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#1
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On Wed, 24 Jan 2007 12:40:32 GMT, gwatts
wrote: I was tired of design reviews where management pushed the 'you can cut this out, it won't be so bad' line. Hi OM, My very first EE professor (also an engineer at the HP division in Colorado Springs) taught us the merits of designs meeting the expectations of Mad Man Muntz. Muntz was a car salesman who entered the nascent field of TV in the late 40s and would wander the design lab with a pair of dikes in his pocket. Looking over the shoulder of any designer he would snip out components until they lost the picture, it would roll, or the sound would go dead. Then he would suggest they put back in the last snipped component. He discovered his TVs didn't need synchronization circuits because his market was in urban cities where the signal was so powerful as to provide enough level to be self-syncing. I know, because I fixed many of those TVs that eventually found their way into the Burbs, and were forever rolling unless you found the sweet spot on the horizontal or vertical adjustment (always in the back). 73's Richard Clark, KB7QHC |
#2
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Richard Clark wrote:
On Wed, 24 Jan 2007 12:40:32 GMT, gwatts wrote: I was tired of design reviews where management pushed the 'you can cut this out, it won't be so bad' line. Hi OM, My very first EE professor (also an engineer at the HP division in Colorado Springs) taught us the merits of designs meeting the expectations of Mad Man Muntz...he would snip out components until they lost the picture, it would roll, or the sound would go dead. Then he would suggest they put back in the last snipped component. He discovered his TVs didn't need synchronization circuits because his market was in urban cities where the signal was so powerful as to provide enough level to be self-syncing. I know, because I fixed many of those TVs that eventually found their way into the Burbs, and were forever rolling unless you found the sweet spot on the horizontal or vertical adjustment (always in the back). Yes, I've heard the tales of M. M. Muntz, but apparently so had the head designer at the audio mfr I worked at. They had a VCA circuit using a well known VCA chip. The data sheet notes mentioned a small value capacitor across two pins for stability. The designer discovered his circuit would work just as well without the cap and thus left it out of his design, so far out that there weren't even traces or pads to put the cap in should it become necessary (you can see where this is going, no?). The VCA vendor outsourced fabrication of the chip and all of a sudden the noise level of the VCA circuit would jump about 70 dB as the fader reached the bottom of travel, not desirable in an audio application. I spent a little time perusing the data sheets and our schematics, noticed the cap omission, soldered a cap across the pins of an offending circuit and within the hour we had the assemblers tack soldering caps we bought at a local electronics shop (not RS) onto assembled modules. The designer's comment was 'Well, it worked for quite a while...' Later we found customers with similar noise level jumps using pre-outsourced VCAs. Yes, they saved a few pennies on each module but lost about two dozen customers when they figured out what had been left out of their very expensive audio equipment. When I started at that place I was told not to make suggestions regarding modifications of existing designs lest I offend the managing 'engineer'. |
#3
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gwatts wrote:
Richard Clark wrote: On Wed, 24 Jan 2007 12:40:32 GMT, gwatts wrote: I was tired of design reviews where management pushed the 'you can cut this out, it won't be so bad' line. Hi OM, My very first EE professor (also an engineer at the HP division in Colorado Springs) taught us the merits of designs meeting the expectations of Mad Man Muntz...he would snip out components until they lost the picture, it would roll, or the sound would go dead. Then he would suggest they put back in the last snipped component. He discovered his TVs didn't need synchronization circuits because his market was in urban cities where the signal was so powerful as to provide enough level to be self-syncing. I know, because I fixed many of those TVs that eventually found their way into the Burbs, and were forever rolling unless you found the sweet spot on the horizontal or vertical adjustment (always in the back). Yes, I've heard the tales of M. M. Muntz, but apparently so had the head designer at the audio mfr I worked at. They had a VCA circuit using a well known VCA chip. The data sheet notes mentioned a small value capacitor across two pins for stability. The designer discovered his circuit would work just as well without the cap and thus left it out of his design, so far out that there weren't even traces or pads to put the cap in should it become necessary (you can see where this is going, no?). The VCA vendor outsourced