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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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Golden Rules of Troubleshooting
Amen to that- the working unit to compare!
I finished the Dynaco ST120 from hell last night. It came to me "fuzzy in one channel". And it was. First run-through: One output transistor in the 'good' channel, one output and one driver in the other, still fuzzy. I wound up ohming out every part, comparing to the good channel. Six drifted resistors later, I got to the 5..1V zener diode. Bingo. It had become a 94 ohm resistor. Given that these beasts blow up by the numbers, I generally install sockets for the outputs, and do the TIP mod once ALL else is under control. Peter Wieck Melrose Park, PA |
#43
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Golden Rules of Troubleshooting
On 12/17/2015 9:56 AM, Jeff Liebermann wrote:
On Wed, 16 Dec 2015 11:34:43 -0800, (Dave Platt) wrote: In article , Jeff Liebermann wrote: However, it also helps to pay attention. Do you see a problem here? http://802.11junk.com/jeffl/crud/GX520-bad-caps.jpg A blue one with a headache. The "bad-caps" is in the URL, so that's rather obvious. However, that's the result, not the problem. The cause is quite obvious once you see it. I posted the picture previously and Phil Allison caught the problem almost instantly. I didn't. Are *all* *four* of those large caps installed backwards?!? Yep. When I do something wrong, I'm consistent. As I previously ranted, when I find one bad cap of a type and value, I replace *ALL* the caps of the same type and value. My time is more expensive than the extra caps. Yah. Amazing you didn't have a chassis full of oily linguine there. Actually, the machine ran quite nicely for a day or two the first time I put the caps in backwards. Eventually, it started acting strangely so I retreived it from the customers. All 4 caps were bulging. So, I replaced all 4 caps again, putting them in backwards again. That's when I noticed that they were getting hot, which prompted my initial Usenet posting. I too would have expected at least a small explosion, but nothing happened. Nice that there were no explosions - I'm sure your customer would have been nonplussed. (ducking from the coffee explosion) John ;-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
#44
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Golden Rules of Troubleshooting
"Jeff Liebermann" wrote in message ... Yep. When I do something wrong, I'm consistent. As I previously ranted, when I find one bad cap of a type and value, I replace *ALL* the caps of the same type and value. My time is more expensive than the extra caps. Yah. Amazing you didn't have a chassis full of oily linguine there. Actually, the machine ran quite nicely for a day or two the first time I put the caps in backwards. Eventually, it started acting strangely so I retreived it from the customers. All 4 caps were bulging. So, I replaced all 4 caps again, putting them in backwards again. That's when I noticed that they were getting hot, which prompted my initial Usenet posting. I too would have expected at least a small explosion, but nothing happened. Interisting it ran at all. It is easy to get into a bad pattern of doing things. A coworker and I were repairing some flouresence lights in the plant. Got to one and put in new tubes and it did not come on. This did not phase us as we often will get a bad tube or so as there are thousands in the plant we often will replace over 100 tubes in a day. Sometimes we get bad tubes so put in another set and still no light. Decided it was the ballast, so replaced that. Still no light. Knew we had power as there were about 20 other lights in the room. Replaced the ballast 2 more times and sitll no light. This ballast had been replaced before as there were several places where the wires were spliced together with wire nuts. One would thing with only 8 wires it would be easy to get it going. Got time to go home. I went up the next day by myself and decided to try one more time. This time I removed all the wires and instead of just going by the color of the wires, actually trace the wiring out. This time it lite just fine. What we were doing wrong was just matching the wire colors and as it had been replaced before the colors did not go to the same place. |
#45
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Golden Rules of Troubleshooting
On Thu, 17 Dec 2015 05:22:59 -0800 (PST), "
wrote: Amen to that- the working unit to compare! I finished the Dynaco ST120 from hell last night. It came to me "fuzzy in one channel". And it was. First run-through: One output transistor in the 'good' channel, one output and one driver in the other, still fuzzy. I wound up ohming out every part, comparing to the good channel. Six drifted resistors later, I got to the 5.1V zener diode. Bingo. It had become a 94 ohm resistor. Given that these beasts blow up by the numbers, I generally install sockets for the outputs, and do the TIP mod once ALL else is under control. Peter Wieck Melrose Park, PA Peter, Who in their right mind would still be using one of these? They were considered to be an awful amps back in the 70s. One I saw burned down a house. The carbon resistors caught fire and there happened to be a curtain draped across the top of the amplifier. After seeing this amp, I refused to work on them. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#46
