff's 'learn by destruction' method, and a daily part of anyone in the repair business's routine. I've been professionally engaged in repairs for getting on for 40 years, and I still find myself regularly taking apart things that I only *think* that I will be able to reassemble by experience ... Arfa If you honestly think you can put it back together, then you are still following the one true path. It is only those who take something apart knowing they will not be able to reassemble it, or sometimes not even thinking ahead that far, who are consigned to outer darkness... I've met these people. Some of them have occasionally given me a cardboard box of pieces, wanting me to make it work again. The digital camera is a wonderful tool for documenting each step of the process, and I use it often. Hurrah for macro focus. Note, as a "TV Repairman" before I got into broadcasting, I was fixing things that belonged to other people. If I destroyed their stuff, I would have had to pay them for it. It was far better economics to know those rare times when one has to say "Sorry, I can't fix this for less than it's replacement cost" and give it back in it's original condition. That doesn't happen very often, I've taken apart and repaired defective motors in tape cassette decks several times, when replacement motors were not available. I've even rewound a power supply transformer once. Sometimes you can't win even if you do fix the problem. I repaired an old clock radio once, (This was in the mid-1970's, in a shop in Wichita, Kansas) and cleaned up its grimy case as well. This revealed an old crack in the plastic, and the owner accused me of breaking his radio. Needless to say, that was not a profitable repair. No good deed goes unpunished... |
#18
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Jeff Liebermann wrote:
On Sat, 25 Jul 2009 23:32:00 +1000, Bob Larter wrote: Jeff Liebermann wrote: Well, there are many ways to fix electonics. My motto is "Learn By Destroying". I've even registered the domain name. Basically, one doesn't really understand how something works until after they've destroyed it, and frantically attempted to repair it before the spouse, customer, or owner finds out. grin I blew up my mother's TV when I was about 14 (I'd run a tap into it for composite video, but it was a live-chassis unit - I'm sure you can guess the failure mode...), & managed to fix it before she got home. (Only a transistor & a few resistors, thank god.) Boy, was that educational! Mind you, that was back in the days when TV's came with a schematic. Huh? Transistors in a TV with an AC-DC power supply? AC only. This was circa 1980, or thereabouts. I doubt it. That was the case with some tube type TV's and of course, the classic 5 tube radio, but not xsitorized TV's. You've never seen transistor + IC TV with a live chassis? - I'm surprised. Bear in mind that this was back in the days when (cheap) TVs didn't have external inputs of any kind, so the manufacturers could save money by not isolating the DC rails from the mains with a transformer. My first experience was not electronic in nature. I was about 12 years old. We had a wind up mechanical clock on the mantle which caught my attention. I wanted to know what made it tick, literally. When the main spring went "sprong!", I knew that I had seriously erred. I attempted to repair the damage, with no useful results. The best I could do was cram all the parts and screws back into the case, and hope that nobody noticed. Unfortunately, the lack of clock hands and the lack of ticking made it all too obvious that something was amiss. I was duly interrogated by the parents, and after the usual improbable lies failed badly, I confessed. Prior to this incident, every time I destroyed something, my father would do his best to repair the damage. Broken windows, broken toys, broken furniture, etc. This time was different. He demanded that I repair the clock, while he watched. My son is at about that stage. I'm not sure that I could be as patient as your father. ;^) -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
#19
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msg wrote:
On Sat, 25 Jul 2009 23:32:00 +1000, Bob Larter wrote: snip grin I blew up my mother's TV when I was about 14 (I'd run a tap into it for composite video, but it was a live-chassis unit - I'm sure you can guess the failure mode...), & managed to fix it before she got home. (Only a transistor & a few resistors, thank god.) Boy, was that educational! Mind you, that was back in the days when TV's came with a schematic. Jeff Liebermann wrote: Huh? Transistors in a TV with an AC-DC power supply? I doubt it. That was the case with some tube type TV's and of course, the classic 5 tube radio, but not xsitorized TV's. Au contraire, mon ami; in 1979 I added a 75 video input connection (BNC) to a Ward's branded 13 inch color set which did not have a power transformer and I needed to use an isolation transformer with it when it was connected to a video source (IIRC, it had a full wave and not bridge rectifier, with one lead from the AC mains connected to the chassis (through a filter)). I made the mistake of failing to check AC plug polarity one time (without using the isolation transformer) and got a nasty current loop through the video source that fortunately only blew a fuse. nods The only differences in my case was that I didn't have an isolation transformer, & blew a few components in the video amp circuit. I was damn lucky that it didn't take out the jungle chip. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
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Michael A. Terrell wrote:
Bob Larter wrote: grin I blew up my mother's TV when I was about 14 Did you burn your lips? ;-) groan Cue the old joke about the Irish terrorist who blew up a bus. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^--------------------------------------------------------------- |
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Bob Larter wrote: Michael A. Terrell wrote: Bob Larter wrote: grin I blew up my mother's TV when I was about 14 Did you burn your lips? ;-) groan Cue the old joke about the Irish terrorist who blew up a bus. In the US, its about a mafia Don's stupid nephew. -- You can't have a sense of humor, if you have no sense! |
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On Mon, 27 Jul 2009 17:03:26 +1000, Bob Larter
wrote: You've never seen transistor + IC TV with a live chassis? - I'm surprised. Bear in mind that this was back in the days when (cheap) TVs didn't have external inputs of any kind, so the manufacturers could save money by not isolating the DC rails from the mains with a transformer. Nope. I never saw one. For good reason as when I was repairing consumer electronics, we just didn't get too many bottom end TV's to fix. I mostly did warranty work on imported tape recorders and hi-fi's with a few odd TV's mixed in. AC-DC xsistor TV repair is one experience I'm glad I missed. Prior to this incident, every time I destroyed something, my father would do his best to repair the damage. Broken windows, broken toys, broken furniture, etc. This time was different. He demanded that I repair the clock, while he watched. My son is at about that stage. I'm not sure that I could be as patient as your father. ;^) His patience and my attention span were both short. We would do the clock repair about 20-30 minutes at a time. It was a race between my tendency to get easily bored, and his frustration with my ineptitude. The real trick was that I had to do it all, with no direct help from my father. That way, I would have some pride in the work. I've semi-convinced some of my friends to do the same with their kids, with mixed results. Incidentally, I got my revenge many years later. I was working for Heathkit, so naturally, I bought my father a Heathkit digital clock kit to build. The roles were reversed. I sat there helping him solder the kit together while I watched and helped. With all the mechanical expertise he taught me, I expected this to be fairly trivial. It wasn't and he struggled with it for several weeks. It eventually worked and I still have the clock. One of my friends is a programmer. His father was an auto mechanic and did not want his son to also become an auto mechanic. Every time his son picked up a tool, his father would take it away. The son grew up to be a very competent programmer, but is a total disaster with anything mechanical. Such things require practice, preferably early in life. Good luck with your son. Despite the attention span problem, the experience is worthwhile. Without it, I'm sure my life would have taken a different direction. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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