fabrication of the chip and all of a sudden the noise level of the VCA circuit would jump about 70 dB as the fader reached the bottom of travel, not desirable in an audio application. I spent a little time perusing the data sheets and our schematics, noticed the cap omission, soldered a cap across the pins of an offending circuit and within the hour we had the assemblers tack soldering caps we bought at a local electronics shop (not RS) onto assembled modules. The designer's comment was 'Well, it worked for quite a while...' Later we found customers with similar noise level jumps using pre-outsourced VCAs. Yes, they saved a few pennies on each module but lost about two dozen customers when they figured out what had been left out of their very expensive audio equipment. When I started at that place I was told not to make suggestions regarding modifications of existing designs lest I offend the managing 'engineer'. This reminds me of an old story about how you can become a hero in Detroit. Save 1/2 cent each on 10 million washers. To become a bum in Detroit, have those washers cause a 10 million car recall. Dave N |
#4
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On Wed, 24 Jan 2007 18:20:51 GMT, gwatts
wrote: When I started at that place I was told not to make suggestions regarding modifications of existing designs lest I offend the managing 'engineer'. I feel your pain. I followed one bum who couldn't figure out the gozinta from the comesoutta on a linear IC. The design (heart monitor) went all the way through to production, then testing, and they wondered why the processor only produced a flat line for any patient. I also came to the conclusion that the project engineer was brain dead too (design review an exercise in swinging rubber stamps). I have forever after examined the equipment of any hospital I had procedures in. There was one trademark I didn't want to see. Consulting can be a tough life of techno-whoring. Praise the idiots (or repress the urge to strangle) and clean up their mess. 73's Richard Clark, KB7QHC |
#5
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![]() "Richard Clark" wrote in message ... On Wed, 24 Jan 2007 12:40:32 GMT, gwatts wrote: I was tired of design reviews where management pushed the 'you can cut this out, it won't be so bad' line. Hi OM, My very first EE professor (also an engineer at the HP division in Colorado Springs) taught us the merits of designs meeting the expectations of Mad Man Muntz. Muntz was a car salesman who entered the nascent field of TV in the late 40s and would wander the design lab with a pair of dikes in his pocket. Looking over the shoulder of any designer he would snip out components until they lost the picture, it would roll, or the sound would go dead. Then he would suggest they put back in the last snipped component. He discovered his TVs didn't need synchronization circuits because his market was in urban cities where the signal was so powerful as to provide enough level to be self-syncing. I know, because I fixed many of those TVs that eventually found their way into the Burbs, and were forever rolling unless you found the sweet spot on the horizontal or vertical adjustment (always in the back). 73's Richard Clark, KB7QHC Oh, you reveal you age. I worked on a bunch of those until I just started not letting them in the door. Seems a guy bought a bunch(100+) from a motel(s) that had gotten new TVs and had sold the for about $30 a piece. I think they had a 1 tube IF if I remember right. They wouldnt work at all in our area unles you had a really good antenna on a tall tower. The only places that had this was the shop I worked in and the local motels. Jimmie |
#6
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On Wed, 24 Jan 2007 16:12:24 -0500, "Jimmie D"
wrote: Oh, you reveal you age. Hi Jimmie, I did my apprentice work in TV as a teen in the mid 60s. The real challenge came when I was in the Navy (1970) and we put out a call to the Bay area for folks to donate their TVs for charity (Xmas of 1970), and the ET school would fix them for free for redistribution to the needy. My crew took in 100-150 TVs and 200 radios and turned out 60 or 70 TVs and nearly all the radios. Some TVs were so old as to have vertically mounted tubes with a mirror to view them. I taught the fellows how to cannibalize the truly dead to resurrect the lame. This was the gift of a Navy technical education. At sea, there was no mall to pull into and go to Radio Shack - you had to make the broken stuff work or the Captain would keel haul you. This demanded every tech know electronics, not board swapping. I never had such an enthusiastic class. These guys learned like sponges, and tackled every problem like a commando gutting a commie. One interesting incident came when a student asked me for a set of rabbit ears to test his work on a tough-dog TV. My budget was like $20 a week from the Old Man's wallet (and I wasn't going to ask him for that). I told the student that we had a ground bus-bar that ran the length around the repair shed (a former laundry) that would work just as well as it was many wavelengths longs so as to not short the signal (sitting in the middle of SF bay offered huge amounts of available RF). He connected an alligator clip lead to the antenna input, the other to the bus bar; the lead turned to smoke, the insulation dripped right off like a length of spaghetti, and then fused open. The astonished crew quickly learned the hazards of poorly engineered grounds in commercial equipment, the hazards of using a service cord to defeat an interlock, and why we in the trade called it a suicide adapter. 73's Richard Clark, KB7QHC |