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Golden Rules of Troubleshooting
On Wed, 16 Dec 2015 20:13:52 -0600, "Shaun"
wrote: "Cursitor Doom" wrote in message ... 1. Assume nothing. 1a. Trust nobody (except your certificate authority). 1b. Believe no one. 1c. Presume nothing. 1d. Ignore fashionable explanations. 1e. Distrust authority. 1f. Ignore all advice. 1g. Test all new replacement components. 2. If at first you don't succeed, destroy any evidence that you even tried! I never make the same mistake twice. Five or six times is my average. 3. Try Percussive maintenance first. If it works after you bang it, it has intermitant connections, or components. Nope. Clean the device first. Depending on the type of filth, that can be blowing off the dust with compressed air, or washing with a household cleaner to remove fingerprints, dirt, crud, slime, food, whatever. Cleaning allows you time to inspect the device, where you might visually find the problem. Often, the problems go away with the filth. Customers don't believe that anything has been repaired unless it's clean. Instead of beating on the box, try turning it upside down and shaking. If you hear something rattle around, you've either found the problem, or what's left of some component. Loose screws and spare parts on new electronics are amazingly common. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#47
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Golden Rules of Troubleshooting
Ah, they ain't no how as bad as all that these days. Between the various mods, Factory and susequent, they have been rendered pretty bullet-proof, very stable, and as simple SS amps go, fairly melifluous. They were made in the uncounted tens of thousands, and uncounted thousands survive. With a few hours of simple work and not much cost, a decent 50+ watt amp may be had. As it happens, I keep two (full mods) that see very rough service, and have done so in one case for 2 years of 24/7 use in a desert climate, not conditioned. 100F+ from may to November. It now sits in my shop system seeing about 3 hours per week, these days.
Who would put a curtain over an amp capable of frying an egg in the first place?? That smacks of terminal idiocy. Peter Wieck Melrose Park, PA |
#48
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Golden Rules of Troubleshooting
Ralph Mowery wrote:
"Cydrome Leader" wrote in message ... I helps to try to figure out what a device should do when it is working. Extracting this information is sometimes really hard when people are fixating on what's broken and keep talking in circles. I got a call at the plant I worked at from an equipment operator. When I got there he said an indicator light would not come on. He had changed bulbs and even swappend a glowing one with the one that would not come on to show me it was not the bulb. I asked him about the equipment as I did not know anything about it. He said he presses one button and a light comes on , then he presses the second button and another light comes on, but now the second light would not come on. As this was just in a control room and the equipment could be located anywhere in the plant I asked him several times about the equipment and all I could get out of him was he just pressse the buttons and the lights should come. He did not seem to know where the equipment was, just the indicator lights.. Give him credit for at least swapping out indicator bulbs. |
#49
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Golden Rules of Troubleshooting
Ralph Mowery wrote:
"Cydrome Leader" wrote in message ... I've stared at well written service manuals (these actually exist, but tend to be old) that just made no sense until the next day, or after a break. Not a fan of touching service manuals with diry hands either. Where I worked we had a copy machine in the shop and I would usually copy the important pages of the service manual to take with me. Usually had them already copied in a book I kept so I could fine the important pages quick and took a copy of that with me. The electrical blue prints for much of the wiring and some equipment was on a computer and we had a large plotter so could run off what we needed to take with us. Sometimes I would make notes on the copies and leave them in the electrical cabinet, or just write inside the cabinet with a marking pen. There always seems to come a point when people stop updating the stickers inside the cabinet or the service books with all updates, past problems and more importantly field modifications and why they were done. This seems to happen around the time the safety switches start wear out and get bypassed or panels and covers start to go missing. |
#50