#7
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![]() "Richard Clark" wrote in message ... On Wed, 24 Jan 2007 16:12:24 -0500, "Jimmie D" wrote: Oh, you reveal you age. Hi Jimmie, I did my apprentice work in TV as a teen in the mid 60s. The real challenge came when I was in the Navy (1970) and we put out a call to the Bay area for folks to donate their TVs for charity (Xmas of 1970), and the ET school would fix them for free for redistribution to the needy. My crew took in 100-150 TVs and 200 radios and turned out 60 or 70 TVs and nearly all the radios. Some TVs were so old as to have vertically mounted tubes with a mirror to view them. I taught the fellows how to cannibalize the truly dead to resurrect the lame. This was the gift of a Navy technical education. At sea, there was no mall to pull into and go to Radio Shack - you had to make the broken stuff work or the Captain would keel haul you. This demanded every tech know electronics, not board swapping. I never had such an enthusiastic class. These guys learned like sponges, and tackled every problem like a commando gutting a commie. One interesting incident came when a student asked me for a set of rabbit ears to test his work on a tough-dog TV. My budget was like $20 a week from the Old Man's wallet (and I wasn't going to ask him for that). I told the student that we had a ground bus-bar that ran the length around the repair shed (a former laundry) that would work just as well as it was many wavelengths longs so as to not short the signal (sitting in the middle of SF bay offered huge amounts of available RF). He connected an alligator clip lead to the antenna input, the other to the bus bar; the lead turned to smoke, the insulation dripped right off like a length of spaghetti, and then fused open. The astonished crew quickly learned the hazards of poorly engineered grounds in commercial equipment, the hazards of using a service cord to defeat an interlock, and why we in the trade called it a suicide adapter. 73's Richard Clark, KB7QHC I always called them fool killers, especilly the ones that used gator clips on the end.. |
#8
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On Thu, 25 Jan 2007 09:24:00 -0500, "Jimmie D"
wrote: The astonished crew quickly learned the hazards of poorly engineered grounds in commercial equipment, the hazards of using a service cord to defeat an interlock, and why we in the trade called it a suicide adapter. I always called them fool killers, especilly the ones that used gator clips on the end.. Our name for them was a "Kills-me-quick." One of my buddies aboard ship was holding just such a cord, plugged in, and while he talked, or was telling a joke, we watched him flick the cord around. Occassionally he would absent mindedly smack it into his hand to emphasize a point. Absolutely no one was paying attention to what he was saying. We all followed the arc of those leads wondering when the big moment would come. Of course we all knew CPR.... 73's Richard Clark, KB7QHC |
#9
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![]() "Richard Clark" wrote in message ... On Thu, 25 Jan 2007 09:24:00 -0500, "Jimmie D" wrote: The astonished crew quickly learned the hazards of poorly engineered grounds in commercial equipment, the hazards of using a service cord to defeat an interlock, and why we in the trade called it a suicide adapter. I always called them fool killers, especilly the ones that used gator clips on the end.. Our name for them was a "Kills-me-quick." One of my buddies aboard ship was holding just such a cord, plugged in, and while he talked, or was telling a joke, we watched him flick the cord around. Occassionally he would absent mindedly smack it into his hand to emphasize a point. Absolutely no one was paying attention to what he was saying. We all followed the arc of those leads wondering when the big moment would come. Of course we all knew CPR.... 73's Richard Clark, KB7QHC Ive done this watching a guy play with a charged cap. He had just charged it up to place on the bench for some unsuspecting sole to grap, started running his mouth and zapped himself. |
#10
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On Thu, 25 Jan 2007 13:39:32 -0500, "Jimmie D"
wrote: Ive done this watching a guy play with a charged cap. He had just charged it up to place on the bench for some unsuspecting sole to grap, started running his mouth and zapped himself. As Cartman would say "SWEET!" |
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