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Golden Rules of Troubleshooting
On Tue, 15 Dec 2015 18:31:14 -0500, "Ralph Mowery"
wrote: Sometimes I would make notes on the copies and leave them in the electrical cabinet, or just write inside the cabinet with a marking pen. What? You don't like my method of documenting changes? http://members.cruzio.com/~jeffl/k6bj/K6BJ%20Repeater/slides/Documentation.html I think it's been like that since at least 2001. Incidentally, I use a special ink for the purpose, that fades to invisibility in about a year. It helps keep the manuals nice and clean. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#51
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Golden Rules of Troubleshooting
wrote in message
... Ah, they ain't no how as bad as all that these days. Between the various mods, Factory and susequent, they have been rendered pretty bullet-proof, very stable, and as simple SS amps go, fairly melifluous. They were made in the uncounted tens of thousands, and uncounted thousands survive. With a few hours of simple work and not much cost, a decent 50+ watt amp may be had. As it happens, I keep two (full mods) that see very rough service, and have done so in one case for 2 years of 24/7 use in a desert climate, not conditioned. 100F+ from may to November. It now sits in my shop system seeing about 3 hours per week, these days. Who would put a curtain over an amp capable of frying an egg in the first place?? That smacks of terminal idiocy. Peter Wieck Melrose Park, PA Personally I wouldn't use an ST-120 simply because I find capacitor-coupled amps to sound muddy, and yeah - I hated working on the things. Piece of crap really. Prefer direct-coupled amps (with a competent protection circuit!) although I do like an autoformer coupled McIntosh... Mark Z. |
#52
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Golden Rules of Troubleshooting
On Friday, December 18, 2015 at 7:37:37 AM UTC-5, Mark Zacharias wrote:
Prefer direct-coupled amps (with a competent protection circuit!) Mark Z. Funny how certain things trigger a memory of something forgotten for years. I had a Hitachi brand receiver that the customer said blew out several speakers on one side. I checked the outputs, nothing shorted so I hooked up some cheap TV speakers at low volume and there was no DC to speak of on either side and it was clean and clear. I let it run a couple of hours and suddenly there was a loud hum, pop, and one TV speaker that puked it's voice coil. This was direct coupled amp with no type of speaker protection. Ended up junking it. |
#53
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Golden Rules of Troubleshooting
Jeff Liebermann wrote:
On Tue, 15 Dec 2015 18:31:14 -0500, "Ralph Mowery" wrote: Sometimes I would make notes on the copies and leave them in the electrical cabinet, or just write inside the cabinet with a marking pen. What? You don't like my method of documenting changes? http://members.cruzio.com/~jeffl/k6bj/K6BJ%20Repeater/slides/Documentation.html I think it's been like that since at least 2001. ha. Love the metal can transistor diagram. At least these aren't drawn on paper bags or cardboard and then thrown away. Incidentally, I use a special ink for the purpose, that fades to invisibility in about a year. It helps keep the manuals nice and clean. They should make heated pens for writing on thermal paper. |
#54
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Golden Rules of Troubleshooting
On Fri, 18 Dec 2015 20:31:53 +0000 (UTC), Cydrome Leader
wrote: Jeff Liebermann wrote: On Tue, 15 Dec 2015 18:31:14 -0500, "Ralph Mowery" wrote: Sometimes I would make notes on the copies and leave them in the electrical cabinet, or just write inside the cabinet with a marking pen. What? You don't like my method of documenting changes? http://members.cruzio.com/~jeffl/k6bj/K6BJ%20Repeater/slides/Documentation.html I think it's been like that since at least 2001. ha. Love the metal can transistor diagram. At least these aren't drawn on paper bags or cardboard and then thrown away. That scribbling wasn't one of mine. I usually draw an isometric scribbling of the transistor or IC so that one can tell if it's a top or bottom view. I think the red markings on the various drawings are mine. Red is useful because it disappears when copied. Incidentally, I use a special ink for the purpose, that fades to invisibility in about a year. It helps keep the manuals nice and clean. They should make heated pens for writing on thermal paper. Ummm... They do. It's called a soldering iron. However, there's a trick to using a soldering iron for writing. Be sure to grab the correct end of the soldering iron. The rest is self evident and easy. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#55
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Golden Rules of Troubleshooting
Jeff Liebermann wrote:
On Fri, 18 Dec 2015 20:31:53 +0000 (UTC), Cydrome Leader wrote: Jeff Liebermann wrote: On Tue, 15 Dec 2015 18:31:14 -0500, "Ralph Mowery" wrote: Sometimes I would make notes on the copies and leave them in the electrical cabinet, or just write inside the cabinet with a marking pen. What? You don't like my method of documenting changes? http://members.cruzio.com/~jeffl/k6bj/K6BJ%20Repeater/slides/Documentation.html I think it's been like that since at least 2001. ha. Love the metal can transistor diagram. At least these aren't drawn on paper bags or cardboard and then thrown away. That scribbling wasn't one of mine. I usually draw an isometric scribbling of the transistor or IC so that one can tell if it's a top or bottom view. I think the red markings on the various drawings are mine. Red is useful because it disappears when copied. What the color of highlighter that would copy solid black even though you could still read the original? The copiers here are just color scanner/printers so they don't have the same spectral sensitivity as the old machines so I can't test. Incidentally, I use a special ink for the purpose, that fades to invisibility in about a year. It helps keep the manuals nice and clean. They should make heated pens for writing on thermal paper. Ummm... They do. It's called a soldering iron. However, there's a trick to using a soldering iron for writing. Be sure to grab the correct end of the soldering iron. The rest is self evident and easy. Too hot and the thermal paper cycles back to white. It does weird things when heated to the transition temp range. |
#56
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Golden Rules of Troubleshooting
On Fri, 18 Dec 2015 23:28:59 +0000 (UTC), Cydrome Leader
wrote: What the color of highlighter that would copy solid black even though you could still read the original? I don't know and too lazy to test it on my copier. Interesting stuff: http://www.protectedpaper.com/category_s/17.htm The copiers here are just color scanner/printers so they don't have the same spectral sensitivity as the old machines so I can't test. I have an (old) Canon PC785 mono copier which should work. However, I don't have any highlighters to try. Incidentally, I use a special ink for the purpose, that fades to invisibility in about a year. It helps keep the manuals nice and clean. They should make heated pens for writing on thermal paper. Ummm... They do. It's called a soldering iron. However, there's a trick to using a soldering iron for writing. Be sure to grab the correct end of the soldering iron. The rest is self evident and easy. Too hot and the thermal paper cycles back to white. It does weird things when heated to the transition temp range. Too hot and the paper catches fire. As I recall, the paper was black or brown before it started burning. I just tried it with some thermal receipt printer paper. It didn't go back to white. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#57
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Golden Rules of Troubleshooting
Cursitor Doom wrote:
Anyone care to share their experience on the correct approach to troubleshooting? Maybe I've been hanging out around too many manager or business types, but I'd suggest: Find out if a working new (or used) example of the item in question is available, and what it costs. Under a certain amount, it won't pay to spend time fixing it, unless there are some other circumstances involved. (It was grandma's radio, or whatever.) Between that amount and some other, really high amount, it might pay to spend time fixing it. Above that really high amount, they are either wanting confirmation that it is broken, so they can persuade their boss to buy a new one, OR hoping to blame you for an inability to fix it, so *you* have to buy the new one. Just because you're paranoid doesn't mean that they *aren't* out to get you. Matt Roberds |
#58
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Golden Rules of Troubleshooting
"OR
hoping to blame you for an inability to fix it, so *you* have to buy the new one. " For that, they are going to need weapons. I mean like the government has. |
#59
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Golden Rules of Troubleshooting
wrote in message ... Cursitor Doom wrote: Anyone care to share their experience on the correct approach to troubleshooting? Maybe I've been hanging out around too many manager or business types, but I'd suggest: Find out if a working new (or used) example of the item in question is available, and what it costs. Under a certain amount, it won't pay to spend time fixing it, unless there are some other circumstances involved. (It was grandma's radio, or whatever.) That is the way I have looked at lots of things. The repair parts often cost more than the origional item. At work there was a motor and gear box of around 1/2 HP. To get a new motor or gear box actually cost within $ 5 of a whole new motor and gearbox. Then the company would have to pay the mechanic over $ 40 an hour to rebuild the unit as they were always replaced as a unit. |
#60
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Golden Rules of Troubleshooting
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#61
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Golden Rules of Troubleshooting
MAKE NO PROMISES.
Ever. |
#62
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Golden Rules of Troubleshooting
On Sat, 19 Dec 2015 01:55:44 -0800, jurb6006 wrote:
MAKE NO PROMISES. Ever. Reminds me of that fellow, Ainit da Troot |
#63
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Golden Rules of Troubleshooting
On Saturday, December 19, 2015 at 11:18:03 AM UTC-5, Wond wrote:
On Sat, 19 Dec 2015 01:55:44 -0800, jurb6006 wrote: MAKE NO PROMISES. Ever. Reminds me of that fellow, Ainit da Troot Yup, those words to not emit from my mouth or keyboard. I have learned how to manage this planet. I also do not get ****ed off unless it is really severe provocation. Aggravation is not a choice but anger is. If I kick you in the balls, whether you get ****ed off or not you want to kick my ass. If you are not ****ed off you want to do it to make the world a better place, which is the same reason I will shoot to kill if someone tries to rob me. But if a baby steps on your balls with those ****ing cement baby shoes (no wonder they can't walk) you are not angry. If you can avoid anger in physical pain like that you got no excuse any other time. (I should probably teach an anger management class huh) I try to do what I say I am gong to do, but II always allow for Murphy's Law. If I say I'll be there at noon I will plan to be there by eleven. Actually I say "I'll be there BY...", not "at". When you learn electronics, especially service, you pick up a frew things. My last good job, I go to boss and say I know what is wrong and we got the part. That is all I said, but that stupid **** would schedule delivery for later that day. Sometimes I felt like cutting his goddam fingers off so he couldn't dial the phone. But see, if something went wrong he was the one to explain it to the customer. Fine with me. And if they ****ed me off I could look at the clock for a couple of minutes and see one more dollar in my pocket. Wanna say something about it I could go to the bathroom. Got them by the balls, and after a little while they know it. In a way I was the boss. Order some of these, and we need this and that, and get this **** the **** out of my way before I shoot it or take an axe to it. Some places, they asked ME what I wanted for lunch and they would go get it. Well I gotta admit there is a reason for that lol. Rich, a coworker, became a friend. I lived 25 miles from the shop and he lived twice as far. I rode with him to and from work for quite a while. then we sat at my house for a bit and got smoked a bit. We almost died together. He had this Ford Escort and we were on I-90 in the fast lane, which is the correct lane because the exit to my house was on the left. A semi changed lanes and we were underneath it right along the dividing wall. An extremely stressful situation. He drove expertly and matched speed and piloted the thing perfectly, with the horn blaring all the time. Eventually the semi got out of the fast lane and I said "Get us to the nearest bar". He agreed. Anyway, we got tight and one day we decided, since we were both "Electrasound graduates" where you DID go out for lunch, that we were going to the Ground Round for lunch. The boss said "Don't go, you guys won't come back". We went, had surf n turf and a few beers and Rich says "I don't like how he was saying we won't come back". I said "Yeah". And then that lightbulb (a dim one) lit up and one of us said "Know what we should do ?". you know what happened then. So we sat there for about an hour drinking and then decided to call the shop. Told the boss we need money because we cannot pay the tab ! That was a lie but **** it. Told him we need someone to bring down about $50. The boss said "I can't leave, I am the only one here". I have had some really bad times in life, and I have had some really good times in life. In some jobs, the employee is really the boss. Like construction. Brick layers smoke pot and therefore cannot pass a drug test. Know what the union does here ? They hire one guy who does not smoke it and whether or not he can lay brick, he takes all the drug tests for everybody. These brickies make around $30 an hour plus super benefits, and that is because they do something that not all that many people can do, at least at their level of performance. They are the boss. As a matter of fact, you offer most of them the foreman position they will refuse. My Father was a pretty damn good job shop machinist (worked with the engineers on the prototype for the first floppy disk making machine) and was offered management positions more than once. He said no, in fact he said **** no. the reason ? Everyone bitches at you. you got the suits wanting **** that can't be done and employees you have a hard time getting to do what can be done. Middle management is not a good place all the time. And back then the labor market was such that you could not get 100 people to suck donkey dick for two bucks an hour. We had real industry and skilled people were important to the economy. Things were different then. Now, money is made on paper. They even have paper gold. The world is junk. One more good reason and I am ready to leave it. Honest Men with real skills have no place in this country anymore. |
#64
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Golden Rules of Troubleshooting
On 12/19/2015 2:53 PM, wrote:
On Saturday, December 19, 2015 at 11:18:03 AM UTC-5, Wond wrote: On Sat, 19 Dec 2015 01:55:44 -0800, jurb6006 wrote: MAKE NO PROMISES. Ever. Reminds me of that fellow, Ainit da Troot Yup, those words to not emit from my mouth or keyboard. I have learned how to manage (on) this planet. I also do not get ****ed off unless it is really severe provocation. Aggravation is not a choice but anger is. If I kick you in the balls, whether you get ****ed off or not you want to kick my ass. If you are not ****ed off you want to do it to make the world a better place, which is the same reason I will shoot to kill if someone tries to rob me. But if a baby steps on your balls with those ****ing cement baby shoes (no wonder they can't walk) you are not angry. If you can avoid anger in physical pain like that you got no excuse any other time. (I should probably teach an anger management class huh) I like your analogy - if your baby/child kicks you and you do not respond with rage, then why when an adult does? Sounds like a good trick for anger management. Perhaps some world leaders (or would be leaders) need to think about that! Thanks! John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
#65
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Golden Rules of Troubleshooting
On Sat, 19 Dec 2015 01:55:44 -0800 (PST), wrote:
MAKE NO PROMISES. Ever. Ok, I promise not to make any more promises. - If I did everything I promised to do, I'd never get anything done. - Everyone lies, but that's ok, because nobody listens. - Do unto others. Then run. - Troubleshooting: Find the person giving you trouble and shoot them. - Most embarrassing moment: When the Chinese clone works better than the original. - Election time: Promise the voters anything, and then do whatever the opposition promised to do. It happens every 4 years. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#66
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Golden Rules of Troubleshooting
Jeff Liebermann wrote:
On Sat, 19 Dec 2015 01:55:44 -0800 (PST), wrote: [stuff cut] - Most embarrassing moment: When the Chinese clone works better than the original. Anybody have good stories of this? |
#67
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Golden Rules of Troubleshooting
On Mon, 21 Dec 2015 17:23:02 +0000 (UTC), Cydrome Leader
wrote: Jeff Liebermann wrote: On Sat, 19 Dec 2015 01:55:44 -0800 (PST), wrote: [stuff cut] - Most embarrassing moment: When the Chinese clone works better than the original. Anybody have good stories of this? No. I'm taking the 5th ammendment. What you don't know, won't hurt me. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#68
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Golden Rules of Troubleshooting
Jeff Liebermann wrote:
On Mon, 21 Dec 2015 17:23:02 +0000 (UTC), Cydrome Leader wrote: Jeff Liebermann wrote: On Sat, 19 Dec 2015 01:55:44 -0800 (PST), wrote: [stuff cut] - Most embarrassing moment: When the Chinese clone works better than the original. Anybody have good stories of this? No. I'm taking the 5th ammendment. What you don't know, won't hurt me. Ha. Did the unnamed parties steal back some of the enhancements? |
#69
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Golden Rules of Troubleshooting
On Mon, 21 Dec 2015 21:02:55 +0000 (UTC), Cydrome Leader
wrote: Jeff Liebermann wrote: On Mon, 21 Dec 2015 17:23:02 +0000 (UTC), Cydrome Leader wrote: Jeff Liebermann wrote: On Sat, 19 Dec 2015 01:55:44 -0800 (PST), wrote: [stuff cut] - Most embarrassing moment: When the Chinese clone works better than the original. Anybody have good stories of this? No. I'm taking the 5th ammendment. What you don't know, won't hurt me. Ha. Did the unnamed parties steal back some of the enhancements? Of course, with my help. But when they wanted some of the money they paid me back, I diplomatically declined. Business ethics in many parts of the planet are very different from the US. [Q] What's the difference between a bribe and a commission? [A] A bribe is paid in advance. A commission after. Otherwise, they're the same. I know of several other cloned products were are better than the original, but I'm not talking and not worried. A fair chunk of my income comes from what I euphemistically call "design reviews"[1]. There are also companies that can't even copy a product and get it right. One favorite is a company that fired its outsourced designers, only to find that the documentation they had supplied with the product was fatally inaccurate. The company then had to reverse engineer their own product. The resulting clone was dead on arrival. I was hired to fix the problem without changing anything. Right. I traced the problem to whomever measured the parts misreading the range setting on the LRC meter. All the values were off by a factor of 10 because someone had removed the range knob, and replaced it rotated by one detent. It was obviously not an accident. After that was fixed, I had to deal with an "improved" PCB that closely matched the schematic, but not quite. The highlight of the project was when one employee, with a very guilty conscience, offered me a bribe to not blame him for any of the problems. I didn't take the money because I thought it might be a trap. It wasn't. [1] The difficult part is keeping a straight face. I once worked on a BlueGoof wireless speaker system, where the designers had placed the BT chip dead center in the middle of the PCB, located the chip antenna nearby, and put a shield over both. Range was suppose to be about 30 meters minimum, but was only about 0.5 meters. I couldn't believe it, but there it was. It was amazingly difficult for me to NOT burst out laughing during my initial fee negotiations and artificially protracted circuit analysis. I found plenty of other problems and mistakes, so they got their money's worth. -- 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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